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Primosome assembly requirement for replication restart in the Escherichia coli holD G10 replication mutant
Author(s) -
Flores Maria Jose,
Ehrlich S. Dusko,
Michel Bénédicte
Publication year - 2002
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2002.02913.x
Subject(s) - biology , mutant , mutation , replication (statistics) , dna replication , mutagenesis , microbiology and biotechnology , spheroplast , function (biology) , genetics , escherichia coli , gene , virology
Summary In this report, we study the role of pre‐primosome proteins in a strain in which the frequency of replication arrest is increased because of a mutation in a replication protein. The holD G10 mutant was used, in which replication restart involves replication fork reversal. As expected, PriA primosome assembly function is essential for growth of the holD G10 mutant. The priA300 mutation, which inactivates only the helicase function of PriA in vitro , and priB inactivation strongly impair viability. In contrast, priC inactivation has no effect. Therefore, PriB is more important than PriC for PriA‐dependent replication fork restart in vivo . The gain of function mutation dnaC809 restores the viability of holD G10 priA and holD G10 priB mutants only to some extent. The dnaC809 820 double mutation restores full viability to the holD G10 mutant lacking either PriA or PriB. Similarly to the holD G10 single mutant, the holD G10 priA dnaC809 820 strain is depend‐ent on RecBC for viability, indicating that facilitating primosome assembly using the dnaC809 820 mutation does not allow bypass of replication fork reversal.