Publication Date:
1993-11-26
Description:
A DNA sequence rich in (A+T), located upstream of the -10, -35 region of the Escherichia coli ribosomal RNA promoter rrnB P1 and called the UP element, stimulates transcription by a factor of 30 in vivo, as well as in vitro in the absence of protein factors other than RNA polymerase (RNAP). When fused to other promoters, such as lacUV5, the UP element also stimulates transcription, indicating that it is a separate promoter module. Mutations in the carboxyl-terminal region of the alpha subunit of RNAP prevent stimulation of these promoters by the UP element although the mutant enzymes are effective in transcribing the "core" promoters (those lacking the UP element). Protection of UP element DNA by the mutant RNAPs is severely reduced in footprinting experiments, suggesting that the selective decrease in transcription might result from defective interactions between alpha and the UP element. Purified alpha binds specifically to the UP element, confirming that alpha acts directly in promoter recognition. Transcription of three other promoters was also reduced by the COOH-terminal alpha mutations. These results suggest that UP elements comprise a third promoter recognition region (in addition to the -10, -35 recognition hexamers, which interact with the sigma subunit) and may account for the presence of (A+T)-rich DNA upstream of many prokaryotic promoters. Since the same alpha mutations also block activation by some transcription factors, mechanisms of promoter stimulation by upstream DNA elements and positive control by certain transcription factors may be related.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ross, W -- Gosink, K K -- Salomon, J -- Igarashi, K -- Zou, C -- Ishihama, A -- Severinov, K -- Gourse, R L -- AI90035/AI/NIAID NIH HHS/ -- GM49242/GM/NIGMS NIH HHS/ -- R01 GM37048/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1993 Nov 26;262(5138):1407-13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Bacteriology, University of Wisconsin-Madison 53706.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8248780" target="_blank"〉PubMed〈/a〉
Keywords:
Base Sequence
;
Binding Sites
;
Carrier Proteins/metabolism
;
DNA, Bacterial/*metabolism
;
DNA-Binding Proteins/metabolism
;
DNA-Directed RNA Polymerases/*metabolism
;
Escherichia coli/enzymology/*genetics
;
*Escherichia coli Proteins
;
Integration Host Factors
;
Molecular Sequence Data
;
*Promoter Regions, Genetic
;
Transcription Factors/metabolism
;
Transcription, Genetic
;
*rRNA Operon
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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