[Multi-origin usage for chromosome replication of suppressive integration strain of dnaA46 mutant of Escherichia coli integrated with R6K].
The chromosome of temperature sensitive initiation mutant dnaA46 of Escherichia coli K-12 fails to replicate at 42 degrees C. Suppressive integration (Sin) strain integrated with the R6K plasmid was screened at 42 degrees C. Marker frequency determination of the Sin strain reveals that replication was initiated at the normal site of initiation at 30 degrees C, while at three different sites at 42 degrees C. Two of the sites have been reported in the stable DNA replication mutant, one of them is a novel site. Inhibition of chromosome replication was not observed for the recA derivative of Sin initiated at two of the initiation sites close to the normal initiation site. Inhibition was observed for chromosome replication initiated near the site where chromosome replication normally terminates. It indicates that chromosome replication initiated at sites close to the terminus is recA gene dependent.
Lu
J
J
Institute of Genetics, Fudan University, Shanghai.
Mao
Y
Y
Sheng
Z
Z
D002876:Chromosomes, Bacterial; D004261:DNA Replication; D004269:DNA, Bacterial / Q000096:biosynthesis*; D004926:Escherichia coli / Q000235:genetics* / Q000648:ultrastructure; D016153:Genes, Suppressor; D009154:Mutation; D010957:Plasmids / Q000235:genetics*
D004269:DNA, Bacterial