Mammalian oocytes have the ability to reset the transcriptional program of differentiated somatic cells into that of totipotent embryos through somatic cell nuclear transfer (SCNT). However, the mechanisms underlying SCNT-mediated reprogramming are largely unknown. To understand the mechanisms governing chromatin reprogramming during SCNT, we profiled DNase I hypersensitive sites (DHSs) in donor cumulus cells and one-cell stage SCNT embryos. To our surprise, the chromatin accessibility landscape of the donor cells is drastically changed to recapitulate that of the in vitro fertilization (IVF)-derived zygotes within 12 hr. Interestingly, this DHS reprogramming takes place even in the presence of a DNA replication inhibitor, suggesting that SCNT-mediated DHS reprogramming is independent of DNA replication. Thus, this study not only reveals the rapid and drastic nature of the changes in chromatin accessibility through SCNT but also establishes a DNA replication-independent model for studying cellular reprogramming.
Keywords: DNA replication; DNase I hypersensitive sites; SCNT; reprogramming.
Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.