1993 Fiscal Year Final Research Report Summary
Tissue Specific Function of Basement Membrane and Heterogeneity in Matrix Molecules
| Project/Area Number |
04454564
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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 |
内分泌・代謝学
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| Research Institution | Okayama University Medical School |
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Principal Investigator |
NINOMIYA Yoshifumi Okayama University Medical School, Department of Molecular Biology and Biochemistry, Professor, 医学部, 教授 (70126241)
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| Co-Investigator(Kenkyū-buntansha) |
OOHASHI Toshitaka Okayama University Medical School Department of Molecular Biology and Biochemist, 医学部, 助手 (50194262)
YOSHIOKA Hidekatsu Okayama University Medical School Department of Molecular Biology and Biochemist, 医学部, 助教授 (00222430)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Basement Membrane / Type IV Collagen / Tissue Specificity / Gene Structure / cDNA |
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| Research Abstract |
We isolated overlapping cDNAs encoding the human and rabbit alpha4(IV) collagen chains. Charcterization and sequencing of the clones demonstrated the primary structure of the human and rabbit alpha4(IV) collagen chains. The amino acid sequence of the chain is homologous to that of the alpha2(IV) collagen chain. Chromosomal location of the gene was assigned to chromosome 2q35-37.1 by in situ hybridization. Interestingly, the size of the mRNA coding for the alpha4(IV) collagen chain is significantly larger than the other four mRNAs for type IV collagen chains. Comparison of the sequences for these five alpha(IV) chains revealed that there are two subclasses of the gene ; the genes for alpha1, alpha3, and alpha5 chains and genes for alpha2 and alpha4 chains. By these analyzes we predicted that there was one more alpha(IV) chain that belonged to the genes for the alpha2(IV) and alpha4(IV) chains. Using low stringency conditions we successfully isolated a novel cDNA encoding yet another alpha(IV) collagen chain. We designated his new chain as alpha6(IV) chain. Of interest was that the chromosomal location of the gene was assigned to chromosome Xq22, which is the same location as the gene for alpha5(IV) collagen chain. We furtheer isolated several fragments of the gene coding for the alpha6(IV) chain and also the alpha5(IV) chain at the same time. Precise analysis of the fragment of the genes revealed that the genes were located on the same fragement but aligned onto the opposite directions sharing bidirectional promoter in the center of the genes. Further, there was an alternativepromoter approximately 1000 bases downstream of the authentic promoter for the alpha6(IV) gene.
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