The Herpes Simplex Virus Type 1 Alkaline Nuclease is Not Essential for Viral DNA Synthesis: Isolation and Characterization of a lacZ Insertion Mutant

• Published in: Journal of general virology 1990-12, Vol.71 (12), p.2941-2952
• Main Authors: Weller, Sandra K, Seghatoleslami, M. Reza, Shao, Lei, Rowse, Debra, Carmichael, Ellen P
• Format: Article
• Language: English
• Subjects: Animals; beta-Galactosidase - genetics; Biological and medical sciences; DNA Replication; DNA, Viral - genetics; Fundamental and applied biological sciences. Psychology; Genes, Viral; Genetics; Microbiology; Molecular Weight; Mutagenesis, Insertional; Plasmids; Restriction Mapping; Ribonucleases - genetics; Ribonucleases - metabolism; Simplexvirus - enzymology; Simplexvirus - genetics; Vero Cells; Viral Plaque Assay; Viral Proteins - biosynthesis; Viral Proteins - genetics; Viral Proteins - isolation & purification; Viral Structural Proteins - genetics; Virology
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/0022-1317-71-12-2941

Department of Microbiology, University of Connecticut Health Center, Farmington, Connecticut 06030, U.S.A. Herpes simplex virus type 1 (HSV-1) encodes a novel enzyme activity, the alkaline nuclease, whose precise role in the viral replication cycle remains obscure. The alkaline nuclease gene corresponds to the UL12 open reading frame, which is predicted to encode a protein of 626 amino acid residues. We describe the isolation and characterization of a null mutant of the gene for the viral alkaline nuclease in which 917 bp from the N-terminal half of the gene (corresponding to residues 70 to 375) were deleted and replaced by the insertional mutagen ICP6:: lac Z. The resulting mutant virus, AN-1, was propagated in helper cells (S22) which express the wild-type version of the alkaline nuclease gene. Mutant AN-1 growth in Vero cells is severely restricted, although small amounts of infectious virus are produced. On the other hand, wild-type levels of viral DNA and late viral proteins are expressed in virus AN-1-infected Vero cells. These results indicate that the HSV-1 alkaline nuclease gene product is not essential for viral DNA synthesis but may play a role in the processing or packaging of viral DNA into infectious virions. Possible roles in the viral infectious cycle will be discussed. Present address: Department of Pediatrics, University of Connecticut Health Center, Farmington, Connecticut 06030, U.S.A. > Present address: Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030, U.S.A. Present address: Department of Cellular and Molecular Biology, Bristol-Myers-Squibb, Wallingford, Connecticut, U.S.A. Received 25 July 1990; accepted 4 September 1990.