Family relationships of murine major histocompatibility complex class I genes. Sequence of the T2Aa pseudogene, a member of gene family 3 (original) (raw)
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Annales de l'Institut Pasteur / Immunologie, 1985
The t-haplotypes of the house mouse are defined by several genetic events which involve about one-third of chromosome 17 and include the major histocompatibility complex (MHC). One of the primary features of complete t-haplotypes is the nearly complete suppression of recombination between a t-chromosome and a wild-type chromosome 17. If we assume that all genetic exchanges are abolished because of the inhibition of recombination, the class I genes of the MHC can be used as vicinity markers of t-haplotypes. We have studied the H-2K, D and L genes of l0 independant t-haplotypes and have found that their H-2K genes are rather polymorphic, although always very similar or identical to H-2K genes of laboratory mice. By contrast, the DL-Tla region is nearly constant. It is suggested that the t-haplotypes reveal the existence of several mechanisms involved in the evolution of the MHC, one of which is possibly the greater ((mobility), of H-2K genes in the genome.
Cloning and expression of class I major histocompatibility complex genes of the rat
Journal of Experimental Medicine, 1992
Little is known about the organization of class I genes in the rat although there is prima facie evidence that it is distinct from that of the mouse. We report the cloning of 61 nonclassical rat class I genes into cosmid clusters with a total mapped length of 1,264 kb. It is certain that the total number of class I genes in the rat must exceed this number. From restriction maps it is possible to identify substantial regions of duplication. By transfection of cosmids into mouse L cells, it has been possible to demonstrate at least seven different nonclassical rat class I genes that are expressible on the cell surface. Crossreaction of a single mouse monoclonal antibody with all of these class I molecules is consistent with sequence homogenization within the rat nonclassical system. Attempts to find rat homologues of the mouse T/a genes by crosshybridization of rat cosmids with a range of different TLa-specific probes were unsuccessful, suggesting that this large group of divergent class I genes is absent or nearly so from the rat. The large number of class I genes in the rat appears to have arisen by expansion of genes more closely related to the classical sequence.
Evolutionary relationships of class II major-histocompatibility-complex genes in mammals
Molecular biology and evolution, 1990
The major histocompatibility complex (MHC) class II molecule consists of noncovalently associated alpha and beta chains. In mammals studied so far, the class II MHC can be divided into a number of regions, each containing one or more alpha-chain genes (A genes) and beta-chain genes (B genes), and it has been known for some time that orthologous relationships exist between genes in corresponding regions from different mammalian species. A phylogenetic analysis of DNA sequences of class II A and B genes confirmed these relationships; but no such orthologous relationship was observed between the B genes of mammals and those of birds. Thus, the class II regions have diverged since the separation of birds and mammals (approximately 300 Mya) but before the radiation of the placental mammalian orders (60-80 Mya). Comparison of the phylogenetic trees for A and B genes revealed an unexpected characteristic of DP-region genes: DPB genes are most closely related to DQB genes, whereas DPA chain...
The Genomic Sequence and Comparative Analysis of the Rat Major Histocompatibility Complex
Genome Research, 2004
We have determined the sequence of a 4-Mb interval on rat chromosome 20p12 that encompasses the rat major histocompatibility complex (MHC). This is the first report of a finished sequence for a segment of the rat genome and constitutes one of the largest contiguous sequences thus far for rodent genomes in general. The rat MHC is, next to the human MHC, the second mammalian MHC sequenced to completion. Our analysis has resulted in the identification of at least 220 genes located within the sequenced interval. Although gene content and order are well conserved in the class II and class III gene intervals as well as the framework gene regions, profound rat-specific features were encountered within the class I gene regions, in comparison to human and mouse. Class I region-associated differences were found both at the structural level, the number, and organization of class I genes and gene families, and, in a more global context, in the way that evolution worked to shape the present-day ...
Evolution of mouse major histocompatibility complex genes borne by t chromosomes
Proceedings of the National Academy of Sciences, 1985
Virtually all wild mouse populations carry t haplotypes that cause embryonic lethality or semilethality, distortion of segregation ratios, suppression of crossing-over, and male sterility. The t complex of genes is located on chromosome 17, closely linked to the H-2, the major histocompatibility complex of the mouse. The t haplotypes differ from each other not only in lethal genes they carry but also in their linked H-2 haplotypes. In this study, we compared the class II H-2 genes present on 31 t chromosomes extracted from wild populations in different parts of the world. The comparison was based on the analysis of DNA fragments obtained after digestion with restriction endonucleases. The results reveal the existence of three major groups of class II alleles representing main branches on the evolutionary tree of the t chromosomes. Alleles within each group are similar if not identical, although they are borne by chromosomes that have been separated in time and space. The presence of...