Study on the Gene Transcription Level of Hippocampus NGF in C_(57) Mouse Development

β-Nerve growth factor (β NGF) mRNA levels in hippocampa from C57BL/6J mice of different ages were compared by semi-quantitative RT-PCR method, taking β-actin gene as an internal control. The levels of 6-and 12-month-old C57 mice were much lower compared with that of the l-month-old mouse. However, there was no significant difference between these two groups. This result suggests that gene transcription level of hippocampus β NGF in a C57, mouse descends evidently as it grows up. Base T at Site 294 of β NGF cDNA was substituted by C in the C57, mouse, as revealed by DNA sequencing for the first time. Nevertheless, this polymorphism of nucleotide did not make any difference in amino acid composition.

Effects of p75 neurotrophin receptor knockout on axonal regeneration in a mouse model of facial nerve injury

BACKGROUND： Previous studies have shown that p75 neurotrophin receptor plays an important role in peripheral nerve injury. However, the role of p75 neurotrophin receptor in the regeneration of peripheral nerves remains poorly understood. OBJECTIVE： To study the effect of p75 neurotrophin receptor on facial nerve regeneration. DESIGN, TIME AND SETTING： A randomized controlled experiment was performed in the Regeneration Laboratory of Flinders University, Australia and the Biomedical Laboratory of Dentistry School, Shandong University from March 2005 to February 2006. MATERIALS： Cholera toxin B subunit, fast blue, and biotin rabbit-anti goat IgG were provided by Sigma, USA; goat-anti choleratoxin B subunit ant/body was provided by List Biologicals, USA. METHODS： In p75 neurotrophin receptor knockout and wild type 129/sv mice, the facial nerves on one side were crushed. At days 2 and 4 following injury, regenerating motor neurons in the facial nuclei were labeled by fast blue, and the regenerating axon was labeled by the anterograde tracer choleratoxin B subunit. MAIN OUTCOME MEASURES： Axonal regenerative velocity and number were detected by immunohistochemical staining of choleratoxin B subunit, growth-associated protein, protein gene product 9.5, and calcitonin-gene-related peptide; survival of motor neurons in the facial nuclei was detected by retrograde fast blue. RESULTS： Axonal growth in the facial nerve of p75 neurotrophin receptor knockout mice was significantly less than in wild type mice. At day 7 after injury, the number of regenerating motor neurons in p75 neurotrophin receptor knockout mice remained significantly less than in wild type mice （P 〈 0.05）. The number of positively stained fibers for growth-associated protein-43, protein gene product 9.5, and calcitonin-gene-related peptide in p75 neurotrophin receptor knockout mice was significantly less than in wild type mice （P 〈 0.01）. CONCLUSION： p75 neurotrophin receptor promoted axonal regeneration and enhanced the survival rate of motor neurons following facial nerve injury.

High-throughput screening of mouse gene knockouts identifies established and novel skeletal phenotypes

Screening gene function in vivo is a powerful approach to discover novel drug targets. We present high-throughput screening （HTS） data for 3 762 distinct global gene knockout （KO） mouse lines with viable adult homozygous mice generated using either gene-trap or homologous recombination technologies. Bone mass was determined from DEXA scans of male and female mice at 14 weeks of age and by microCT analyses of bones from male mice at 16 weeks of age. Wild-type （WT） cagemates/littermates were examined for each gene KO. Lethality was observed in an additional 850 KO lines. Since primary HTS are susceptible to false positive findings, additional cohorts of mice from KO lines with intriguing HTS bone data were examined. Aging, ovariectomy, histomorphometry and bone strength studies were performed and possible non-skeletal phenotypes were explored. Together, these screens identified multiple genes affecting bone mass： 23 previously reported genes （Calcr, Cebpb, Crtap, Dcstamp, Dkkl, Duoxa2, Enppl, Fgf23, Kissl/Kisslr, Kl （Klotho）, Lrp5, Mstn, Neol, Npr2, Ostml, Postn, Sfrp4, S1c30a5, Sic39a13, Sost, Sumf1, Src, Wnt10b）, five novel genes extensively characterized （Cldn18, Fam20c, Lrrkl, Sgpll, Wnt16）, five novel genes with preliminary characterization （Agpat2, RassfS, Slc10a7, Stc26a7, Slc30a10） and three novel undisclosed genes coding for potential osteoporosis drug targets.

Construction of Prokaryotic Expression Vector of Mouse Nanog Gene and Its Expression

The aim of this study is to construct a prokaryotic expression vector of mouse Nanog gene and to express it in E. coli. A pair of primers was designed according to digestion sites in plasmid pGEX-KG and the Nanog gene sequence published by GenBank. The DNA fragment of 918 bp was amplified by polymerase chain reaction （PCR） from the pNA992 recombinant plasmid with Nanog gene, then cloned into pGEX-KG and transformed into the host E. coli strain TG Ⅰ. The sequence of the fragment was matched with the original sequence of pNA992. It indicated that fusion expression vector, pGEX-KG- Nanog, was constructed successfully. The pGEX-KG-Nanog plasmid was extracted from E. coli strain TG Ⅰ and was transformed into BL21（DE3） for expression. After induction by isopropyl-β-D-thiogalactoside （IPTG） at 37℃, the expression product of Nanog gene was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE）, and the expression condition was optimized. Nanog fusion protein was successfully expressed in the form of inclusion bodies. The molecular weight of the inclusion body was 63 kDa. Meanwhile, the optimum condition for the expression of Nanog fusion protein was induced with 0.8 mmol L^-1 IPTG for 5 h. The mouse Nanog gene was successfully expressed in E. coli, which laid a foundation for the purification of Nanog protein and for the preparation of polyclonal antibody.

Expression and Chromosomal Mapping of Mouse Gpx2 Gene Encoding the Gastrointestinal Form of Glutathione Peroxidase, GPX-GI

GPX-GI is a cytosolic tetrameric Se-dependent glutathione peroxidase, similar in properties to GPX-1. Unlike the almost ubiquitous GPX-1, GPX-GI is mainly expressed in the epithelium of gastrointestinal tract. GPX-GI contributes to at least fifty percent of GPX activity in rodent small intestmal epithelium. The total GPX activity consists of at least 70% of selenium-dependent GPX activity in this compartment.By analyzing a panel of mouse mterspecies DNA from the Jackson Laboratory's backcross resource,we mapped Gpx2 gene to mouse chromosome 12 between D12Mit4 and D12Mit5, near the Ccs1 locus which contains a colon cancer susceptibility gene. A pseudogene, Gpx2-ps is mapped to mouse chromosome 7.Comparison of Gpx2 gene expression in three pairs of C57BL/6Ha and ICR/Ha mice which are respectively resistant and sensitive to dimethylhydrazine-induced colon cancer, we found a higher Gpx2 mRNA level in C57BL/6Ha colon than ICR/Ha colon. Interestingly, a lower level of GPX activity is found in the resistant strain of mice. Because GPX-1 has three times higher specific activity than GPX GI, our data suggest that the decreased GPX activity may result from a higher level of Gpx2 gene expression in those cells co-express GPx1 gene

FT Ⅰ, a novel positive myeloid-lineage-speciflc transcription regulatory element within the mouse myeloperoxidase gene enhancer, En 1

FT Ⅰ (AAAAGGGGAAGCAGAG), a poly purine ele-ment within the myloid-lineage specific enhancer (En 1) of the mouse myeloperoxidase gene [1, 2] has been fur-ther characterised. 1, FT Ⅰ functions as a myeloid-lineage specific transcription regulatory element; 2, WEHI 3BD+ cells have higher binding activity to FT Ⅰ and express the proteins which could form the unique DNA-protein com-plex(es) of FT Ⅰ;. 3, The essential sequence for the specific DNA-protein interactions of FT Ⅰ is AAAAGGGGAAGC; 4, South-western analysis in conjunction with the compe-tition assay of the proteins binding to FT Ⅰ, has revealed a 28 kd protein in WEHI 3BD+ cells that displays the properties of the putative transcription factor which acts through FT Ⅰ. These new findings have demonstrated both the functional myeloid-lineage specificity and the novelty of FT Ⅰ.

Effect of RNA Interference Hsp72 Gene Expression on Development of Mouse Preimplantation Embryos

The method of RNAi was used to inhibit the expression of induced heat shock protein 70 （Hsp72） in the 4-cell stage mouse embryos and the embryo development competence was analyzed to identify the functions of Hsp72 on embryonic heat resistance. The results indicated that the inhibition rates of siRNA1 for Hsp72 mRNA and Hsp72 protein were 87.1 and 78.5%, respectively. The blastocysts development rates were 41, 86, and 84% for the siRNA1 group, the LipofectamineTM 2 000 exposed group, and the 37℃ group, respectively, and the hatched blastocysts development rates for the above three groups were 35, 72, and 68%, respectively. The data suggest that the siRNAI has a significant inhibiting effect on Hsp72 gene, and Hsp72 gene silence reduces the blastocysts development rate and hatched blastocysts rate after heat shock during the development of mouse preimplantation embryos.

Pattern of expression of the CREG gene and CREG protein in the mouse embryo

Background The cellular repressor of ElA-stimulated genes(CREG) is a secreted glycoprotein that inhibits cell proliferation and/or enhances differentiation.CREG is widely expressed in adult tissues such as the brain,heart, lungs,liver,intestines and kidneys in mice.We investigated the level of CREG expression during mouse embryogenesis and its distribution at 18.5 days post coitus(dpc).Methods Immunohistochemical staining with diaminobenzidine,western blotting and reverse transcription-polymerase chain reaction were used.Results CREG expression was rst detected in mouse embryos at 4.5 dpc.It was expressed at almost all stages up to 18.5 dpc.The level of CREG was found to increase gradually and was highest at 18.5 dpc.Western blotting showed that the CREG protein was expressed at higher levels in the brain,heart,intestines and kidneys than in the lungs and liver at 18.5 dpc.In 9.5 dpc embryos,CREG was expressed only in the endothelial cells of blood vessels,after the vascular lumen had formed.With advanced differentiation, vascular smooth muscle cells developed in the embryonic vascular structures;the expression of smooth muscle a-actin protein and CREG were positive and increased gradually in 10.5 dpc embryonic vessels.CREG expression in the embryonic blood vessels peaked at 15.5 dpc and was reduced slightly at 18.5 dpc.Conclusions These results indicate that CREG is expressed during mouse embryogenesis and might participate in the differentiation of these organs during embryogenesis.

Glucose Metabolism During Kunming Mouse Preimplantation Development:Analysis of Gene Transcription in Embryos in Vivo

In order to investigate glucose metabolism pathways and their changes in Kunming mouse preimplantation 1-,2-,4-,8-cell,and morula embryos,the mRNA level for the genes involved in glucose metabolism was tested by nested RT-PCR on embryos at different development stages in vivo.These genes were glucose 6-phosphate dehydrogenase(G6PDH),phospho-fructokinase(PFK),and phosphoglucomutase(PGM),representing pentose phosphate pathway(PPP),glycolysis,and glycogensis and glycogenolysis respectively.Three sets of inner and outer primers were designed and synthesized based on cDNA sequences of G6PDH,PFK and PGM.RT-PCR results revealed that G6PDH gene transcription was found in Kunming mouse 1-8 cell embryos,and not in morula embryos;it indicated that 1-8 cell embryos may metabolize glucose by pentose phosphate pathway,but morula embryos can not do so.PFK gene transcription was found in 1-8 cell and morula embryos;it is probable that there exists glycolysis in those embryos.PGM gene transcription was not found in 1-8 cell and morula embryos,so glycogenesis and glycogenolysis in these embryos were not present.

Hepatocellular carcinoma mouse models:Hepatitis B virusassociatedhepatocarcinogenesis and haploinsufficienttumor suppressor genes

The multifactorial and multistage pathogenesis of hepatocellular carcinoma(HCC)has fascinated a wide spectrum of scientists for decades.While a number of major risk factors have been identified,their mechanistic roles in hepatocarcinogenesis still need to be elucidated.Many tumor suppressor genes(TSGs)have been identified as being involved in HCC.These TSGs can be classified into two groups depending on the situation with respect to allelic mutation/loss in the tumors:the recessive TSGs with two required mutated alleles and the haploinsufficient TSGs with one required mutated allele.Hepatitis B virus(HBV)is one of the most important risk factors associated with HCC.Although mice cannot be infected with HBV due to the narrow host range of HBV and the lack of a proper receptor,one advantage of mouse models for HBV/HCC research is the numerous and powerfulgenetic tools that help investigate the phenotypic effects of viral proteins and allow the dissection of the dose-dependent action of TSGs.Here,we mainly focus on the application of mouse models in relation to HBV-associated HCC and on TSGs that act either in a recessive or in a haploinsufficient manner.Discoveries obtained using mouse models will have a great impact on HCC translational medicine.

Mouse models for the discovery of colorectal cancer drivergenes

Colorectal cancer(CRC) constitutes a major publichealth problem as the third most commonly diagnosed and third most lethal malignancy worldwide. The prevalence and the physical accessibility to colorectal tumors have made CRC an ideal model for the study of tumor genetics. Early research efforts using patient derived CRC samples led to the discovery of several highly penetrant mutations(e.g., APC, KRAS, MMR genes) in both hereditary and sporadic CRC tumors. This knowledge has enabled researchers to develop genetically engineered and chemically induced tumor models of CRC, both of which have had a substantial impact on our understanding of the molecular basis of CRC. Despite these advances, the morbidity and mortality of CRC remains a cause for concern and highlight the need to uncover novel genetic drivers of CRC. This review focuses on mouse models of CRC with particular emphasis on a newly developed cancer gene discovery tool, the Sleeping Beauty transposon-based mutagenesis model of CRC.

The expression of Usp26 gene in mouse testis and brain

Deubiquitinating enzymes （DUBs） play an important role in ubiquitin-dependent processes as negative regulators of protein ubiquitination. Ubiquitin-specific protease 26 （USP26） is a member of this family. The expression of Usp26 in mammalian testis and in other tissues has yet to be fully elucidated. To study the expression of Usp26 mRNA and protein in various murine tissues, reverse transcription （RT）-PCR and immunohistochemistry analyses were carried out. The RT-PCR analysis showed that the Usp26 transcript was expressed in all of the tested tissues. USP26 protein localization was examined by immunohistochemistry, and it was shown that USP26 was not detectable at 20 days postpartum, with the expression restricted to the cytoplasm of condensing spermatids （steps 9-16）, Leydig cells and nerve fibers in the brain. In addition, the USP26 protein was detected at moderate levels in myocardial ceils, the corpus of epidydimis, epithelium of the renal tubules and the seminal gland of postnatal day 35 mice. Its spatial and temporal expression pattern suggests that Usp26 may play an important role in development or function of the testis and brain. Further research into these possibilities is in progress.

Gankyrin expression during mouse embryogenesis

Objective: To observe the gene expression of Gankyrin during mouse embryogenesis and reveal the gene biological significance during organs and tissues formation. Methods: The expressions of Gankyrin mRNA in various organs and tissues were detected by in situ hybridization at indicated times during embryogenesis. Results: The expression of Gankyrin mRNA in mouse day 12.5 embryo was mainly in midbrain, interbrain and endbrain; in mouse day 14.5 embryo mainly in midbrain, aorta, liver, gonad, cranium and rib; in mouse day 16.5 embryo mainly in cranium, rib and vertebra; and in mouse day 18.5 embryo mainly in cranium, rib and intestinal mucosa. Conclusion: Gankyrin gene probably participates in the development of the neural tissues (such as midbrain, interbrain and endbrain etc.), aorta, liver and gonad, intestinal mucosa and bone tissues, which may be closely associated with the function of the organs and tissues.

Characterization of 5'-proximal sequence of mouse GABAtransporter gene(GAT-1)

The cDNA molecule encoding the mouse GABA transporter gene (GAT-1) was used as probe for selecting GAT-1 gene from mouse genomic library. A positive clone, harboring the whole open reading frame of the GAT-1 protein and designated as MGABAT-G, was fished out from the library, the 5’ proximal region and nitron 1 were sequenced and analysed, and low homology was found in the above region between GAT-1 genes from mouse and human except some short conserved sequences. The DNA-protein interactions between DNA fragments containing the conserved sequences in the 5’ proximal region and nuclear proteins from different tissues of mouse were studied by means of gel-shift assay, and Southern-Western blot. The results indicate a possible positive-negative regulation mode controlling the expression of the mouse GAT-1 gene.

Study on the Gene Transcription Level of Hippocampus NGF in C57 Mouse Development

β-Nerve growth factor (β NGF) mRNA levels in hippocampa from C57BL/6J mice of different ages were compared by semi-quantitative RT-PCR method, taking β-actin gene as an internal control. The levels of 6-and 12-month-old C57 mice were much lower compared with that of the l-month-old mouse. However, there was no significant difference between these two groups. This result suggests that gene transcription level of hippocampus β NGF in a C57, mouse descends evidently as it grows up. Base T at Site 294 of β NGF cDNA was substituted by C in the C57, mouse, as revealed by DNA sequencing for the first time. Nevertheless, this polymorphism of nucleotide did not make any difference in amino acid composition.

Anti-tumor effects induced by gene vaccines co-expressing truncated human prostate specific membrane antigen gene and mouse 4-1BBL

Objective To investigate the influence of m4-1BBL on anti-tumor effects induced by truncated human prostate specific membrane antigen ( tPSMA ) gene in mice. Methods A eukaryotic expression plasmid encoding tPSMA and m4-1BBL ( pDC316-tPSMA-IRES m4-1BBL) ,pDC316-tPSMA and pDC316 were constructed.

Cloning and Characterization of β-actin Gene in Dunaliella parva

[Objective] The aim was to obtain the full-length cDNA sequence of Dunaliella parva β-actin gene.[Method] Based on the highly conserved amino acid regions of known β-actin,a pair of degenerate primers was synthesized to amplify 533 bp cDNA sequences in Dunaliella parva.Then,the 5＇ genomic DNA and 3＇ cDNA sequences were obtained by Genome walking and 3＇-RACE technology based on the obtained sequence.According to the sequences of the 5＇-termini and 3＇-termini,specific primers were synthesized to obtain the full-length cDNA.[Result] The full-length β-actin cDNA included 1 137 bp open reading frame（ORF）,617 bp of 3＇ noncoding region.Similarity analysis indicated that the highest similarity was found between Dunaliella parva and Dunaliella salina.The Dunaliella parva β-actin also showed wide similarity with other algae.[Conclusion] The full-length cDNA sequence of D.parva was firstly obtained,which was highly conserved.

Construction of pINC-lacZ Retroviral Vector and its Expression in Mouse Embryonic Stem Cells

A retroviral vector pINC-lacZ containing an E coli β-galactosidase(β-gal)gene was constructed and introduced into the MESPU-13 cells by electroporation.Four G418-resistant colonies were obtained from 1×107,electroporated MESPU-13 cells. Histochemical staining for β-gal activity showed that lacZ gene was expressed in at least three of the four colonies.Southern analysis proved that one copy of foreign gene was integrated in the chromosome of one of the transformed lines(MC15).These results showed that the expression of lacZ gene driven by SiCMVIE promoter can be detected in the transformed MESPU-13 cells.

Analysis of Proteotranscriptomics Landscape Reveals Differentially Regulated Pathways in Toxoplasma gondii Infected Mouse Liver

Toxoplasma gondii (T. gondii) an intracellular protozoan parasite, infects mammals including human population world-wide. Upon primary infection, the parasite contributes to mild flu like symptoms in immune competent host, but life threatening complication is seen in immune compromised patients and in pregnant women. Understanding the host-parasite interaction is critical for understanding the pathogenesis and biology parasite reactivation in the host. In this study, we used proteotrasncriptomics analyses by integrating the transcriptomics and proteomics data of T. gondii infected mouse liver to uncover the effector molecules responsible for disease pathogenesis that can be used as candidate markers for diagnosis and drug target. With this aim, we systematically integrated transcriptomicand proteomic data, representing the parasite infected mouse liver. Out of 2758 differentially expressed genes (DEGs) and 301 differentially expressed proteins (DEPs), 159 overlapping genes were identified. Among them, 86 genes were upregulated and 72 were downregulated in their respective mRNA and protein levels in the infected condition. Gene Ontology (GO) analysis revealed that the upregulated genes were mostly associated with immune system processes whereas the downregulated genes were involved in oxidation-reduction process and metabolism of lipid, and fatty acids. Protein-protein interaction (PPI) network analysis uncovered an interaction-hub including, Psmb8, Psmb9 and Tap1 for upregulated proteins and Cyp1A2, Cyp4A10 and Cyp3A11 for down-regulated proteins. Further studies are needed to validating these effector molecules. These molecules are likely to play a vital role in disease pathogenesis, as well as can be used as potential diagnostic marker and drug target candidates.