Mouse histocompatibility genes: structure and organisation of a Kd gene.

The gene coding for the mouse H-2Kd antigen has been isolated by using a K-locus specific cDNA probe. The complete nucleotide sequence of the gene reveals eight exons separated by seven introns. Transcriptionally important DNA sequences (CCAAT and TATA) precede the first exon. Comparison with other H-2 genes shows extensive homology in exons as well as in introns. Two cDNA clones encoding Kd antigens have been analysed and provide evidence for at least two expressed Kd genes in the DBA/2 mouse. Comparison of the Kd antigen sequence to three other H-2 antigens indicates that gene conversion mechanism(s) act on H-2 genes. Analyses of exon donor and acceptor sites of different H-2 genes and cDNAs show that alternative splicing sites are used by different genes.