PT  - JOURNAL ARTICLE
AU  - Cohen, A
AU  - Clark, A J
TI  - Synthesis of linear plasmid multimers in Escherichia coli K-12.
AID  - 10.1128/jb.167.1.327-335.1986
DP  - 1986 Jul 01
TA  - Journal of Bacteriology
PG  - 327--335
VI  - 167
IP  - 1
4099  - http://jb.asm.org/content/167/1/327.short
4100  - http://jb.asm.org/content/167/1/327.full
SO  - J. Bacteriol.1986 Jul 01; 167
AB  - Linear plasmid multimers were identified in extracts of recB21 recC22 strains containing derivatives of the ColE1-type plasmids pACYC184 and pBR322. A mutation in sbcB increases the proportion of plasmid DNA as linear multimers. A model to explain this is based on proposed roles of RecBC enzyme and SbcB enzyme (DNA exonuclease I) in preventing two types of rolling-circle DNA synthesis. Support for this hypothesis was obtained by derepressing synthesis of an inhibitor of RecBC enzyme and observing a difference in control of linear multimer synthesis and monomer circle replication. Reinitiation of rolling-circle DNA synthesis was proposed to occur by recA+-dependent and recA+-independent recombination events involving linear multimers. The presence of linear plasmid multimers in recB and recC mutants sheds new light on plasmid recombination frequencies in various mutant strains.