Actin and hnRNP U cooperate for productive transcription by RNA polymerase II

Nat Struct Mol Biol. 2005 Mar;12(3):238-44. doi: 10.1038/nsmb904. Epub 2005 Feb 13.


To determine the role of actin-ribonucleoprotein complexes in transcription, we set out to identify novel actin-binding proteins associated with RNA polymerase II (Pol II). Using affinity chromatography on fractionated HeLa cells, we found that hnRNP U binds actin through a short amino acid sequence in its C-terminal domain. Post-transcriptional gene silencing of hnRNP U and nuclear microinjections of a short peptide encompassing the hnRNP U actin-binding sequence inhibited BrUTP incorporation in vivo. In living cells, we found that both actin and hnRNP U are associated with the phosphorylated C-terminal domain of Pol II, and antibodies to actin and hnRNP U blocked Pol II-mediated transcription. Taken together, our results indicate that a general actin-based mechanism is implicated in the transcription of most Pol II genes. Actin in complex with hnRNP U may carry out its regulatory role during the initial phases of transcription activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Actins / physiology*
  • Amino Acid Sequence
  • Gene Silencing
  • HeLa Cells
  • Heterogeneous-Nuclear Ribonucleoprotein U / genetics
  • Heterogeneous-Nuclear Ribonucleoprotein U / metabolism
  • Heterogeneous-Nuclear Ribonucleoprotein U / physiology*
  • Humans
  • Molecular Sequence Data
  • Phosphorylation
  • Protein Interaction Mapping
  • Protein Structure, Tertiary
  • RNA Polymerase II / metabolism*
  • RNA, Messenger / analysis
  • RNA, Messenger / metabolism
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / pharmacology
  • Transcription, Genetic / drug effects
  • Transcription, Genetic / genetics
  • Transcription, Genetic / physiology*


  • Actins
  • Heterogeneous-Nuclear Ribonucleoprotein U
  • RNA, Messenger
  • RNA, Small Interfering
  • RNA Polymerase II