Constraints in chromosomal inversions in Escherichia coli are not explained by replication pausing at inverted terminator-like sequences.
Regions close to the replication terminus of the Escherichia coli chromosome are strongly refractory to genomic inversions. Since these regions also harbour polar replication terminator-like sequences or pause sites, we have investigated the possibility that slowing of replication as a result of pausing at inverted pause sites is responsible for inability to isolate stable inversions affecting these regions. A mutation in the tus gene is known to abolish replication pausing at terminators. We show here that the distribution of invertible and noninvertible segments along the chromosome is not affected by tus mutations. This observation eliminates replication pausing as a cause for the reduced fitness of bacteria harbouring certain chromosomal inversions.
Centre de Biochimie et de Génétique Cellulaires du CNRS, Toulouse, France.
V
V
François
J
J
Louarn
J
J
Patte
J E
JE
Rebollo
J M
JM
Louarn
D007446:Chromosome Inversion; D002875:Chromosomes / Q000648:ultrastructure*; D004261:DNA Replication; D004269:DNA, Bacterial / Q000096:biosynthesis*; D004926:Escherichia coli / Q000235:genetics*; D005809:Genes, Regulator; D005838:Genotype; D009154:Mutation; D013728:Terminator Regions, Genetic; D015534:Trans-Activators / Q000235:genetics
D004269:DNA, Bacterial; D015534:Trans-Activators