Open AccessDifferential roles of phosphorylation in the formation of transcriptional active RNA polymerase I
Author(s) -
Stephan Fath,
Philipp Milkereit,
Gérald Peyroche,
Michel Riva,
Christophe Carles,
Herbert Tschochner
Publication year - 2001
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.231181398
Subject(s) - rna polymerase ii , phosphorylation , transcription factor ii f , rna polymerase iii , transcription (linguistics) , transcription factor ii d , microbiology and biotechnology , transcription factor ii e , biology , transcription factor ii b , dephosphorylation , general transcription factor , transcriptional regulation , chemistry , transcription factor , rna polymerase , genetics , rna , phosphatase , promoter , gene expression , gene , linguistics , philosophy
Regulation of rDNA transcription depends on the formation and dissociation of a functional complex between RNA polymerase I (pol I) and transcription initiation factor Rrn3p. We analyzed whether phosphorylation is involved in this molecular switch. Rrn3p is a phosphoprotein that is predominantly phosphorylated in vivo when it is not bound to pol I. In vitro, Rrn3p is able both to associate with pol I and to enter the transcription cycle in its nonphosphorylated form. By contrast, phosphorylation of pol I is required to form a stable pol I-Rrn3p complex for efficient transcription initiation. Furthermore, association of pol I with Rrn3p correlates with a change in the phosphorylation state of pol I in vivo. We suggest that phosphorylation at specific sites of pol I is a prerequisite for proper transcription initiation and that phosphorylation/dephosphorylation of pol I is one possibility to modulate cellular rDNA transcription activity.