Histone variant H2A.Z regulates zygotic genome activation

Nat Commun. 2021 Dec 1;12(1):7002. doi: 10.1038/s41467-021-27125-7.


During embryogenesis, the genome shifts from transcriptionally quiescent to extensively active in a process known as Zygotic Genome Activation (ZGA). In Drosophila, the pioneer factor Zelda is known to be essential for the progression of development; still, it regulates the activation of only a small subset of genes at ZGA. However, thousands of genes do not require Zelda, suggesting that other mechanisms exist. By conducting GRO-seq, HiC and ChIP-seq in Drosophila embryos, we demonstrate that up to 65% of zygotically activated genes are enriched for the histone variant H2A.Z. H2A.Z enrichment precedes ZGA and RNA Polymerase II loading onto chromatin. In vivo knockdown of maternally contributed Domino, a histone chaperone and ATPase, reduces H2A.Z deposition at transcription start sites, causes global downregulation of housekeeping genes at ZGA, and compromises the establishment of the 3D chromatin structure. We infer that H2A.Z is essential for the de novo establishment of transcriptional programs during ZGA via chromatin reorganization.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases
  • Animals
  • Cell Division
  • Chromatin
  • Chromatin Immunoprecipitation Sequencing
  • Down-Regulation
  • Drosophila
  • Embryonic Development / genetics*
  • Embryonic Development / physiology*
  • Epigenomics
  • Female
  • Gene Expression Regulation, Developmental
  • Gene Knockdown Techniques
  • Genes, Essential
  • Genome*
  • Histone Chaperones
  • Histones / classification*
  • Histones / genetics*
  • Histones / metabolism*
  • Male
  • RNA Polymerase II
  • Transcription Initiation Site
  • Transcriptional Activation
  • Zygote / metabolism*


  • Chromatin
  • Histone Chaperones
  • Histones
  • RNA Polymerase II
  • Adenosine Triphosphatases