These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Mutations affecting two adjacent amino acid residues in the alpha subunit of RNA polymerase block transcriptional activation by the bacteriophage P2 Ogr protein.
    Author: Ayers DJ, Sunshine MG, Six EW, Christie GE.
    Journal: J Bacteriol; 1994 Dec; 176(24):7430-8. PubMed ID: 8002564.
    Abstract:
    The bacteriophage P2 ogr gene product is a positive regulator of transcription from P2 late promoters. The ogr gene was originally defined by compensatory mutations that overcame the block to P2 growth imposed by a host mutation, rpoA109, in the gene encoding the alpha subunit of RNA polymerase. DNA sequence analysis has confirmed that this mutation affects the C-terminal region of the alpha subunit, changing a leucine residue at position 290 to a histidine (rpoAL290H). We have employed a reporter plasmid system to screen other, previously described, rpoA mutants for effects on activation of a P2 late promoter and have identified a second allele, rpoA155, that blocks P2 late transcription. This mutation lies just upstream of rpoAL290H, changing the leucine residue at position 289 to a phenylalanine (rpoAL289F). The effect of the rpoAL289F mutation is not suppressed by the rpoAL290H-compensatory P2 ogr mutation. P2 ogr mutants that overcome the block imposed by rpoAL289F were isolated and characterized. Our results are consistent with a direct interaction between Ogr and the alpha subunit of RNA polymerase and support a model in which transcription factor contact sites within the C terminus of alpha are discrete and tightly clustered.
    [Abstract] [Full Text] [Related] [New Search]