Transcriptionally permissive heterochromatin domains emerge from fast-evolving genetic elements

The replisome recycles parental histones through the cell cycle, but how this is accomplished in vivo and impacts epigenetic inheritance remains unknown. Here, we show that Caenorhabditis elegans mutants with disrupted replisome-mediated histone recycling display transgenerational defects in RNAi inheritance and fertility.

These strains uncovered a particular kind of heterochromatic domain that we called Corrie domains, which are located at the borders of relatively high and low H3K9me3-rich regions and contain gene and AT-rich transposable-element (TE) clusters poised for activation upon deficient H3K9me3 maintenance. Corrie domains are conserved in Mus musculus highlighting an evolutionarily conserved heterochromatic architecture that operates as a hub for regulatory diversity.