The herpes simplex virus type 2 ul3 open reading frame encodes a nuclear localizing phosphoprotein

Diane M. Worrad, Sal Caradonna

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


The herpes simplex virus type 2 (HSV-2, strain 333) UL3 open reading frame (ORF) codes for a protein with a predicted molecular weight of 29,681. Comparisons of the UL3, strain 333 ORF show essentially complete amino acid identity with HSV-2 (strain HG52) and a 75% amino acid identity with HSV type 1 (strain 17). To characterize the expression of this gene, a hydrophilic region of the HSV-2 UL3 gene was cloned into a bacterial expression vector. The resulting fusion protein was used to generate antibodies in rabbits. In vitro translation of HSV-2-derived mRNA followed by immunoprecipitation with the rabbit antisera reveals a major 28,000-Da protein as judged by SDS-polyacrylamide gel electrophoresis. This is consistent with the predicted molecular weight of an unmodified UL3 protein. Pulse-labeling of infected cells, with [35S]methionine, followed by immunoprecipitation and electrophoretic analysis reveals three distinct bands of 28,000, 30,500, and 33,000 Da. Labeling infected cells with [32P]orthophosphate shows that the 30,500- and the 33,000-Da species are post-translationally phosphorylated. The 30,500-Da species can be converted to the 28,000-Da species with alkaline phosphatase treatment. Interestingly, the 33,000-Da species is resistant to this treatment. Immunohistochemical analysis of infected cells reveals that the UL3 protein has a perinuclear location early in infection and at later times becomes associated with the nucleus as discrete particles. A mutant of HSV, which has a major deletion of the UL3 coding region does not show any immunohistochemical staining with the UL3 antisera. The wild-type virus-infected cell staining pattern remains the same subsequent to DNAse and RNAse treatment, indicating that the UL3 protein product is not directly associated with nucleic acid.

Original languageEnglish (US)
Pages (from-to)364-376
Number of pages13
Issue number2
StatePublished - 1993
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Virology


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