Extraction of cell-associated varicella-zoster virus DNA with Triton X-100-NaCl

Varicella-zoster virus (VZV) DNA was extracted from infected cells with 0.25% Triton X-100-0.2 M NaCl and purified by isopycnic centrifugation in CsCl. In each of eight experiments, 1.8-9.8 μg VZV DNA was obtained from 10⁷ infected cells. The VZV DNA obtained by this procedure had a molecular weight of 88-100 × 10⁶ as determined by sucrose gradient sedimentation and electron microscopy, and cleavage patterns after digestion with four restriction enzymes that corresponded to patterns previously described with six strains of VZV; the pattern of BamHI-cleaved Triton-NaCl-extracted VZV DNA was identical to the pattern seen after DNA extraction from virions. These studies expand the usefulness of Triton X-100-NaCl for extraction of large molecular weight viral DNA from a system where considerable cell-free virus is produced (Pignatti et al., 1979, Virology 93, 260) to a system known for its marked cell association.