Double-stranded RNA adenosine deaminase activity during measles virus infection.
It has been postulated that the cellular double-stranded (ds) RNA adenosine deaminase enzyme is responsible for biased hypermutation during persistent SSPE measles infections in humans. As a test of this hypothesis we studied the effect of negative-strand RNA virus infection on enzyme activity. The adenosine deaminase activity was found in nuclear extracts of both uninfected CV-1 and A549 cells and in cytoplasmic extracts of A549, but not CV-1, cells. During measles or Sendai virus infection of either CV-1 or A549 cells the adenosine deaminase activity in the nucleus remained fairly constant up to 24 h post infection, and there was no apparent re-partitioning of the enzyme between the nucleus and the cytoplasm. Transcription complexes of Sendai virus in vitro or measles virus in vivo did not serve as substrates for the enzyme. These data suggest that even though some portion of the adenosine deaminase enzyme may be present in the cytoplasm of at least some cells during virus infection, modification of the viral RNAs by this enzyme, if it occurs at all, must be at a very low level not directly detectable by biochemical analysis.
Horikami
S M
SM
Department of Immunology and Medical Microbiology, University of Florida College of Medicine, Gainesville 32610, USA.
Moyer
S A
SA
D000243:Adenosine Deaminase / Q000378:metabolism*; D000249:Adenosine Monophosphate / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D007291:Inosine Monophosphate / Q000378:metabolism; D008459:Measles virus / Q000201:enzymology*; D010222:Parainfluenza Virus 1, Human / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism*; D016601:RNA-Binding Proteins; D013379:Substrate Specificity; D014158:Transcription, Genetic / Q000502:physiology; D014779:Virus Replication / Q000502:physiology
D012333:RNA, Messenger; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D007291:Inosine Monophosphate; D000249:Adenosine Monophosphate; C567955:ADARB1 protein, human; D000243:Adenosine Deaminase