Nucleation-dependent propagation of Polycomb modifications emerges during the <i>Drosophila</i> maternal to zygotic transition.

ABSTRACT: During zygotic genome activation (ZGA) in Drosophila, broad domains of Polycomb-modified chromatin are rapidly established across the genome. Here, we investigate the spatial and temporal dynamics by which Polycomb group (PcG) histone modifications, H3K27me3 and H2Aub, emerge during early embryogenesis. Using ChIP-seq and live imaging of CRISPR-engineered GFP-tagged PcG components, we show that PRC2-dependent H3K27me3 accumulates adjacent to a subset of E(z)-bound prospective Polycomb Response Elements (PREs) beginning in nuclear cycle 14 (NC14), with patterns indicative of nucleation followed by spreading. Surprisingly, PRE-binding factors Pho, Combgap, and GAGA-factor are excluded from interphase nuclei prior to NC10 despite nuclear localization of E(z) throughout early interphase

SUBMITTER: Gonzaga-Saavedra N 

PROVIDER: S-EPMC12236588 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature