title: Vaccinia virus temperature-sensitive mutants in the A28 gene produce non-infectious virions that bind to cells but are defective in entry.
abstract: The vaccinia virus temperature-sensitive mutations Cts6 and Cts9 were mapped by marker rescue and DNA sequencing to the A28 gene. Cts6 and Cts9 contain an identical 2-bp deletion truncating the A28 protein and removing the fourth conserved cysteine near the C-terminus. Cts9 mutant virions produced at 40 degrees C were non-infectious and unable to cause cytopathic effect. However, the mutant A28 protein localized to purified mature virions (MV) at 31 degrees C and 40 degrees C. MV of Cts9 produced at 40 degrees C bound to cells but did not enter cells. Low pH treatment of Cts9-infected cells at 18 h p.i. failed to produce fusion from within at 40 degrees C, but gave fusion at 31 degrees C. Adsorption of Cts9 mutant virions to cells followed by low pH treatment showed a defect in fusion from without. The Cts9 phenotype suggests that the A28 protein is involved in both virus entry and cell-cell fusion, and supports the linkage between the two processes.
authors.affiliation: Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610-0266, USA. pturner@mgm.ufl.edu
authors.forename: Peter C
authors.initials: PC
authors.lastname: Turner
authors.forename: Bradley P
authors.initials: BP
authors.lastname: Dilling
authors.forename: Cindy
authors.initials: C
authors.lastname: Prins
authors.forename: Steven G
authors.initials: SG
authors.lastname: Cresawn
authors.forename: Richard W
authors.initials: RW
authors.lastname: Moyer
authors.forename: Richard C
authors.initials: RC
authors.lastname: Condit
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D002459:Cell Fusion; D002460:Cell Line; D002522:Chlorocebus aethiops; D004267:DNA Viruses / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D005814:Genes, Viral; D016679:Genome, Viral; D000882:Haplorhini; D009154:Mutation; D011995:Recombination, Genetic; D013696:Temperature; D014616:Vaccinia virus / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity* / Q000502:physiology; D014765:Viral Vaccines; D014771:Virion / Q000235:genetics / Q000502:physiology
chemical_list: D020413:3' Untranslated Regions; D014765:Viral Vaccines