Activated Muscle Stem Cells (IMAGE) Rockefeller University Press Caption Activated muscle stem cells express MyoD (red) and Cdc6 (green) as they begin to proliferate. Credit Zhang, K., et al. 2010. J. Cell Biol. doi:10.1083/jcb.200904144. Usage Restrictions Reporters may freely use these materials in news coverage, with the appropriate credit information. 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.