The human RNA methyltransferase like i gene (RNMTL1) is one of thirteen newly discovered geneswithin a 116 Kb segment of the chromosome 17p13.3 that suffers from a high frequent loss of heterozygosityin human hepatoce...The human RNA methyltransferase like i gene (RNMTL1) is one of thirteen newly discovered geneswithin a 116 Kb segment of the chromosome 17p13.3 that suffers from a high frequent loss of heterozygosityin human hepatocellular carcinoma in China[1-5]. To understand the molecular mechanisms underlyingtranscription control of the RNMTL1 gene in human cancers, we decline using of the conventional approachwhere the cis-elements bound by the known transcription factors are primary targets, and carried out thesystematic analyses to dissect the promoter structure and identify/characterize the key cis-elements thatare responsible for its strong expression in cell. The molecular approaches applied included 1, the primerextension for mapping of the transcription starts; 2, the transient transfection/reporter assays on a largenumber of deletion and site-specific mutants of the promoter segment for defining the minimal promoterand the crucial elements within; and 3, the electrophoresis mobility shift assay with specific antibodies forreconfirming the nature of the transcription factors and their cognate cis-elements. We have shown that theinteraction of an ATF/CREB element (-38 to -31) and its cognate transcription factors play a predominantrole in the promoter activity of the RNMTL1 gene. The secondary DNA structures of the ATF/CREBelement play a more vital role in the protein-DNA interaction. Finally, we reported a novel mechanismunderlying the YY1 mediated transcription repression, namely, the ATF/CREB dependent transcription-repression by YY1 is executed in absence of its own sequence-specific binding.展开更多
The hepatocellular carcinoma suppressor 1 (HCCS1) gene was identified by both positional cloning from a predominant region of loss of heterozygosity (17p 13.3) in liver cancer and by functional screening for genes...The hepatocellular carcinoma suppressor 1 (HCCS1) gene was identified by both positional cloning from a predominant region of loss of heterozygosity (17p 13.3) in liver cancer and by functional screening for genes affecting cell proliferation in large-scale transfection assays. Its overexpression results in inhibition of cell proliferation in cell culture and tumor growth in nude mice. To understand its transcription regulation, the promoter architecture has been dissected in detail. The major start of transcription was mapped by primer extension to a C residue, 177 nucleotides upstream of the ATG codon. By assessing the promoter activity of a set of linker-scanning mutants of the minimal promoter (-60 to +148 region) in a transient transfection assay, we found that the +1 to + 40 region is critical to HCCS1 gene transcription, containing binding sites for transcription factors NF-kB (-21 to +7 and +40 to +26), p53 (+29 to +9) and ETS (+4 to +20 and +23 to +39). Biochemical and molecular analyses revealed that the ETS transcription factors ETS-2 and Elf-1 bind to the two ETS sites in situ and contribute significantly to the transcriptionally active state of the HCCS1 gene, while NF-kB, p53 and two other members of the ETS family (ETS-1 and NERF2) appear to play little role. Our observations provide insight into the mechanistic aspects of HCCS1 transcription regulation.展开更多
The human RNA methyltransferase like 1 gene (RNMTL1) is one of thirteen newly discovered genes within a 116 Kb segment of the chromosome 17pl3.3 that suffers from a high frequent loss of heterozygosity in human hepato...The human RNA methyltransferase like 1 gene (RNMTL1) is one of thirteen newly discovered genes within a 116 Kb segment of the chromosome 17pl3.3 that suffers from a high frequent loss of heterozygosity in human hepatocellular carcinoma in China[1-5]. To understand the molecular mechanisms underlying transcription control of the RNMTL1 gene in human cancers, we decline using of the conventional approach where the cis-elements bound by the known transcription factors are primary targets, and carried out the systematic analyses to dissect the promoter structure and identify/characterize the key cis-elements that are responsible for its strong expression in cell. The molecular approaches applied included 1, the primer extension for mapping of the transcription starts; 2, the transient transfection/reporter assays on a large number of deletion and site-specific mutants of the promoter segment for defining the minimal promoter and the crucial elements within; and 3, the electrophoresis mobility shift assay with specific antibodies for reconfirming the nature of the transcription factors and their cognate cis-elements. We have shown that the interaction of an ATF/CREB element (-38 to -31) and its cognate transcription factors play a predominant role in the promoter activity of the RNMTL1 gene. The secondary DNA structures of the ATF/CREB element play a more vital role in the protein-DNA interaction. Finally, we reported a novel mechanism underlying the YY1 mediated transcription repression, namely, the ATF/CREB dependent transcription-repression by YY1 is executed in absence of its own sequence-specific binding.展开更多
Poly(ADP-ribose) polymerase 1 (PARP1) plays important roles in the regulation of transcription factors. Mounting evidence has shown that inhibition of PARP1 influences the expression of genes associated with inflammat...Poly(ADP-ribose) polymerase 1 (PARP1) plays important roles in the regulation of transcription factors. Mounting evidence has shown that inhibition of PARP1 influences the expression of genes associated with inflammatory response. Interferon regulatory factor 1 (IRF1) is a critical transcription factor for the development of both the innate and adaptive immune responses against infections. However, the molecular mechanism through which PARP1 mediates the effects has not been clearly demonstrated. Jurkat cells were exposed to dexamethasone (Dex) or PARP1 inhibitor PJ34. The expression levels of IL-12, LMP2, OAS1 and PKR were detected using real-time RT-PCR. The interactions between PARP1 and IRF1 were examined by coimmunoprecipitation (co-IP) assays. We further explored the mechanism of PARP1 suppressing IRF1 by assessing the activities of interferon stimulated response element (ISRE). The mRNA expression of IL-12, LMP2, OAS1 and PKR was obviously suppressed by Dex in Jurkat cells, which could be rescued by PJ34 treatment. Luciferase study revealed that poly(ADP-ribosyl)- ation suppressed IRF1-mediated transcription through preventing the binding of IRF1 to ISREs. PARP1 inhibited IRF1-mediated transcription in Jurkat cells by preventing IRF1 binding to ISREs in the promoters of target genes. It is suggested that PARP1 is a crucial regulator of IRF1-mediated immune response. This study provides experimental evidence for the possible application of PARP1 inhibitors in the treatment of IRF1-related immune anergy.展开更多
Heterogeneous nuclear ribonucleoprotein (hnRNP) C plays a key role in RNA processing but also exerts a dominant negative effect on responses to 1,25-dihydroxyvitamin D (1,25(OH)2D) by functioning as a vitamin D ...Heterogeneous nuclear ribonucleoprotein (hnRNP) C plays a key role in RNA processing but also exerts a dominant negative effect on responses to 1,25-dihydroxyvitamin D (1,25(OH)2D) by functioning as a vitamin D response element-binding protein (VDRE-BP). hnRNPC acts a tetramer of hnRNPC1 (huC1) and hnRNPC2 (huC2), and organization of these subunits is critical to in vivo nucleic acid-binding. Overexpression of either huC1 or huC2 in human osteoblasts is sufficient to confer VDRE-BP suppression of 1,25(OH)2D-mediated transcription. However, huC1 or huC2 alone did not suppress 1,25(OH)2D-induced transcription in mouse osteoblastic cells. By contrast, overexpression of huC1 and huC2 in combination or transfection with a bone-specific polycistronic vector using a "self-cleaving" 2A peptide to co-express huC1/C2 suppressed 1,25D-mediated induction of osteoblast target gene expression. Structural diversity of hnRNPC between human/NWPs and mouse/rat/rabbit/dog was investigated by analysis of sequence variations within the hnRNP CLZ domain. The predicted loss of distal helical function in hnRNPC from lower species provides an explanation for the altered interaction between huC1/C2 and their mouse counterparts. These data provide new evidence of a role for hnRNPC1/C2 in 1,25(OH)2D-driven gene expression, and further suggest that species-specific tetramerization is a crucial determinant of its actions as a regulator of VDR-directed transactivation.展开更多
Expression of P-selectin in injured or activated endothelia cells serves as a permissive step towards leukocyte recruitment and perpetuation of inflammation in the pathogenesis of atherosclerosis.P-selectin can be ind...Expression of P-selectin in injured or activated endothelia cells serves as a permissive step towards leukocyte recruitment and perpetuation of inflammation in the pathogenesis of atherosclerosis.P-selectin can be induced by pro-inflammatory stimuli via the transcription factor NF-κB,but the epigenetic mechanisms remain incompletely understood.Previously we reported that myocardin-related transcription factor A(MRTF-A)mediates the transactivation of a slew of adhesion molecules by oxidized low-density lipoprotein(oxLDL),likely through a crosstalk with brahma-related gene 1(BRGl),a chromatin remodeling protein.Here,we show that MRTF-A was both sufficient and necessary for the transactivation of P-selectin gene in endothelial cells treated with TNF-α.Depletion of MRTF-A using small interfering RNA(siRNA)abrogated the binding of BRGl on the P-selectin promoter.Overexpression of BRG1 up-regulated the activity of P-selectin promoter activity while BRGl knockdown attenuated P-selectin expression.Finally,BRGl silencing suppressed the accumulation of acetylated histone H3 and methylated histone H3K4,and altered the binding of NF-κB on the P-selectin promoter.Therefore,our data demonstrate an essential role for MRTF-A and BRGl in P-selectin transactivation in endothelial cells.展开更多
Developing transgenics that express high levels of Cry1Ac protein, and at the same time, are phenotypically normal, has not been an easy task to achieve. It has been routinely observed that most of the transgenic plan...Developing transgenics that express high levels of Cry1Ac protein, and at the same time, are phenotypically normal, has not been an easy task to achieve. It has been routinely observed that most of the transgenic plants that survive, show no or extremely low levels of Cry1Ac protein. However, all of these plants do express the selectable marker, nptII gene. In the present study, we record an interesting observation of how one of the genes (cry1Ac) on a single T-DNA fragment is selectively silenced, keeping the expression of the other gene (nptII) intact. Further, this silenced state is inherited.展开更多
Objective and Methods: Excessive accumulation of collagen typeⅠ and type Ⅲ causes the formation of keloids and hypertrophic scars. To understand the mechanism by which antisense oligodeoxynucleotide (Oligo) acts on ...Objective and Methods: Excessive accumulation of collagen typeⅠ and type Ⅲ causes the formation of keloids and hypertrophic scars. To understand the mechanism by which antisense oligodeoxynucleotide (Oligo) acts on in vitro transcrption α1 (I) collagen gene, isotopes (α-32pGTP) was incorporated into 2 SP6 in vitro transcription systems. Results and Conclu- sion: Oligo 2 (at the transcription start region) could effectively inhibit in vitro transcription of pGEM3-Col13 and the control (random oligodeoxynucleotides) showed no inhibition. However, oligo 1 (at the transcription start region) obviously inhibited the in vitro transcription of pGEM3-Col14, while Oligo 2, which targeted at the down stream region (about 200 bp) of the promoter showed no significant inhibition effect.展开更多
AIM: To investigate the expression of SNC73, a transcript of the immunoglobulin α-1 gene (IgA1-H chain), in human epitheliα-derived tumor cells. METHODS: Total RNAs and cell lysates were prepared from five diffe...AIM: To investigate the expression of SNC73, a transcript of the immunoglobulin α-1 gene (IgA1-H chain), in human epitheliα-derived tumor cells. METHODS: Total RNAs and cell lysates were prepared from five different human epithelial cell lines derived from lung, stomach, liver, skin, and breast, respectively. RT-PCR and immunoblot analysis of these five cell lines were done. Both RT-PCR and immunochemistry were used to detect the expression of SNC73 in these cell lines. We also examined the expression of SNC73 in normal epithelial cells of colon mucosa by in situ hybridization. RT-PCR and immunoblot analysis were used to determine whether the recombination activating gene1/2 (RAG1 and RAG2) is present. The expression of three immunoglobulin transcription factors, EBF, E2A and Pax5, and the heavy chain of IgA1 and two types of light chains of immunoglobulin (κ and λ) in the aforementioned cell lines were analyzed by RT-PCR and immunochemistry, respectively. All the RT-PCR products were analyzed by sequencing. RESULTS: The results of RT-PCR and immunochemistry showed that both mRNA and protein of SNC73 were expressed in five human epitheliα-derived cancer cell lines. These data were further confirmed in the normal epithelial cells of colon mucosa by in situ hybridization. Also, the heavy chain of IgA1 and κ light chain were detected in these cells, but no λ light chain was observed. Both RAG1 and RAG2 were expressed in these human epitheliα-derived cancer cell lines and the sequence was identical to that expressed in pre-B and pre-T cells. In addition to RAG1 and RAG2, the mRNA in one of the immunoglobulin transcription factors, EBF, was also detected in these cell lines, and Pax5 was only expressed in SW480 cells, but no expression of E2A was observed in all the five cell lines. CONCLUSION: Immunoglobulin A1 is originally expressed and V(D)J recombination machine is also present in non-lymphoid cells, suggesting that V(D)J recombination machine mediates the assembly of immunoglobulin A1 in non-lymphoid cells as in prelymphocytes.展开更多
High temperature stress is one of the major environmental factors that affect the growth and development of plants. Although WRKY transcription factors play a critical role in stress responses, there are few studies o...High temperature stress is one of the major environmental factors that affect the growth and development of plants. Although WRKY transcription factors play a critical role in stress responses, there are few studies on the regulation of heat stress by WRKY transcription factors,especially in tomato. Here, we identified a group I WRKY transcription factor, SlWRKY3, involved in thermotolerance in tomato. First, SlWRKY3 was induced and upregulated under heat stress. Accordingly, overexpression of SlWRKY3 led to an increase, whereas knock-out of SlWRKY3 resulted in decreased tolerance to heat stress. Overexpression of SlWRKY3 accumulated less reactive oxygen species(ROS), whereas knock-out of SlWRKY3 accumulated more ROS under heat stress. This indicated that SlWRKY3 positively regulates heat stress in tomato. In addition,SlWRKY3 activated the expression of a range of abiotic stress-responsive genes involved in ROS scavenging, such as a SlGRXS1 gene cluster.Further analysis showed that SlWRKY3 can bind to the promoters of the SlGRXS1 gene cluster and activate their expression. Collectively, these results imply that SlWRKY3 is a positive regulator of thermotolerance through direct binding to the promoters of the SlGRXS1 gene cluster and activating their expression and ROS scavenging.展开更多
BRI1-EMS-SUPPRESSOR 1(BES1)transcription factor is closely associated with the brassinosteroid(BR)signaling pathway and plays an important role in plant growth and development.SLB3 is a member of BES1 transcription fa...BRI1-EMS-SUPPRESSOR 1(BES1)transcription factor is closely associated with the brassinosteroid(BR)signaling pathway and plays an important role in plant growth and development.SLB3 is a member of BES1 transcription factor family and its expression was previously shown to increase significantly in tomato seedlings under drought stress.In the present study,we used virus-induced gene silencing(VIGS)technology to downregulate SLB3 expression to reveal the function of the SLB3 gene under drought stress further.The downregulated expression of SLB3 weakened the drought tolerance of the plants appeared earlier wilting and higher accumulation of H2 O2 and O2^–·,decreased superoxide dismutase(SOD)activity,and increased proline(PRO)and malondialdehyde(MDA)contents and peroxidase(POD)activity.Quantitative real-time PCR(qRT-PCR)analysis of BR-related genes revealed that the expression of SlCPD,SlDWARF and BIN2-related genes was significantly upregulated in SLB3-silenced seedlings under drought stress,but that the expression of TCH4-related genes was downregulated.These results showed that silencing the SLB3 gene reduced the drought resistance of tomato plants and had an impact on the BR signaling transduction which may be probably responsible for the variation in drought resistance of the tomato plants.展开更多
To examine the expression profiles of oligodendrocyte transcription factors 1 and 2 (Oligl and Olig2) and the interaction between these two proteins, Oligl was transfected into the lateral ventricles of neonatal rat...To examine the expression profiles of oligodendrocyte transcription factors 1 and 2 (Oligl and Olig2) and the interaction between these two proteins, Oligl was transfected into the lateral ventricles of neonatal rats subjected to hypoxia. Immunohistochemistry demonstrated that Olig2 was expressed throughout the nuclei in the brain, and expression increased at 3 days following hypoxia and was higher than levels at 7 days following Ad5-Oligl transfection. Western blot revealed that Oligl and Olig2 expression increased in Oligl-transfected brain cells 3 days after hypoxia, but Oligl and Olig2 expression decreased at 7 days. These results indicate that Oligl overexpression enhances Olig2 expression in brain tissues of hypoxia rats.展开更多
AIM: To observe the growth suppression effect of exogenous introduction of early growth response gene-1 (Egr-1 gene) on esophageal carcinoma tissue as well as on esophageal carcinoma cell line Eca109 and to explore th...AIM: To observe the growth suppression effect of exogenous introduction of early growth response gene-1 (Egr-1 gene) on esophageal carcinoma tissue as well as on esophageal carcinoma cell line Eca109 and to explore the potential application of Egr-1 gene in gene therapy of tumor. METHODS: Eukaryotic expression vector of PCMV-Egr-1 plasmid was introduced into Eca109 cell line which expressed no Egr-1 protein originally with lipofectamine transfection method. The introduction and expression of PCMV-Egr-1 plasmid into Eca109 cell line was confirmed by G418 selection culture, PCR amplification of neogene contained in the vector, Western blot analysis and immunocytochemical analysis. The cell growth curve, soft agar colony formation rate and tumorigenicity in SCID mice were examined to demonstrate the growth suppression effect of exogenous Egr-1 gene on Eca109 cell line. The Egr-1 mRNA and Egr-1 protein were also detected in 50 surgical specimens of esophageal carcinoma by in situ hybridization and immunohistochemistry. RESULTS: Exogenous Egr-1 gene was introduced successfully into Eca109 cell line and expressed Egr-1 protein stably. The transfected Eca109 cell line grew more slowly than control Eca109 as shown by cell growth curves, the soft agar colony formation rate (4.0% vs 6.9%, P 【 0.01) and the average growth rate of tumor in SCID mice (35.5 +/- 7.6 vs 65.8 +/- 7.6, P 【 0.05). The expression level of Egr-1 mRNA and protein significantly increased in dysplastic epithelia adjacent to cancer rather than in cancer tissues (65.8% vs 20.0% by ISH and 57.9% vs 0.01). CONCLUSION: Exogenous Egr-1 gene shows the strong effect of growth inhibition in Eca109 cell line. Egr-1 in the cancer tissue shows down-regulated expression that supports the inhibited function of Egr-1 in cancer growth and suggests Egr-1 may have an important role in gene therapy of esophageal carcinoma.展开更多
The B3 transcription factors(TFs)in plants play vital roles in numerous biological processes.Although B3 genes have been broadly identified in many plants,little is known about their potential functions in mediating s...The B3 transcription factors(TFs)in plants play vital roles in numerous biological processes.Although B3 genes have been broadly identified in many plants,little is known about their potential functions in mediating seed development and material accumulation.Castor bean(Ricinus communis)is a non-edible oilseed crop considered an ideal model system for seed biology research.Here,we identified a total of 61 B3 genes in the castor bean genome,which can be classified into five subfamilies,including ABI3/VP1,HSI,ARF,RAV and REM.The expression profiles revealed that RcABI3/VP1 subfamily genes are significantly up-regulated in the middle and later stages of seed development,indicating that these genes may be associated with the accumulation of storage oils.Furthermore,through yeast one-hybrid and tobacco transient expression assays,we detected that ABI3/VP1 subfamily member RcLEC2 directly regulates the transcription of RcOleosin2,which encodes an oil-body structural protein.This finding suggests that RcLEC2,as a seed-specific TF,may be involved in the regulation of storage materials accumulation.This study provides novel insights into the potential roles and molecular basis of B3 family proteins in seed development and material accumulation.展开更多
The key regulators and regeneration-associated genes involved in axonal regeneration of neurons after injury have not been clarified.In high-throughput sequencing,various factors influence the final sequencing results...The key regulators and regeneration-associated genes involved in axonal regeneration of neurons after injury have not been clarified.In high-throughput sequencing,various factors influence the final sequencing results,including the number and size of cells,the depth of sequencing,and the method of cell separation.There is still a lack of research on the detailed molecular expression profile during the regeneration of dorsal root ganglion neuron axon.In this study,we performed lase r-capture microdissection coupled with RNA sequencing on dorsal root ganglion neurons at 0,3,6,and 12 hours and 1,3,and 7 days after sciatic nerve crush in rats.We identified three stages after dorsal root ganglion injury:early(3-12 hours),pre-regeneration(1 day),and regeneration(3-7 days).Gene expression patterns and related function enrichment res ults showed that one module of genes was highly related to axonal regeneration.We verified the up-regulation of activating transcription factor 3(Atf3),Kruppel like factor 6(Klf6),AT-rich inte raction domain 5A(Arid5α),CAMP responsive element modulator(Crem),and FOS like 1,AP-1 transcription factor Subunit(Fosl1) in dorsal root ganglion neurons after injury.Suppressing these transcription factors(Crem,Arid5o,Fosl1 and Klf6) reduced axonal regrowth in vitro.As the hub transcription factor,Atf3 showed higher expression and activity at the preregeneration and regeneration stages.G protein-coupled estrogen receptor 1(Gper1),inte rleukin 12a(Il12α),estrogen receptor 1(ESR1),and interleukin 6(IL6) may be upstream factors that trigger the activation of Atf3 during the repair of axon injury in the early stage.Our study presents the detailed molecular expression profile during axonal regeneration of dorsal root ganglion neurons after peripheral nerve injury.These findings may provide reference for the clinical screening of molecular targets for the treatment of peripheral nerve injury.展开更多
While human immunodeficiency virus 1(HIV-1) infectionis controlled through continuous, life-long use of a combination of drugs targeting different steps of the virus cycle, HIV-1 is never completely eradicated from th...While human immunodeficiency virus 1(HIV-1) infectionis controlled through continuous, life-long use of a combination of drugs targeting different steps of the virus cycle, HIV-1 is never completely eradicated from the body. Despite decades of research there is still no effective vaccine to prevent HIV-1 infection. Therefore, the possibility of an RNA interference(RNAi)-based cure has become an increasingly explored approach. Endogenous gene expression is controlled at both, transcriptional and post-transcriptional levels by noncoding RNAs, which act through diverse molecular mechanisms including RNAi. RNAi has the potential to control the turning on/off of specific genes through transcriptional gene silencing(TGS), as well as finetuning their expression through post-transcriptional gene silencing(PTGS). In this review we will describe in detail the canonical RNAi pathways for PTGS and TGS, the relationship of TGS with other silencing mechanisms and will discuss a variety of approaches developed to suppress HIV-1 via manipulation of RNAi. We will briefly compare RNAi strategies against other approaches developed to target the virus, highlighting their potential to overcome the major obstacle to finding a cure, which is the specific targeting of the HIV-1 reservoir within latently infected cells.展开更多
Objective-To investigate the effects of heat shock transcription factor 1) gene on the constitutivety expressed αB-CrystaUin (aBC) in mice myocardium. Methods-The expression levels of constitutive aBC in HSF1 knockou...Objective-To investigate the effects of heat shock transcription factor 1) gene on the constitutivety expressed αB-CrystaUin (aBC) in mice myocardium. Methods-The expression levels of constitutive aBC in HSF1 knockout (hsf1 - /- ) and HSFl wild type (As/1 + /+) mice myocardium were evaluated by western blot and immunohistochemistry. Results : The αBC levels in hsfl -/- and hsfl +/+ were 68. 42±4. 16, 100. 00±7. 58, respectively (P<0. 05, cytoso-lic fraction) , and 20. 53±1. 01, 37. 55±1. 91, respectively (P<0. 05, pellet fraction). The aBC signals decreased significantly in hsfl -/- myocardium when compared with those in hsfl +/+ myocardium stained with fluorescence immunohistochemistry. Conclusion-HSF1 is an important, but not the only factor, which mediates the constitutively expressed aBC.展开更多
文摘The human RNA methyltransferase like i gene (RNMTL1) is one of thirteen newly discovered geneswithin a 116 Kb segment of the chromosome 17p13.3 that suffers from a high frequent loss of heterozygosityin human hepatocellular carcinoma in China[1-5]. To understand the molecular mechanisms underlyingtranscription control of the RNMTL1 gene in human cancers, we decline using of the conventional approachwhere the cis-elements bound by the known transcription factors are primary targets, and carried out thesystematic analyses to dissect the promoter structure and identify/characterize the key cis-elements thatare responsible for its strong expression in cell. The molecular approaches applied included 1, the primerextension for mapping of the transcription starts; 2, the transient transfection/reporter assays on a largenumber of deletion and site-specific mutants of the promoter segment for defining the minimal promoterand the crucial elements within; and 3, the electrophoresis mobility shift assay with specific antibodies forreconfirming the nature of the transcription factors and their cognate cis-elements. We have shown that theinteraction of an ATF/CREB element (-38 to -31) and its cognate transcription factors play a predominantrole in the promoter activity of the RNMTL1 gene. The secondary DNA structures of the ATF/CREBelement play a more vital role in the protein-DNA interaction. Finally, we reported a novel mechanismunderlying the YY1 mediated transcription repression, namely, the ATF/CREB dependent transcription-repression by YY1 is executed in absence of its own sequence-specific binding.
基金grants to Jing De Zhu from the Shanghai Science Foundation (04DZ14006 , 05DZ19318) the National Science Foundation (30450001, 30570850 , 10574134) the National Research Program for Basic Research of China (2004CB518804 , 2002CB713700).
文摘The hepatocellular carcinoma suppressor 1 (HCCS1) gene was identified by both positional cloning from a predominant region of loss of heterozygosity (17p 13.3) in liver cancer and by functional screening for genes affecting cell proliferation in large-scale transfection assays. Its overexpression results in inhibition of cell proliferation in cell culture and tumor growth in nude mice. To understand its transcription regulation, the promoter architecture has been dissected in detail. The major start of transcription was mapped by primer extension to a C residue, 177 nucleotides upstream of the ATG codon. By assessing the promoter activity of a set of linker-scanning mutants of the minimal promoter (-60 to +148 region) in a transient transfection assay, we found that the +1 to + 40 region is critical to HCCS1 gene transcription, containing binding sites for transcription factors NF-kB (-21 to +7 and +40 to +26), p53 (+29 to +9) and ETS (+4 to +20 and +23 to +39). Biochemical and molecular analyses revealed that the ETS transcription factors ETS-2 and Elf-1 bind to the two ETS sites in situ and contribute significantly to the transcriptionally active state of the HCCS1 gene, while NF-kB, p53 and two other members of the ETS family (ETS-1 and NERF2) appear to play little role. Our observations provide insight into the mechanistic aspects of HCCS1 transcription regulation.
基金This work is supported by the 973 projects of China (G1998051004) to Jingde Zhu and (G199805l200) to Dafang Wan, respectively.Thanks are due to Hongyu Zhang and other mem-bers in Jingde Zhu's lab for assistance and helps onnumerous occasions.
文摘The human RNA methyltransferase like 1 gene (RNMTL1) is one of thirteen newly discovered genes within a 116 Kb segment of the chromosome 17pl3.3 that suffers from a high frequent loss of heterozygosity in human hepatocellular carcinoma in China[1-5]. To understand the molecular mechanisms underlying transcription control of the RNMTL1 gene in human cancers, we decline using of the conventional approach where the cis-elements bound by the known transcription factors are primary targets, and carried out the systematic analyses to dissect the promoter structure and identify/characterize the key cis-elements that are responsible for its strong expression in cell. The molecular approaches applied included 1, the primer extension for mapping of the transcription starts; 2, the transient transfection/reporter assays on a large number of deletion and site-specific mutants of the promoter segment for defining the minimal promoter and the crucial elements within; and 3, the electrophoresis mobility shift assay with specific antibodies for reconfirming the nature of the transcription factors and their cognate cis-elements. We have shown that the interaction of an ATF/CREB element (-38 to -31) and its cognate transcription factors play a predominant role in the promoter activity of the RNMTL1 gene. The secondary DNA structures of the ATF/CREB element play a more vital role in the protein-DNA interaction. Finally, we reported a novel mechanism underlying the YY1 mediated transcription repression, namely, the ATF/CREB dependent transcription-repression by YY1 is executed in absence of its own sequence-specific binding.
基金This work was supported by the National Natural Science Foundation of China (No.81370263 and No.81500348).
文摘Poly(ADP-ribose) polymerase 1 (PARP1) plays important roles in the regulation of transcription factors. Mounting evidence has shown that inhibition of PARP1 influences the expression of genes associated with inflammatory response. Interferon regulatory factor 1 (IRF1) is a critical transcription factor for the development of both the innate and adaptive immune responses against infections. However, the molecular mechanism through which PARP1 mediates the effects has not been clearly demonstrated. Jurkat cells were exposed to dexamethasone (Dex) or PARP1 inhibitor PJ34. The expression levels of IL-12, LMP2, OAS1 and PKR were detected using real-time RT-PCR. The interactions between PARP1 and IRF1 were examined by coimmunoprecipitation (co-IP) assays. We further explored the mechanism of PARP1 suppressing IRF1 by assessing the activities of interferon stimulated response element (ISRE). The mRNA expression of IL-12, LMP2, OAS1 and PKR was obviously suppressed by Dex in Jurkat cells, which could be rescued by PJ34 treatment. Luciferase study revealed that poly(ADP-ribosyl)- ation suppressed IRF1-mediated transcription through preventing the binding of IRF1 to ISREs. PARP1 inhibited IRF1-mediated transcription in Jurkat cells by preventing IRF1 binding to ISREs in the promoters of target genes. It is suggested that PARP1 is a crucial regulator of IRF1-mediated immune response. This study provides experimental evidence for the possible application of PARP1 inhibitors in the treatment of IRF1-related immune anergy.
基金supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Number 5R01AR037399the UCLA Vector Core (Emmanuelle Faure and Kip Hermann) for vector and viral preparations supported by JCCC/P30 CA016042 and CURE/P30 DK41301
文摘Heterogeneous nuclear ribonucleoprotein (hnRNP) C plays a key role in RNA processing but also exerts a dominant negative effect on responses to 1,25-dihydroxyvitamin D (1,25(OH)2D) by functioning as a vitamin D response element-binding protein (VDRE-BP). hnRNPC acts a tetramer of hnRNPC1 (huC1) and hnRNPC2 (huC2), and organization of these subunits is critical to in vivo nucleic acid-binding. Overexpression of either huC1 or huC2 in human osteoblasts is sufficient to confer VDRE-BP suppression of 1,25(OH)2D-mediated transcription. However, huC1 or huC2 alone did not suppress 1,25(OH)2D-induced transcription in mouse osteoblastic cells. By contrast, overexpression of huC1 and huC2 in combination or transfection with a bone-specific polycistronic vector using a "self-cleaving" 2A peptide to co-express huC1/C2 suppressed 1,25D-mediated induction of osteoblast target gene expression. Structural diversity of hnRNPC between human/NWPs and mouse/rat/rabbit/dog was investigated by analysis of sequence variations within the hnRNP CLZ domain. The predicted loss of distal helical function in hnRNPC from lower species provides an explanation for the altered interaction between huC1/C2 and their mouse counterparts. These data provide new evidence of a role for hnRNPC1/C2 in 1,25(OH)2D-driven gene expression, and further suggest that species-specific tetramerization is a crucial determinant of its actions as a regulator of VDR-directed transactivation.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20141498)a grant from Jiangsu Jiankang Vocational University(JKC201505)
文摘Expression of P-selectin in injured or activated endothelia cells serves as a permissive step towards leukocyte recruitment and perpetuation of inflammation in the pathogenesis of atherosclerosis.P-selectin can be induced by pro-inflammatory stimuli via the transcription factor NF-κB,but the epigenetic mechanisms remain incompletely understood.Previously we reported that myocardin-related transcription factor A(MRTF-A)mediates the transactivation of a slew of adhesion molecules by oxidized low-density lipoprotein(oxLDL),likely through a crosstalk with brahma-related gene 1(BRGl),a chromatin remodeling protein.Here,we show that MRTF-A was both sufficient and necessary for the transactivation of P-selectin gene in endothelial cells treated with TNF-α.Depletion of MRTF-A using small interfering RNA(siRNA)abrogated the binding of BRGl on the P-selectin promoter.Overexpression of BRG1 up-regulated the activity of P-selectin promoter activity while BRGl knockdown attenuated P-selectin expression.Finally,BRGl silencing suppressed the accumulation of acetylated histone H3 and methylated histone H3K4,and altered the binding of NF-κB on the P-selectin promoter.Therefore,our data demonstrate an essential role for MRTF-A and BRGl in P-selectin transactivation in endothelial cells.
文摘Developing transgenics that express high levels of Cry1Ac protein, and at the same time, are phenotypically normal, has not been an easy task to achieve. It has been routinely observed that most of the transgenic plants that survive, show no or extremely low levels of Cry1Ac protein. However, all of these plants do express the selectable marker, nptII gene. In the present study, we record an interesting observation of how one of the genes (cry1Ac) on a single T-DNA fragment is selectively silenced, keeping the expression of the other gene (nptII) intact. Further, this silenced state is inherited.
文摘Objective and Methods: Excessive accumulation of collagen typeⅠ and type Ⅲ causes the formation of keloids and hypertrophic scars. To understand the mechanism by which antisense oligodeoxynucleotide (Oligo) acts on in vitro transcrption α1 (I) collagen gene, isotopes (α-32pGTP) was incorporated into 2 SP6 in vitro transcription systems. Results and Conclu- sion: Oligo 2 (at the transcription start region) could effectively inhibit in vitro transcription of pGEM3-Col13 and the control (random oligodeoxynucleotides) showed no inhibition. However, oligo 1 (at the transcription start region) obviously inhibited the in vitro transcription of pGEM3-Col14, while Oligo 2, which targeted at the down stream region (about 200 bp) of the promoter showed no significant inhibition effect.
文摘AIM: To investigate the expression of SNC73, a transcript of the immunoglobulin α-1 gene (IgA1-H chain), in human epitheliα-derived tumor cells. METHODS: Total RNAs and cell lysates were prepared from five different human epithelial cell lines derived from lung, stomach, liver, skin, and breast, respectively. RT-PCR and immunoblot analysis of these five cell lines were done. Both RT-PCR and immunochemistry were used to detect the expression of SNC73 in these cell lines. We also examined the expression of SNC73 in normal epithelial cells of colon mucosa by in situ hybridization. RT-PCR and immunoblot analysis were used to determine whether the recombination activating gene1/2 (RAG1 and RAG2) is present. The expression of three immunoglobulin transcription factors, EBF, E2A and Pax5, and the heavy chain of IgA1 and two types of light chains of immunoglobulin (κ and λ) in the aforementioned cell lines were analyzed by RT-PCR and immunochemistry, respectively. All the RT-PCR products were analyzed by sequencing. RESULTS: The results of RT-PCR and immunochemistry showed that both mRNA and protein of SNC73 were expressed in five human epitheliα-derived cancer cell lines. These data were further confirmed in the normal epithelial cells of colon mucosa by in situ hybridization. Also, the heavy chain of IgA1 and κ light chain were detected in these cells, but no λ light chain was observed. Both RAG1 and RAG2 were expressed in these human epitheliα-derived cancer cell lines and the sequence was identical to that expressed in pre-B and pre-T cells. In addition to RAG1 and RAG2, the mRNA in one of the immunoglobulin transcription factors, EBF, was also detected in these cell lines, and Pax5 was only expressed in SW480 cells, but no expression of E2A was observed in all the five cell lines. CONCLUSION: Immunoglobulin A1 is originally expressed and V(D)J recombination machine is also present in non-lymphoid cells, suggesting that V(D)J recombination machine mediates the assembly of immunoglobulin A1 in non-lymphoid cells as in prelymphocytes.
基金supported by grants from the National Key Research&Development Plan,China (Grant Nos.2021YFD1200201,2022YFD1200502)National Natural Science Foundation of China(31972426,31991182)+3 种基金Key Project of Hubei Hongshan Laboratory(Grant No.2021hszd007)Wuhan Major Project of Key Technologies in Biological Breeding (Grant No.2022021302024852)Fundamental Research Funds for the Central Universities,China (Grant No.2662022YLPY001)International Cooperation Promotion Plan of Shihezi University (Grant No.GJHZ202104)。
文摘High temperature stress is one of the major environmental factors that affect the growth and development of plants. Although WRKY transcription factors play a critical role in stress responses, there are few studies on the regulation of heat stress by WRKY transcription factors,especially in tomato. Here, we identified a group I WRKY transcription factor, SlWRKY3, involved in thermotolerance in tomato. First, SlWRKY3 was induced and upregulated under heat stress. Accordingly, overexpression of SlWRKY3 led to an increase, whereas knock-out of SlWRKY3 resulted in decreased tolerance to heat stress. Overexpression of SlWRKY3 accumulated less reactive oxygen species(ROS), whereas knock-out of SlWRKY3 accumulated more ROS under heat stress. This indicated that SlWRKY3 positively regulates heat stress in tomato. In addition,SlWRKY3 activated the expression of a range of abiotic stress-responsive genes involved in ROS scavenging, such as a SlGRXS1 gene cluster.Further analysis showed that SlWRKY3 can bind to the promoters of the SlGRXS1 gene cluster and activate their expression. Collectively, these results imply that SlWRKY3 is a positive regulator of thermotolerance through direct binding to the promoters of the SlGRXS1 gene cluster and activating their expression and ROS scavenging.
基金This research was supported by the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province,China(UNPYSCT-2018169)the China Postdoctoral Science Foundation Grant(2018 M630333)+1 种基金the National Key R&D Program of China(2017YFD0101900)the earmarked fund for China Agriculture Research System(CARS-23-A-16).
文摘BRI1-EMS-SUPPRESSOR 1(BES1)transcription factor is closely associated with the brassinosteroid(BR)signaling pathway and plays an important role in plant growth and development.SLB3 is a member of BES1 transcription factor family and its expression was previously shown to increase significantly in tomato seedlings under drought stress.In the present study,we used virus-induced gene silencing(VIGS)technology to downregulate SLB3 expression to reveal the function of the SLB3 gene under drought stress further.The downregulated expression of SLB3 weakened the drought tolerance of the plants appeared earlier wilting and higher accumulation of H2 O2 and O2^–·,decreased superoxide dismutase(SOD)activity,and increased proline(PRO)and malondialdehyde(MDA)contents and peroxidase(POD)activity.Quantitative real-time PCR(qRT-PCR)analysis of BR-related genes revealed that the expression of SlCPD,SlDWARF and BIN2-related genes was significantly upregulated in SLB3-silenced seedlings under drought stress,but that the expression of TCH4-related genes was downregulated.These results showed that silencing the SLB3 gene reduced the drought resistance of tomato plants and had an impact on the BR signaling transduction which may be probably responsible for the variation in drought resistance of the tomato plants.
基金the National Natural Science Foundation of China, No. 30872778/C1704the Natural Science Foundation of Beijing, No. 7072023+1 种基金the Clinical Basic Cooperation Foundation of Capital Medical University, No. 2009jl18the Clinical Basic Cooperation Foundation of Capital Medical University, No.11JL-L03
文摘To examine the expression profiles of oligodendrocyte transcription factors 1 and 2 (Oligl and Olig2) and the interaction between these two proteins, Oligl was transfected into the lateral ventricles of neonatal rats subjected to hypoxia. Immunohistochemistry demonstrated that Olig2 was expressed throughout the nuclei in the brain, and expression increased at 3 days following hypoxia and was higher than levels at 7 days following Ad5-Oligl transfection. Western blot revealed that Oligl and Olig2 expression increased in Oligl-transfected brain cells 3 days after hypoxia, but Oligl and Olig2 expression decreased at 7 days. These results indicate that Oligl overexpression enhances Olig2 expression in brain tissues of hypoxia rats.
基金Supported by the National Natural Science Foundation of China,No.39670298.
文摘AIM: To observe the growth suppression effect of exogenous introduction of early growth response gene-1 (Egr-1 gene) on esophageal carcinoma tissue as well as on esophageal carcinoma cell line Eca109 and to explore the potential application of Egr-1 gene in gene therapy of tumor. METHODS: Eukaryotic expression vector of PCMV-Egr-1 plasmid was introduced into Eca109 cell line which expressed no Egr-1 protein originally with lipofectamine transfection method. The introduction and expression of PCMV-Egr-1 plasmid into Eca109 cell line was confirmed by G418 selection culture, PCR amplification of neogene contained in the vector, Western blot analysis and immunocytochemical analysis. The cell growth curve, soft agar colony formation rate and tumorigenicity in SCID mice were examined to demonstrate the growth suppression effect of exogenous Egr-1 gene on Eca109 cell line. The Egr-1 mRNA and Egr-1 protein were also detected in 50 surgical specimens of esophageal carcinoma by in situ hybridization and immunohistochemistry. RESULTS: Exogenous Egr-1 gene was introduced successfully into Eca109 cell line and expressed Egr-1 protein stably. The transfected Eca109 cell line grew more slowly than control Eca109 as shown by cell growth curves, the soft agar colony formation rate (4.0% vs 6.9%, P 【 0.01) and the average growth rate of tumor in SCID mice (35.5 +/- 7.6 vs 65.8 +/- 7.6, P 【 0.05). The expression level of Egr-1 mRNA and protein significantly increased in dysplastic epithelia adjacent to cancer rather than in cancer tissues (65.8% vs 20.0% by ISH and 57.9% vs 0.01). CONCLUSION: Exogenous Egr-1 gene shows the strong effect of growth inhibition in Eca109 cell line. Egr-1 in the cancer tissue shows down-regulated expression that supports the inhibited function of Egr-1 in cancer growth and suggests Egr-1 may have an important role in gene therapy of esophageal carcinoma.
基金National Natural Science Foundation of China(31661143002,81760507,31571709,31771839,31701123 and 31501034)Yunnan Applied Basic Research Projects(2016FA011,2016FB060 and 2016FB040)+1 种基金the National R&D Infrastructure and Facility development Program of China"Fundamental Science Data Sharing Platform(DKA 201712-02-16)the 13th Five-year informatization Plan of Chinese Academy of Sciences(No.XXH13506)。
文摘The B3 transcription factors(TFs)in plants play vital roles in numerous biological processes.Although B3 genes have been broadly identified in many plants,little is known about their potential functions in mediating seed development and material accumulation.Castor bean(Ricinus communis)is a non-edible oilseed crop considered an ideal model system for seed biology research.Here,we identified a total of 61 B3 genes in the castor bean genome,which can be classified into five subfamilies,including ABI3/VP1,HSI,ARF,RAV and REM.The expression profiles revealed that RcABI3/VP1 subfamily genes are significantly up-regulated in the middle and later stages of seed development,indicating that these genes may be associated with the accumulation of storage oils.Furthermore,through yeast one-hybrid and tobacco transient expression assays,we detected that ABI3/VP1 subfamily member RcLEC2 directly regulates the transcription of RcOleosin2,which encodes an oil-body structural protein.This finding suggests that RcLEC2,as a seed-specific TF,may be involved in the regulation of storage materials accumulation.This study provides novel insights into the potential roles and molecular basis of B3 family proteins in seed development and material accumulation.
基金supported by the National Natural Science Foundation of China,Nos. 31730031 and 32130060the National Major Project of Research and Development,No. 2017YFA0104700the Natural Science Foundation of Jiangsu Province,No. BK20202013 (all to XSG)。
文摘The key regulators and regeneration-associated genes involved in axonal regeneration of neurons after injury have not been clarified.In high-throughput sequencing,various factors influence the final sequencing results,including the number and size of cells,the depth of sequencing,and the method of cell separation.There is still a lack of research on the detailed molecular expression profile during the regeneration of dorsal root ganglion neuron axon.In this study,we performed lase r-capture microdissection coupled with RNA sequencing on dorsal root ganglion neurons at 0,3,6,and 12 hours and 1,3,and 7 days after sciatic nerve crush in rats.We identified three stages after dorsal root ganglion injury:early(3-12 hours),pre-regeneration(1 day),and regeneration(3-7 days).Gene expression patterns and related function enrichment res ults showed that one module of genes was highly related to axonal regeneration.We verified the up-regulation of activating transcription factor 3(Atf3),Kruppel like factor 6(Klf6),AT-rich inte raction domain 5A(Arid5α),CAMP responsive element modulator(Crem),and FOS like 1,AP-1 transcription factor Subunit(Fosl1) in dorsal root ganglion neurons after injury.Suppressing these transcription factors(Crem,Arid5o,Fosl1 and Klf6) reduced axonal regrowth in vitro.As the hub transcription factor,Atf3 showed higher expression and activity at the preregeneration and regeneration stages.G protein-coupled estrogen receptor 1(Gper1),inte rleukin 12a(Il12α),estrogen receptor 1(ESR1),and interleukin 6(IL6) may be upstream factors that trigger the activation of Atf3 during the repair of axon injury in the early stage.Our study presents the detailed molecular expression profile during axonal regeneration of dorsal root ganglion neurons after peripheral nerve injury.These findings may provide reference for the clinical screening of molecular targets for the treatment of peripheral nerve injury.
文摘While human immunodeficiency virus 1(HIV-1) infectionis controlled through continuous, life-long use of a combination of drugs targeting different steps of the virus cycle, HIV-1 is never completely eradicated from the body. Despite decades of research there is still no effective vaccine to prevent HIV-1 infection. Therefore, the possibility of an RNA interference(RNAi)-based cure has become an increasingly explored approach. Endogenous gene expression is controlled at both, transcriptional and post-transcriptional levels by noncoding RNAs, which act through diverse molecular mechanisms including RNAi. RNAi has the potential to control the turning on/off of specific genes through transcriptional gene silencing(TGS), as well as finetuning their expression through post-transcriptional gene silencing(PTGS). In this review we will describe in detail the canonical RNAi pathways for PTGS and TGS, the relationship of TGS with other silencing mechanisms and will discuss a variety of approaches developed to suppress HIV-1 via manipulation of RNAi. We will briefly compare RNAi strategies against other approaches developed to target the virus, highlighting their potential to overcome the major obstacle to finding a cure, which is the specific targeting of the HIV-1 reservoir within latently infected cells.
文摘Objective-To investigate the effects of heat shock transcription factor 1) gene on the constitutivety expressed αB-CrystaUin (aBC) in mice myocardium. Methods-The expression levels of constitutive aBC in HSF1 knockout (hsf1 - /- ) and HSFl wild type (As/1 + /+) mice myocardium were evaluated by western blot and immunohistochemistry. Results : The αBC levels in hsfl -/- and hsfl +/+ were 68. 42±4. 16, 100. 00±7. 58, respectively (P<0. 05, cytoso-lic fraction) , and 20. 53±1. 01, 37. 55±1. 91, respectively (P<0. 05, pellet fraction). The aBC signals decreased significantly in hsfl -/- myocardium when compared with those in hsfl +/+ myocardium stained with fluorescence immunohistochemistry. Conclusion-HSF1 is an important, but not the only factor, which mediates the constitutively expressed aBC.