ISOLATION AND CHARACTERIZATION OF A NOVEL H-2 CLASS I GENE

新型 H-2 I 类基因的分离和表征

• 批准号: 3916423
• 负责人: D SINGER
• 金额: --
• 依托单位: DIVISION OF CANCER BIOLOGY AND DIAGNOSIS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3916423
• 关键词: biochemical evolution; gene expression; genetic mapping; genetic recombination; genetic strain; genome; histocompatibility gene; laboratory mouse; membrane proteins; nucleic acid sequence

A new sub-family of H-2 class I genes has been identified in the genome of the C57BL/1O mouse. The family consists of at least two genes which have not been previously identified. One of these, Mb1, has now been extensively characterized. Using a series of recombinant strains of mice, and taking advantage of restriction enzyme polymorphisms, it has been possible to map the Mb1 gene to the right of the Qa locus. DNA sequence analysis of Mb1 demonstrates that the exon organization of this gene resembles that of other class I genes. Furthermore, it is capable of encoding a transmembrane protein with a structure similar to other class I molecules. However, the level of DNA sequence homology of Mb1 to other H-2 genes is no greater than to either human, pig, or rabbit. Furthermore, the over-all organization of Mb1 is more similar to man and pig than to mouse. Whereas all previously reported H-2 class I genes have third introns of 1.2-2 kb, Mb1 has an intron of 600 bp, similar to those of human and porcine class I genes. Taken together, these data suggest that Mb1 may represent a direct descendant of a primordial class I gene, which antedates speciation. In support of this conclusion is the observation that a variety of wild mice, representing millions of years of evolutionary divergence, contain Mb1 in their genomes. Although other members of the Mb1 family appear to be expressed, no direct evidence for Mb1 expression has been obtained, despite the fact that it is a structurally competent gene.

一个新的H-2 I类基因亚家族已在 C57BL/10小鼠基因组。这个家庭至少由两个人组成 以前没有被识别过的基因。其中之一， Mb1，现在已经被广泛地表征。使用一系列 重组小鼠品系，并利用限制 酶的多态，已经有可能将Mb1基因定位到 QA轨迹的右侧。Mb1基因的DNA序列分析 表明该基因的外显子组织类似于 其他I类基因。此外，它还能够编码一个 结构类似于其他I类的跨膜蛋白 分子。然而，Mb1的DNA序列同源性水平 其他H-2基因并不比人类、猪或兔子的H-2基因大。 此外，MB1的总体组织结构更类似于 人和猪比老鼠强。鉴于之前报道的所有H-2病毒 I类基因有1.2-2kb的第三内含子，Mb1基因有一个内含子 600个碱基，与人和猪的I类基因相似。已被占用 总而言之，这些数据表明，Mb1可能代表着一种直接的 一种原始的I类基因的后代，它可以追溯到 物种形成。支持这一结论的是观察到的 各种各样的野生老鼠，代表着数百万年来 进化分化，在它们的基因组中含有Mb1。虽然 Mb1家族的其他成员似乎也有表达，没有直接表达 已经获得了Mb1表达的证据，尽管事实是 这是一种结构上有能力的基因。