Key result
The muzak mutation in Xenopus tropicalis, caused by a premature stop codon in the myh6 gene, results in non-contractile hearts and subsequent failure to form cardiac valves and trabeculae.
This study identifies a nonsense mutation in the myh6 gene as the cause of the muzak phenotype in Xenopus tropicalis, demonstrating that early cardiac morphogenesis can proceed despite the absence of contractile activity and a major structural protein.
Mechanisms coupling heart function and cardiac morphogenesis can be accessed in lower vertebrate embryos that can survive to swimming tadpole stages on diffused oxygen. Forward genetic screens in Xenopus tropicalis have identified more than 80 mutations affecting diverse developmental processes, including cardiac morphogenesis and function. In the first positional cloning of a mutation in X. tropicalis, we show that non-contractile hearts in muzak (muz) embryos are caused by a premature stop codon in the cardiac myosin heavy chain gene myh6. The mutation deletes the coiled-coil domain responsible for polymerization into thick filaments, severely disrupting the cardiomyocyte cytoskeleton. Despite the lack of contractile activity and absence of a major structural protein, early stages of cardiac morphogenesis including looping and chamber formation are grossly normal. Muz hearts subsequently develop dilated chambers with compressed endocardium and fail to form identifiable cardiac valves and trabeculae.
No takes yet. Share an insight, caveat, or question.
Abu‐Daya et al. (2009) studied muzak mutation (non-contractile hearts). muzak (muz) mutation in myh6 gene was evaluated on Cardiac morphogenesis and function. The muzak mutation in Xenopus tropicalis, caused by a premature stop codon in the myh6 gene, results in non-contractile hearts and subsequent failure to form cardiac valves and trabeculae.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: