The null mutant of the U sub(L)31 gene of herpes simplex virus 1: Construction and phenotype in infected cells

• Published in: Journal of virology Vol. 71; no. 11; pp. 8307 - 8315
• Main Authors: Chang, Yijan E, Van Sant, C, Krug, P W, Sears, A E, Roizman, B
• Format: Journal Article
• Language: English
• Published: 01.11.1997
• ISSN: 0022-538X

Earlier studies have shown that the U sub(L)31 protein is homogeneously distributed throughout the nucleus and cofractionates with nuclear matrix. We report the construction from an appropriate cosmid library a deletion mutant which replicates in rabbit skin cells carrying the U sub(L)31 gene under a late ( gamma sub(1)) viral promoter. The mutant virus exhibits cytopathic effects and yields 0.01 to 0.1% of the yield of wild-type parent virus in noncomplementing cells but amounts of virus 10- to 1,000-fold higher than those recovered from the same cells 3 h after infection. Electron microscopic studies indicate the presence of small numbers of full capsids but a lack of enveloped virions. Viral DNA extracted from the cytoplasm of infected cells exhibits free termini indicating cleavage/packaging of viral DNA from concatemers for packaging into virions, but analyses of viral DNAs by pulsed-field electrophoresis indicate that at 16 h after infection, both the yields of viral DNA and cleavage of viral DNA for packaging are decreased. The repaired virus cannot be differentiated from the wild-type parent. These results suggest the possibility that U sub(L)31 protein forms a network to enable the anchorage of viral products for the synthesis and/or packaging of viral DNA into virions.