Molecular Mechanisms Underlying Stem Cell Reprogramming (IMAGE) University of Pennsylvania School of Medicine Caption At the beginning of cellular reprogramming, gene regulatory proteins Oct 4 (O), Sox2 (S) and Klf4 (K) enter the chromosomes at silent genes and allow c-Myc (M) binding. However, there are large chromosomal domains that contain particular epigenetic marks (red triangles) that prevent O, S, K, M from binding. Erasing the marks allows the regulatory proteins to bind and promotes the process of cellular reprogramming. Credit Kenneth Zaret, PhD, at the Perelman School of Medicine, University of Pennsylvania 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.