Mouse platelet-derived growth factor receptor α gene is deleted in W(19H) and patch mutations on chromosome 5

The mouse W(19H) mutation is an x-ray-induced deletion of more than 2 centimorgans on chromosome 5 encompassing the white spotting mutation W (encoded by the Kit protooncogene), patch (Ph), and recessive lethal (l) loci. The platelet-derived growth factor receptor α gene (PDGFRA) like Kit encodes a transmembrane receptor tyrosine kinase. By using mouse-Chinese hamster somatic cell hybrids and haplotype analysis in interspecific backcross mice, mouse Pdgfra was mapped to chromosome 5 in tight linkage with Kit. Hybridization of a PDGFRA probe to DNAs from W(19H)/+ heterozygous mice and patch heterozygous mice, and their wild-type littermates, demonstrated deletion of Pdgfra. Pulsed-field gel electrophoresis indicated that Kit and Pdgfra are linked on a 630-kilobase Mlu I DNA fragment. Thus the W(19H) deletion removes at least two receptor tyrosine kinases and the results suggest Pdgfra as a candidate for the Ph locus.