Epigenetic inheritance is gated by naïve pluripotency and Dppa2

Abstract

Environmental factors can trigger cellular responses that propagate across mitosis or even generations. Perturbations to the epigenome could underpin such acquired changes, however, the extent and contexts in which modified chromatin states confer heritable memory in mammals is unclear. Here, we exploit a precision epigenetic editing strategy and forced Xist activity to programme de novo heterochromatin domains (epialleles) at endogenous loci and track their inheritance in a developmental model. We find that na€ ıve pluripotent phases systematically erase ectopic domains of heterochromatin via active mechanisms, which likely acts as an intergenerational safeguard against transmission of epialleles. Upon lineage specification, however, acquired chro-matin states can be probabilistically inherited under selectively favourable conditions, including propagation of p53 silencing through in vivo development. Using genome-wide CRISPR screening , we identify molecular factors that restrict heritable memory of epialleles in na€ ıve pluripotent cells, and demonstrate that removal of chromatin factor Dppa2 unlocks the potential for epige-netic inheritance uncoupled from DNA sequence. Our study outlines a mechanistic basis for how epigenetic inheritance is constrained in mammals, and reveals genomic and developmental contexts in which heritable memory is feasible.