Belmonte muscle science image (IMAGE) Salk Institute Caption Induction of Yamanaka factors (OKSM) in muscle fibers increases the number of myogenic progenitors. Top, control; bottom, treatment. Red-pink color is Pax7, a muscle stem-cell marker. Blue indicates muscle nuclei. Credit Salk Institute Usage Restrictions with credit and related coverage. 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.