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Inactivating and mutagenic effects of nitrosoguanide on human cytomegalovirus
C Hamelin1, M Dion, L Cousineau
1Centre de recherche en virologie, Institut Armand-Frappier, Laval-des-Rapides, Québec, Canada.
Abstract:
Human cytomegalovirus (HCMV) was exposed for 24 hr to 10-30 micrograms/ml nitrosoguanidine (NG) at different times postinfection. NG treatments performed 24 to 48 hr after infection of human IAFP-1 fibroblasts with HCMV interfered most significantly with the replication of the virus. No correlation was found, however, between the inactivating effect of NG at this particular stage of the replication cycle and the induction of HCMV temperature-sensitive mutants. All the 17 HCMV mutant strains isolated on this occasion showed the same BamHI, Cfo I, Hpa II and Sph I restriction profiles which is indicative of mutations caused by single base changes.
Insights
Nitrosoguanidine (NG) treatment significantly inhibited human cytomegalovirus (HCMV) replication when applied 24 to 48 hours post-infection. This viral inactivation did not correlate with the induction of temperature-sensitive mutants, suggesting a different mechanism of action.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus with significant clinical implications.
- Understanding viral replication mechanisms is crucial for developing antiviral strategies.
- Nitrosoguanidine (NG) is a chemical mutagen known to induce mutations in DNA.
Purpose of the Study:
- To investigate the effect of nitrosoguanidine (NG) on human cytomegalovirus (HCMV) replication.
- To determine the optimal timing for NG treatment to inhibit HCMV replication.
- To explore the relationship between NG-induced viral inactivation and the generation of temperature-sensitive mutants.
Main Methods:
- Human IAFP-1 fibroblasts were infected with HCMV.
- Cells were treated with 10-30 micrograms/ml nitrosoguanidine (NG) at various time points post-infection.
- Viral replication was assessed, and viral strains were analyzed for mutations using restriction enzyme digestion (BamHI, Cfo I, Hpa II, Sph I).
Main Results:
- NG treatment between 24 and 48 hours post-infection demonstrated the most significant inhibition of HCMV replication.
- No correlation was observed between NG's inactivating effect and the induction of HCMV temperature-sensitive mutants.
- All 17 isolated HCMV mutant strains exhibited identical restriction profiles, indicating single base change mutations.
Conclusions:
- Nitrosoguanidine effectively inhibits HCMV replication during a specific post-infection window.
- The mechanism of NG-induced HCMV inactivation may not involve the generation of temperature-sensitive mutants.
- The observed mutations are likely single base changes, providing insights into NG's mutagenic activity on HCMV DNA.