Blue Enhancers (IMAGE) DOE/Lawrence Berkeley National Laboratory Caption On the left, a mouse embryo is showing enhancer activity (blue staining) in the developing heart. On the right, a closeup of this heart, is showing that the enhancer is active in the left ventricle, left atrium, and right atrium of the heart. Credit Mammalian Functional Genomics Laboratory/Berkeley Lab Usage Restrictions Commercial use prohibited. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.