The pathway of myofibrillogenesis determines the interrelationship between myosin and paramyosin synthesis in Caenorhabditis elegans.
Examination of null mutants in myosin B and paramyosin yields insights into the complex mechanisms that regulate expression of the three major components of Caenorhabditis elegans body-wall muscle thick filaments myosin A, myosin B and paramyosin. In the absence of myosin B, paramyosin accumulation is reduced, although neither its synthesis nor that of myosin A is affected. This implies that the interaction of myosin B with paramyosin inhibits paramyosin degradation. By contrast, the absence of paramyosin results in reduced synthesis and accumulation of myosin B but has no effect on myosin A synthesis. The non-reciprocal effects of the null mutants on turnover and synthesis are best understood as an epigenetic phenomenon that reflects the pathway of thick filament assembly. The synthesis of myosin A and paramyosin, which are involved in the initial steps of thick filament formation, is independent of myosin B; however, a properly assembled paramyosin-containing thick filament core is essential for efficient synthesis of myosin B.
Department of Cell Biology-Box 3011, Duke University Medical School, Durham, NC 27710, USA.
Glenn E
GE
White
Christine M
CM
Petry
Fred
F
Schachat
D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics; D001345:Autoradiography; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D003720:Densitometry; D024510:Muscle Development / Q000502:physiology*; D020125:Mutation, Missense / Q000235:genetics; D009218:Myosins / Q000096:biosynthesis*; D014335:Tropomyosin / Q000096:biosynthesis*
D014335:Tropomyosin; D009218:Myosins