Molecular cloning and physical mapping of varicella-zoster virus DNA

Varicella-zoster virus (VZV) DNA was cleaved with restriction endonuclease EcoRI, and most of the resulting fragments were successfully cloned in the phage vector lambda gtWES . lambda B. Double digestions of cloned fragments with EcoRI and BamHI and hybridizations to blot-transferred BamHI digests of VZV DNA were used to construct a physical map of the genome. The molecular termini of the DNA were identified by restriction enzyme analysis after exonuclease III digestion. The data indicate that VZV DNA exists in two isomeric forms that differ by inversion of one short terminal genome segment. Electron microscopic studies revealed that the short genome segment consists of a terminal revealed that the short genome segment consists of a terminal sequence of about 3.4 X 10(6) daltons that is separated from an internal inverted repeat of itself by a 5.8 X 10(60)-dalton unique DNA segment.