1998 Fiscal Year Final Research Report Summary
Studies on the mechanism of allorecognition in botryllid ascidians
| Project/Area Number |
08459005
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
広領域
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| Research Institution | University of Tsukuba |
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Principal Investigator |
SAITO Yasunori Univ.of Tsukuba, Inst.of Biol.Sci., Assistant Professor, 生物科学系, 講師 (00196015)
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| Project Period (FY) |
1996 – 1998
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| Keywords | ascidian / botryllid / allorecognition / reiection / immunity / MHC / phylogeny / evolution |
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| Research Abstract |
1. Among several species of botryllid ascidians, the manners of allorecognition of those species are slightly different from each other. This variety of the allorecognition manners is caused by the difference of blood cell types participating in allorejection, and the difference of function in the same type blood cells, as well as allorecognition sites distributed in the colony. 2.
From the comparative study of allorejection reaction among a compound styelid ascidian and some botryllid ascidians, it was cleared that the allorejection in which morula cells mainly participate is the mpst primitive reaction in botryllids. Furthermore, the phylogeny of botryllids obtained from rDNA analysis is almost the same as that speculated from the variety of allorecognition manners.
3. The specific or specifically increasing mRNAs in the blood cells at the allorejection reaction were investigated, and 23 cDNA were gained from this experiment. Six of them were similar to the genes related with immunity of mammals. Furthermore, three of them showed high similarity to the heat shock protein 70 (HSP 70) linked with MHCIII of mammals. Two of these three were the same as the already known proteins in B.schlosseri, HSP 70.1 and HSP 70.2, respectively, but the last one was a new heat shock protein of which gene is about 3 kb in length. The sequence of 900 bases of this gene has been cleared, and that sequence shows 77%similarity to that of HSP 70 linked with MHCIII of mammals. The amino acid sequence of this protein also shows high similarity (83 %) to that of HSP 70 linked with MHCIII of mammals. Now, we are investigating on the role of this protein in the allorejection and distribution in the colony during allorejection.
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