|Budget Amount *help
¥1,600,000 (Direct Cost : ¥1,600,000)
Fiscal Year 1998 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1997 : ¥800,000 (Direct Cost : ¥800,000)
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.
3. ウスイタボヤ(Botryllus schlosseri)において,allo群体の感作を受けた血球に,特異的に,または,より多く発現しているmRNAのcDNA Libraryをサブトラクション法を用いて作成し,23種の有効なcDNAを得,これら遺伝子の組織内での発現を調べるためにin situハイブリダイゼーション法を確立した.そして,得られた23の遺伝子のうち,ほ乳類の免疫関連遺伝子に類似性を持つものが6つあることが明らかとなった.これら免疫関連遺伝子のcDNAの中から,ほ乳類のMHCIIIにリンクしたヒートショックタンパク質HSP70に非常に高い類似性を持つ遺伝子で,既知のB.schlosseri HSP70.1とHSP70.2の遺伝子とは異なる遺伝子を発見した.これまでに推定全長約3kbのうち900base程が判明し、この配列はほ乳類のMHCIII関連HSP70に塩基配列で77%,アミノ酸配列で83%の相同性があった.このHSP70類似タンパク質の拒絶反応時における組織内での分布やその役割については,今後,in situハイブリダイゼーションなどで詳細に調べたい. Less