dDsk2 regulates H2Bub1 and RNA polymerase II pausing at dHP1c complex target genes

Nat Commun. 2015 Apr 28:6:7049. doi: 10.1038/ncomms8049.

Abstract

dDsk2 is a conserved extraproteasomal ubiquitin receptor that targets ubiquitylated proteins for degradation. Here we report that dDsk2 plays a nonproteolytic function in transcription regulation. dDsk2 interacts with the dHP1c complex, localizes at promoters of developmental genes and is required for transcription. Through the ubiquitin-binding domain, dDsk2 interacts with H2Bub1, a modification that occurs at dHP1c complex-binding sites. H2Bub1 is not required for binding of the complex; however, dDsk2 depletion strongly reduces H2Bub1. Co-depletion of the H2Bub1 deubiquitylase dUbp8/Nonstop suppresses this reduction and rescues expression of target genes. RNA polymerase II is strongly paused at promoters of dHP1c complex target genes and dDsk2 depletion disrupts pausing. Altogether, these results suggest that dDsk2 prevents dUbp8/Nonstop-dependent H2Bub1 deubiquitylation at promoters of dHP1c complex target genes and regulates RNA polymerase II pausing. These results expand the catalogue of nonproteolytic functions of ubiquitin receptors to the epigenetic regulation of chromatin modifications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Carrier Proteins / chemistry
  • Carrier Proteins / metabolism*
  • Cell Cycle Proteins / chemistry
  • Cell Cycle Proteins / metabolism*
  • Chromatin Immunoprecipitation
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Drosophila Proteins / chemistry
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster / enzymology*
  • Drosophila melanogaster / genetics*
  • Histones / chemistry
  • Histones / metabolism*
  • Multiprotein Complexes / metabolism
  • Promoter Regions, Genetic
  • Protein Binding
  • Protein Structure, Tertiary
  • Proteolysis
  • RNA Polymerase II / metabolism*
  • Transcription Initiation Site
  • Transcription, Genetic
  • Ubiquitination

Substances

  • Carrier Proteins
  • Cell Cycle Proteins
  • Chromosomal Proteins, Non-Histone
  • Drosophila Proteins
  • HP1c protein, Drosophila
  • Histones
  • Multiprotein Complexes
  • Ubqn protein, Drosophila
  • RNA Polymerase II