Temporal, Spatial and Tissue-Specific Expression of a Myogenin-lacZ Transgene Targeted to the Hprt Locus in Mice

Abstract

A lacZ transgene, expressed by the myogenin promoter, was introduced into the mouse hypoxanthine phosphoribosyltransferase (Hprt) locus by gene targeting in embryonic stem cells. Embryos between E10.5—E18.5 days were analyzed for expression of the transgene after staining for β-galactosidase activity. Transgene expression was restricted to the skeletal muscle lineages reflecting a similar temporal and spatial pattern previously demonstrated for the endogenous myogenin gene. Additionally, a second transgene, MC1tk, showed expression in 87% of the clones when targeted to Hprt. This strategy, called targeted transgenesis, provides control for analyzing promoter sequences and for comparing various transgenes expressed by the same promoter.