Transient and transgenic analysis of the zebrafish ventricular myosin heavy chain (vmhc) promoter: An inhibitory mechanism of ventricle‐specific gene expression

R Zhang, X Xu - Developmental Dynamics, 2009 - Wiley Online Library
R Zhang, X Xu
Developmental Dynamics, 2009Wiley Online Library
The zebrafish ventricular myosin heavy chain (vmhc) gene exhibits restricted expression in
the ventricle. However, the molecular mechanism underlying this chamber‐specific
expression is unclear. Here, we exploited both transient and transgenic technologies to
dissect the zebrafish vmhc promoter. We demonstrated that a combination of two transient
assays in this animal model quickly identified chamber‐specific cis‐elements, isolating a 2.2
kb fragment upstream from the vmhc gene that can drive ventricle‐specific expression …
Abstract
The zebrafish ventricular myosin heavy chain (vmhc) gene exhibits restricted expression in the ventricle. However, the molecular mechanism underlying this chamber‐specific expression is unclear. Here, we exploited both transient and transgenic technologies to dissect the zebrafish vmhc promoter. We demonstrated that a combination of two transient assays in this animal model quickly identified chamber‐specific cis‐elements, isolating a 2.2 kb fragment upstream from the vmhc gene that can drive ventricle‐specific expression. Furthermore, deletion analysis identified multiple cis‐elements that exhibited cardiac‐specific expression. To achieve chamber specificity, a distal element was required to coordinate with and suppress a proximal enhancer element. Finally, we discovered that Nkx2.5‐binding sites (NKE) were essential for this repressive function. In summary, our study of the zebrafish vmhc promoter suggests that ventricle‐specific expression is achieved through an inhibitory mechanism that suppresses expression in the atrium. Developmental Dynamics 238:1564–1573, 2009. © 2009 Wiley‐Liss, Inc.
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