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Evidence that F plasmid transfer replication underlies apparent adaptive mutation
1Department of Biology, University of Utah, Salt Lake City 84112, USA.
Science (New York, N.Y.)
|April 21, 1995
Summary
Adaptive mutations in Escherichia coli are linked to F factor transfer functions. Fertility inhibition prevents RecA-dependent reversion, suggesting adaptive mutations occur during replication from the F factor
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- Escherichia coli K12 strain FC40 is a model for studying adaptive mutability.
- This strain possesses a revertible lac allele on an F plasmid, enabling the study of lactose utilizing (Lac+) revertants.
- Adaptive mutations are a specific subset of spontaneous mutations dependent on RecABC functions.
Purpose of the Study:
- To investigate the role of F factor transfer functions in adaptive mutability.
- To determine if F factor transfer is necessary for the formation of adaptive Lac+ revertants.
Main Methods:
- Utilizing Escherichia coli K12 strain FC40.
- Employing selective media to observe the accumulation of Lac+ revertants.
- Investigating the effect of fertility inhibition on RecA-dependent adaptive reversion.
Main Results:
- Adaptive mutations are dependent on RecABC functions.
- The formation of adaptive revertants is linked to the transfer functions of the F factor.
- Fertility inhibition abrogates RecA-dependent adaptive reversion.
Conclusions:
- Adaptive mutations appear to arise during replication from the F factor's transfer origin.
- Genetic loci on the nonreplicating chromosome exhibit minimal adaptive mutation compared to F factor-associated loci.