title: The COOH-terminal domain of the RNA polymerase alpha subunit in transcriptional enhancement and deactivation at the bacteriophage T4 late promoter.
abstract: Many activator proteins generate their positive control of transcription through interactions with the COOH-terminal domain of the Escherichia coli RNA polymerase alpha subunit. We have examined the participation of this alpha-domain in transcriptional enhancement and suppression at bacteriophage T4 late promoters. Enhancement is generated by the T4 gene 45 protein, which is the DNA-tracking processivity factor of viral DNA replication; suppression of unenhanced transcription is generated by the RNA polymerase-binding co-activator T4 gene 33 protein. Enhanced and unenhanced transcription by RNA polymerase reconstituted with intact and truncated alpha subunits and by RNA polymerase containing ADP-ribosylated alpha has been compared; the internal structures of transcription complexes formed with these RNA polymerases have also been analyzed by footprinting and photocross-linking. Comparison of these structural and functional analyses suggests that enhancement of T4 late transcription by gp45 is not compatible with any significant role of the COOH-terminal domain of the RNA polymerase core alpha subunit in transcriptional initiation. Suppression of unenhanced T4 late transcription by the gene 33 protein also does not require the COOH-terminal domain of alpha.
authors.affiliation: Department of Biology, University of California, San Diego 92093-0634, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Tinker
authors.forename: G M
authors.initials: GM
authors.lastname: Sanders
authors.forename: K
authors.initials: K
authors.lastname: Severinov
authors.forename: G A
authors.initials: GA
authors.lastname: Kassavetis
authors.forename: E P
authors.initials: EP
authors.lastname: Geiduschek
mesh_terms: D017122:Bacteriophage T4 / Q000235:genetics*; D004247:DNA / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000502:physiology; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
chemical_list: D004247:DNA; D012321:DNA-Directed RNA Polymerases