Présentation
Department of Developmental and Stem Cell Biology
2017 Seminar Series
Friday 17th March — at 12.00 pm @ Amphi Jacques Monod (Bât.66)
SEMINAR ” Epigenetic mechanisms in early mammalian development “
Invited Speaker ⇒ Maria Elena Torres-Padilla
IES – Institute of Epigenetics ans Stem Cells
Helmholtz Zentrum München- Germany
Abstract : In mammals, the terminally differentiated sperm and oocyte fuse to create a totipotent zygote upon fertilisation. The mechanisms underlying the epigenetic reprogramming towards totipotency that follows fertilisation are not fully understood, and the molecular features of totipotent cells remain scarce. Embryonic cells remain totipotent only for a restricted time window. During this time, embryonic cells are characterised by an atypical chromatin structure and reactivation of specific families of retrotransposons. Recently, it was reported that totipotent-like cells arise in ES cell cultures in vitro. Like in the embryo, these cells are characterised by the expression of MERVL LTR retrotransposons. To address how the expression of these elements is regulated during the transition between totipotent and pluripotent states, we first examined histone modifications and chromatin structure in early mouse embryos. Remarkably, we have found that specific features of embryonic chromatin are also present in totipotent-like cells in vitro. Based on this analysis, we have begun to decipher key molecular regulators of repetitive elements in the embryo. Our results have identified candidate proteins that regulate chromatin function and expression of these elements and show that they can induce totipotency. We are currently examining the role of these molecules in sustaining totipotency in the embryo. We will present our latest results that reveal a new role for chromatin integrity in promoting epigenetic reprogramming and sustaining molecular features of totipotent cells.
Hosted by Han Li