Open AccessA novel yeast protein influencing the response of RNA polymerase II to transcriptional activators
Author(s) -
Andrew Emili,
Ryûji Kobayashi,
Ingles Cj
Publication year - 1998
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.95.19.11122
Subject(s) - rna polymerase ii , repressor lexa , transcription factor ii d , rna polymerase , polymerase , biology , activator (genetics) , microbiology and biotechnology , rna polymerase ii holoenzyme , rna polymerase iii , biochemistry , rna polymerase i , transcription (linguistics) , rna , repressor , promoter , dna , gene , transcription factor , gene expression , linguistics , philosophy
A sensitivein 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 theXTC1 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 activatorsin vivo .