Document Detail

Characterization of pre-transcription complexes made at a bacteriophage T4 middle promoter: involvement of the T4 MotA activator and the T4 AsiA protein, a sigma 70 binding protein, in the formation of the open complex.
MedLine Citation:
PMID:  8594193     Owner:  NLM     Status:  MEDLINE    
Bacteriophage T4 middle promoters have excellent matches to the -10 consensus sequence for the sigma 70 subunit of Escherichia coli RNA polymerase, but a binding site for the T4 transcriptional activator MotA replaces the sigma 70 -35 consensus. E. Coli RNA polymerase transcribes from middle promoters with or without the activator. In contrast, transcription by T4-modified E. coli RNA polymerase, which is present during T4 infection, requires NotA. We show that transcription by unmodified polymerase from the T4 middle promoter P uvsx is independent of the specific sequences within the -35 region, and the Dnase I footprint obtained with unmodified polymerase and P uvsx resembles those seen previously with E. coli extended -10" promoters. In contrast, although T4-modified polymerase alond binds P uvsx, promoter unwinding and detection of a Dnase I footprint requires MotA. This footprint is significantly different from that obtained with unmodified polymerase, starting upstream of around position -20. Previous work has indicated that the T4 AsiA protein, which binds tightly to sigma 70, is the phage modification required for MotA activation. We show that in the presence of AsiA, MotA, and otherwise unmodified polymerase, Dnase I protection of P uvsx is now similar to that obtained with the fully modified polymerase and MotA up to around position -40. However, protection upstream of -40 is still similar to that seen with unmodified polymerase. Our results support the idea that MotA-dependent activation requires AsiA binding to sigma 70 to achieve specific protein-DNA contacts within the -20 to -40 region of a middle promoter.
D M Hinton; R March-Amegadzie; J S Gerber; M Sharma
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of molecular biology     Volume:  256     ISSN:  0022-2836     ISO Abbreviation:  J. Mol. Biol.     Publication Date:  1996 Feb 
Date Detail:
Created Date:  1996-04-11     Completed Date:  1996-04-11     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  2985088R     Medline TA:  J Mol Biol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  235-48     Citation Subset:  IM    
Laboratory of Molecular and Cellular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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MeSH Terms
Bacteriophage T4 / genetics*
Base Sequence
DNA Footprinting
DNA, Viral / metabolism
DNA-Binding Proteins / genetics,  metabolism*
DNA-Directed RNA Polymerases / metabolism*
Deoxyribonuclease I / metabolism
Membrane Proteins / genetics
Molecular Sequence Data
Promoter Regions, Genetic*
Protein Binding
Sigma Factor / metabolism*
Transcription Factors / metabolism*
Transcription, Genetic*
Viral Proteins / genetics,  metabolism*
Reg. No./Substance:
0/AsiA protein, Enterobacteria phage T4; 0/DNA, Viral; 0/DNA-Binding Proteins; 0/Membrane Proteins; 0/MotA protein, Enterobacteria phage T4; 0/Sigma Factor; 0/Trans-Activators; 0/Transcription Factors; 0/UvsX protein, Enterobacteria phage T4; 0/Viral Proteins; EC 2.7.7.-/RNA polymerase sigma 70; EC RNA Polymerases; EC I

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