Triggering Myogenesis (IMAGE) University of Oregon Caption Graphic depicts protein interaction in muscle formation: The bottom embryo is normal, not yet expressing the early muscle genes. In the top embryo, researchers forced early expression of Smarcd3, which switches on the muscle genes (dark blue) earlier than normal. This and other experiments showed that Smarcd3 is the limiting factor that regulates when a cell will turn into a muscle. The middle part shows the Smarcd3-protein complex (pink, orange, green) altering the shape of the chromosome. Credit Illustration courtesy of Monte Westerfield Usage Restrictions None 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.