Isolation of a ventricle‐specific promoter for the zebrafish ventricular myosin heavy chain ( vmhc ) gene and its regulation by GATA factors during embryonic heart development

We investigated chamber‐specific gene expression by isolating a 2.2‐kb polymerase chain reaction product containing the 5′‐flanking region of the zebrafish ventricular myosin heavy‐chain gene ( vmhc ). Promoter analysis revealed that the fragment, consisting of nucleotides from −301 to +26, is sufficient for vmhc promoter activity. Among several putative cis ‐acting elements in the region, a GATA‐binding site was identified to be crucial for the activity of the promoter, as evidenced by the complete abolishment of promoter activity by a single nucleotide substitution of GATA‐binding site (−287, C→T). Knockdown of GATA‐binding proteins 4 and 6 (GATA4 and ‐6) by their antisense morpholino oligonucleotides resulted in reduced green fluorescent protein (GFP) reporter gene and endogenous vmhc expression. These findings suggest that GATA4 and ‐6 play a key role in the regulation of vmhc expression in the ventricle. In addition, the vmhc promoter and the transgenic zebrafish ( vmhc:gfp ) are useful tools to study the formation and function of the ventricle. Developmental Dynamics 238:1574–1581, 2009. © 2009 Wiley‐Liss, Inc.