1994 Fiscal Year Final Research Report Summary
Reles of TGF beta-1 induckble novel gence in giowth regulation
| Project/Area Number |
05454572
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Biological pharmacy
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| Research Institution | Showa University |
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Principal Investigator |
NOSE Kiyoshi Showa University School of Pharmaceutical Sciences Proferssor, 薬学部, 教授 (70012747)
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| Co-Investigator(Kenkyū-buntansha) |
SHIBANUMA Motoko Showa University School of Pharmaceutical Sciences Research associate, 薬学部, 助手 (60245876)
ARATA Satoru Showa University School of Pharmaceutical Sciences Research associate, 薬学部, 助手 (20159502)
MASHIMO Junichi Showa University School of Pharmaceutical Sciences Research associate, 薬学部, 助手 (60054045)
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| Project Period (FY) |
1993 – 1994
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| Keywords | TGF-beta / Senescence / Zn-finger / gene expression |
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| Research Abstract |
Six cDNA clones were isolated as TGF beta1-inducible genes, and functions of two of them (TSC-36, HIC-5) in growth regulation were examined. Expression of TSC-36 was dramatically induced by TGF beta1 and was reduced in v-ras-transformed cells. TSC-36 was found to encode a protein with 36kDa that is secreted into culture medium. Partially purified TSC-36 protein was added into culture medium of mouse fibroblastic cells, but no effect on cell growth was observed. It, however, shows striking similarity to follistatin that is regulated by FSH,and TSC-36 is supposed to be involved in development.
An another clone, HIC-5, was found to encode a nuclear protein with molecular mass of 55 kDa. It contains 7 putative Zn-finger motifs some of which have significant homology to the LIM motif. Using antibody raised against synthetic peptides, it was shown that HIC-5 protein localizes in nuclei and can bind to double stranded DNA.Eukaryotic expression vectors for HIC-5 cDNA were constructed using CMV promoter, and were introduced into human immortalized fibroblasts. The transformants were selected by resistance to G418, and several clones expressing low or high levels of HIC-5 mRNA were isolated. Cells expressing high levels of HIC-5 mRNA became a senescence-like form after passage of clones for 20 to 40 population doublings, and ceased to divide. Expression of extracellular matrix proteins and WAF-1 that is known to be increased in aged fibroblasts was elevated in HIC-5 high expression clones. These results suggest that HIC-5 regulates multiple gene expression and that it induces senescence in immortalized fibroblasts. The trancription of extracellular matrix protein genes was not affected by HIC-5, and hence higher order structure of chromatin seems to be a target of HIC-5 protein.
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