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A serine/arginine-rich nuclear matrix cyclophilin interacts with the C-terminal domain of RNA polymerase II

Bourquin, Jean-Pierre ; Stagljar, Igor ; Meier, Pascal ; Moosmann, Peter ; Silke, John ; Baechi, Thomas ; Georgiev, Oleg ; Schaffner, Walter

In: Nucleic Acids Research, 1997, vol. 25, no. 11, p. 2055-2061

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    Titre
    • A serine/arginine-rich nuclear matrix cyclophilin interacts with the C-terminal domain of RNA polymerase II
    Auteur
    • Bourquin, Jean-Pierre. Institut für Molekularbiologie, Abteilung II, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland, Gloriastrasse 30, CH-8028 Zürich, Switzerland
    • Stagljar, Igor. Institut für Molekularbiologie, Abteilung II, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland, Gloriastrasse 30, CH-8028 Zürich, Switzerland
    • Meier, Pascal. Institut für Molekularbiologie, Abteilung II, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland, Gloriastrasse 30, CH-8028 Zürich, Switzerland
    • Moosmann, Peter. Institut für Molekularbiologie, Abteilung II, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland, Gloriastrasse 30, CH-8028 Zürich, Switzerland
    • Silke, John. Institut für Molekularbiologie, Abteilung II, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland, Gloriastrasse 30, CH-8028 Zürich, Switzerland
    • Baechi, Thomas. Elektronenmikroskopisches Zentrallaboratorium, Universität Zürich, Gloriastrasse 30, CH-8028 Zürich, Switzerland
    • Georgiev, Oleg. Institut für Molekularbiologie, Abteilung II, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland, Gloriastrasse 30, CH-8028 Zürich, Switzerland
    • Schaffner, Walter. Institut für Molekularbiologie, Abteilung II, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland, Gloriastrasse 30, CH-8028 Zürich, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Nucleic Acids Research, 1997, vol. 25, no. 11, p. 2055-2061. Oxford University Press
    Autre version électronique
    Classification
    • Santé
    Identifiant OAI-PMH
    • oai:doc.rero.ch:298477
    Summary
    The largest subunit of RNA polymerase II shows a striking difference in the degree of phosphorylation, depending on its functional state: initiating and elongating polymerases are unphosphorylated and highly phosphorylated respectively. Phosphorylation mostly occurs at the C-terminal domain (CTD), which consists of a repetitive heptapeptide structure. Using the yeast two-hybrid system, we have selected for mammalian proteins that interact with the phosphorylated CTD of mammalian RNA polymerase II. A prominent isolate, designated SRcyp/CASP10, specifically interacts with the CTD not only in vivo but also in vitro. It contains a serine/arginine-rich (SR) domain, similar to that found in the SR protein family of pre-mRNA splicing factors, which is required for interaction with the CTD. Most remarkably, the N-terminal region of SRcyp includes a peptidyl-prolyl cis-trans isomerase domain characteristic of immunophilins/cyclophilins (Cyp), a protein family implicated in protein folding, assembly and transport. SRcyp is a nuclear protein with a characteristic distribution in large irregularly shaped nuclear speckles and co-localizes perfectly with the SR domaincontaining splicing factor SC35. Recent independent investigations have provided complementary data, such as an association of the phosphorylated form of RNA polymerase II with the nuclear speckles, impaired splicing in a CTD deletion background and inhibition of in vitro splicing by CTD peptides. Taken together, these data indicate that factors directly or indirectly involved in splicing are associated with the elongating RNA polymerases, from where they might translocate to the nascent transcripts to ensure efficient splicing, concomitant with transcription