Inhibition of Retrovirus RNA-dependent DNA Polymerase by Novobiocin and Nalidixic Acid

Abstract

SUMMARYInhibitors of bacterial DNA gyrase and eukaryotic DNA topoisomerase (novobiocin and nalidixic acid) were investigated with respect to their effect on the activity of RNA-dependent DNA polymerases from murine and avian retroviruses. Purified RNA-dependent DNA polymerase from AKR virus was inhibited more than 90~ by 0-3 mg/ml and almost completely by 1 mg/ml of the drugs when poly(A)-oligo(dT)l 2-1 s was used as a template-primer. In contrast to the enzyme from AKR virus, purified enzyme from avian myeloblastosis virus was less sensitive, i.e. nearly 50~ activity remained even in the presence of I mg/ml of the drugs with the same template-primer. RNA-dependent DNA polymerase activity in AKR virus particles was inhibited, but was resistant to low concentrations of the drugs. The inhibition was not due to specific interaction between drugs and the template-primer or labelled precursor, since RNAdependent DNA polymerase was inhibited by the drugs with activated calf thymus DNA or poly(C), oligo(dG)l 2-1 s as the template. Endogenous DNA synthesis by AKR virus particles was inhibited by novobiocin to the same extent.RNA-dependent DNA polymerase (RDDPase) plays a central role during the life cycle of retroviruses. After retrovirus infection of cells, it uses viral RNA as a template for singlestranded DNA and the single-stranded DNA is then converted to linear double-stranded DNA (Verma, 1977(Verma, , 1981. The linear double-stranded DNA molecules are further converted into covalently closed circular DNA which is subsequently integrated into the host chromosomal DNA. Although the precise mechanism remains unknown, RDDPase may play an important role in the above reaction with the possible cooperation of host-derived factors (HaginoYamagishi et al., 1981).

Theiler’s murine encephalomyelitis virus infection induces a redistribution of heat shock proteins 70 and 90 in BHK-21 cells, and is inhibited by novobiocin and geldanamycin

“…Although the anti-viral effect of Nov was reported years ago (Franke and Margolin 1981;Landini and Baldassarri 1982;Sumiyoshi et al 1983), to date, no studies have described its effect on picornavirus infection. Novobiocin, a member of the coumarin group of antibiotics, exhibits potent activity against Gram-positive bacteria by inhibiting ATP hydrolysis (Reece and Maxwell 1991).…”

“…It should be noted, however, that treatment of cells with Nov, even in the absence of virus, led to detachment from the growth surface at the 48-h time point at a dose of 250 μM, and at 24 hpi at doses of 100 and 1,000 μM. The Nov doses chosen for these provisional experiments were based on previous studies of this kind where a similar range of concentrations was used in various cells types (Landini and Baldassarri 1982;Sumiyoshi et al 1983;Lührmann et al 1998;Singh et al 2005). The results presented here indicate that BHK-21 cells may be more susceptible to the effects of Nov than are other cell lines, and therefore not able to support translation and processing of viral nonstructural proteins at the doses used.…”

Sedimentation of an RNA polymerase complex from vaccinia virus that specifically initiates and terminates transcription.

“…Glycerol gradient centrifugation of virion extracts, however, gave effective separation of topoisomerase from the transcription complex, yet transcription remained sensitive to novobiocin. Our demonstration that RNA polymerase and DNAdependent ATPase activities are sensitive to the antibiotic (27), and avian retrovirus reverse transcriptase (27,33) …”

Pilot Study of Ofloxacin and Interferon-Alpha Combination Therapy for Chronic Hepatitis C without Sustained Response to Initial Interferon Therapy

“…OFLX inhibits topoisomerase activity and propagation of DNA viruses such as vaccinia virus and herpes simplex virus (17). OFLX reportedly inhibits reverse transcriptase of murine and avian retroviruses, which are both RNA viruses (18). Moreover, a therapeutic effect on HIV infection has been reported (19).…”