title: Comprehensive RNA Polymerase II Interactomes Reveal Distinct and Varied Roles for Each Phospho-CTD Residue.
abstract: Transcription controls splicing and other gene regulatory processes, yet mechanisms remain obscure due to our fragmented knowledge of the molecular connections between the dynamically phosphorylated RNA polymerase II (Pol II) C-terminal domain (CTD) and regulatory factors. By systematically isolating phosphorylation states of the CTD heptapeptide repeat (Y1S2P3T4S5P6S7), we identify hundreds of protein factors that are differentially enriched, revealing unappreciated connections between the Pol II CTD and co-transcriptional processes. These data uncover a role for threonine-4 in 3' end processing through control of the transition between cleavage and termination. Furthermore, serine-5 phosphorylation seeds spliceosomal assembly immediately downstream of 3' splice sites through a direct interaction with spliceosomal subcomplex U1. Strikingly, threonine-4 phosphorylation also impacts splicing by serving as a mark of co-transcriptional spliceosome release and ensuring efficient post-transcriptional splicing genome-wide. Thus, comprehensive Pol II interactomes identify the complex and functional connections between transcription machinery and other gene regulatory complexes.
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Harlen
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Kristine L
authors.initials: KL
authors.lastname: Trotta
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Erin E
authors.initials: EE
authors.lastname: Smith
authors.affiliation: Department of Biology, Tufts University, Medford, MA 02155, USA.
authors.forename: Mohammad M
authors.initials: MM
authors.lastname: Mosaheb
authors.affiliation: Department of Biology, Tufts University, Medford, MA 02155, USA.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Fuchs
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Electronic address: churchman@genetics.med.harvard.edu.
authors.forename: L Stirling
authors.initials: LS
authors.lastname: Churchman
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism*; D016681:Genome, Fungal; D008957:Models, Genetic; D010766:Phosphorylation; D000072417:Protein Domains; D060066:Protein Interaction Maps; D040901:Proteomics; D012319:RNA Polymerase II / Q000737:chemistry* / Q000378:metabolism*; D012326:RNA Splicing / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics*; D017381:Spliceosomes / Q000378:metabolism; D013329:Structure-Activity Relationship; D061806:Transcription Termination, Genetic
chemical_list: D000596:Amino Acids; D012319:RNA Polymerase II