Related Experiment Video
Updated: Jun 28, 2026

Vaccinia Reporter Viruses for Quantifying Viral Function at All Stages of Gene Expression
Published on: May 15, 2014
The effect of nitric oxide on vaccinia virus-encoded ribonucleotide reductase
Yuzo Fujikura1, Pavla Kudlackova, Martin Vokurka
1Institute of Pathological Physiology, 1st Medical Faculty, Charles University, Prague, Czech Republic.
Abstract:
Growth inhibition of the DNA virus vaccinia (VACV) by NO is known to occur at the level of DNA synthesis. This inhibition is partially reversed by addition of deoxyribonucleosides, suggesting that NO or NO-related species inhibit viral ribonucleotide reductase (RR). However, the effect of NO on VACV-encoded RR or other DNA-synthesizing enzymes has not been demonstrated. In order to study the effects of NO on VACV-encoded RR, DNA polymerase (DNA pol) and thymidine kinase (TK), we generated a VACV recombinant expressing murine macrophage iNOS under control of a VACV early/late promoter p7.5. Using this recombinant, we demonstrate that expression of iNOS and the resulting production of NO inhibit activity of the viral RR, but not of viral DNA pol and TK. This NO-mediated inhibition of viral RR occurred around the same time as the increase of ADP levels, while it preceded the block in VACV DNA synthesis and the decrease of ATP levels. In addition, we tested the effects of DPTA/NONOate on the growth of different VACV mutants. Fold-inhibition of the growth of VACV deletion mutant for TK was comparable to that of wild-type VACV. VACV containing amplification of the gene for the small subunit of RR appeared to be least sensitive to DPTA/NONOate, while VACV deletion mutant for the large subunit of RR was most sensitive. The results provide a direct evidence for NO-mediated inhibition of VACV-encoded RR.
Related Concept Videos
Inhibitors Of Virion Release
Inhibitors of Virion Maturation and Assembly
Nitric Oxide Signaling Pathway
Inhibitors of Viral Protein Synthesis
Antiviral Nucleoside Inhibitors
Regulation of Bacterial Virulence

