Download MendeleyA hand-off mechanism for primosome assembly in replication restart.
Lopper, M., Boonsombat, R., Sandler, S.J., Keck, J.L.(2007) Mol Cell 26: 781-793
- PubMed: 17588514
- DOI: https://doi.org/10.1016/j.molcel.2007.05.012
- Primary Citation of Related Structures:
2PNH - PubMed Abstract:
Collapsed DNA replication forks must be reactivated through origin-independent reloading of the replication machinery (replisome) to ensure complete duplication of cellular genomes. In E. coli, the PriA-dependent pathway is the major replication restart mechanism and requires primosome proteins PriA, PriB, and DnaT for replisome reloading. However, the molecular mechanisms that regulate origin-independent replisome loading are not fully understood. Here, we demonstrate that assembly of primosome protein complexes represents a key regulatory mechanism, as inherently weak PriA-PriB and PriB-DnaT interactions are strongly stimulated by single-stranded DNA. Furthermore, the binding site on PriB for single-stranded DNA partially overlaps the binding sites for PriA and DnaT, suggesting a dynamic primosome assembly process in which single-stranded DNA is handed off from one primosome protein to another as a repaired replication fork is reactivated. This model helps explain how origin-independent initiation of DNA replication is restricted to repaired replication forks, preventing overreplication of the genome.
Organizational Affiliation:
Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, 550 Medical Sciences Center, 1300 University Avenue, Madison, WI 53706, USA.
