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Eclipse period during replication of plasmid R1: contributions from structural events and from the copy‐number control system by Jan A. Olsson; Otto G. Berg; Santanu Dasgupta; Kurt Nordström is a Biochemistry, Genetics and Molecular Biology article available to read on EtoBox.

What is Eclipse period during replication of plasmid R1: contributions from structural events and from the copy‐number control system about?

## Summary The eclipse period (the time period during which a newly replicated plasmid copy is not available for a new replication) of plasmid R1 in __Escherichia coli__ was determined with the classic Meselson–Stahl density‐shift experiment. A mini‐plasmid with the wild‐type R1 replicon and a mutant with a thermo‐inducible runaway‐replication phenotype were used in this work. The eclipses of the chromosome and of the wild‐type plasmid were 0.6 and 0.2 generation times, respectively, at temperatures ranging from 30°C to 42°C. The mutant plasmid had a similar eclipse at temperatures up to 38°C. At 42°C, the plasmid copy number increased rapidly because of the absence of replication control and replication reached a rate of 350–400 plasmid replications per cell and cell generation. During uncontrolled replication, the eclipse was about 3 min compared with 10 min at controlled replication (the wild‐type plasmid at 42°C). Hence, the copy‐number control system contributed significantly to the eclipse. The eclipse in the absence of copy‐number control (3 min) presumably is caused by structural requirements: the covalently closed circular plasmid DNA has to regain the right degree of supe

Who reads Eclipse period during replication of plasmid R1: contributions from structural events and from the copy‐number control system?

Author

Jan A. Olsson; Otto G. Berg; Santanu Dasgupta; Kurt Nordström

Publisher

John Wiley and Sons; Wiley (Blackwell Publishing); Blackwell Publishing Inc.; Wiley (ISSN 0950-382X)

Published

2003

Language

EN

Field

Biochemistry, Genetics and Molecular Biology (Life Sciences)