Additional Sex Combs-like Family Genes Regulate Embryonic Development

Additional sex combs-like proteins are chromatin-associated proteins that regulate gene transcription via their interaction with Polycomb Group (PcG) proteins and transcriptional coactivators and/or corepressors. ASXL proteins are required for normal development and anterior-posterior patterning. We report here that ASXL2 and ASXL1 are novel regulators of heart development. ASXL2 regulates myocardial thickness in the left ventricle and postnatal closure of the ductus arteriosus. ASXL1 regulates atrioventricular septation. Further, we report that ASXL2 is required for normal development of the epicardium and melanocytes, and ASXL1 is required for eye and palate development. These findings uncover new roles for chromatin regulation during cardiac development, and bear implications for our understanding of Bohring-Opitz syndrome.