Limited diffusibility of gene products directed by a single nucleus in the cytoplasm of multinucleated myofibres

AbstractTwo types of β-galactosidase genes, whose products are distributed in the nucleus (Nα-gal) or cytoplasm (Cβ-gal), were injected with fructose intramuscularly into the quadriceps of adult mice. Regionally restricted and overlapped distributions of both gene products were observed in the myofibres. These findings indicate that Nβ-gal is incorporated into the nucleus responsible for its synthesis and that Cβ-gal becomes located in the vicinity of the nucleus after its synthesis. This restricted location of C β-gal in myofibres remained unchanged during the development of infant mouse muscle. Thus, the gene products directed by the nucleus of myofibres seem to show limited diffusibility, suggesting a universal localization of subcellular domains in myofibres