title: Regulatory and structural genes for lysozymes of mice.
abstract: The molecular and genetic basis of large differences in the concentration of P lysozyme in the small intestine has been investigated by crossing inbred strains of two species of house mouse (genus Mus). The concentration of P in domesticus is about 130-fold higher than in castaneus. An autosomal genetic element determining the concentration of P has been identified and named the P lysozyme regulator, Lzp-r. The level of P in interspecific hybrids (domesticus X castaneus) as well as in certain classes of backcross progeny is intermediate relative to parental levels, which shows that the two alleles of Lzp-r are inherited additively. There are two forms of P lysozyme in the intestine of the interspecific hybrid--one having the heat stability of domesticus P, the other being more stable and presumably the product of the castaneus P locus. These two forms occur in equal amounts, and it appears that Lzp-r acts in trans. The linkage of Lzp-r to three structural genes (Lzp-s, Lzm-sl, and Lzm-s2), one specifying P lysozyme and two specifying M lysozymes, was shown by electrophoretic analysis of backcrosses involving domesticus and castaneus and also domesticus and spretus. The role of regulatory mutations in evolution is discussed in light of these results.
mesh_terms: D000375:Aging; D000818:Animals; D004795:Enzyme Stability; D005796:Genes; D005809:Genes, Regulator; D007421:Intestine, Small / Q000201:enzymology* / Q000254:growth & development; D007700:Kinetics; D051379:Mice; D008815:Mice, Inbred Strains; D009113:Muramidase / Q000235:genetics* / Q000378:metabolism; D013045:Species Specificity
chemical_list: D009113:Muramidase