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Heart chamber size in zebrafish is regulated redundantly by duplicated tbx2 genes
Author(s) -
Sedletcaia Anya,
Evans Todd
Publication year - 2011
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.22622
Subject(s) - zebrafish , biology , ventricle , heart development , gene , phenotype , transcription factor , microbiology and biotechnology , genetics , medicine , embryonic stem cell
The Tbx2 transcription factor is implicated in growth control based on its association with human cancers. In the heart, Tbx2 represses cardiac differentiation to mediate development of the atrioventricular canal (AVC). The zebrafish genome retains two tbx2 genes, and both are required for formation of the AVC. Here, we show that both genes are also expressed earlier in the primitive heart tube, and we describe a previously unrecognized role for Tbx2 in promoting proliferation of presumptive myocardium at the heart tube stage. In contrast to single knockdowns, depletion of both gene products causes chamber defects, resulting in an expanded atrium and a smaller ventricle, associated with decreased proliferation of ventricular cardiomyocytes. The phenotype correlates with changes in the expression for known cardiac growth factors. Therefore, in zebrafish, two tbx2 genes are functionally redundant for regulating chamber development, while each gene is required independently for development of the AVC. Developmental Dynamics 240:1548–1557, 2011. © 2011 Wiley‐Liss, Inc.