Molecular genetics of herpes simplex virus. V. Characterization of a mutant defective in ability to form plaques at low temperatures and in a viral function which prevents accumulation of coreless capsids at nuclear pores late in infection

In herpes simplex virus-infected cells, coreless capsids accumulate at the nuclear pores soon after infection, but subsequently disappear, suggesting that, as in adenovirus-infected cells (S. Dales and Y. Chardonnet, Virology 56:465-483, 1973), the release of viral DNA from nucleocapsids takes place at the nuclear pores. A nonlethal mutant, HSV-1(50B), produced by mutagenesis of HSV DNA fragments and selected for delayed production of plaques at 31°C, accumulated coreless capsids at the nuclear pores late in infection in contrast to wild-type viruses. Recombinants selected for ability to produce plaques at 31°C by marker rescue with digests of herpes simplex virus 2 DNA and selected cloned fragments of HSV-1 DNA no longer accumulated empty capsids at nuclear pores late in infection. These results suggest that herpes simplex viruses encode a function which prevents accumulation of coreless capsids at nuclear pores, presumably by preventing uptake, unenvelopment, and DNA release from progeny virus, and indicate that the cold sensitivity of plaque formation and accumulation of coreless capsids might be related or comap in the S component of the genome.