Variant histone H2A.Z, but not the HMG proteins Nhp6a/b, is essential for the recruitment of Swi/Snf, Mediator, and SAGA to the yeast GAL1 UAS(G).
Chromatin architecture is very important for the regulation of transcriptional activation. Here, we investigated the role of two different chromatin components, the histone variant H2A.Z and HMG proteins Nhp6a/b, in regulating GAL1 gene expression. We have shown that recruitment of the Mediator complex is significantly affected in the absence of H2A.Z. Furthermore, H2A.Z is also required to fully recruit the SAGA and Swi/Snf complexes to the yeast GAL1-10 UAS(G). On the other hand, the HMG protein Nhp6a/b is not required to recruit the aforementioned components to the GAL1 promoter. The Nhp6 protein has been shown to interact with nucleosomes, and we show that its distribution is unaffected in the absence of H2A.Z. Our results suggest that the incorporation of the histone variant H2A.Z, but not the HMG proteins Nhp6a/b, in promoter regions creates a specialized chromatin domain that is required for pre-initiation complex assembly at the GAL1 locus.
Lemieux
Karine
K
Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, Que., Canada.
Larochelle
Marc
M
Gaudreau
Luc
L
D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005686:Galactokinase / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D024001:HMGN Proteins; D006609:High Mobility Group Proteins / Q000378:metabolism*; D051548:Histone Acetyltransferases / Q000378:metabolism; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D056892:Mediator Complex; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation; D000099224:p300-CBP-Associated Factor
D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D005686:Galactokinase; D024001:HMGN Proteins; D006609:High Mobility Group Proteins; D051548:Histone Acetyltransferases; D006657:Histones; D056892:Mediator Complex; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C493530:Htz1 protein, S cerevisiae; C086471:NHP6A protein, S cerevisiae; C086472:NHP6B protein, S cerevisiae; C507785:SAGA complex, S cerevisiae; C082148:SRB4 protein, S cerevisiae; C078562:SWI1 protein, S cerevisiae; C501392:GCN5 protein, S cerevisiae; D000099224:p300-CBP-Associated Factor; C524219:GAL1 protein, S cerevisiae