The DM and DN/DO Loci
Among the array of class II genes families known in eutherian mammals, the DM loci are the most recent to be described (Cho et al. 1991; Kelly et al. 1991). The sequences, determined in mouse and human, gave an indication of why the loci were not detected in rapid succession to the other class II loci. Many features are unconventional and indicate that DM has long diverged from the other known eutherian families. Although the unusual history of DM genes renders them of interest in the study of MHC evolution, to date only the human and mouse genes have been studied in detail. Characterization of the bovine DMA and DMB loci is under way (Niimi et al. 1995). Partial sequence data available from lemur (this report) give some indication of sequence conservation within primates. However, the organization and function of DM genes in nonhuman primates must be inferred by analysis of the human and mouse genes. Thus this section will focus on features of DM common to these species and compare and contrast the DM genes to the other class II gene families in order to ascertain what can be learned from the nonhuman primate DM genes.
KeywordsMajor Histocompatibility Complex Simple Majority Major Histocompatibility Complex Gene Conserve Amino Acid Residue Invariant Chain
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- Inoko H, Ando A, Kimura M, Tsuji K. Isolation and characterization of the cDNA clone and genomic clones of a new HLA class II antigen heavy chain, DOa. J Immunol 135: 2156–2159, 1985Google Scholar
- Jonsson A-K, Rask L. Human class II DNA and DOB genes display low sequence variability. Immunogenetics 29:411–413, 1989Google Scholar
- Kasahara M, Vasquez M, Sato K, McKinney EC, Flajnik M. Evolution of the major histocompatibility complex: Isolation of class II cDNA clones from the cartilaginous fish. Proc Natl Acad Sci USA 89: 6688–6692, 1992Google Scholar
- Tonelle C, DeMars R, Long EO. DOB: a new B chain gene in HLA-D with a distinct regulation of expression. EMBO J 4: 2839–2847, 1985Google Scholar