ORGANIZATION OF MHC CLASS-II B-GENES IN THE ZEBRAFISH (BRACHYDANIO-RERIO)
ORGANIZATION OF MHC CLASS-II B-GENES IN THE ZEBRAFISH (BRACHYDANIO-RERIO)
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DOI：
10.1006/geno.1994.1452
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发表时间：
1994-09-01
期刊：
影响因子：
4.4
通讯作者：
KLEIN, J
中科院分区：
文献类型：
--
作者：
SULTMANN, H;MAYER, WE;KLEIN, J
利用3个基因组噬菌体文库，从斑马鱼MHC II类B区分离出26个克隆。通过限制映射，克隆可以被排列成6个簇，大多数簇由多个重叠的克隆组成。合并后的集群覆盖了斑马鱼II类区域的161 kb。与特异性探针杂交表明，在2个II类A和6个II类B基因簇中存在。B基因的测序显示它们代表了6个不同的II类位点家族。只有两个II类B基因和一个II类A基因是完整的；其他的是截断的假基因。只有一个II类B位点表现出广泛的限制性片段长度多态性。这也是在有大量淋巴细胞或髓细胞的器官中发现的唯一转录位点。斑马鱼II类基因具有启动子区域，其序列元件先前在哺乳动物基因中发现，并且已知参与表达调节。斑马鱼II类基因的外显子-内含子结构与哺乳动物基因相似，但内含子较短，长度在74 - 362 bp之间。在一对给定的A和B基因之间的距离也很短，但B基因之间的距离与哺乳动物II类B基因之间的距离一样长或更长。所有的斑马鱼II类B基因似乎都是在硬骨鱼类与其他脊椎动物分类群分离后，由单一祖先B基因的重复和多样化而产生的。(C) 1994学术出版社，Inc.
Using three genomic phage libraries, we isolated 26 clones from the zebrafish MHC class II B region. By restriction mapping, the clones could be arranged into six clusters, most clusters consisting of several over lapping clones. The combined clusters cover a total of 161 kb of the zebrafish class II region. Hybridization with specific probes demonstrated the presence in the clusters of two class II A and six class II B genes. Sequencing of the B genes revealed that they represented six different families of class II loci. Only two of the class II B and one of the class II A genes are complete; the others are truncated pseudogenes. Only one of the class II B loci shows extensive restriction fragment length polymorphism. This is also the only locus found to be transcribed in organs with large numbers of lymphoid or myeloid cells. The zebrafish class II genes have promoter regions with sequence elements found previously in mammalian genes and known to be involved in regulation of expression. The exon-intron organization of the zebrafish class II genes is similar to that of the mammalian genes, but the introns are characteristically short, ranging in length from 74 to 362 bp. The distances between A and B genes in a given pair are also short, but the distances between B genes are as long as or longer than those between mammalian class II B genes. All of the zebrafish class II B genes appear to have arisen by duplication and diversification of a single ancestral B gene after the separation of bony fishes from other vertebrate taxa. (C) 1994 Academic Press, Inc.