Actin and hnRNP U cooperate for productive transcription by RNA polymerase II.
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.
Mesh Terms:
Actins, Amino Acid Sequence, Gene Silencing, HeLa Cells, Heterogeneous-Nuclear Ribonucleoprotein U, Humans, Molecular Sequence Data, Phosphorylation, Protein Interaction Mapping, Protein Structure, Tertiary, RNA Polymerase II, RNA, Messenger, RNA, Small Interfering, Transcription, Genetic
Actins, Amino Acid Sequence, Gene Silencing, HeLa Cells, Heterogeneous-Nuclear Ribonucleoprotein U, Humans, Molecular Sequence Data, Phosphorylation, Protein Interaction Mapping, Protein Structure, Tertiary, RNA Polymerase II, RNA, Messenger, RNA, Small Interfering, Transcription, Genetic
Nat. Struct. Mol. Biol.
Date: Mar. 01, 2005
PubMed ID: 15711563
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