Identification and characterisation of cardiac defects in mouse models isolated from a random chemical mutagenesis screen

Abstract

Congenital heart defects represent a major burden on medical resources, being the leading cause of infant death in the developed world. An average of 1% of all live births are thought to involve a congenital heart defect.The mouse has long been a key model in the study of mammalian cardiac development, with traditional mouse knockouts leading the way. As next generation sequencing technologies progress, random mutagenesis screens offer a phenotype driven approach to the identification of new genes involved in developmental pathways. A targeted ENU mutagenesis screen for mouse chromosome 11 lead to the isolation of the L11Jus27 line, from which two embryonic lethal mutations were isolated.A combination of meiotic mapping and high throughput sequencing has identified a candidate mutation in the K27 mouse, in the pre-mRNA spliceosome gene, Prpf8, implicated in retinitis pigmentosa. Morphological analysis and ultrasound have identified a midgestation-lethal phenotype, with K27 mice exhibiting a distended heart tube and reversal of cardiac looping. Expression analysis suggests the K27 mouse may represent a Pitx2 independent model of laterality defects.The Embryonic Hydrocephalus and Cardiac defects (EHC) mutation has previously been identified in the nonmuscle myosin gene, Myh10. A combination of histological analysis and protein localisation studies, have been used to identify a specific requirement for Myh10 in the development of the epicardium. Loss of epicardial adhesion leads to a loss of coronary vasculature.Together the L11Jus27mouse lines demonstrate a role for mutagenesis screens in the study of clinically applicable mammalian models.

Date of Award	1 Aug 2013
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Kathryn Hentges (Supervisor)