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

AUTOR(ES)

Voit, Renate

FONTE

The National Academy of Sciences

RESUMO

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 G1-specific cyclin-dependent kinase (cdk)/cyclin complexes. After G1 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.

Documentos Relacionados

• RNA polymerase I associated factor 53 binds to the nucleolar transcription factor UBF and functions in specific rDNA transcription.
• RNA polymerase switch in transcription of yeast rDNA: Role of transcription factor UAF (upstream activation factor) in silencing rDNA transcription by RNA polymerase II
• Histones H3 and H4 are components of upstream activation factor required for the high-level transcription of yeast rDNA by RNA polymerase I
• Localization of small nuclear polymerase I RNA sequences at the 5' end of the human rDNA transcription unit.
• The recruitment of RNA polymerase I on rDNA is mediated by the interaction of the A43 subunit with Rrn3