THE LOCATION AND SEQUENCE COMPOSITION OF THE MURINE CYTOMEGALOVIRUS REPLICATOR (ORILYT)

DNA replication during human or simian cytomegalovirus (CMV) infection has been shown to be under control of a replicator region referred to as oriLyt. The murine CMV oriLyt has been mapped to a region of the g enome located upstream or the gene encoding the herpesvirus-conserved single-stranded DNA binding protein, analogous to human and simian CMV oriLyts. A minimal oriLyt of approximately 1.7 kbp has been identifie d using a transient replication system. Like occurs with human and sim ian CMV counterparts, addition of flanking sequences to this minimal o rigin-stimulated replication efficiency. Analysis of the DNA sequence in this region shows that murine CMV oriLyt is complex and exhibits an asymmetric distribution of nucleotides as well as many repeat sequenc e elements, including distinct AT- and GC-rich regions and region with arrays of closely spaced direct repeats. Despite similarities in orga nization of all three CMV oriLyts, no sequence identity and only limit ed DNA sequence similarity was detectable. Consistent with this sequen ce divergence, the human and marine CMV oriLyts were unable to substit ute for one another in transient replication assays. (C) 1997 Academic Press.