Comparative genomic analysis of the proteasome β5t subunit gene: implications for the origin and evolution of thymoproteasomes.
Comparative genomic analysis of the proteasome β5t subunit gene: implications for the origin and evolution of thymoproteasomes.
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DOI：
10.1007/s00251-011-0558-0
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发表时间：
2012-01
期刊：
影响因子：
3.2
通讯作者：
Kasahara, Masanori
中科院分区：
文献类型：
--
作者：
Sutoh, Yoichi;Kondo, Mizuho;Ohta, Yuko;Ota, Tatsuya;Tomaru, Utano;Flajnik, Martin F.;Kasahara, Masanori
胸腺蛋白酶体是最近发现的一种专门形式的20S蛋白酶体，仅在胸腺皮层表达。尽管胸腺蛋白酶体发挥其功能的确切分子机制仍有待阐明，但越来越多的证据表明，它在T细胞的阳性选择中起着至关重要的作用。在本研究中，我们分析了β5t亚基的进化，β5t亚基是胸腺蛋白酶体中特有的β型催化亚基。编码β5t亚基的基因被命名为PSMB11，在与其他有颌脊椎动物相比差异最大的有颌脊椎动物群体软骨鱼中被发现，但在无颌脊椎动物和无脊椎动物中没有发现。有趣的是，硬骨鱼有两个具有明显功能的PSMB11基因拷贝，分别命名为PSMB11a和PSMB11b，它们编码S1口袋中具有不同氨基酸的β5t亚基。基因组数据库的BLAST搜索表明，鸡、火鸡和斑胸草雀等鸟类失去了PSMB11基因，既没有胸腺蛋白酶体，也没有免疫蛋白酶体。在哺乳动物、爬行动物、两栖动物和硬骨鱼中，PSMB11基因（硬骨鱼中的PSMB11a基因）位于编码标准20S蛋白酶体β5亚基的PSMB5基因旁边，表明PSMB11基因是由进化上更古老的PSMB5基因串联复制而来的。PSMB11中内含子的普遍缺失以及颌骨脊椎动物PSMB5中不寻常的外显子-内含子结构表明，PSMB5在颌骨脊椎动物的共同祖先中丢失内含子并串联复制，PSMB5随后获得两个内含子，而PSMB11则没有内含子。
The thymoproteasome is a recently discovered, specialized form of 20S proteasomes expressed exclusively in the thymic cortex. Although the precise molecular mechanism by which the thymoproteasome exerts its function remains to be elucidated, accumulating evidence indicates that it plays a crucial role in positive selection of T cells. In the present study, we analyzed the evolution of the β5t subunit, a β-type catalytic subunit uniquely present in thymoproteasomes. The gene coding for the β5t subunit, designated PSMB11, was identified in the cartilaginous fish, the most divergent group of jawed vertebrates compared to the other jawed vertebrates, but not in jawless vertebrates or invertebrates. Interestingly, teleost fish have two copies of apparently functional PSMB11 genes, designated PSMB11a and PSMB11b, that encode β5t subunits with distinct amino acids in the S1 pocket. BLAST searches of genome databases suggest that birds such as chickens, turkey, and zebra finch lost the PSMB11 gene, and have neither thymoproteasomes nor immunoproteasomes. In mammals, reptiles, amphibians, and teleost fishes, the PSMB11 gene (the PSMB11a gene in teleost fish) is located next to the PSMB5 gene coding for the β5 subunit of the standard 20S proteasome, indicating that the PSMB11 gene arose by tandem duplication from the evolutionarily more ancient PSMB5 gene. The general absence of introns in PSMB11 and an unusual exon–intron structure of jawed vertebrate PSMB5 suggest that PSMB5 lost introns and duplicated in tandem in a common ancestor of jawed vertebrates, with PSMB5 subsequently gaining two introns and PSMB11 remaining intronless.
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影响因子：
5.4
作者：
Balakrishnan CN;Ekblom R;Völker M;Westerdahl H;Godinez R;Kotkiewicz H;Burt DW;Graves T;Griffin DK;Warren WC;Edwards SV
通讯作者：
Edwards SV
DOI：
10.1038/nrg2487
发表时间：
2009-01
期刊：
Nature reviews. Genetics
影响因子：
--
作者：
通讯作者：
--
DOI：
10.1038/nrg2703
发表时间：
2010-01
期刊：
Nature reviews. Genetics
影响因子：
--
作者：
通讯作者：
--
影响因子：
100.3
作者：
Groettrup, Marcus;Kirk, Christopher J.;Basler, Michael
通讯作者：
Basler, Michael
DOI：
10.1084/jem.187.1.97
发表时间：
1998-01-05
期刊：
The Journal of experimental medicine
影响因子：
--
作者：
Griffin TA;Nandi D;Cruz M;Fehling HJ;Kaer LV;Monaco JJ;Colbert RA
通讯作者：
Colbert RA