DESCRIPTION (provided by applicant): The objective of this proposal is to examine the regulation and biologic role of EGLN-3 in cardiac muscle. EGLN-3 is a member of the Egl-9 (EGLN) gene family that encodes intracellular proteins that exhibit prolyl hydroxylase activity. This results in the degradation of HIF-1 alpha via the ubiquitin proteosome pathway and attenuation of HIF-1 alpha responsive genes, such as vascular endothelial growth factor (VEGF) and erythropoietin.The exact role of EGLN-3 regulation in hypoxia is unclear and it remains to be determined whether the up-regulation of EGLN-3 in hypoxia is protective or deleterious. We hypothesize that EGLN -3 is regulated in cardiac muscle and plays a role in the response of cardiac muscle to ischemia . In order to study this we propose the following aims:1) To examine the regulation of EGLN-3 in cardiac muscle.2) To examine the regulation of EGLN-3 in models of cardiac ischemia and 3) To test the hypothesis that EGLN-3 regulates the response of cardiac muscle to ischemia.