Program in Cellular Reprogramming and Epigenetics


The IRM Program in Cellular Reprogramming and Epigenetics consists of investigators from Penn’s Schools of Medicine, Veterinary Medicine, and Engineering and Applied Science. 

The Program investigates the means by which cells in embryonic development and tissue regeneration gain specialized functions, and how a cell of one function can be converted to another.  Understanding these principles facilitates other IRM Programs to generate new cells and tissues for treating a wide variety of human injuries and disease.


  • IRM studies discovered cell culture conditions whereby stem cells could be programmed to make functional insulin-producing cells  (Cheng, et al.: 2012 Cell Stem Cell).
  • Program members discovered chromosomal modifications in early embryonic cells that predict the ability of the cells to make liver or pancreas tissue.  This information is useful for IRM efforts to program stem cells for liver diseases and diabetes  (Xu, et al.: 2011 Science).
  • IRM researchers tested subunits of chromosomal proteins for novel functions in reproductive cells in fungi and discovered important protein modifications that are conserved in function in mammalian sperm.  These studies integrate with IRM research on human fertility and reproduction  (Govin, et al.: 2010 Genes & Development).


  • Understanding the fundamental basis by which gene regulatory factors gain access to chromosomal sites to modify cell function.
  • Understanding chromosomal modifications that can serve as targets for small molecule drugs and thereby modify cell function.
  • Discovering new ways to program stem cells for human disease therapies.

“This is a very exciting time to be studying the basis for cell identity and for converting one type of cell into another. We finally know the underlying principles, and their application will have a profound impact in the field of regenerative medicine.”
Kenneth S. Zaret, Ph.D., is Director of the IRM, Co-Director of IRM Program in Cellular Reprogramming and Epigenetics, and Joseph Leidy Professor.  Dr. Zaret discovered signals and genetic programs that initiate the development of liver and pancreas tissue in embryos.  These discoveries are now used to develop liver and pancreas cells from stem cells for regenerative medicine.
Shelley L. Berger, Ph.D., is Director of Penn Epigenetics Program and Daniel S. Och University Professor.  Dr. Berger has identified many chemical modifications that occur in chromosomes and revealed how those modifications affect gene activity and the inheritance of gene expression states.