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The RdgC protein of Escherichia coli binds DNA and counters a toxic effect of RecFOR in strains lacking the replication restart protein PriA
Author(s) -
Moore Timothy,
McGlynn Peter,
Ngo HienPing,
Sharples Gary J.,
Lloyd Robert G.
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg048
Subject(s) - queen (butterfly) , research centre , library science , biology , genetics , hymenoptera , botany , computer science
PriA protein provides a means to load the DnaB replicative helicase at DNA replication fork and D loop structures, and is therefore a key factor in the rescue of stalled or broken forks and subsequent replication restart. We show that the nucleoid‐associated RdgC protein binds non‐specifically to single‐stranded (ss) DNA and double‐stranded DNA. It is also essential for growth of a strain lacking PriA, indicating that it might affect replication fork progression or fork rescue. dnaC suppressors of priA overcome this inviability, especially when RecF, RecO or RecR is inactivated, indicating that RdgC avoids or counters a toxic effect of these proteins. Mutations modifying ssDNA‐binding (SSB) protein also negate this toxic effect, suggesting that the toxicity reflects inappropriate loading of RecA on SSB‐coated ssDNA, leading to excessive or untimely RecA activity. We suggest that binding of RdgC to DNA limits RecA loading, avoiding problems at replication forks that would otherwise require PriA to promote replication restart. Mutations in RNA polymerase also reduce the toxic effect of RecFOR, providing a further link between DNA replication, transcription and repair.