title: A novel yeast protein influencing the response of RNA polymerase II to transcriptional activators.
abstract: A sensitive in vitro crosslinking technique using a photoactive derivative of the chimeric activator LexA-E2F-1 was used to identify yeast proteins that might influence the response of RNA polymerase II to transcriptional activators. We found that a novel yeast protein, Xtc1p, could be covalently crosslinked to the activation domain of LexA-E2F-1 when this derivatized activator was bound to DNA upstream of an activator-responsive RNA polymerase II promoter. Because affinity chromatography experiments showed that Xtc1p also bound directly and specifically to the activation domains of E2F-1, the viral activator VP16, and the yeast activator Gal4p and copurified with the RNA polymerase II holoenzyme complex, Xtc1p may modulate the response of RNA polymerase II to multiple activators. Consistent with this notion, yeast strains deleted for the XTC1 gene exhibited pleiotropic growth defects, including temperature sensitivity, galactose auxotrophy, and a heightened sensitivity to activator overexpression, as well as an altered response to transcriptional activators in vivo.
authors.affiliation: Banting and Best Department of Medical Research and Department of Molecular and Medical Genetics, University of Toronto, Toronto, Canada M5G 1L6.
authors.forename: A
authors.initials: A
authors.lastname: Emili
authors.forename: R
authors.initials: R
authors.lastname: Kobayashi
authors.forename: C J
authors.initials: CJ
authors.lastname: Ingles
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000235:genetics; D003001:Cloning, Molecular; D003432:Cross-Linking Reagents / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D017930:Genes, Reporter / Q000235:genetics; D017405:Herpes Simplex Virus Protein Vmw65 / Q000378:metabolism; D009687:Nuclear Proteins; D012319:RNA Polymerase II / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D056465:Retinoblastoma-Binding Protein 1; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017421:Sequence Analysis; D012697:Serine Endopeptidases / Q000235:genetics; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics*; D000099160:LexA Repressor Protein
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D005656:Fungal Proteins; D017405:Herpes Simplex Virus Protein Vmw65; D009687:Nuclear Proteins; D012319:RNA Polymerase II; D011993:Recombinant Fusion Proteins; D056465:Retinoblastoma-Binding Protein 1; D029701:Saccharomyces cerevisiae Proteins; D012697:Serine Endopeptidases; D014157:Transcription Factors; D000099160:LexA Repressor Protein; C052130:GAL4 protein, S cerevisiae; C417727:MHR1 protein, S cerevisiae