title: Tuning the replication fork progression by the initiation frequency.
abstract: The thermo-resistant period of the thermo-sensitive ribonucleotide reductase RNR101 encoded by the nrdA101 allele in Escherichia coli is prolonged for 50 min at 42°C, enabling an increase in DNA content of about 45%. Assuming that fork progression in the nrdA101 mutant is impaired, the question whether reduced number of ongoing replication rounds altered the thermo-resistant period in this strain was investigated. Decreases in the oriC/terC ratio and in the number of oriC per cell at 30°C were found in the presence of oriC228, oriC229 and oriC239 alleles in strain nrdA101. Correlated with this effect, increased thermo-resistance period of the RNR101 was allowed, and the detrimental effects on cell division, chromosome segregation and cell viability observed in the nrdA101 mutant at 42°C were suppressed. These results indicate that conditions leading to chromosome initiation deficiency at 30°C enhance the replication fork progression in the nrdA101 mutant at 42°C. We propose that coordination between initiation frequency and replication fork progression could be significant for most of the replication systems with important consequences in their cell cycle regulation.
authors.affiliation: Departmento de Bioquímica Biología Molecular y Genética, Universidad de Extremadura, 06071, Badajoz, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: González Moreno
authors.forename: Carmen
authors.initials: C
authors.lastname: Mata Martín
authors.forename: Encarna
authors.initials: E
authors.lastname: Ferrera Guillén
authors.forename: Elena C
authors.initials: EC
authors.lastname: Guzmán
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D002455:Cell Division; D002876:Chromosomes, Bacterial / Q000378:metabolism*; D004261:DNA Replication; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D050296:Microbial Viability; D009154:Mutation; D051738:Origin Recognition Complex / Q000378:metabolism*; D010641:Phenotype; D018741:Replication Origin; D012264:Ribonucleotide Reductases / Q000235:genetics* / Q000378:metabolism; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D029968:Escherichia coli Proteins; C114650:OriC chromosomal replication origin; D051738:Origin Recognition Complex; D012264:Ribonucleotide Reductases