An autonomous replicating element within the KSHV genome

Abstract

Propagation of episomally maintained KSHV genome into new daughter cells requires replication of its genome once every cell division. This study demonstrates a potential alternative mechanism of KSHV latent DNA replication independent of LANA expression. A cis-acting DNA element within the Long Unique Region is capable of initiating replication shown by DpnI analysis, Meselson-Stahl analysis, BrdU incorporation and single molecule analysis of replicated DNA. This DNA element supports replication of the plasmid which persists in its native form. Human ORC2 and MCM3 also associate with this region of the KSHV genome and depletion of cellular ORC2 by RNAi abolished replication of the plasmids. Thus recruitment of the host cellular replication machinery is important for latent replication. This autonomously replicating DNA element demonstrates that KSHV can initiate replication of its genome independent of any trans-acting viral factors and identifies a secondary replicator element for the initiation of KSHV DNA replication.