Vangl2 and Early Cardiac Development

• Main Author: Rhee, Hong Jun
• Published: University of Newcastle upon Tyne 2007
• Subjects: 611
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485573

The establishment of polarity is a crucial event for creating asymmetry during development. Planar cell polarity (PCP) is essential for polarity within the plane of a tissue and is required for a number of developmental processes including gastrulation, neurulation and development of the heart. Recently, a novel cell population, referred to as the second heart field· (SHF), has been identified, which contributes cells to the primitive heart tube and forms the outflow tract and the right ventricle of the mature heart. This study set out to investigate possible roles for the PCP gene, Vangl2, in the SHF during early cardiac development. In the first part of this thesis, the cardiac defects in Lp have been studied using classical histological and genetic methods. These data suggest that an abnormality in the addition of SHF cells to the developing outflow tract may underlie the cardiac defects in Lp. This is supported by co-localization of Vangl2 with SHF markers. In the second part of the thesis, the transcriptional start site of the Vangl2 gene has been identified using 5' RACE and the upstream regulatory sequences of Vangl2 have been cloned in order to identify possible regulation by SHF genes. Putative transcriptional regulation sites for SHF genes have been identified using bioinformatic approaches and functionally tested by transfection of' vectors containing these regulatory regions into cell lines, and zebrafish and mouse embryos. These studies have suggested that regulation of Vangl2 may require, at least in part, long distance elements rather than proximal promoter elements. In the third part of the thesis, construction of a vector for conditional knockout of the Vang12 gene is described. This was produced in order to generate' a tissue-specific knockout of Vangl2 which will help to understand the specific role of Vang12 in heart development.