1994 Fiscal Year Final Research Report Summary
Analysis of molecular basis for allo-recognition
| Project/Area Number |
05454212
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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 |
Immunology
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| Research Institution | Institute for Comprehensive Medical Science, Fujita Health Univ. |
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Principal Investigator |
KUROSAWA Yoshikazu Inst. for Comprehensive Med. Sci. Fujita Health Univ. Professor, 総医研, 教授 (10109259)
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| Co-Investigator(Kenkyū-buntansha) |
OKAMURA Kazuhiko Fujita Health Univ. College Assisitant, 助手 (60132255)
HASHIMOTO Keiichiro Inst. for Comprehensive Med. Sci. Fujita Health Univ. Associate Prof., 総医研, 講師 (70192268)
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| Project Period (FY) |
1993 – 1994
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| Keywords | MHC class I genes / cyprinid fish / elasmoblanch / human / MR1 gene / evolution |
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| Research Abstract |
(1) We have analyzed three genomic genes and three cDNA clones that encode MHC class I molecules in cyprinid fishes, namely the ginbuna crucian carp and the carp. Since these six genes have been isolated by the homology of the sequence of alpha3 domain, the amino acid sequences of the alpha3 domains showed 70-90% identities among them. Based on the extent of homology, they can be classified into four classes. Each of the class consists of several to more than ten members. Thus, this group of MHC genes is composed of 30 to 40 members. Since there are several groups, there are at least 100 genes that encode MHC class I genes in cyprinid fish.
(2) We have characterized the genes encoding MHC class I-like molecules in elasmoblanchs (shark).One of the genes encodes a typical class I molecule that consists of three extra-cellular domains. The amino acid sequence of alpha1 and alpha2 domains showed 40 to 50 % identities to those of human HLA and mouse H2. This result idicated that a typical MHC class I gene exists in elasmoblanchs and that the sequences of alpha1 and alpha2 domains have been kept at a high degree during evolution from elasmobranch to mammalian.
(3) We have isolated a new gene that encodes MHC class I-like molecule outside of human HLA.While HLA genes are encoded at human chromosome 6, a newly isolated gene, MR1, is encoded at chromosome 1q25. The amino acid sequence of alpha1 and alpha2 of MR1 showed 40 to 50 % identities to those of HLA and mouse H2, even chicken MHC.Since we have already isolated one more gene, MR2, there should be many other genes that encode MHC class I-like genes to be analyzed in human genome. This suggested that the number of MHC genes and their diversification was much larger than expected before.
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