title: Differences in the degree of inhibition of NDP reductase by chemical inactivation and by the thermosensitive mutation nrdA101 in Escherichia coli suggest an effect on chromosome segregation.
abstract: NDP reductase activity can be inhibited either by treatment with hydroxyurea or by incubation of an nrdA (ts) mutant strain at the non-permissive temperature. Both methods inhibit replication, but experiments on these two types of inhibition yielded very different results. The chemical treatment immediately inhibited DNA synthesis but did not affect the cell and nucleoid appearance, while the incubation of an nrdA101 mutant strain at the non-permissive temperature inhibited DNA synthesis after more than 50 min, and resulted in aberrant chromosome segregation, long filaments, and a high frequency of anucleate cells. These phenotypes are not induced by SOS. In view of these results, we suggest there is an indirect relationship between NDP reductase and the chromosome segregation machinery through the maintenance of the proposed replication hyperstructure.
authors.affiliation: Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain. a.jimenezsanchez@gmail.com
authors.forename: José
authors.initials: J
authors.lastname: Riola
authors.forename: Estrella
authors.initials: E
authors.lastname: Guarino
authors.forename: Elena C
authors.initials: EC
authors.lastname: Guzmán
authors.forename: Alfonso
authors.initials: A
authors.lastname: Jiménez-Sánchez
mesh_terms: D002455:Cell Division / Q000187:drug effects / Q000528:radiation effects; D020090:Chromosome Segregation / Q000187:drug effects / Q000528:radiation effects; D002876:Chromosomes, Bacterial / Q000378:metabolism*; D004269:DNA, Bacterial / Q000096:biosynthesis; D004789:Enzyme Activation / Q000187:drug effects / Q000528:radiation effects; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006918:Hydroxyurea / Q000494:pharmacology; D007211:Indoles; D008027:Light; D009154:Mutation / Q000235:genetics*; D012262:Ribonucleoside Diphosphate Reductase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D012542:Scattering, Radiation; D013696:Temperature
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D007211:Indoles; C007293:DAPI; C449642:NrdA protein, E coli; D012262:Ribonucleoside Diphosphate Reductase; D006918:Hydroxyurea