Mitotic repression of RNA polymerase III transcription in vitro mediated by phosphorylation of a TFIIIB component.
Interphase cytosol extracts prepared from Xenopus laevis eggs are active in RNA polymerase III (Pol III) transcription. Addition of recombinant B1 cyclin to these extracts activates mitotic protein kinases that repress transcription. Affinity-purified p34cdc2-cyclin B kinase (mitosis-promoting factor) is sufficient to effect this repression in a simplified Pol III transcription system. This mitotic repression involves the direct phosphorylation of a component of the Pol III transcription initiation factor TFIIIB, which consists of the TATA box-binding protein (TBP) and associated Pol III-specific factors. The transcriptional activity of the TFIIIB-TBP fraction can be modulated in vitro by phosphorylation with mitotic kinases and by dephosphorylation with immobilized alkaline phosphatase.
Gottesfeld
J M
JM
Department of Molecular Biology, Scripps Research Institute, La Jolla, CA 92037.
Wolf
V J
VJ
Dang
T
T
Forbes
D J
DJ
Hartl
P
P
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D007399:Interphase; D008938:Mitosis; D010063:Ovum / Q000378:metabolism; D010766:Phosphorylation; D012320:RNA Polymerase III / Q000378:metabolism*; D016385:TATA Box; D035181:TATA-Box Binding Protein; D035361:Transcription Factor TFIIIB; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014982:Xenopus laevis
D004268:DNA-Binding Proteins; D035181:TATA-Box Binding Protein; D035361:Transcription Factor TFIIIB; D014157:Transcription Factors; D016203:CDC2 Protein Kinase; D012320:RNA Polymerase III; D000469:Alkaline Phosphatase