The mouse p52 subunit of the transcription DNA repair factor TFIIH is located in the class III region of the H2 complex: cloning and sequence polymorphism

Loci controlling susceptibility to a number of diseases, including cortison e-induced cleft palate, experimental allergic orchitis, and chemically-indu ced transplacental lung tumors have been mapped to a 27 kilobase (kb) regio n within the class III region of the mouse major histocompatibility complex (H2). This region, contains three genes G7e, which resembles a viral envel ope gene, Bat6 (G7a), which encodes a valyl-tRNA synthetase, and G7c, which has no known function. We cloned a set of overlapping cosmid clones contai ning 115 kb of DNA surrounding Bat6. Exon trapping has identified a new gen e located telomeric of Bat6. Northern blot analysis detected a transcript o f 1.7 kb with highest expression in the testis. DNA sequence analysis ident ified this gene as the mouse homologue of the human gene encoding the p52 s ubunit of the TFIIH transcription /DNA repair factor. Nucleotide sequence i dentity was 91% between mouse and human, and the protein sequence was 98% i dentical. Sequence analysis of p52 cDNA from congenic mouse strains detecte d an amino acid polymorphism at position 209, which results in the substitu tion of a threonine in the H2(b) haplotype to a methionine in the H2(a,d) h aplotypes.