Herpes Simplex Virus 2 ICP0− Mutant Viruses Are Avirulent and Immunogenic: Implications for a Genital Herpes Vaccine
(A) Mutations in the HSV-2 ICP0 gene. Schematics indicate the relative size and location of a GFP-coding sequence that replaced codons 19–104 in all HSV-2 ICP0− mutants, as well as the size and location of secondary deletions in HSV-2 0ΔRING, 0ΔNLS, 0Δ254, or 0Δ810. (B) Regions of ICP0 conserved between HSV-1 and HSV-2 are color-coded above, and below is shown the effects of deletions on ICP0's conserved RING finger region, nuclear localization signal (NLS) region, and/or oligomerization domain. (C) Southern blot analysis of SacI – StuI digested DNA harvested from cells that were uninfected (UI) or were inoculated with 2.5 pfu per cell of each indicated HSV-2 virus. Replicate Southern blots were hybridized with an ICP0 exon 2-specific oligonucleotide (shown on left) or a GFP-specific oligonucleotide (shown on right). The approximate locus to which the ICP0-specific and GFP-specific probes hybridized is depicted in panel A. (D) Western blot analysis of proteins harvested from cells that were uninfected (UI) or were inoculated with 2.5 pfu per cell of each indicated HSV-2 virus. GFP or chimeric ICP0 proteins bearing a GFP tag were labeled with rabbit polyclonal GFP-specific antibody. Molecular weight markers are shown on the right.