Analysis of topoisomerase function in bacterial replication fork movement: use of DNA microarrays.
We used DNA microarrays of the Escherichia coli genome to trace the progression of chromosomal replication forks in synchronized cells. We found that both DNA gyrase and topoisomerase IV (topo IV) promote replication fork progression. When both enzymes were inhibited, the replication fork stopped rapidly. The elongation rate with topo IV alone was 1/3 of normal. Genetic data confirmed and extended these results. Inactivation of gyrase alone caused a slow stop of replication. Topo IV activity was sufficient to prevent accumulation of (+) supercoils in plasmid DNA in vivo, suggesting that topo IV can promote replication by removing (+) supercoils in front of the chromosomal fork.
Khodursky
A B
AB
Department of Molecular and Cell Biology, University of California, Berkeley 94720, USA.
Peter
B J
BJ
Schmid
M B
MB
DeRisi
J
J
Botstein
D
D
Brown
P O
PO
Cozzarelli
N R
NR
D004261:DNA Replication / Q000187:drug effects; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D004278:DNA, Superhelical / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D016680:Genome, Bacterial; D007700:Kinetics; D009068:Movement / Q000187:drug effects; D009154:Mutation / Q000235:genetics; D009675:Novobiocin / Q000494:pharmacology; D020411:Oligonucleotide Array Sequence Analysis; D010957:Plasmids / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D059005:Topoisomerase II Inhibitors
D004269:DNA, Bacterial; D004278:DNA, Superhelical; D059005:Topoisomerase II Inhibitors; D009675:Novobiocin; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II