Identification and characterization of CIA/ASF1 as an interactor of bromodomains associated with TFIID.
General transcription initiation factor IID (TFIID) plays a central and critical role in transcription initiation from both naked and chromatin templates. Although interaction between several DNA-binding proteins and TFIID were identified and well characterized, functional linkage between TFIID and chromatin factors has remained to be elucidated. Here we show the identification and characterization of human CIA/hASF1 (identified previously as a histone chaperone) as an interactor of two tandem bromodomain modules of human (h)TAF(II)250/CCG1, the largest subunit of TFIID. Although yeast (y)TAF(II)145, a homologue of hTAF(II)250/CCG1 in Saccharomyces cerevisiae, lacks bromodomains, glutathione S-transferase pull-down and immunoprecipitation assays revealed that Asf1p (antisilencing function 1), the counterpart of CIA in S. cerevisiae, interacts with Bdf1p (bromodomain factor 1), which is reported to serve as the missing bromodomain in yTAF(II)145. Furthermore, yeast strain lacking the BDF1 gene shows the Spt phenotype that is shown also by the ASF1 gene disruptant, and a double-knockout strain of both genes shows synthetic lethality, indicating that ASF1 genetically interacts with bromodomains associated with yTFIID. We also found that Asf1p coprecipitates with yTFIID subunits from yeast whole-cell extract, and overexpression of yTFIID subunits suppress the Spt phenotype caused by gene disruption of the ASF1. This study describes the functional linkage between TFIID and a histone chaperone.
Chimura
Takahiko
T
Laboratory of Developmental Biology, Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
Kuzuhara
Takashi
T
Horikoshi
Masami
M
D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D017353:Gene Deletion; D006801:Humans; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D018832:Molecular Chaperones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019473:Transcription Factors, TFII / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D000092468:Bromodomain Containing Proteins
D018797:Cell Cycle Proteins; D046911:Macromolecular Substances; D018832:Molecular Chaperones; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII; C109731:ASF1 protein, S cerevisiae; C491641:ASF1A protein, human; C491640:ASF1B protein, human; C091342:BDF1 protein, S cerevisiae; D000092468:Bromodomain Containing Proteins