Regulation of expression of the Escherichia coli dnaG gene and amplification of the dnaG primase

M S Wold; R McMacken

doi:10.1073/pnas.79.16.4907

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Regulation of expression of the Escherichia coli dnaG gene and amplification of the dnaG primase

Journal article

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Regulation of expression of the Escherichia coli dnaG gene and amplification of the dnaG primase

M S Wold and R McMacken

Proceedings of the National Academy of Sciences - PNAS, Vol.79(16), pp.4907-4911

08/1982

DOI: 10.1073/pnas.79.16.4907

PMCID: PMC346794

PMID: 6214788

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Abstract

We have isolated lambda transducing phages carrying the Escherichia coli primase gene (dnaG) and mapped restriction sites in the cloned bacterial DNA segments. Several different DNA fragments containing the dnaG gene were inserted into multicopy plasmids. An analysis of the primase levels in cells harboring such plasmids indicates that sequences far upstream from the dnaG gene are required for optimal primase expression. Using this knowledge, we constructed a plasmid with a thermoinducible copy-number, pRLM61, which was employed to amplify intracellular primase levels approximately 100-fold. The dnaG gene is transcribed clockwise with respect to the E. coli genetic map, and a HindIII site located 180 base pairs upstream from the dnaG gene separates the gene from its primary promoter. An apparent transcription termination signal is positioned 30-70 base pairs in front of the primase gene. Transcription proceeds past this strong terminator only when RNA polymerase has first transcribed the bacterial DNA segment proximal to the HindIII site. We suggest that primase expression in E. coli is positively regulated by a mechanism of transcription antitermination mediated by a bacterial factor. We propose, furthermore, that the neighboring structural genes for primase and for the sigma subunit of RNA polymerase are coordinately regulated as part of an operon. This arrangement may enable the bacterial cell to readily control the level of initiation of DNA and RNA synthesis and thus to respond quickly and efficiently to changing conditions.

Genes

Genes, Bacterial

Operon

Bacteriophage lambda

Bacterial Proteins - genetics

Gene Expression Regulation

DNA-Directed RNA Polymerases - genetics

Gene Amplification

Escherichia coli - genetics

RNA Nucleotidyltransferases - genetics

DNA, Recombinant

Transcription, Genetic

Nucleic Acid Conformation

DNA Primase

Details

Title: Subtitle: Regulation of expression of the Escherichia coli dnaG gene and amplification of the dnaG primase
Creators: M S Wold
R McMacken
Resource Type: Journal article
Publication Details: Proceedings of the National Academy of Sciences - PNAS, Vol.79(16), pp.4907-4911
DOI: 10.1073/pnas.79.16.4907
PMID: 6214788
PMCID: PMC346794
NLM abbreviation: Proc Natl Acad Sci U S A
ISSN: 0027-8424
eISSN: 1091-6490
Publisher: National Academy of Sciences; United States
Grant note: GM-24282 / NIGMS NIH HHS
Language: English
Date published: 08/1982
Academic Unit: Radiation Oncology; Biochemistry and Molecular Biology
Record Identifier: 9984025293702771

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