Osteoarthritis (OA), the most common form of joint disease, is characterized clinically by joint pain, stiffness,and deformity. OA is now considered a whole joint disease;however, the breakdown of the articular cartil...Osteoarthritis (OA), the most common form of joint disease, is characterized clinically by joint pain, stiffness,and deformity. OA is now considered a whole joint disease;however, the breakdown of the articular cartilage remains themajor hallmark of the disease. Current treatments targeting OA symptoms have a limited impact on impeding orreversing the OA progression. Understanding the molecular and cellular mechanisms underlying OA development isa critical barrier to progress in OA therapy. Recent studies by the current authors’ group and others have revealedthat the nuclear factor of activated T cell 1 (NFAT1), a member of the NFAT family of transcription factors, regulatesthe expression of many anabolic and catabolic genes in articular chondrocytes of adult mice. Mice lacking NFAT1exhibit normal skeletal development but display OA in both appendicular and spinal facet joints as adults. Thisreview mainly focuses on the recent advances in the regulatory role of NFAT1 transcription factor in the activities ofarticular chondrocytes and its implication in the pathogenesis of OA.展开更多
Avian pathogenic Escherichia coli(APEC)belonging to extraintestinal pathogenic E.coli(ExPEC)can cause severe infections in extraintestinal tissues in birds and humans,such as the lungs and blood.MprA(microcin producti...Avian pathogenic Escherichia coli(APEC)belonging to extraintestinal pathogenic E.coli(ExPEC)can cause severe infections in extraintestinal tissues in birds and humans,such as the lungs and blood.MprA(microcin production regulation,locus A,herein renamed AbsR,a blood survival regulator),a member of the MarR(multiple antibiotic resistance regulator)transcriptional regulator family,governs the expression of capsule biosynthetic genes in human ExPEC and represents a promising druggable target for antimicrobials.However,a deep understanding of the AbsR regulatory mechanism as well as its regulon is lacking.In this study,we present a systems-level analysis of the APEC AbsR regulon using ChIP-Seq(chromatin immunoprecipitation sequencing)and RNA-Seq(RNA sequencing)methods.We found that AbsR directly regulates 99 genes and indirectly regulates 667 genes.Furthermore,we showed that:1)AbsR contributes to antiphagocytotic effects by macrophages and virulence in a mouse model for systemic infection by directly activating the capsular gene cluster;2)AbsR positively impacts biofilm formation via direct regulation of the T2SS(type II secretion system)but plays a marginal role in virulence;and 3)AbsR directly upregulates the acid tolerance signaling system EvgAS to withstand acid stress but is dispensable in ExPEC virulence.Finally,our data indicate that the role of AbsR in virulence gene regulation is relatively conserved in ExPEC strains.Altogether,this study provides a comprehensive analysis of the AbsR regulon and regulatory mechanism,and our data suggest that AbsR likely influences virulence primarily through the control of capsule production.Interestingly,we found that AbsR severely represses the expression of the type I-F CRISPR(clustered regularly interspaced short palindromic repeats)-Cas(CRISPR associated)systems,which could have implications in CRISPR biology and application.展开更多
Hippeastrum, a highly diverse genus in the Amaryllidaceae family, is a valuable ornamental bulbous flowering plant. Somatic embryogenesis(SE) is an efficient method for mass production of Hippeastrum plantlets. Previo...Hippeastrum, a highly diverse genus in the Amaryllidaceae family, is a valuable ornamental bulbous flowering plant. Somatic embryogenesis(SE) is an efficient method for mass production of Hippeastrum plantlets. Previous studies have been devoted to the in vitro propagation of Hippeastrum, but the SE and its regulatory networks are rarely reported. In this study, we established a direct SE method of Hippeastrum Bangkok Rose' using leaf bases as explants. MS supplemented with 1.00 mg·L^(-1)NAA +1.00 mg·L^(-1)KT + 0.25 mg·L^(-1)TDZ was the optimal medium for SE. Histological observations showed that the bipolar somatic embryo originated from the epidermal cell layer and underwent initiation,globular, scutellar and coleoptile stages. During SE, endogenous hormones of IAA, CTK, ABA, and SA were highly accumulated. Transcriptomic analysis revealed the genes encoding auxin biosynthesis/metabolic enzymes and efflux carriers were induced, while the auxin receptor of TIR1 and ARF transcriptional repressor of Aux/IAA were down-regulated and up-regulated, respectively, leading to suppression of auxin signaling. In contrast, cytokine signaling was promoted at the early stage of SE, as biosynthesis, transport, and signaling components were up-regulated.Various stress-related genes were up-regulated at the early or late stages of SE. Chromatin remodeling could also be dynamically regulated via distinct expression enzymes that control histone methylation and acetylation during SE. Moreover, key SE regulators, including WOXs and SERKs were highly expressed along with SE. Overall, the present study provides insights into the SE regulatory mechanisms of the Hippeastrum.展开更多
The recent progress in neural stem cells (NSCs) research has shed lights on possibility of repair and restoration of neuronal function in neurodegenerative diseases using stem cells. Induction of stem cells differen...The recent progress in neural stem cells (NSCs) research has shed lights on possibility of repair and restoration of neuronal function in neurodegenerative diseases using stem cells. Induction of stem cells differentiate into mature neurons is critical to achieve the clinical applications of NSCs. At present, molecular mechanisms modulating NSC differentiation are not fully understood. Differentiation of stem cells into neuronal and glial cells involves an array of changes in expression of transcription factors. Transcription factors then trigger the expression of a variety of central nervous system (CNS) genes that lead NSCs to differentiate towards different cell types. In this paper, we summarized the recent findings on the gene regulation of NSCs differentiation into neuronal cells.展开更多
Background Goose, descendants of migratory ancestors, have undergone extensive selective breeding, resulting in their remarkable ability to accumulate fat in the liver and exhibit a high tolerance for significant ener...Background Goose, descendants of migratory ancestors, have undergone extensive selective breeding, resulting in their remarkable ability to accumulate fat in the liver and exhibit a high tolerance for significant energy intake. As a result, goose offers an excellent model for studying obesity, metabolic disorders, and liver diseases in mammals. Although the impact of the three-dimensional arrangement of chromatin within the cell nucleus on gene expression and transcriptional regulation is widely acknowledged, the precise functions of chromatin architecture reorganization during fat deposition in goose liver tissues still need to be fully comprehended.Results In this study, geese exhibited more pronounced changes in the liver index and triglyceride(TG) content following the consumption of the high-fat diet(HFD) than mice without significant signs of inflammation. Additionally, we performed comprehensive analyses on 10 goose liver tissues(5 HFD, 5 normal), including generating highresolution maps of chromatin architecture, conducting whole-genome gene expression profiling, and identifying H3K27ac peaks in the livers of geese and mice subjected to the HFD. Our results unveiled a multiscale restructuring of chromatin architecture, encompassing Compartment A/B, topologically associated domains, and interactions between promoters and enhancers. The dynamism of the three-dimensional genome architecture, prompted by the HFD, assumed a pivotal role in the transcriptional regulation of crucial genes. Furthermore, we identified genes that regulate chromatin conformation changes, contributing to the metabolic adaptation process of lipid deposition and hepatic fat changes in geese in response to excessive energy intake. Moreover, we conducted a cross-species analysis comparing geese and mice exposed to the HFD, revealing unique characteristics specific to the goose liver compared to a mouse. These chromatin conformation changes help elucidate the observed characteristics of fat deposition and hepatic fat regulation in geese under conditions of excessive energy intake.Conclusions We examined the dynamic modifications in three-dimensional chromatin architecture and gene expression induced by an HFD in goose liver tissues. We conducted a cross-species analysis comparing that of mice. Our results contribute significant insights into the chromatin architecture of goose liver tissues, offering a novel perspective for investigating mammal liver diseases.展开更多
Eukaryotic chromatin consisting of nucleosomes connected by linker DNA is organized into higher order structures,which is facilitated by linker histone H1.Formation of chromatin compacts and protects the genome,but al...Eukaryotic chromatin consisting of nucleosomes connected by linker DNA is organized into higher order structures,which is facilitated by linker histone H1.Formation of chromatin compacts and protects the genome,but also hinders DNA transactions.Cells have evolved mechanisms to modify/remodel chromatin resulting in chromatin states suitable for genome functions.The high mobility group box(HMGB)proteins are non-histone chromatin architectural factors characterized by one or more HMGB motifs that bind DNA in a sequence nonspecific fashion.They play a major role in chromatin dynamics.The Saccharomyces cerevisiae(yeast hereafter)HMGB protein Hmo1 contains two HMGB motifs.However,unlike a canonical HMGB protein that has an acidic C-terminus,Hmo1 ends with a lysine rich,basic,C-terminus,resembling linker histone H1.Hmo1 exhibits characteristics of both HMGB proteins and linker histones in its multiple functions.For instance,Hmo1 promotes transcription by RNA polymerases I and II like canonical HMGB proteins but makes chromatin more compact/stable like linker histones.Recent studies have demonstrated that Hmo1 destabilizes/disrupts nucleosome similarly as other HMGB proteins in vitro and acts to maintain a common topological architecture of genes in yeast genome.This minireview reviews the functions of Hmo1 and the underlying mechanisms,highlighting recent discoveries.展开更多
AIM: To construct subtracted cDNA libraries and further identify differentially expressed genes that are related to the development of colorectal carcinoma(CRC). METHODS: Suppression subtractive hybridization(SSH) was...AIM: To construct subtracted cDNA libraries and further identify differentially expressed genes that are related to the development of colorectal carcinoma(CRC). METHODS: Suppression subtractive hybridization(SSH) was done on cDNAs of normal mucosa, adenoma and adenocarcinoma tissues from the same patient. Three subtracted cDNA libraries were constructed and then hybridized with forward and backward subtracted probes for differential screening. Positive clones from each subtracted cDNA library were selected for sequencing and BLAST analysis. Finally, virtual Northern Blot confirmed such differential expression. RESULTS: By this way, there were about 3-4 X 10(2) clones identified in each subtracted cDNA library, in which about 85% positive clones were differentially screened. Sequencing and BLAST homology search revealed some clones containing sequences of known gene fragments and several possibly novel genes showing few or no sequence homologies with any known sequences in the database. CONCLUSION: All results confirmed the effectiveness and sensitivity of SSH. The differentially expressed genes during the development of CRC can be used to shed light on the pathogenesis of CRC and be useful genetic markers for early diagnosis and therapy.展开更多
INTRODUCTIONHepatocellular carcinoma(HCC)is one of the major causes of death in the word.The mechanism of carcinogenesis is unknown,although it is widely accepted that HBV and HCV are clsely related to liver cancer[1-...INTRODUCTIONHepatocellular carcinoma(HCC)is one of the major causes of death in the word.The mechanism of carcinogenesis is unknown,although it is widely accepted that HBV and HCV are clsely related to liver cancer[1-5[1-5].Previously,a variety of studies have described the differences in gene expression which distinguished tumor from nontumor[6-11].Cloning of the genes,especially the genes associated with HBV and HCV,is still very important to account for the development of liver cancer.展开更多
A systemic study was initiated to identify stage-specific expression genes in fish embryogenesis by using suppression subtractive hybridization (SSH) technique. In this study, we presented a preliminary result on scre...A systemic study was initiated to identify stage-specific expression genes in fish embryogenesis by using suppression subtractive hybridization (SSH) technique. In this study, we presented a preliminary result on screen for stage-specific expression genes between tail bud stage (TBS) and heartbeat beginning stage (HBS) in gynogenetic silver crucian carp (Carassius auratus gibelio). Two SSH plasmid libraries specific for TBS embryos and HBS embryos were constructed, and stage-specific expression genes were screened between the two stages. 1963 TBS positive clones and 2466 HBS positive clones were sampled to PCR amplification, and 1373 TBS and 1809 HBS PCR positive clones were selected to carry out dot blots. 169 TBS dot blot positive clones and 272 HBS dot blot positive clones were sequenced. Searching GenBank by using these nucleotide sequences indicated that most of the TBS dot blot positive clones could not be found homologous sequences in the database, while known genes were mainly detected from HBS dot blot positive clones. Of the 79 known genes, 20 were enzymes or kinases involved in important metabolism of embryonic development. Moreover, specific expressions of partial genes were further confirmed by virtual northern blots. This study is the first step for making a large attempt to study temporal and spatial control of gene expression in the gynogenetic fish embryogenesis.展开更多
After pre-culture and treatment of osmosis, cotyledons of immature peanut (Arachis hypogaea L.) zygotic embryos were transformed via particle bombardment with a plasmid containing a chimeric hph gene conferring resist...After pre-culture and treatment of osmosis, cotyledons of immature peanut (Arachis hypogaea L.) zygotic embryos were transformed via particle bombardment with a plasmid containing a chimeric hph gene conferring resistance to hygromycin and a chimeric intron-gus gene. Selection for hygromycin resistant calluses and somatic embryos was initiated at 10th d post-bombardment on medium containing 10-25 mg/L hygromycin. Under continuous selection, hygromycin resistant plantlets were regenerated from somatic embryos and were recovered from nearly 1.6% of the bombarded cotyledons. The presence and integration of foreign DNA in regenerated hygromycin resistant plants was confirmed by PCR (polymerase chain reaction) for the intron-gus gene and by Southern hybridization of the hph gene. GUS enzyme activity was detected in leaflets from transgenic plants but not from control, non-transformed plants. The production of transgenic plants are mainly based on a newly improved somatic embryogenesis regeneration system developed by us.展开更多
AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method b...AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method by using abundant double-stranded cDNA messages provided by two self-constructed cDNA libraries (Allitridi-treated and paternal HGC cell line BGC823 cells cDNA libraries respectively). Bam H I and Xho I restriction sites harbored in the library vector were used to select representations. Northern and Slot blots analyses were employed to identify the obtained difference products. RESULTS: Fragments released from the cDNA library vector after restriction endonuclease digestion acted as good marker indicating the appropriate digestion degree for library DNA. Two novel expressed sequence tags (ESTs) and a recombinant gene were obtained. Slot blots result showed a 8-fold increase of glia-derived nexin/protease nexin 1 (GDN/PN1) gene expression level and 4-fold increase of hepatitis B virus x-interacting protein (XIP) mRNA level in BGC823 cells after Allitridi treatment for 72h. CONCLUSION: Elevated levels of GDN/PN1 and XIP mRNAs induced by Allitridi provide valuable molecular evidence for elucidating the garlic's efficacies against neurodegenerative and inflammatory diseases. Isolation of a recombinant gene and two novel ESTs further show cDNA RDA based on cDNA libraries to be a powerful method with high specificity and reproducibility in cloning differentially expressed genes.展开更多
AIM: To establish the role of vascular endothelial growth factor (VEGF) in the oncogenesis of human gastric carcinoma more directly. METHODS: The expression of VEGF and its receptor kinase-domain insert containing rec...AIM: To establish the role of vascular endothelial growth factor (VEGF) in the oncogenesis of human gastric carcinoma more directly. METHODS: The expression of VEGF and its receptor kinase-domain insert containing receptor (KDR) in human gastric cancer tissue were observed by immunohistochemical staining. VEGF levels were manipulated in human gastric cancer cell using eukaryotic expression constructs designed to express the complete VEGF(165) complimentary DNA in either the sense or antisense orientation. The biological changes of the cells were observed in which VEGF was up-regulated or down-regulated. RESULTS: VEGF-positive rate was 50%, and VEGF was mainly localized in the cytoplasm and membrane of the tumor cells, while KDR was mainly located in the membrane of vascular endothelial cells in gastric cancer tissues and peri-cancerous tissue. In 2 cases of 50 specimens, the gastric cancer cells expressed KDR, localized in both the cytoplasm and membrane. Introduction of VEGF(165) antisense into human gastric cancer cells (SGC-7901, immunofluorescence intensity, 31.6%)) resulted in a significant reduction in VEGF-specific messenger RNA and total and cell surface VEGF protein (immunofluorescence intensity, 8.9%) (P【0.05). Conversely, stable integration of VEGF(165) in the sense orientation resulted in an increase in cellular and cell surface VEGF (immunofluorescence intensity, 75.4%) (P【0.05). Lowered VEGF levels were associated with a marked decrease in the growth of nude mouse xenografted tumor (at 33 days postimplantation, tumor volume: 345.40 +/- 136.31 mm3)(P【0.05 vs control SGC-7901 group: 1534.40 +/- 362.88 mm3), whereas up-regulation of VEGF resulted in increased xenografted tumor size (at 33 days postimplantation, tumor volume: 2350.50 +/- 637.70 mm3) (P【0.05 vs control SGC-7901 group). CONCLUSION: This study provides direct evidence that VEGF plays an important role in the oncogenesis of human gastric cancer.展开更多
INTRODUCTIONThe mechanism of hepatocellular carcinoma(HCC)is still unclear,although some genes have been found to play a role in the transformation of liver cells,and a variety of studies have described differences in...INTRODUCTIONThe mechanism of hepatocellular carcinoma(HCC)is still unclear,although some genes have been found to play a role in the transformation of liver cells,and a variety of studies have described differences in gene expression which distinguished tumor from nontumor[1-6].The new genes,especially the functional genes directly related with tumor are still worth being found.The purpose of our study is to find the different genes between human liver tumor and normal tissues using suppression subtractive hybridization.展开更多
BACKGROUND:Pancreatic cancer(PCa)is one of the most aggressive human solid tumors,with rapid growth and metastatic spread as well as resistance to chemotherapeutic drugs,leading rapidly to virtually incurable disease....BACKGROUND:Pancreatic cancer(PCa)is one of the most aggressive human solid tumors,with rapid growth and metastatic spread as well as resistance to chemotherapeutic drugs,leading rapidly to virtually incurable disease.Over the last 20 years,however,significant advances have been made in our understanding of the molecular biology of PCa,with a focus on the cytogenetic abnormalities in PCa cell growth and differentiation. DATA SOURCES:A MEDLINE search and manual cross- referencing were utilized to identify published data for PCa molecular biology studies between 1986 and 2008, with emphasis on genetic alterations and developmental oncology. RESULTS:Activation of oncogenes,deregulation of tumor suppressor and genome maintenance genes,upregulation of growth factors/growth factor receptor signaling cascade systems,and alterations in cytokine expression,have been reported to play important roles in the process of pancreatic carcinogenesis.Alterations in the K-ras proto- oncogene and the p16INK4a,p53,FHIT,and DPC4 tumor suppressor genes occur in a high percentage of tumors. Furthermore,a variety of growth factors are expressed at increased levels.In addition,PCa often exhibits alterations in growth inhibitory pathways and evades apoptosis through p53 mutations and aberrant expression of apoptosis-regulating genes,such as members of the Bcl family.Additional pathways in the development of an aggressive phenotype,local infiltration and metastasis are still under ongoing genetic research.The present paper reviews recent studies on the pathogenesis of PCa,and includes a brief reference to alterations reported for other types of pancreatic tumor. CONCLUSIONS:Advances in molecular genetics and biology have improved our perception of the pathogenesis of PCa.However,further studies are needed to better understand the fundamental changes that occur in PCa,thus leading to better diagnostic and therapeutic management.展开更多
Bicoid is one of the important Drosophila maternal genes involved in the control of embryo polarity and larvae segmentation. To clone and characterize the rice bicoid-related genes, one cDNA clone, Rb24 (EMBL accessio...Bicoid is one of the important Drosophila maternal genes involved in the control of embryo polarity and larvae segmentation. To clone and characterize the rice bicoid-related genes, one cDNA clone, Rb24 (EMBL accession number: AJ2771380), was isolated by screening of rice unmature seed cDNA library. Sequence analysis indicates that Rb24 contains a putative amino acid sequence, which is homologous to unique 8 amino acids sequence within Drosophila bicoid homeodomain (50% identity, 75% similarity) and involves a lys-9 in putative helix 3. Northern blot analysis of rice RNA has shown that this sequence is expressed in a tissue-specific manner. The transcript was detected strongly in young panicles, but less in young leaves and roots. This results are further confirmed with paraffin section in situ hybridization. The signal is intensive in rice globular embryo and located at the apical tip of the embryo, then, along with the development of embryo, the signal is getting reduced and transfers into both sides of embryo. The existence of bicoid-related sequence in rice embryo and the similarity of polar distribution of bicoid and Rb24 mRNA in early embryo development may implicates a conserved maternal regulation mechanism of body axis presents in Drosophila and in rice.展开更多
Phytophthora root rot is one of the most prevalent diseases in the world,which can infect the seedlings and plants,with substantial negative impact on soybean yield and quality.MicroRNAs (miRNAs) are a class of post...Phytophthora root rot is one of the most prevalent diseases in the world,which can infect the seedlings and plants,with substantial negative impact on soybean yield and quality.MicroRNAs (miRNAs) are a class of post-transcriptional regulators of gene expression during growth and development of organisms.A soybean disease-resistance variety Suinong 10 was inoculated with Phytophthora sojae race No.1,and the specific miRNA resistant expression profile was acquired by microarray for the first time.Different expressional miRNAs have been found after comparing the results of the treated sample with the control sample.Furthermore,the target genes of different expressional miRNAs were predicted.Two miRNAs,cbr-mir-241 and ath-miR854a,regulated the disease-resistance process directly through their targets,some enzymes.Another two miRNAs,gma-miR169a and ath-miR169h,participated in disease-resistance regulation as transcription factors.Similarly,one miRNA,ptc-miR164f,has been reported to regulate the plant development.All of these studies would be served as the foundation for exploring the resistance mechanism.展开更多
In searching of differentially expressed genes in human uterine leiomyomas, differential display was used with twelve pairs of primers to compare human uterine leiomyomas with matched myometrium. False positives were ...In searching of differentially expressed genes in human uterine leiomyomas, differential display was used with twelve pairs of primers to compare human uterine leiomyomas with matched myometrium. False positives were eliminated by reverse Northern analysis. Positives were confirmed by Northern blot analysis. RESULTS: Four of 69 cDNA fragments (3 up-regulated named L1, L2 and L3 and 1 down-regulated named M1 in leiomyoma) were confirmed by Northern analysis. Sequence comparison and Northern analysis proved that L1 is exactly the human ribosomal protein S19. It was present ubiquitously in 13 tissues tested but in various levels and even in different size. L1 was highly expressed in parotidean cystadenocarcinoma, pancreatic cancer and breast cancer examined. No mutations have been found in human uterine leiomyomas (n=6). CONCLUSIONS: hRPS19 overexpression might be a universal signal in rapid cell growth tissues.展开更多
In this study, we employed chromatin immunoprecipitation, a useful method for studying the locations of transcription factors bound to specific DNA regions in specific cells, to investigate amyloid precursor protein i...In this study, we employed chromatin immunoprecipitation, a useful method for studying the locations of transcription factors bound to specific DNA regions in specific cells, to investigate amyloid precursor protein intracellular domain binding sites in chromatin DNA from hippocampal neurons of rats, and to screen out five putative genes associated with the learning and memory functions. The promoter regions of the calcium/calmodulin-dependent protein kinase II alpha and glutamate receptor-2 genes were amplified by PCR from DNA products immunoprecipitated by amyloid precursor protein intracellular domain. An electrophoretic mobility shift assay and western blot analysis suggested that the promoter regions of these two genes associated with learning and memory were bound by amyloid precursor protein intracellular domain (in complex form). Our experimental findings indicate that the amyloid precursor protein intracellular domain is involved in the transcriptional regulation of learning- and memory-associated genes in hippocampal neurons. These data may provide new insights into the molecular mechanism underlying the symptoms of progressive memory loss in Alzheimer's disease.展开更多
Xylanase 1 (Xyn1) is one of the two major representatives of the xylanase system of T. reesei; the mechanisms governing its expression were analysed throughout this study. All factors and regulatory motifs responsible...Xylanase 1 (Xyn1) is one of the two major representatives of the xylanase system of T. reesei; the mechanisms governing its expression were analysed throughout this study. All factors and regulatory motifs responsible for transcriptional regulation and the model of their interplay in induction and repression will be presented. Using in vivo foot printing analysis of xylan-induced and glucose repressed mycelia, we detected three adjacent nucleotide sequences contacted by DNA-binding proteins. Protection within the inverted repeat of the Cre1 (SYGGRG) consensus sequence on the non coding strand under repressing conditions is in perfect agreement with the previously reported Cre1 dependent glucose repression of xyn1. Constitutive protein binding could be observed to a CCAAT-box and an inverted repeat of a 5′ GGCTAA 3′ sequence. EMSA with crude extracts from induced and repressed mycelia revealed that the latter motifs are sufficient for formation of the basal transcriptional complex under all conditions. The inverted repeat of GGCTAA closely resembles the consensus sequences of the cellulase and xylanase regulators Ace1, Ace2 and, Xyr1 (encoded by xyr1, cloned and characterised in this study) EMSA with heterologously expressed components of each factor and of the T. reesei Hap2/3/5 protein complex revealed that the basal transcriptional complex is formed by Xyr1 and the Hap2/3/5. Additionally to the Cre1 mediated carbon catabolite repression a yet unknown mechanism antagonizing induction of xyn1 expression could be elucidated. Latter occurs through competition of the repressor Ace1 and Xyr1 for the GGCTAA motif. In vivo proof for the relevance of identified motifs could be given through analysis of T. reesei transformants containing correspondingly mutated versions of the xyn1 promoter fused to the A. niger goxA gene. The results indicated that the basal as well as the induction level of xyn1 gene transcription is dependent on an interaction of Xyr1 with the GGCTAA motif while formation of the CCAAT-Hap2/3/5 complex slightly reduces induction. It can be concluded that mutations impairing protein binding in vitro lead to a loss of distinct regulatory functions in xyn1 gene expression in vivo. A respective model of gene regulation will be presented.展开更多
The regulation of gene expression in brain vicissitudes during aging is still not much known and explored. Differential gene expression and regulation is a key factor involved to identify the important landmarks withi...The regulation of gene expression in brain vicissitudes during aging is still not much known and explored. Differential gene expression and regulation is a key factor involved to identify the important landmarks within the brain transcriptome to study neuronal aging. Recently</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> transcriptomic studies are highly explored to understand and depict diseased versus normal as next generation sequencing enable</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> to capture the complete biological context to the entire genome. Study of gene expression during aging compared to young flies provides a signature and scenario of gene expression and regulation during aging. In this study</span><span style="font-family:Verdana;">,</span><span style="font-family:""><span style="font-family:Verdana;"> we took advantage of NGS raw data of young and old flies head from SRA database of NCBI and decrypted the gene expression regulation during normal aging in drosophila model. We identified 350 genes with significant differential expression between young and old flies having 0.01% FDR. Various pathways in context to identified genes which are involved in aging include autophagy </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;"> cell death and apoptosis, proteolysis</span><span style="font-family:Verdana;">, oxidative</span><span style="font-family:Verdana;"> stress, declination grey and white matter and neurotransmitter levels, mitochondrial discrepancy, electron transport chain, sugar degradation pathways, activation of transcription factors involved in epigenetic changes, regulators involved in negative and positive regulation WNT signaling pathways, G protein coupled receptor etc. as all these factors contribute to neurodegeneration and possibly dementia in normal aging. So, to find the specific genes and regulators which are differentially expressed in normal aging</span></span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> we investigate brain transcriptome of normal aging flies compared to young flies which offer a repertoire of genes, regulators and factors involved in network of neurodegeneration to establish direct correlation between aging and dementia. We also identified the pathways which are involved in aging and corresponding gene regulation in these pathways in aging flies brain. It is found that there are some common pathways whose genes and regulators are highly differentially regulated in both aging and dementia.展开更多
基金supported by the United States National Institutes of Health(NIH)under Award Number R01 AR059088(to J.W.)the Mary A.and Paul R.Harrington Distinguished Professorship Endowment.
文摘Osteoarthritis (OA), the most common form of joint disease, is characterized clinically by joint pain, stiffness,and deformity. OA is now considered a whole joint disease;however, the breakdown of the articular cartilage remains themajor hallmark of the disease. Current treatments targeting OA symptoms have a limited impact on impeding orreversing the OA progression. Understanding the molecular and cellular mechanisms underlying OA development isa critical barrier to progress in OA therapy. Recent studies by the current authors’ group and others have revealedthat the nuclear factor of activated T cell 1 (NFAT1), a member of the NFAT family of transcription factors, regulatesthe expression of many anabolic and catabolic genes in articular chondrocytes of adult mice. Mice lacking NFAT1exhibit normal skeletal development but display OA in both appendicular and spinal facet joints as adults. Thisreview mainly focuses on the recent advances in the regulatory role of NFAT1 transcription factor in the activities ofarticular chondrocytes and its implication in the pathogenesis of OA.
基金supported by the National Natural Science Foundation of China Young Scholars Project(31902242)the Agricultural Science and Technology Innovation Program(ASTIP)of Chinese Academy of Agricultural Sciences(2017–2020)。
文摘Avian pathogenic Escherichia coli(APEC)belonging to extraintestinal pathogenic E.coli(ExPEC)can cause severe infections in extraintestinal tissues in birds and humans,such as the lungs and blood.MprA(microcin production regulation,locus A,herein renamed AbsR,a blood survival regulator),a member of the MarR(multiple antibiotic resistance regulator)transcriptional regulator family,governs the expression of capsule biosynthetic genes in human ExPEC and represents a promising druggable target for antimicrobials.However,a deep understanding of the AbsR regulatory mechanism as well as its regulon is lacking.In this study,we present a systems-level analysis of the APEC AbsR regulon using ChIP-Seq(chromatin immunoprecipitation sequencing)and RNA-Seq(RNA sequencing)methods.We found that AbsR directly regulates 99 genes and indirectly regulates 667 genes.Furthermore,we showed that:1)AbsR contributes to antiphagocytotic effects by macrophages and virulence in a mouse model for systemic infection by directly activating the capsular gene cluster;2)AbsR positively impacts biofilm formation via direct regulation of the T2SS(type II secretion system)but plays a marginal role in virulence;and 3)AbsR directly upregulates the acid tolerance signaling system EvgAS to withstand acid stress but is dispensable in ExPEC virulence.Finally,our data indicate that the role of AbsR in virulence gene regulation is relatively conserved in ExPEC strains.Altogether,this study provides a comprehensive analysis of the AbsR regulon and regulatory mechanism,and our data suggest that AbsR likely influences virulence primarily through the control of capsule production.Interestingly,we found that AbsR severely represses the expression of the type I-F CRISPR(clustered regularly interspaced short palindromic repeats)-Cas(CRISPR associated)systems,which could have implications in CRISPR biology and application.
基金funded by Guangdong Basic and Applied Basic Research Foundation (Grant No.2023A1515010237)the 2021 Dongguan Provincial Rural Revitalization Program (Grant No.20211800400022)+2 种基金the Guangdong Key Technology Research and Development Program (Grant Nos.2020B020220005,2022B1111040003)the Guangdong Modern Agricultural Industry Technology System Program (Grant No.2023KJ121)the South China Botanical Garden,the Chinese Academy of Sciences (Grant No.QNXM-02)。
文摘Hippeastrum, a highly diverse genus in the Amaryllidaceae family, is a valuable ornamental bulbous flowering plant. Somatic embryogenesis(SE) is an efficient method for mass production of Hippeastrum plantlets. Previous studies have been devoted to the in vitro propagation of Hippeastrum, but the SE and its regulatory networks are rarely reported. In this study, we established a direct SE method of Hippeastrum Bangkok Rose' using leaf bases as explants. MS supplemented with 1.00 mg·L^(-1)NAA +1.00 mg·L^(-1)KT + 0.25 mg·L^(-1)TDZ was the optimal medium for SE. Histological observations showed that the bipolar somatic embryo originated from the epidermal cell layer and underwent initiation,globular, scutellar and coleoptile stages. During SE, endogenous hormones of IAA, CTK, ABA, and SA were highly accumulated. Transcriptomic analysis revealed the genes encoding auxin biosynthesis/metabolic enzymes and efflux carriers were induced, while the auxin receptor of TIR1 and ARF transcriptional repressor of Aux/IAA were down-regulated and up-regulated, respectively, leading to suppression of auxin signaling. In contrast, cytokine signaling was promoted at the early stage of SE, as biosynthesis, transport, and signaling components were up-regulated.Various stress-related genes were up-regulated at the early or late stages of SE. Chromatin remodeling could also be dynamically regulated via distinct expression enzymes that control histone methylation and acetylation during SE. Moreover, key SE regulators, including WOXs and SERKs were highly expressed along with SE. Overall, the present study provides insights into the SE regulatory mechanisms of the Hippeastrum.
基金supported by the National Natural Science Foundation of China(No.30470587)the Natural Science Foundation of Jiangsu Province(No.BK2004037)the Department of Personnel of Jiangsu Province(No.L2134501).
文摘The recent progress in neural stem cells (NSCs) research has shed lights on possibility of repair and restoration of neuronal function in neurodegenerative diseases using stem cells. Induction of stem cells differentiate into mature neurons is critical to achieve the clinical applications of NSCs. At present, molecular mechanisms modulating NSC differentiation are not fully understood. Differentiation of stem cells into neuronal and glial cells involves an array of changes in expression of transcription factors. Transcription factors then trigger the expression of a variety of central nervous system (CNS) genes that lead NSCs to differentiate towards different cell types. In this paper, we summarized the recent findings on the gene regulation of NSCs differentiation into neuronal cells.
基金supported by the National Key R&D Program of China (2022YFF1000100 to Long Jin and 2023YFD1300012 to Long Jin)the Sichuan Science and Technology Program (2022JDJQ0054 to Long Jin and 2021YFYZ0009 to Mingzhou Li)the National Natural Science Foundation of China (32225046 to Mingzhou Li)。
文摘Background Goose, descendants of migratory ancestors, have undergone extensive selective breeding, resulting in their remarkable ability to accumulate fat in the liver and exhibit a high tolerance for significant energy intake. As a result, goose offers an excellent model for studying obesity, metabolic disorders, and liver diseases in mammals. Although the impact of the three-dimensional arrangement of chromatin within the cell nucleus on gene expression and transcriptional regulation is widely acknowledged, the precise functions of chromatin architecture reorganization during fat deposition in goose liver tissues still need to be fully comprehended.Results In this study, geese exhibited more pronounced changes in the liver index and triglyceride(TG) content following the consumption of the high-fat diet(HFD) than mice without significant signs of inflammation. Additionally, we performed comprehensive analyses on 10 goose liver tissues(5 HFD, 5 normal), including generating highresolution maps of chromatin architecture, conducting whole-genome gene expression profiling, and identifying H3K27ac peaks in the livers of geese and mice subjected to the HFD. Our results unveiled a multiscale restructuring of chromatin architecture, encompassing Compartment A/B, topologically associated domains, and interactions between promoters and enhancers. The dynamism of the three-dimensional genome architecture, prompted by the HFD, assumed a pivotal role in the transcriptional regulation of crucial genes. Furthermore, we identified genes that regulate chromatin conformation changes, contributing to the metabolic adaptation process of lipid deposition and hepatic fat changes in geese in response to excessive energy intake. Moreover, we conducted a cross-species analysis comparing geese and mice exposed to the HFD, revealing unique characteristics specific to the goose liver compared to a mouse. These chromatin conformation changes help elucidate the observed characteristics of fat deposition and hepatic fat regulation in geese under conditions of excessive energy intake.Conclusions We examined the dynamic modifications in three-dimensional chromatin architecture and gene expression induced by an HFD in goose liver tissues. We conducted a cross-species analysis comparing that of mice. Our results contribute significant insights into the chromatin architecture of goose liver tissues, offering a novel perspective for investigating mammal liver diseases.
文摘Eukaryotic chromatin consisting of nucleosomes connected by linker DNA is organized into higher order structures,which is facilitated by linker histone H1.Formation of chromatin compacts and protects the genome,but also hinders DNA transactions.Cells have evolved mechanisms to modify/remodel chromatin resulting in chromatin states suitable for genome functions.The high mobility group box(HMGB)proteins are non-histone chromatin architectural factors characterized by one or more HMGB motifs that bind DNA in a sequence nonspecific fashion.They play a major role in chromatin dynamics.The Saccharomyces cerevisiae(yeast hereafter)HMGB protein Hmo1 contains two HMGB motifs.However,unlike a canonical HMGB protein that has an acidic C-terminus,Hmo1 ends with a lysine rich,basic,C-terminus,resembling linker histone H1.Hmo1 exhibits characteristics of both HMGB proteins and linker histones in its multiple functions.For instance,Hmo1 promotes transcription by RNA polymerases I and II like canonical HMGB proteins but makes chromatin more compact/stable like linker histones.Recent studies have demonstrated that Hmo1 destabilizes/disrupts nucleosome similarly as other HMGB proteins in vitro and acts to maintain a common topological architecture of genes in yeast genome.This minireview reviews the functions of Hmo1 and the underlying mechanisms,highlighting recent discoveries.
基金This study is supported by Science Foundation of the Education Department of Zhejiang Province.
文摘AIM: To construct subtracted cDNA libraries and further identify differentially expressed genes that are related to the development of colorectal carcinoma(CRC). METHODS: Suppression subtractive hybridization(SSH) was done on cDNAs of normal mucosa, adenoma and adenocarcinoma tissues from the same patient. Three subtracted cDNA libraries were constructed and then hybridized with forward and backward subtracted probes for differential screening. Positive clones from each subtracted cDNA library were selected for sequencing and BLAST analysis. Finally, virtual Northern Blot confirmed such differential expression. RESULTS: By this way, there were about 3-4 X 10(2) clones identified in each subtracted cDNA library, in which about 85% positive clones were differentially screened. Sequencing and BLAST homology search revealed some clones containing sequences of known gene fragments and several possibly novel genes showing few or no sequence homologies with any known sequences in the database. CONCLUSION: All results confirmed the effectiveness and sensitivity of SSH. The differentially expressed genes during the development of CRC can be used to shed light on the pathogenesis of CRC and be useful genetic markers for early diagnosis and therapy.
文摘INTRODUCTIONHepatocellular carcinoma(HCC)is one of the major causes of death in the word.The mechanism of carcinogenesis is unknown,although it is widely accepted that HBV and HCV are clsely related to liver cancer[1-5[1-5].Previously,a variety of studies have described the differences in gene expression which distinguished tumor from nontumor[6-11].Cloning of the genes,especially the genes associated with HBV and HCV,is still very important to account for the development of liver cancer.
基金This work was supported by the National Nat-ural Science Foundation of China(Grant No.30130240),the Chinese Academy of Sciences(GrantNo.KSCX2-SW-303).
文摘A systemic study was initiated to identify stage-specific expression genes in fish embryogenesis by using suppression subtractive hybridization (SSH) technique. In this study, we presented a preliminary result on screen for stage-specific expression genes between tail bud stage (TBS) and heartbeat beginning stage (HBS) in gynogenetic silver crucian carp (Carassius auratus gibelio). Two SSH plasmid libraries specific for TBS embryos and HBS embryos were constructed, and stage-specific expression genes were screened between the two stages. 1963 TBS positive clones and 2466 HBS positive clones were sampled to PCR amplification, and 1373 TBS and 1809 HBS PCR positive clones were selected to carry out dot blots. 169 TBS dot blot positive clones and 272 HBS dot blot positive clones were sequenced. Searching GenBank by using these nucleotide sequences indicated that most of the TBS dot blot positive clones could not be found homologous sequences in the database, while known genes were mainly detected from HBS dot blot positive clones. Of the 79 known genes, 20 were enzymes or kinases involved in important metabolism of embryonic development. Moreover, specific expressions of partial genes were further confirmed by virtual northern blots. This study is the first step for making a large attempt to study temporal and spatial control of gene expression in the gynogenetic fish embryogenesis.
基金the Natinnal Biotechnology Reseaxch Project of 863 High Technology, contract No. 101-01-01-02.
文摘After pre-culture and treatment of osmosis, cotyledons of immature peanut (Arachis hypogaea L.) zygotic embryos were transformed via particle bombardment with a plasmid containing a chimeric hph gene conferring resistance to hygromycin and a chimeric intron-gus gene. Selection for hygromycin resistant calluses and somatic embryos was initiated at 10th d post-bombardment on medium containing 10-25 mg/L hygromycin. Under continuous selection, hygromycin resistant plantlets were regenerated from somatic embryos and were recovered from nearly 1.6% of the bombarded cotyledons. The presence and integration of foreign DNA in regenerated hygromycin resistant plants was confirmed by PCR (polymerase chain reaction) for the intron-gus gene and by Southern hybridization of the hph gene. GUS enzyme activity was detected in leaflets from transgenic plants but not from control, non-transformed plants. The production of transgenic plants are mainly based on a newly improved somatic embryogenesis regeneration system developed by us.
基金the Natural Scientific Foundation of China (NSFC3962526)National High-Technology Project-863 (102-10-01-04)
文摘AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method by using abundant double-stranded cDNA messages provided by two self-constructed cDNA libraries (Allitridi-treated and paternal HGC cell line BGC823 cells cDNA libraries respectively). Bam H I and Xho I restriction sites harbored in the library vector were used to select representations. Northern and Slot blots analyses were employed to identify the obtained difference products. RESULTS: Fragments released from the cDNA library vector after restriction endonuclease digestion acted as good marker indicating the appropriate digestion degree for library DNA. Two novel expressed sequence tags (ESTs) and a recombinant gene were obtained. Slot blots result showed a 8-fold increase of glia-derived nexin/protease nexin 1 (GDN/PN1) gene expression level and 4-fold increase of hepatitis B virus x-interacting protein (XIP) mRNA level in BGC823 cells after Allitridi treatment for 72h. CONCLUSION: Elevated levels of GDN/PN1 and XIP mRNAs induced by Allitridi provide valuable molecular evidence for elucidating the garlic's efficacies against neurodegenerative and inflammatory diseases. Isolation of a recombinant gene and two novel ESTs further show cDNA RDA based on cDNA libraries to be a powerful method with high specificity and reproducibility in cloning differentially expressed genes.
文摘AIM: To establish the role of vascular endothelial growth factor (VEGF) in the oncogenesis of human gastric carcinoma more directly. METHODS: The expression of VEGF and its receptor kinase-domain insert containing receptor (KDR) in human gastric cancer tissue were observed by immunohistochemical staining. VEGF levels were manipulated in human gastric cancer cell using eukaryotic expression constructs designed to express the complete VEGF(165) complimentary DNA in either the sense or antisense orientation. The biological changes of the cells were observed in which VEGF was up-regulated or down-regulated. RESULTS: VEGF-positive rate was 50%, and VEGF was mainly localized in the cytoplasm and membrane of the tumor cells, while KDR was mainly located in the membrane of vascular endothelial cells in gastric cancer tissues and peri-cancerous tissue. In 2 cases of 50 specimens, the gastric cancer cells expressed KDR, localized in both the cytoplasm and membrane. Introduction of VEGF(165) antisense into human gastric cancer cells (SGC-7901, immunofluorescence intensity, 31.6%)) resulted in a significant reduction in VEGF-specific messenger RNA and total and cell surface VEGF protein (immunofluorescence intensity, 8.9%) (P【0.05). Conversely, stable integration of VEGF(165) in the sense orientation resulted in an increase in cellular and cell surface VEGF (immunofluorescence intensity, 75.4%) (P【0.05). Lowered VEGF levels were associated with a marked decrease in the growth of nude mouse xenografted tumor (at 33 days postimplantation, tumor volume: 345.40 +/- 136.31 mm3)(P【0.05 vs control SGC-7901 group: 1534.40 +/- 362.88 mm3), whereas up-regulation of VEGF resulted in increased xenografted tumor size (at 33 days postimplantation, tumor volume: 2350.50 +/- 637.70 mm3) (P【0.05 vs control SGC-7901 group). CONCLUSION: This study provides direct evidence that VEGF plays an important role in the oncogenesis of human gastric cancer.
文摘INTRODUCTIONThe mechanism of hepatocellular carcinoma(HCC)is still unclear,although some genes have been found to play a role in the transformation of liver cells,and a variety of studies have described differences in gene expression which distinguished tumor from nontumor[1-6].The new genes,especially the functional genes directly related with tumor are still worth being found.The purpose of our study is to find the different genes between human liver tumor and normal tissues using suppression subtractive hybridization.
文摘BACKGROUND:Pancreatic cancer(PCa)is one of the most aggressive human solid tumors,with rapid growth and metastatic spread as well as resistance to chemotherapeutic drugs,leading rapidly to virtually incurable disease.Over the last 20 years,however,significant advances have been made in our understanding of the molecular biology of PCa,with a focus on the cytogenetic abnormalities in PCa cell growth and differentiation. DATA SOURCES:A MEDLINE search and manual cross- referencing were utilized to identify published data for PCa molecular biology studies between 1986 and 2008, with emphasis on genetic alterations and developmental oncology. RESULTS:Activation of oncogenes,deregulation of tumor suppressor and genome maintenance genes,upregulation of growth factors/growth factor receptor signaling cascade systems,and alterations in cytokine expression,have been reported to play important roles in the process of pancreatic carcinogenesis.Alterations in the K-ras proto- oncogene and the p16INK4a,p53,FHIT,and DPC4 tumor suppressor genes occur in a high percentage of tumors. Furthermore,a variety of growth factors are expressed at increased levels.In addition,PCa often exhibits alterations in growth inhibitory pathways and evades apoptosis through p53 mutations and aberrant expression of apoptosis-regulating genes,such as members of the Bcl family.Additional pathways in the development of an aggressive phenotype,local infiltration and metastasis are still under ongoing genetic research.The present paper reviews recent studies on the pathogenesis of PCa,and includes a brief reference to alterations reported for other types of pancreatic tumor. CONCLUSIONS:Advances in molecular genetics and biology have improved our perception of the pathogenesis of PCa.However,further studies are needed to better understand the fundamental changes that occur in PCa,thus leading to better diagnostic and therapeutic management.
文摘Bicoid is one of the important Drosophila maternal genes involved in the control of embryo polarity and larvae segmentation. To clone and characterize the rice bicoid-related genes, one cDNA clone, Rb24 (EMBL accession number: AJ2771380), was isolated by screening of rice unmature seed cDNA library. Sequence analysis indicates that Rb24 contains a putative amino acid sequence, which is homologous to unique 8 amino acids sequence within Drosophila bicoid homeodomain (50% identity, 75% similarity) and involves a lys-9 in putative helix 3. Northern blot analysis of rice RNA has shown that this sequence is expressed in a tissue-specific manner. The transcript was detected strongly in young panicles, but less in young leaves and roots. This results are further confirmed with paraffin section in situ hybridization. The signal is intensive in rice globular embryo and located at the apical tip of the embryo, then, along with the development of embryo, the signal is getting reduced and transfers into both sides of embryo. The existence of bicoid-related sequence in rice embryo and the similarity of polar distribution of bicoid and Rb24 mRNA in early embryo development may implicates a conserved maternal regulation mechanism of body axis presents in Drosophila and in rice.
基金supported by the National Natural Science Fundation of China (30971809)
文摘Phytophthora root rot is one of the most prevalent diseases in the world,which can infect the seedlings and plants,with substantial negative impact on soybean yield and quality.MicroRNAs (miRNAs) are a class of post-transcriptional regulators of gene expression during growth and development of organisms.A soybean disease-resistance variety Suinong 10 was inoculated with Phytophthora sojae race No.1,and the specific miRNA resistant expression profile was acquired by microarray for the first time.Different expressional miRNAs have been found after comparing the results of the treated sample with the control sample.Furthermore,the target genes of different expressional miRNAs were predicted.Two miRNAs,cbr-mir-241 and ath-miR854a,regulated the disease-resistance process directly through their targets,some enzymes.Another two miRNAs,gma-miR169a and ath-miR169h,participated in disease-resistance regulation as transcription factors.Similarly,one miRNA,ptc-miR164f,has been reported to regulate the plant development.All of these studies would be served as the foundation for exploring the resistance mechanism.
文摘In searching of differentially expressed genes in human uterine leiomyomas, differential display was used with twelve pairs of primers to compare human uterine leiomyomas with matched myometrium. False positives were eliminated by reverse Northern analysis. Positives were confirmed by Northern blot analysis. RESULTS: Four of 69 cDNA fragments (3 up-regulated named L1, L2 and L3 and 1 down-regulated named M1 in leiomyoma) were confirmed by Northern analysis. Sequence comparison and Northern analysis proved that L1 is exactly the human ribosomal protein S19. It was present ubiquitously in 13 tissues tested but in various levels and even in different size. L1 was highly expressed in parotidean cystadenocarcinoma, pancreatic cancer and breast cancer examined. No mutations have been found in human uterine leiomyomas (n=6). CONCLUSIONS: hRPS19 overexpression might be a universal signal in rapid cell growth tissues.
基金supported by the Natural Science Foundation of Guangdong Province,China,No.8151051501000004
文摘In this study, we employed chromatin immunoprecipitation, a useful method for studying the locations of transcription factors bound to specific DNA regions in specific cells, to investigate amyloid precursor protein intracellular domain binding sites in chromatin DNA from hippocampal neurons of rats, and to screen out five putative genes associated with the learning and memory functions. The promoter regions of the calcium/calmodulin-dependent protein kinase II alpha and glutamate receptor-2 genes were amplified by PCR from DNA products immunoprecipitated by amyloid precursor protein intracellular domain. An electrophoretic mobility shift assay and western blot analysis suggested that the promoter regions of these two genes associated with learning and memory were bound by amyloid precursor protein intracellular domain (in complex form). Our experimental findings indicate that the amyloid precursor protein intracellular domain is involved in the transcriptional regulation of learning- and memory-associated genes in hippocampal neurons. These data may provide new insights into the molecular mechanism underlying the symptoms of progressive memory loss in Alzheimer's disease.
文摘Xylanase 1 (Xyn1) is one of the two major representatives of the xylanase system of T. reesei; the mechanisms governing its expression were analysed throughout this study. All factors and regulatory motifs responsible for transcriptional regulation and the model of their interplay in induction and repression will be presented. Using in vivo foot printing analysis of xylan-induced and glucose repressed mycelia, we detected three adjacent nucleotide sequences contacted by DNA-binding proteins. Protection within the inverted repeat of the Cre1 (SYGGRG) consensus sequence on the non coding strand under repressing conditions is in perfect agreement with the previously reported Cre1 dependent glucose repression of xyn1. Constitutive protein binding could be observed to a CCAAT-box and an inverted repeat of a 5′ GGCTAA 3′ sequence. EMSA with crude extracts from induced and repressed mycelia revealed that the latter motifs are sufficient for formation of the basal transcriptional complex under all conditions. The inverted repeat of GGCTAA closely resembles the consensus sequences of the cellulase and xylanase regulators Ace1, Ace2 and, Xyr1 (encoded by xyr1, cloned and characterised in this study) EMSA with heterologously expressed components of each factor and of the T. reesei Hap2/3/5 protein complex revealed that the basal transcriptional complex is formed by Xyr1 and the Hap2/3/5. Additionally to the Cre1 mediated carbon catabolite repression a yet unknown mechanism antagonizing induction of xyn1 expression could be elucidated. Latter occurs through competition of the repressor Ace1 and Xyr1 for the GGCTAA motif. In vivo proof for the relevance of identified motifs could be given through analysis of T. reesei transformants containing correspondingly mutated versions of the xyn1 promoter fused to the A. niger goxA gene. The results indicated that the basal as well as the induction level of xyn1 gene transcription is dependent on an interaction of Xyr1 with the GGCTAA motif while formation of the CCAAT-Hap2/3/5 complex slightly reduces induction. It can be concluded that mutations impairing protein binding in vitro lead to a loss of distinct regulatory functions in xyn1 gene expression in vivo. A respective model of gene regulation will be presented.
文摘The regulation of gene expression in brain vicissitudes during aging is still not much known and explored. Differential gene expression and regulation is a key factor involved to identify the important landmarks within the brain transcriptome to study neuronal aging. Recently</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> transcriptomic studies are highly explored to understand and depict diseased versus normal as next generation sequencing enable</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> to capture the complete biological context to the entire genome. Study of gene expression during aging compared to young flies provides a signature and scenario of gene expression and regulation during aging. In this study</span><span style="font-family:Verdana;">,</span><span style="font-family:""><span style="font-family:Verdana;"> we took advantage of NGS raw data of young and old flies head from SRA database of NCBI and decrypted the gene expression regulation during normal aging in drosophila model. We identified 350 genes with significant differential expression between young and old flies having 0.01% FDR. Various pathways in context to identified genes which are involved in aging include autophagy </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;"> cell death and apoptosis, proteolysis</span><span style="font-family:Verdana;">, oxidative</span><span style="font-family:Verdana;"> stress, declination grey and white matter and neurotransmitter levels, mitochondrial discrepancy, electron transport chain, sugar degradation pathways, activation of transcription factors involved in epigenetic changes, regulators involved in negative and positive regulation WNT signaling pathways, G protein coupled receptor etc. as all these factors contribute to neurodegeneration and possibly dementia in normal aging. So, to find the specific genes and regulators which are differentially expressed in normal aging</span></span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> we investigate brain transcriptome of normal aging flies compared to young flies which offer a repertoire of genes, regulators and factors involved in network of neurodegeneration to establish direct correlation between aging and dementia. We also identified the pathways which are involved in aging and corresponding gene regulation in these pathways in aging flies brain. It is found that there are some common pathways whose genes and regulators are highly differentially regulated in both aging and dementia.