Spt3 and Mot1 cooperate in nucleosome remodeling independently of TBP recruitment.
We have investigated the requirements for nucleosome remodeling upon transcriptional induction of the GAL1 promoter. We found that remodeling was dependent on two SAGA complex components, Gcn5 and Spt3. The involvement of the latter was surprising as its function has been suggested to be directly involved in TATA-binding protein (TBP) recruitment. We demonstrated that this novel function was in fact independent of TBP recruitment and this was further validated using a Gal4-driven synthetic promoter. Most importantly, we showed that the involvement of Spt3 in chromatin remodeling was independent of transcription, as it was also observed for a nonpromoter nucleosome located next to an activator-binding site. In an effort to explore how the Spt3 function was elicited, we found that Mot1, an ATPase of the Snf2 family that genetically interacts with Spt3, was also required for nucleosome remodeling independently of TBP recruitment. Interestingly enough, Spt3 and Mot1 were recruited on the GAL1 promoter as well as on the nonpromoter site in an interdependent manner. These findings show that the two proteins cooperate in nucleosomal transactions.
Topalidou
Irini
I
Institute of Molecular Biology and Biotechnology, FORTH, Crete, Greece.
Papamichos-Chronakis
Manolis
M
Thireos
George
G
Tzamarias
Dimitris
D
D000251:Adenosine Triphosphatases; D042002:Chromatin Assembly and Disassembly / Q000502:physiology*; D047369:Chromatin Immunoprecipitation; D004265:DNA Helicases / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D015870:Gene Expression; D051548:Histone Acetyltransferases; D009707:Nucleosomes / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011494:Protein Kinases / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D035381:TATA-Binding Protein Associated Factors / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics; D015003:Yeasts; D000099224:p300-CBP-Associated Factor
D000251:Adenosine Triphosphatases; D004265:DNA Helicases; D004268:DNA-Binding Proteins; D051548:Histone Acetyltransferases; D009707:Nucleosomes; D011494:Protein Kinases; D029701:Saccharomyces cerevisiae Proteins; D035381:TATA-Binding Protein Associated Factors; D014157:Transcription Factors; C052130:GAL4 protein, S cerevisiae; C075582:SPT3 protein, S cerevisiae; C501392:GCN5 protein, S cerevisiae; D000099224:p300-CBP-Associated Factor; C073676:MOT1 protein, S cerevisiae