Prox1 maintains muscle structure and growth in the developing heart

• DOI: 10.1242/dev.030007
• Publication Date: 2008-12-18T01:25:04Z
• Authors: Catherine A. Risebro; Richelle G. Searles; Athalie A. D. Mel...; Elisabeth Ehler; Nipurna Jina; Sonia Shah; Jacky Pallas; Mike Hubank; Miriam Dillard; Natasha L. Harvey; Robert J. Schwartz; Kenneth R. Chien; Guillermo Oliver; Paul R. Riley
• Keywords: Heart Defects, Congenital; Sarcomeres; 570; N-RAP (Nrap); Mouse; Myopathy; 610; Muscle Proteins; Mice, Transgenic; zyxin; Heart development; hypertrophy mouse; 1309 Developmental Biology; Mice; 03 medical and health sciences; Prox1; Metalloproteins; 1312 Molecular Biology; myocardium; Animals; Actinin; Homeodomain Proteins; 0303 health sciences; Myocardium; Tumor Suppressor Proteins; Sarcomere; Gene Expression Regulation, Developmental; Heart; Hypertrophy; heart development; Embryo, Mammalian; Myocardial Contraction; Zyxin; 3. Good health; sarcomere; myopathy

Impaired cardiac muscle growth and aberrant myocyte arrangement underlie congenital heart disease and cardiomyopathy. We show that cardiac-specific inactivation of the murine homeobox transcription factor Prox1 results in the disruption of expression and localisation of sarcomeric proteins, gross myofibril disarray and growth-retarded hearts. Furthermore, we demonstrate that Prox1 is required for direct transcriptional regulation of the genes encoding the structural proteins α-actinin, N-RAP and zyxin, which collectively function to maintain an actin-α-actinin interaction as the fundamental association of the sarcomere. Aspects of abnormal heart development and the manifestation of a subset of muscular-based disease have previously been attributed to mutations in key structural proteins. Our study reveals an essential requirement for direct transcriptional regulation of sarcomere integrity, in the context of enabling foetal cardiomyocyte hypertrophy, maintenance of contractile function and progression towards inherited or acquired myopathic disease.