The disposition of nascent strands at stalled replication forks dictates the pathway of replisome loading during restart.
Rescue of arrested and collapsed replication forks is essential for maintenance of genomic integrity. One system for origin of replication-independent loading of the DnaB replicative helicase and subsequent replisome reassembly requires the structure-specific recognition factor PriA and the assembly factors PriB and DnaT. Here, we provide biochemical evidence for an alternate system for DnaB loading that requires only PriC. Furthermore, the choice of which system is utilized during restart is dictated by the nature of the structure of the stalled replication fork. PriA-dependent reactions are most robust on fork structures with no gaps in the leading strand, such as is found at the junction of a D loop, while the PriC-dependent system preferentially utilizes fork structures with large gaps in the leading strand. These observations suggest that the type of initial damage on the DNA template and how the inactivated fork is processed ultimately influence the choice of enzymatic restart pathway.
Heller
Ryan C
RC
Program in Molecular Biology, Weill Graduate School of Medical Sciences, Cornell University, New York, New York 10021, USA.
Marians
Kenneth J
KJ
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000502:physiology; D001426:Bacterial Proteins / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D004249:DNA Damage; D004265:DNA Helicases / Q000737:chemistry / Q000502:physiology; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000502:physiology; D053488:DnaB Helicases; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000502:physiology; D016678:Genome
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C104198:DnaT protein, E coli; D029968:Escherichia coli Proteins; D004247:DNA; D000251:Adenosine Triphosphatases; C506730:dnaB protein, E coli; C506743:priA protein, E coli; D004265:DNA Helicases; D053488:DnaB Helicases