Chromosomal insertions localized around oriC affect the cell cycle in Escherichia coli.
The present work reports the effects of localized insertions around the origin of Escherichia coli chromosome, oriC, on cell cycle parameters. These insertions cause an increase of the C period with an inverse correlation to the distance from oriC. In addition, Omega insertion near oriC causes an increase in the number of replication forks per chromosome, n, and Tn10 insertion causes a decrease in growth rate. We found that the same insertion positioned in another region of the chromosome, outside of oriC, has a negligible effect on the C period. Marker frequency analysis suggests a slower replication velocity along the whole chromosome. We propose that the insertions positioned at less than 2 kbp from oriC could create a structural alteration in the origin of replication that would result in a longer C period. Flow cytometry reveals that asynchrony is not associated with these alterations.
Molina
F
F
Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz 06080, Spain.
Jiménez-Sánchez
A
A
Zyskind
J W
JW
Guzmán
E C
EC
D002453:Cell Cycle / Q000235:genetics*; D002455:Cell Division; D002876:Chromosomes, Bacterial / Q000235:genetics; D004261:DNA Replication; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000166:cytology* / Q000235:genetics* / Q000378:metabolism; D005819:Genetic Markers; D007700:Kinetics; D018741:Replication Origin
D004251:DNA Transposable Elements; D005819:Genetic Markers