ZFIN ID: ZDB-PUB-031103-20
Mutation of weak atrium/atrial myosin heavy chain disrupts atrial function and influences ventricular morphogenesis in zebrafish
Berdougo, E., Coleman, H., Lee, D.H., Stainier, D.Y., and Yelon, D.
Date: 2003
Source: Development (Cambridge, England) 130(24): 6121-6129 (Journal)
Registered Authors: Stainier, Didier, Yelon, Deborah
Keywords: zebrafish, ventricle, atrium, cardiac myosin heavy chain, chamber formation, atrial natriuretic factor
MeSH Terms: Animals; Atrial Function/physiology*; Atrial Myosins/genetics; Atrial Myosins/metabolism*; Atrial Natriuretic Factor/genetics (all 24) expand
PubMed: 14573521 Full text @ Development
The embryonic vertebrate heart is composed of two major chambers, a ventricle and an atrium, each of which has a characteristic size, shape and functional capacity that contributes to efficient circulation. Chamber-specific gene expression programs are likely to regulate key aspects of chamber formation. Here, we demonstrate that epigenetic factors also have a significant influence on chamber morphogenesis. Specifically, we show that an atrium-specific contractility defect has a profound impact on ventricular development. We find that the zebrafish locus weak atrium encodes an atrium-specific myosin heavy chain that is required for atrial myofibrillar organization and contraction. Despite their atrial defects, weak atrium mutants can maintain circulation through ventricular contraction. However, the weak atrium mutant ventricle becomes unusually compact, exhibiting a thickened myocardial wall, a narrow lumen and changes in myocardial gene expression. As weak atrium/atrial myosin heavy chain is expressed only in the atrium, the ventricular phenotypes in weak atrium mutants represent a secondary response to atrial dysfunction. Thus, not only is cardiac form essential for cardiac function, but there also exists a reciprocal relationship in which function can influence form. These findings are relevant to our understanding of congenital defects in cardiac chamber morphogenesis.