Cdk1 triggers association of RNA polymerase to cell cycle promoters only after recruitment of the mediator by SBF.
Activation of HO in yeast involves recruitment of transcription factors in two waves. The first is triggered by inactivation of Cdk1 at the end of mitosis, which promotes import into the nucleus of the Swi5 transcription factor. Swi5 recruits the Swi/Snf chromatin-remodeling complex, which then facilitates recruitment of the SAGA histone acetylase, which in turn permits the binding of the SBF transcription factor. We show here that SBF then recruits the SRB/mediator complex and that this process occurs in the absence of Cdk1 activity. The second wave is triggered by reactivation of Cdk1, which leads to recruitment of PolII, TFIIB, and TFIIH. RNA polymerase is, therefore, recruited to HO in two steps and not as a holoenzyme. A similar sequence of events occurs at other SBF-regulated promoters, such as CLN1, CLN2, and PCL1.
Cosma
M P
MP
Research Institute of Molecular Pathology, A-1030, Vienna, Austria.
Panizza
S
S
Nasmyth
K
K
D016203:CDC2 Protein Kinase / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins; D018844:Cyclin-Dependent Kinases; D004258:DNA Polymerase III / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D035381:TATA-Binding Protein Associated Factors; D035581:Transcription Factor TFIIB; D035362:Transcription Factor TFIID; D051758:Transcription Factor TFIIH; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D019473:Transcription Factors, TFII; D015003:Yeasts
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C081540:SBF protein, S cerevisiae; C080218:SWI5 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C490039:TAF6 protein, S cerevisiae; D035381:TATA-Binding Protein Associated Factors; D035581:Transcription Factor TFIIB; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII; D051758:Transcription Factor TFIIH; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; D018844:Cyclin-Dependent Kinases; C084210:Kin28 protein kinase, S cerevisiae; D012321:DNA-Directed RNA Polymerases; D004258:DNA Polymerase III; C530845:HO protein, S cerevisiae; C037725:SCEI protein, S cerevisiae; D015252:Deoxyribonucleases, Type II Site-Specific