CHARACTERIZATION OF 6 NEW LOCI WITHIN THE SWINE MAJOR HISTOCOMPATIBILITY COMPLEX CLASS-III REGION

A search for new potential coding sequences was conducted within two o verlapping cosmid genomic DNA clusters of about 170 and 45 kb from the swine major histocompatibility complex class III region. The sequence s were detected with various probes, including pools of swine cDNA, ho mologous and heterologous genomic sequences, and synthetic oligonucleo tides. The 170 kb cluster was centered on the tumor necrosis factor ge nes (TNF), and the 45 kb cluster contained the heat-shock protein 70 g enes (HSP70). The TNF cluster revealed the presence of five new genes: lymphotoxin beta, BAT1, BAT2, BAT3, and a sequence related to DNA-bin ding factors. No sequence homologous to B144 was found in the TNF clus ter, although other unidentified coding sequences may be present in th is cluster. The HSP70 cluster contained a gene identified as BAT6, tha t is, tRNA-valyl synthetase. These results provide new evidence that t he genomic maps of these various genes in the TNF and HSP70 sub-region s are similar in swine and human.