title: Vaccinia virions deficient in transcription enzymes lack a nucleocapsid.
abstract: The poxvirus virion contains an inner tubular nucleocapsid structure. The nucleocapsid is apparently labile to conventional electron microscopy fixation procedures and has therefore been largely ignored for decades. Advancements in electron microscopy sample preparation, notably high pressure freezing, better preserve the nucleocapsid structure. Using high pressure freezing and electron microscopy, we have compared the virion structures of wt virus and mutant viruses known to be deficient in packaging of viral transcription enzymes. We show that the mutant viruses lack a defined nucleocapsid. These results support the hypothesis that the nucleocapsid contains the viral DNA genome complexed with viral transcription enzymes and structural proteins. The studies open the door to further investigation of the composition and ultrastructure of the poxvirus nucleocapsid.
authors.affiliation: Department of Molecular Genetics and Microbiology, FL, USA.
authors.forename: Baron D H
authors.initials: BD
authors.lastname: McFadden
authors.forename: Nissin
authors.initials: N
authors.lastname: Moussatche
authors.forename: Karen
authors.initials: K
authors.lastname: Kelley
authors.forename: Byung-Ho
authors.initials: BH
authors.lastname: Kang
authors.forename: Richard C
authors.initials: RC
authors.lastname: Condit
mesh_terms: D000818:Animals; D002460:Cell Line; D020285:Cryoelectron Microscopy; D006801:Humans; D019251:Nucleocapsid / Q000648:ultrastructure*; D014158:Transcription, Genetic; D014616:Vaccinia virus / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014771:Virion / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D014764:Viral Proteins