Open AccessPositive regulation of general transcription factor SIII by a tailed ubiquitin homolog.
Author(s) -
Karla P. Garrett,
Teijiro Aso,
John Bradsher,
Stephen I. Foundling,
William S. Lane,
Ronald C. Conaway,
Joan Weliky Conaway
Publication year - 1995
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.92.16.7172
Subject(s) - rna polymerase ii , protein subunit , biology , ubiquitin , transcription (linguistics) , microbiology and biotechnology , polymerase , transcription factor , general transcription factor , transcription factor ii d , gene , chemistry , genetics , rna polymerase , rna , promoter , gene expression , linguistics , philosophy
General transcription factor SIII, a heterotrimer composed of 110-kDa (p110), 18-kDa (p18), and 15-kDa (p15) subunits, increases the catalytic rate of transcribing RNA polymerase II by suppressing transient pausing by polymerase at multiple sites on DNA templates. Here we report molecular cloning and biochemical characterization of the SIII p18 subunit, which is found to be a member of the ubiquitin homology (UbH) gene family and functions as a positive regulatory subunit of SIII. p18 is a 118-amino acid protein composed of an 84-residue N-terminal UbH domain fused to a 34-residue C-terminal tail. Mechanistic studies indicate that p18 activates SIII transcriptional activity above a basal level inherent in the SIII p110 and p15 subunits. Taken together, these findings establish a role for p18 in regulating the activity of the RNA polymerase II elongation complex, and they bring to light a function for a UbH domain protein in transcriptional regulation.