Zhang Ruilin, Xu Xiaolei
Department of Biochemistry and Molecular Biology/Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.
Dev Dyn. 2009 Jun;238(6):1564-73. doi: 10.1002/dvdy.21929.
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. (c) 2009 Wiley-Liss, Inc.
斑马鱼心室肌球蛋白重链（vmhc）基因在心室中呈现限制性表达。然而，这种特定腔室表达背后的分子机制尚不清楚。在此，我们利用瞬时转染和转基因技术剖析斑马鱼vmhc启动子。我们证明，在该动物模型中进行的两种瞬时分析相结合，能够快速鉴定出特定腔室的顺式元件，分离出vmhc基因上游一个2.2 kb的片段，该片段可驱动心室特异性表达。此外，缺失分析确定了多个呈现心脏特异性表达的顺式元件。为实现腔室特异性，一个远端元件需要与近端增强子元件协同并抑制它。最后，我们发现Nkx2.5结合位点（NKE）对于这种抑制功能至关重要。总之，我们对斑马鱼vmhc启动子的研究表明，心室特异性表达是通过一种抑制心房表达的机制实现的。《发育动力学》238:1564 - 1573，2009年。（c）2009年威利 - 利斯出版公司。
