Ser7 phosphorylation of the CTD recruits the RPAP2 Ser5 phosphatase to snRNA genes.

Journal article

The carboxy-terminal domain (CTD) of the large subunit of RNA polymerase II (Pol II) comprises multiple heptapeptide repeats of the consensus Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7. Reversible phosphorylation of Ser2, Ser5, and Ser7 during the transcription cycle mediates the sequential recruitment of transcription/RNA processing factors. Phosphorylation of Ser7 is required for recruitment of the gene type-specific Integrator complex to the Pol II-transcribed small nuclear (sn)RNA genes. Here, we show that RNA Pol II-associated protein 2 (RPAP2) specifically recognizes the phospho-Ser7 mark on the Pol II CTD and also interacts with Integrator subunits. siRNA-mediated knockdown of RPAP2 and mutation of Ser7 to alanine cause similar defects in snRNA gene expression. In addition, we show that RPAP2 is a CTD Ser5 phosphatase. Taken together, our results indicate that during transcription of snRNA genes, Ser7 phosphorylation facilitates recruitment of RPAP2, which in turn both recruits Integrator and dephosphorylates Ser5.

Authors: Egloff, S; Zaborowska, J; Laitem, C; Kiss, T; Murphy, S

• Publication status: Published
• Journal: Molecular cell
• Volume: 45
• Issue: 1
• Pages: 111-122
• Publication date: 2012-01-01
• DOI: 10.1016/j.molcel.2011.11.006
• EISSN: 1097-4164
• ISSN: 1097-2765
• Language: English
• Keywords: Protein Structure, Tertiary; Molecular Sequence Data; Phosphorylation; Humans; Transcription, Genetic; Carrier Proteins; Amino Acid Sequence; Protein Interaction Mapping; Serine; RNA Polymerase II; RNA, Small Nuclear