Partial nucleotide sequence of a novel bovine major histocompatibility complex class II beta-chain gene, BoLA-DIB.

A bovine genomic clone that hybridized to HLA-DQ beta cDNA was isolated and fragments containing the beta 1, beta 2 and transmembrane (TM) exons subcloned. The nucleotide sequences of the exons and flanking intron regions were determined. Comparisons of these exon nucleotide sequences and derived amino acid sequences to human class II beta-chain sequences showed that this gene is only 77% identical to HLA-DQ beta and about 75% identical to bovine DQ beta-like genes. The exon sequences were more divergent from other class II beta-chain genes. However, structural features such as conserved cysteines and regions of amino acids strongly suggest this to be a class II beta-chain gene. When exon-containing fragments were used as hybridization probes on Southern blots of bovine genomic DNA digested with Eco RI or Pvu II, each exon hybridized to a single band. Based on these results we have referred to this gene as a novel bovine class II beta-chain gene, BoLA-DIB.