title: Modulation of ppp(A2'p)nA-dependent RNase by a temperature-sensitive mutant of vaccinia virus.
abstract: Activation of the ppp(A2'p)nA (2-5A)-dependent RNase was investigated during the abortive infection of BSC40 cells by a temperature-sensitive mutant of vaccinia virus, ts22. At the nonpermissive temperature, ts22 has an abortive late phenotype. At the onset of late-viral-gene expression, viral mRNA is degraded and rRNA is cleaved into discrete fragments in the absence of prior interferon treatment (R. F. Pacha and R. C. Condit, J. Virol. 56:395-403, 1985). Concomitant with rRNA cleavage, an increase in 2-5A occurred late during infection. Discrete 18S- and 28S-rRNA degradation products from BSC40 cells infected with ts22 at the nonpermissive temperature comigrated in denaturing agarose gels with rRNA cleaved fragments produced by the activation of 2-5A-dependent RNase in uninfected cells transfected with exogenous 2-5A. An increase in 2-5A levels and a similar discrete and characteristic degradation of rRNA were observed in BSC40 cells infected with wild-type vaccinia virus in the presence of isatin-beta-thiosemicarbazone. The results show that the ts22 lesion and the action of isatin-beta-thiosemicarbazone may affect the same pathway, leading to the activation of latent 2-5A-dependent RNase and resulting in indiscriminate RNA degradation and inhibition of viral replication.
authors.affiliation: Laboratory of Molecular Biology, AMC Cancer Research Center, Denver, Colorado 80214.
authors.forename: R J
authors.initials: RJ
authors.lastname: Cohrs
authors.forename: R C
authors.initials: RC
authors.lastname: Condit
authors.forename: R F
authors.initials: RF
authors.lastname: Pacha
authors.forename: C L
authors.initials: CL
authors.lastname: Thompson
authors.forename: O K
authors.initials: OK
authors.lastname: Sharma
mesh_terms: D000227:Adenine Nucleotides / Q000032:analysis; D002460:Cell Line; D004722:Endoribonucleases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D007510:Isatin / Q000031:analogs & derivatives / Q000494:pharmacology; D009843:Oligoribonucleotides / Q000032:analysis; D010641:Phenotype; D012335:RNA, Ribosomal / Q000378:metabolism; D013696:Temperature; D014616:Vaccinia virus / Q000235:genetics / Q000502:physiology*; D014779:Virus Replication
chemical_list: D000227:Adenine Nucleotides; D009843:Oligoribonucleotides; D012335:RNA, Ribosomal; C013578:isatin beta-thiosemicarbazone; C023505:2',5'-oligoadenylate; D007510:Isatin; D004722:Endoribonucleases; C031956:2-5A-dependent ribonuclease