Yeast two-hybrid analysis of prib-interacting proteins in replication restart primosome

PriB is one of the components of the replication restart primosome. The activity mediated by the primosomal proteins, including PriB, is required for reinitiating chromosomal DNA replication in bacteria after DNA damage. As such, the study of the interactions between PriB and members in the primosome is essential to better understand their mechanism of action. In this study, we investigated PriB-interacting proteins in the primosome through the yeast two-hybrid system. Yeast two-hybrid analysis using two strains, Y187 and AH109, revealed that PriB interacts with PriA, DnaT, SSB, and itself and does not interact with DnaA, DnaB, DnaC, or DnaG. In addition, mutational analysis showed that PriB may bind to SSB via K82, K84, and K89 in the L45 loop. Based on these preliminary data, we proposed a PriB-SSB interaction model. Further work can focus on determination of how PriB binds to the PriA-SSB complex in replication restart.