Department of Genetics and Pediatrics
Boston Children's Hospital
Howard Hughes Medical Institute
Host: Songtao Jia
Title: Epigenetic and chromatin reprogramming during mammalian preimplantation development & somatic cell nuclear transfer (SCNT)
Abstract: Mammalian sperm and oocytes have different epigenetic landscapes and are organized in different fashion. Following fertilization, the initially distinct parental epigenomes and chromatin organization become largely equalized with the exception of certain loci including imprinting control regions (ICRs). How parental chromatin becomes equalized and how ICRs escape from this reprogramming is largely unknown. In the past several years, we have made great progress in understanding this reprogramming process, including the role of nucleosome assembly in nuclear pore complex formation, role of Tet3 in paternal DNA demethylation, and zygotic genome activation, and the identification of a DNA methylation-independent, H3K27me3-depdendent imprinting mechanism. In addition, we identified H3K9me3 in somatic cells as a barrier preventing preimplantation development, and loss of H3K27me3 imprinting as a barrier preventing post-implantation development of SCNT embryos. We also developed ways to overcome these barriers to increase SCNT efficiency. Our studies shed light on both fundamental biological processes as well as practical applications for regenerative medicine.