Document Detail

Overexpression of the dnaA gene in Escherichia coli B/r: chromosome and minichromosome replication in the presence of rifampin.
MedLine Citation:
PMID:  3032899     Owner:  NLM     Status:  MEDLINE    
The replication of chromosomes and minichromosomes in Escherichia coli B/r was examined under conditions in which the dnaA gene product was overproduced. Increased levels of the DnaA protein were achieved by thermoinduction of the dnaA gene, under the control of the lambda pL promoter, or by cellular maintenance of multicopy plasmids carrying the dnaA gene under the control of its own promoters. Previous work has shown that overproduction of DnaA protein stimulates replication of the chromosomal origin, oriC, but that the newly initiated forks do not progress along the length of the chromosome (T. Atlung, K. V. Rasmussen, E. Clausen, and F. G. Hansen, p. 282-297, in M. Schaechter, F. C. Neidhardt, J. L. Ingraham, and N. O. Kjeldgaard, ed., The Molecular Biology of Bacterial Growth, 1985). In the present study, it was found that overproduction of DnaA protein caused both a two- to threefold increase in the amount of residual chromosome replication and an extended synthesis of minichromosome DNA in the presence of rifampin. The amount of residual chromosome replication was consistent with the appearance of functional replication forks on the majority of the chromosomes. Since the rate of DNA accumulation and the cellular DNA/mass ratios were not increased significantly by overexpression of the dnaA gene, we concluded that the addition of rifampin either enabled stalled replication forks to proceed beyond oriC or enabled new forks to initiate on both chromosomes and minichromosomes, or both.
O Pierucci; C E Helmstetter; M Rickert; M Weinberger; A C Leonard
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of bacteriology     Volume:  169     ISSN:  0021-9193     ISO Abbreviation:  J. Bacteriol.     Publication Date:  1987 May 
Date Detail:
Created Date:  1987-06-12     Completed Date:  1987-06-12     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2985120R     Medline TA:  J Bacteriol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1871-7     Citation Subset:  IM    
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MeSH Terms
Bacterial Proteins / genetics*
Chromosomes, Bacterial
DNA Replication / drug effects*
DNA, Bacterial / biosynthesis*,  genetics
DNA-Binding Proteins / genetics
Escherichia coli / genetics*
Gene Expression Regulation
Rifampin / pharmacology*
Grant Support
Reg. No./Substance:
0/Bacterial Proteins; 0/DNA, Bacterial; 0/DNA-Binding Proteins; 13292-46-1/Rifampin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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