Mitotic Phosphorylation of the TBP-containing Factor SL1 Represses Ribosomal Gene Transcription

J Mol Biol. 1998 Nov 20;284(1):1-5. doi: 10.1006/jmbi.1998.2164.

Abstract

Entry into mitosis is accompanied by a global repression of transcription. To investigate the molecular mechanisms which shut-down rRNA synthesis during mitosis, we have compared RNA polymerase I (Pol I) transcription in extracts from asynchronous and mitotic HeLa cells. We show by several experimental approaches that phosphorylation by cdc2/cyclin B inactivates the TBP-containing factor SL1 and thus abrogates Pol I transcription during mitosis. This finding links the cell's cycle with the transcriptional activity of Pol I and suggests a common mechanism for mitotic silencing of all three classes of nuclear RNA polymerases, i.e. reversible inactivation of the respective TBP-TAF complexes by (a) mitotic kinase(s).

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenine / analogs & derivatives
  • Adenine / pharmacology
  • Animals
  • Cell Cycle Proteins*
  • Cell Extracts
  • Cyclin B / drug effects
  • Cyclin B / metabolism
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / isolation & purification
  • DNA-Binding Proteins / metabolism*
  • Fungal Proteins / genetics
  • Fungal Proteins / pharmacology
  • HeLa Cells / drug effects
  • Humans
  • Mice
  • Mitosis*
  • Nocodazole / pharmacology
  • Okadaic Acid / pharmacology
  • Phosphorylation
  • Pol1 Transcription Initiation Complex Proteins*
  • RNA Polymerase I / genetics
  • RNA Polymerase I / metabolism
  • RNA, Ribosomal / drug effects
  • RNA, Ribosomal / genetics*
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • Schizosaccharomyces pombe Proteins*
  • Thymidine / pharmacology
  • Transcription Factors / genetics*
  • Transcription Factors / isolation & purification
  • Transcription Factors / metabolism*
  • Transcription, Genetic*

Substances

  • Cell Cycle Proteins
  • Cell Extracts
  • Cyclin B
  • DNA-Binding Proteins
  • Fungal Proteins
  • Pol1 Transcription Initiation Complex Proteins
  • RNA, Ribosomal
  • Repressor Proteins
  • Schizosaccharomyces pombe Proteins
  • Suc1 protein, S pombe
  • Transcription Factors
  • transcription initiation factor TIF-IB
  • Okadaic Acid
  • N(6),N(6)-dimethyladenine
  • RNA Polymerase I
  • Adenine
  • Nocodazole
  • Thymidine