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Updated: May 17, 2026

Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
Published on: April 29, 2010
Visualization of the complete preprimosome reveals the structural mechanisms governing DNA replication restart
Peter L Ducos1,2, Alexander T Duckworth1,2, Kenneth A Satyshur3
1John and Jeanne Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, WI, USA.
None:
Replication restart pathways reinitiate DNA replication processes following their premature termination. In Escherichia coli, this essential process begins with regulated assembly of the preprimosome complex, comprising the PriA, PriB, and DnaT proteins, onto an abandoned replication fork. Here, we present two distinct preprimosome structures. One represents an intermediate stage in preprimosome assembly with a single DnaT C-terminal domain (DnaTCTD) bound to PriA/PriB/DNA. The second captures the mature preprimosome, in which filamentation of multiple DnaTCTD molecules catalyzes the handoff of the single-stranded lagging-strand DNA from PriB to DnaT. The DnaT N-terminal domain forms a separate, independent oligomer in the mature structure. Taken together, our results detail the molecular mechanisms underlying replication restart initiation and regulation and suggest mechanistic similarities between DnaT and the canonical initiator protein DnaA.
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