In vitro strand exchange promoted by the herpes simplex virus type-1 single strand DNA-binding protein (ICP8) and DNA helicase-primase

Amitabh V. Nimonkar, Paul E Boehmer

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32 Scopus citations


The genome of herpes simplex virus type-1 undergoes a high frequency of homologous recombination in the absence of a virus-encoded RecA-type protein. We hypothesized that viral homologous recombination is mediated by the combined action of the viral single strand DNA-binding protein (ICP8) and helicase-primase. Our results show that ICP8 catalyzes the formation of recombination intermediates (joint molecules) between circular single-stranded acceptor and linear duplex donor DNA. Joint molecules formed by invasion of a 3′-terminal strand displaces the non-complementary 5′-terminal strand, thereby creating a loading site for the helicase-primase. Helicase-primase acts on these joint molecules to promote ATP-dependent branch migration. Finally, we have reconstituted strand exchange by the synchronous action of ICP8 and helicase-primase. Based on these data, we present a recombination mechanism for a eukaryotic DNA virus in which a single strand DNA-binding protein and helicase cooperate to promote homologous pairing and branch migration.

Original languageEnglish (US)
Pages (from-to)15182-15189
Number of pages8
JournalJournal of Biological Chemistry
Issue number17
Publication statusPublished - Apr 26 2002
Externally publishedYes


ASJC Scopus subject areas

  • Biochemistry

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