Specific interaction of the transcription elongation regulator TCERG1 with RNA polymerase II requires simultaneous phosphorylation at Ser2, Ser5, and Ser7 within the carboxyl-terminal domain repeat.

Published

Journal Article

The human transcription elongation regulator TCERG1 physically couples transcription elongation and splicing events by interacting with splicing factors through its N-terminal WW domains and the hyperphosphorylated C-terminal domain (CTD) of RNA polymerase II through its C-terminal FF domains. Here, we report biochemical and structural characterization of the C-terminal three FF domains (FF4-6) of TCERG1, revealing a rigid integral domain structure of the tandem FF repeat that interacts with the hyperphosphorylated CTD (PCTD). Although FF4 and FF5 adopt a classical FF domain fold containing three orthogonally packed α helices and a 310 helix, FF6 contains an additional insertion helix between α1 and α2. The formation of the integral tandem FF4-6 repeat is achieved by merging the last helix of the preceding FF domain and the first helix of the following FF domain and by direct interactions between neighboring FF domains. Using peptide column binding assays and NMR titrations, we show that binding of the FF4-6 tandem repeat to the PCTD requires simultaneous phosphorylation at Ser(2), Ser(5), and Ser(7) positions within two consecutive Y(1)S(2)P(3)T(4)S(5)P(6)S(7) heptad repeats. Such a sequence-specific PCTD recognition is achieved through CTD-docking sites on FF4 and FF5 of TCERG1 but not FF6. Our study presents the first example of a nuclear factor requiring all three phospho-Ser marks within the heptad repeat of the CTD for high affinity binding and provides a molecular interpretation for the biochemical connection between the Ser(7) phosphorylation enrichment in the CTD of the transcribing RNA polymerase II over introns and co-transcriptional splicing events.

Full Text

Duke Authors

Cited Authors

  • Liu, J; Fan, S; Lee, C-J; Greenleaf, AL; Zhou, P

Published Date

  • April 12, 2013

Published In

Volume / Issue

  • 288 / 15

Start / End Page

  • 10890 - 10901

PubMed ID

  • 23436654

Pubmed Central ID

  • 23436654

Electronic International Standard Serial Number (EISSN)

  • 1083-351X

Digital Object Identifier (DOI)

  • 10.1074/jbc.M113.460238

Language

  • eng

Conference Location

  • United States