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 cortisone-induced cleft palate, experimental allergic orchitis, and chemically-induced transplacental lung tumors have been mapped to a 27 kilobase (kb) region within the class III region of the mouse major histocompatibility complex (H2). This region, contains three genes G7e, which resembles a viral envelope gene, Bat6 (G7a), which encodes a valyl-tRNA synthetase, and G7c, which has no known function. We cloned a set of overlapping cosmid clones containing 115 kb of DNA surrounding Bat6. Exon trapping has identified a new gene located telomeric of Bat6. Northern blot analysis detected a transcript of 1.7 kb with highest expression in the testis. DNA sequence analysis identified this gene as the mouse homologue of the human gene encoding the p52 subunit of the TFIIH transcription/DNA repair factor. Nucleotide sequence identity was 91% between mouse and human, and the protein sequence was 98% identical. Sequence analysis of p52 cDNA from congenic mouse strains detected an amino acid polymorphism at position 209, which results in the substitution of a threonine in the H2b haplotype to a methionine in the H2a,d haplotypes.