权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Origin and Evolution of MHC

MHC的起源和进化

基本信息

批准号：
07044288
负责人：
NONAKA Masaru
金额：
$ 4.29万
依托单位：
Nagoya City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07044288/
关键词：
MHC complement lower vertebrate evolution 連鎖プロテアソーム

项目摘要

The major histocompatibility complex (MHC), best described in mammals, is a large genetic region encompassing more than 4000kb in human. The Xenopus MHC is known to be remarkably similar to its mammalian counterparts. Class Ia, class IIa, class IIb, complement Bf, C4, heat shock protein 70 (HSP70), the proteasome subunit LMP7 genes all map to the Xenopus MHC,demonstrating that the overall organization and the basic genetic components were present at the time of the divergence of amphibians and mammals 300-350 million years ago. Furthermore, I detected a recombinant in previous family studies that demonstrated that the Xenopus LMP7/class II genes could be separated from the Bf/HSP70/class I suggesting that even the gene order is similar to that of mammals.I found a second recombinant in another family where class II/LMP7/C4/class I genes cosegregate away from the Bf/HSP70 loci. Barring a double crossover, this recombinant implies that the class Ia gene is physically associated with the Xenopus class II region. This result is gratifying since the class I processing genes are found in the class II region in all species so far examined, and because class I and class II genes clearly have been derived from a common ancestor. An association with class II/III regions also may explain the remarkably deep and stable MHC-linked class I lineage in Xenopus ; I predict that the translocation of class I to the distal end of the MHC later in vertebrate evolution bestowed on class I genes the capacity to duplicate and diverge, hence giving rise to the celebrated class I plasticity found in mammals.

主要组织相容性复合体（MHC）是一个在哺乳动物中描述最多的基因，在人类中超过4000 kb。已知爪蟾MHC与其哺乳动物对应物非常相似。Ia类、IIa类、IIb类、补体Bf、C4、热休克蛋白70（HSP 70）、蛋白酶体亚基LMP 7基因都映射到非洲爪蟾MHC，表明整体组织和基本遗传组分存在于3亿至3.5亿年前两栖动物和哺乳动物分化的时候。此外，我在以前的家族研究中发现了一个重组体，表明非洲爪蟾LMP 7/II类基因可以从Bf/HSP 70/I类基因中分离出来，这表明甚至基因顺序与哺乳动物相似。除非双交换，这种重组意味着Ia类基因与爪蟾II类区域物理相关。这个结果是令人满意的，因为I类加工基因被发现在II类区域中的所有物种到目前为止检查，因为I类和II类基因显然已经来自一个共同的祖先。与II/III类区域的关联也可以解释显着深和稳定的MHC连锁的I类谱系爪蟾，我预测，易位I类的远端的MHC后来在脊椎动物进化赋予I类基因的能力复制和分歧，从而引起了著名的I类可塑性在哺乳动物中发现。