Genetic Variation at a Locus (TAM-1) for Submaxillary Gland Protease in the Mouse and Its Location on Chromosome 7

Electrophoretic and activity variants for a testosterone-induced esteroprotease have been discovered in submaxillary glands from inbred strains of mice. The enzyme is tentatively designated tamase (TAM-1) and the variant genetic locus is Tam-1. The alleles Tam-1^a and Tam-1^b determine electrophoretically distinct zones of tamase activity, while Tam-1^c produces no detectable enzyme activity. Data from recombinant inbred strains and B6AF₁ x B6 and B6D2F₁ x B6 backcrosses established linkage of Tam-1 to glucose phosphate isomerase (Gpi-1), pink-eyed dilution (p) and β-hemoglobin (Hbb) on chromosome 7. The gene order is Gpi-1—Tam-1—p—Hbb. Analysis of congenic resistant strains indicates that Tam-1 is closely linked to the minor histocompatibility locus, H-4. TAM-1 was not cross-reactive with antisera to mouse nerve growth factor, submaxillary renin, or tamases A and D.