MED26 regulates the transcription of snRNA genes through the recruitment of little elongation complex

Nat Commun. 2015 Jan 9:6:5941. doi: 10.1038/ncomms6941.

Abstract

Regulation of transcription elongation by RNA polymerase II (Pol II) is a key regulatory step in gene transcription. Recently, the little elongation complex (LEC)-which contains the transcription elongation factor ELL/EAF-was found to be required for the transcription of Pol II-dependent small nuclear RNA (snRNA) genes. Here we show that the human Mediator subunit MED26 plays a role in the recruitment of LEC to a subset of snRNA genes through direct interaction of EAF and the N-terminal domain (NTD) of MED26. Loss of MED26 in cells decreases the occupancy of LEC at a subset of snRNA genes and results in a reduction in their transcription. Our results suggest that the MED26-NTD functions as a molecular switch in the exchange of TBP-associated factor 7 (TAF7) for LEC to facilitate the transition from initiation to elongation during transcription of a subset of snRNA genes.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • DNA Polymerase II / metabolism
  • Fibroblasts / metabolism
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Mediator Complex / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Molecular Sequence Data
  • Peptide Chain Elongation, Translational*
  • Point Mutation
  • Protein Binding
  • RNA, Small Nuclear / metabolism*
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Sf9 Cells
  • TATA-Binding Protein Associated Factors / metabolism
  • Transcription Factor TFIID / metabolism
  • Transcription Factors / metabolism
  • Transcription, Genetic*

Substances

  • EAF1 protein, human
  • MED26 protein, human
  • Mediator Complex
  • RNA, Small Nuclear
  • Recombinant Proteins
  • TAF7 protein, human
  • TATA-Binding Protein Associated Factors
  • Transcription Factor TFIID
  • Transcription Factors
  • DNA Polymerase II