[Genetic analysis of the class II region of rat major histocompatibility complex (RT1)]

Class II subregions of rat major histocompatibility complex (RT1) consist of RT1. B (HLA-DQ equivalent), D (HLA-DR equivalent), and a newly defined H (HLA-DP equivalent) subregions, arranged in the order of RT1.A (class I-H-B beta (beta 1, beta 2)-D (alpha, beta) RFLP analyses of RT1. B and D subregions confirmed that RFLP patterns were correlated well with the allelic specificities which have been determined by serology or MLR. RT1.B locus of BDIX was shown to have RT1.Bd. RFLF analyses of intra-RT1 recombinant rats revealed that recombinations occurred at the sites between RT1.H and B in NIG III, WIN, KGH, between RT1.A and H in DA. BI, BDIX, and between RT1. H alpha and H beta in LEJ. Taken together, the order of genes around H subregion was determined as follows: RT1.A (class I)-H beta-H alpha-B-. Expressions of H subregion genes has not been known. However, Northern hybridization analysis with DP alpha probe detected mRNA of approximately 1.7 kb, suggesting the transcription of RT1. H alpha gene.