Loubiere, V., Papadopoulos, G.L., Szabo, Q., Martinez, A.M., Cavalli, G. (2020). Widespread activation of developmental gene expression characterized by PRC1-dependent chromatin looping.  Sci. Adv. 6(2): eaax4001.

FBrf0244576

Research paper

Polycomb repressive complexes 1 and 2 have been historically described as transcriptional repressors, but recent reports suggest that PRC1 might also support activation, although the underlying mechanisms remain elusive. Here, we show that stage-specific PRC1 binding at a subset of active promoters and enhancers during Drosophila development coincides with the formation of three-dimensional (3D) loops, an increase in expression during development and repression in PRC1 mutants. Dissection of the dachshund locus indicates that PRC1-anchored loops are versatile architectural platforms that persist when surrounding genes are transcriptionally active and fine-tune their expression. The analysis of RING1B binding profiles and 3D contacts during neural differentiation in mice suggests that this role is conserved in mammals.

PMC6954061 (PMC) (EuropePMC)