Role of the RNA polymerase alpha subunit in transcription activation.
The N-terminal two-thirds of the alpha subunit of Escherichia coli RNA polymerase plays an essential role in the initiation of subunit assembly, by gathering two large subunits, beta and beta', together into a core-enzyme complex. One group of RNA polymerase mutants deficient in response to transcription activation carries mutations in the C-terminal region of the alpha subunit, indicating that the C-terminal region of the alpha subunit is involved in protein-protein contact in positive control of transcription. A set of activators (class I transcription factors) which make contact with this contact site I region on RNA polymerase alpha subunit bind in most cases to DNA upstream of the promoter -35 signal. Genetic fine mapping indicates that a cluster of subsites exists in the contact site I region, each interacting with a set of the class I factors and each consisting of a structure formed by only 5-10 amino acid residues.
Ishihama
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Department of Molecular Genetics, National Institute of Genetics, Shizuoka, Japan.
D001426:Bacterial Proteins / Q000378:metabolism*; D001665:Binding Sites; D004269:DNA, Bacterial / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D012318:RNA Polymerase I / Q000737:chemistry / Q000502:physiology*; D012045:Regulatory Sequences, Nucleic Acid; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D014157:Transcription Factors; D012318:RNA Polymerase I