Genes Encoding α and β Subunits of Na,K-ATPase are Located on Three Different Chromosomes in the Mouse

We have made use of a panel of mouse-hamster somatic cell hybrids and restriction fragment length polymorphisms between two mouse species (Mus musculus and Mus spretus) to determine the chromosomal localization of genes encoding the α and β subunits of the Na,K-ATPase (Na+,K+-activated ATP phosphohydrolase, EC 3.6.1.3). DNA probes for three distinct isoforms of the Na,K-ATPase α subunit mapped to three different mouse chromosomes: the α 1 gene (Atpa-1) cosegregated with the Egf gene on chromosome 3; α 2 (Atpa-2) with the cytochrome P-450PB gene family/coumarin hydroxylase locus on chromosome 7; α 3 (Atpa-3) with the α -spectrin gene on chromosome 1. The Na,K-ATPase β -subunit gene (Atpb) mapped to the same region of chromosome 1, but it was not tightly linked to the Atpa-3 gene. These results indicate that three isoforms of the Na,K-ATPase α subunit are encoded by three distinct genes. The dispersion of Na,K-ATPase genes suggests that their expression is not likely to be controlled by a common cis-acting regulatory element.