Phenotypic and Functional Reversion of Muscular Dysgenesis by Heterotypic Fibroblast-Myotube Fusion In Vitro

Abstract

Muscular dysgenesis in the mouse (Gluecksohn-Waelsch 1963; Pai 1965^a,b) is a genetic disease with autosomal recessive inheritance characterized by an immature internal organization of foetal muscle (Gluecksohn-Waelsch 1963; Bowden-Essien 1972; Pinçon-Raymond et al., 1985). It is now well established that dysgenic skeletal muscles display important decreases in both the level of the 1,4 dihydropyridine (DHP) receptor (Pinçon-Raymond et al., 1985) and the level of the L-type Ca²⁺ channel activity (Romey et al., 1986; Beam et al., 1986). These molecular defects have been correlated with the total lack of excitation-contraction coupling in the mutant skeletal muscles (Rieger et al., 1987; Tanabe et al., 1988).