Phosphorylation of UBF at serine 388 is required for interaction with RNA polymerase I and activation of rDNA transcription

Proc Natl Acad Sci U S A. 2001 Nov 20;98(24):13631-6. doi: 10.1073/pnas.231071698. Epub 2001 Nov 6.

Abstract

Modulation of the activity of the upstream binding factor (UBF) plays a key role in cell cycle-dependent regulation of rRNA synthesis. Activation of rDNA transcription on serum stimulation requires phosphorylation of UBF at serine 484 by G(1)-specific cyclin-dependent kinase (cdk)/cyclin complexes. After G(1) progression UBF is phosphorylated at serine 388 by cdk2/cyclin E and cdk2/cyclin A. Conversion of serine 388 to glycine abolishes UBF activity, whereas substitution by aspartate enhances the transactivating function of UBF. Protein-protein interaction studies reveal that phosphorylation at serine 388 is required for the interaction between RNA polymerase I and UBF. The results suggest that phosphorylation of UBF represents a powerful means of modulating the assembly of the transcription initiation complex in a proliferation- and cell cycle-dependent fashion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Animals
  • Cell Cycle
  • Cell Line
  • DNA, Ribosomal*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Mice
  • Phosphorylation
  • Pol1 Transcription Initiation Complex Proteins*
  • RNA Polymerase I / metabolism*
  • Serine / genetics
  • Serine / metabolism*
  • Spodoptera
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcriptional Activation*

Substances

  • DNA, Ribosomal
  • DNA-Binding Proteins
  • Pol1 Transcription Initiation Complex Proteins
  • Transcription Factors
  • transcription factor UBF
  • Serine
  • RNA Polymerase I