Publication Date:
2011-12-24
Description:
DNA replication machineries have been studied extensively, but the kinetics of action of their components remains largely unknown. We report a study of DNA synthesis during replication in living Escherichia coli cells. Using single-molecule microscopy, we observed repetitive fluorescence bursts of single polymerase IIIs (Pol IIIs), indicating polymerase exchange at the replication fork. Fluctuations in the amount of DNA-bound single-stranded DNA-binding protein (SSB) reflect different speeds for the leading- and lagging-strand DNA polymerases. Coincidence analyses of Pol III and SSB fluctuations show that they correspond to the lagging-strand synthesis and suggest the use of a new Pol III for each Okazaki fragment. Based on exchanges involving two Pol IIIs, we propose that the third polymerase in the replisome is involved in lagging-strand synthesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lia, Giuseppe -- Michel, Benedicte -- Allemand, Jean-Francois -- New York, N.Y. -- Science. 2012 Jan 20;335(6066):328-31. doi: 10.1126/science.1210400. Epub 2011 Dec 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉CNRS, Centre de Genetique Moleculaire, UPR3404, Gif-sur-Yvette F-91198, France. lia@cgm.cnrs-gif.fr〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22194411" target="_blank"〉PubMed〈/a〉
Keywords:
Bacterial Proteins/metabolism
;
DNA/*biosynthesis
;
DNA Polymerase III/*metabolism
;
*DNA Replication
;
DNA, Bacterial/*biosynthesis
;
DNA, Single-Stranded/metabolism
;
DNA-Binding Proteins/*metabolism
;
Escherichia coli/*metabolism
;
Escherichia coli Proteins/*metabolism
;
Fluorescence
;
Kinetics
;
Luminescent Proteins/metabolism
;
Models, Biological
;
Photobleaching
;
Recombinant Fusion Proteins/metabolism
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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