A HIGHLY CONSERVED MAJOR HISTOCOMPATIBILITY COMPLEX CLASS I-RELATED GENE IN MAMMALS

We report here a cDNA sequence of a murine homolog of the human major histocompatibility complex (MHC) class I-related gene, MR1. The analys es revealed unprecedentedly high conservation of MR1 in the alpha 1 an d alpha 2 domains (corresponding to the peptide-binding domains in the classical MHC class I molecules) between human and mouse (predicted a mino acid identity: 90 and 89% for the alpha 1 and alpha 2 domain, res pectively), compared to MHC class I and other class I molecules. On th e other hand, conservation in the alpha 3 domain (73%) is comparable t o those of others, suggesting domain-specific conservation of MR1. The localization of the mouse MR1 gene was determined to be chromosome 1H 1, which corresponds to the human chromosomal region where the human M R1 gene is located (chromosome 1q25). High conservation of MR1 among m ammals suggests that MR1 may be involved in critical conserved biologi cal function(s). (C) 1997 Academic Press.