PUBLICATION

Establishment of developmental gene silencing by ordered polycomb complex recruitment in early zebrafish embryos

Authors
Hickey, G.J., Wike, C.L., Nie, X., Guo, Y., Tan, M., Murphy, P.J., Cairns, B.R.
ID
ZDB-PUB-220105-8
Date
2022
Source
eLIFE   11: (Journal)
Registered Authors
Keywords
chromosomes, developmental biology, gene expression, zebrafish
Datasets
GEO:GSE168361, GEO:GSE168362, GEO:GSE168359, GEO:GSE168360
MeSH Terms
  • Animals
  • Cell Line
  • Chromatin/genetics*
  • DNA Methylation
  • Drosophila
  • Drosophila Proteins/genetics
  • Gene Expression Regulation, Developmental*
  • Gene Silencing*
  • Genes, Developmental
  • Genomics/methods
  • Polycomb-Group Proteins/genetics
  • Polycomb-Group Proteins/metabolism*
  • Zebrafish/genetics*
  • Zygote/growth & development*
  • Zygote/metabolism
PubMed
34982026 Full text @ Elife
Abstract
Vertebrate embryos achieve developmental competency during zygotic genome activation (ZGA) by establishing chromatin states that silence yet poise developmental genes for subsequent lineage-specific activation. Here, we reveal the order of chromatin states in establishing developmental gene poising in preZGA zebrafish embryos. Poising is established at promoters and enhancers that initially contain open/permissive chromatin with 'Placeholder' nucleosomes (bearing H2A.Z, H3K4me1, and H3K27ac), and DNA hypomethylation. Silencing is initiated by the recruitment of Polycomb Repressive Complex 1 (PRC1), and H2Aub1 deposition by catalytic Rnf2 during preZGA and ZGA stages. During postZGA, H2Aub1 enables Aebp2-containing PRC2 recruitment and H3K27me3 deposition. Notably, preventing H2Aub1 (via Rnf2 inhibition) eliminates recruitment of Aebp2-PRC2 and H3K27me3, and elicits transcriptional upregulation of certain developmental genes during ZGA. However, upregulation is independent of H3K27me3 - establishing H2Aub1 as the critical silencing modification at ZGA. Taken together, we reveal the logic and mechanism for establishing poised/silent developmental genes in early vertebrate embryos.
Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping