Contrasting effect of new HCMV pUL54 mutations on antiviral drug susceptibility: Benefits and limits of 3D analysis

• Published in: Antiviral research 2016-05, Vol.129, p.115-119
• Main Authors: Andouard, D., Mazeron, M.-C., Ligat, G., Couvreux, A., Pouteil-Noble, C., Cahen, R., Yasdanpanah, Y., Deering, M., Viget, N., Alain, S., Hantz, S.
• Format: Article
• Language: English
• Subjects: 3D-model; Antiviral Agents - pharmacology; BAC; Chromosomes, Artificial, Bacterial; Cytomegalovirus; Cytomegalovirus - drug effects; Cytomegalovirus - enzymology; Cytomegalovirus - genetics; Cytomegalovirus - growth & development; Cytosine - pharmacology; DNA, Viral - genetics; DNA-Directed DNA Polymerase - chemistry; DNA-Directed DNA Polymerase - genetics; Drug Resistance, Viral; Foscarnet; Foscarnet - pharmacology; Ganciclovir; Ganciclovir - pharmacology; Human cytomegalovirus; Humans; Models, Molecular; Mutagenesis; Organophosphonates - pharmacology; Phenotype; Point Mutation; Protein Domains; Resistance; Viral Proteins - chemistry; Viral Proteins - genetics
• ISSN: 0166-3542; 1872-9096
• DOI: 10.1016/j.antiviral.2016.02.004

Human cytomegalovirus (HCMV) resistance to antiviral drugs is a major drawback of repeated or long-duration treatment in immunocompromised patients. Resistance testing is usually performed by genotypic assays. For accurate interpretation of these assays, the role of new mutations in HCMV resistance has to be assessed. Two previously unknown UL54 single point mutations (D515Y and V787A) were characterized for phenotypic drug-resistance by marker transfer analysis using bacterial artificial chromosome (BAC) mutagenesis. Increases in 50% inhibitory concentrations of ganciclovir and foscarnet were found for both mutated recombinant strains showing that mutations D515Y and V787A induce resistance to both antivirals. Importantly, none of those impacted the viral growth kinetics. For a better understanding of their molecular resistance mechanisms, a 3D homology model was used to localize the mutated amino-acids in functional domains of UL54 and predict their impact on UL54 function and resistance. However, 3D homology model analysis has limits and phenotypic characterization using BAC-HCMV is still essential to measure the role of unknown mutations. •We characterized two previously unknown HCMV UL54 single point mutations found in immunocompromised patients.•Both mutations induce resistance to ganciclovir and foscarnet, without impact the viral growth kinetics.•UL54 3D theoretical model allows a better understanding impact of mutations on protein function and resistance mechanism.