Structure, function, and evolution of mouse TL genes, nonclassical class I genes of the major histocompatibility complex.
AUTOR(ES)
Obata, Y
RESUMO
In contrast to well-studied "classical" class I genes of the major histocompatibility complex (MHC), the biology of nonclassical class I genes remains largely unexamined. The mouse TL genes constitute one of the best defined systems among nonclassical class I genes in the T region of the MHC. To elucidate the function and the evolution of TL genes and their relationship to classical class I genes, seven TL DNA sequences, including one from a Japanese wild mouse, were examined and compared with those of several mouse and human classical class I genes. The TL genes differ from either classical class I genes or pseudogenes in the extent and pattern of nucleotide substitutions. Natural selection appears to have operated so as to preserve the function of TL, which might have been acquired in an early stage of its evolution. In a putative peptide-binding region encoded by TL genes, the rate of nonsynonymous (amino acid replacing) substitution is considerably lower than that of synonymous substitution. This conservation is completely opposite that in classical class I genes, in which the peptide-binding region has evolved to diversify amino acid sequences so as to recognize a variety of antigens. Thus, it is suggested that the function of TL antigens is distinct from that of classical class I antigens and is related to the recognition of a relatively restricted repertoire of antigens and their presentation to T-cell receptors.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=44248Documentos Relacionados
- Expression in L cells of transfected class I genes from the mouse major histocompatibility complex.
- Gene duplications in the TL region of the mouse major histocompatibility complex.
- Organization and structure of the Qa genes of the major histocompatibility complex of the C3H mouse: implications for Qa function and class I evolution.
- Embryonal carcinoma cells express Qa and Tla class I genes of the major histocompatibility complex.
- Structure, Function, and Evolution of Proton-ATPases