Isolation of nascent DNA fragments from cells synchronously infected with HSV-1 reveals bidirectional initiation of replication at oriL

Abstract

ABSTRACT  Background: How HSV-1 DNA replication is initiated in infected cells is not fully understood. Experiments with temperature-sensitive HSV mutants have shown that DNA replication is a biphasic process that initially depends on the origin binding protein. Aims: The aim of the study was to answer the question at which origin of replication the HSV-1 DNA replication starts in the infected cell. Methods: Using the tsS mutant the HSV-1 infection was synchronized and newly synthesized nascent DNA fragments were analysed. Results: Nascent viral DNA was observed predominantly around the oriL, giving raise to the hypothesis that the replication starts at this origin in vivo. Conclusion: We show for the first time that HSV-1 DNA replication begins exclusively at the oriL site and proceeds in a bidirectional manner.