PHENOTYPIC CHARACTERIZATION OF A VACCINIA VIRUS TEMPERATURE-SENSITIVE COMPLEMENTATION GROUP AFFECTING A VIRION COMPONENT

Genetic and biochemical evidence is presented which shows that the product of the vaccinia virus gene 18R is a virion protein. Western blot analysis of virion proteins using anti-18R serum detects a 78,000-Da protein, localized in the virus core. Of five is mutants which map to gene 18R, two mutants, is 10 and is 44, possess thermolabile virions. Temperature shifts performed during single-step growth of is 44 suggest that precursors required for virion maturation accumulate during nonpermissive infections with ORF 18R mutants and that protein synthesis is required for recovery from nonpermissive condition. © 1991.