title: Transcription cofactor PC4 plays essential roles in collaboration with the small subunit of general transcription factor TFIIE.
abstract: In eukaryotes, positive cofactor 4 (PC4) stimulates activator-dependent transcription by facilitating transcription initiation and the transition from initiation to elongation. It also forms homodimers and binds to single-stranded DNA and various transcriptional activators, including the general transcription factor TFIIH. In this study, we further investigated PC4 from Homo sapiens and the nematode Caenorhabditis elegans (hPC4 and cePC4, respectively). hPC4 strongly stimulated transcription on a linearized template, whereas it alleviated transcription on a supercoiled template. Transcriptional stimulation by PC4 was also alleviated by increasing the amount of TFIID. GST pull-down studies with general transcription factors indicated that both hPC4 and cePC4 bind strongly to TFIIB, TFIIEβ, TFIIFα, TFIIFβ and TFIIH XPB subunits and weakly to TBP and TFIIH p62. However, only hPC4 bound to CDK7. The effect of each PC4 on transcription was studied in combination with TFIIEβ. hPC4 stimulated both basal and activated transcription, whereas cePC4 primarily stimulated activated transcription, especially in the presence of TFIIEβ from C. elegans. Finally, hPC4 bound to the C-terminal region of hTFIIEβ adjacent to the basic region. These results indicate that PC4 plays essential roles in the transition step from transcription initiation to elongation by binding to melted DNA in collaboration with TFIIEβ.
authors.affiliation: Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Akimoto
authors.forename: Seiji
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iida
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Hirose
authors.forename: Aki
authors.initials: A
authors.lastname: Tanaka
authors.forename: Fumio
authors.initials: F
authors.lastname: Hanaoka
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Ohkuma
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D035581:Transcription Factor TFIIB / Q000235:genetics / Q000378:metabolism; D035362:Transcription Factor TFIID / Q000235:genetics / Q000378:metabolism; D051758:Transcription Factor TFIIH / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D019473:Transcription Factors, TFII / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D029742:Caenorhabditis elegans Proteins; D004268:DNA-Binding Proteins; C509201:SUB1 protein, human; D035581:Transcription Factor TFIIB; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII; C066644:transcription factor TFIIE; D051758:Transcription Factor TFIIH