title: Cloning and sequencing of Escherichia coli mutR shows its identity to topB, encoding topoisomerase III.
abstract: We have cloned and sequenced the mutR gene from Escherichia coli, which results in an increased frequency of spontaneous deletions, by using a strain carrying a Tn10 derivative inserted into mutR. The analysis of 1,286 bp of mutR sequence shows that this gene is identical to the topB gene, which encodes topoisomerase III. The increased deletion formation is the first reported phenotype for cells lacking topoisomerase III, and this suggests that topoisomerase III is involved in reactions that normally reduce the levels of spontaneous deletions.
authors.affiliation: Molecular Biology Institute, University of California, Los Angeles 90024.
authors.forename: M A
authors.initials: MA
authors.lastname: Schofield
authors.forename: R
authors.initials: R
authors.lastname: Agbunag
authors.forename: M L
authors.initials: ML
authors.lastname: Michaels
authors.forename: J H
authors.initials: JH
authors.lastname: Miller
mesh_terms: D001483:Base Sequence; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004264:DNA Topoisomerases, Type I / Q000235:genetics* / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data
chemical_list: D004264:DNA Topoisomerases, Type I