Phenotypic characterisation of the human cytomegalovirus (HCMV) pUL54 DNA polymerase is a useful tool for testing for mutations in the UL54 gene thought to render HCMV resistant to foscarnet. In this study, an in-house non-isotopic method for assessing polymerase enzymatic activity in the presence and absence of foscarnet was developed and its utility for HCMV polymerase phenotyping evaluated. Polymerase activity was assessed by monitoring the incorporation of digoxigenin-labelled nucleotides into the growing DNA chain and foscarnet concentrations inhibiting enzymatic activity by 50% were determined. HCMV DNA polymerases were synthesised in vitro by expression of UL54 under the control of the T7 promoter. Mutations of interest were introduced into the wild-type UL54 gene by site-directed mutagenesis. Mutated polymerases and polymerases from HCMV reference strains were studied. The activity of polymerases containing mutations known to confer resistance to foscarnet (V715M, T700A and N495K) was inhibited by concentrations of foscarnet eight to 14 times higher than those required to inhibit wild-type polymerases. Our in-house non-radioactive phenotypic assay was sensitive and reproducible. It is also easy to perform and could provide a convenient method for characterising mutations conferring resistance to foscarnet in HCMV.
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http://dx.doi.org/10.1016/j.jviromet.2006.11.039 | DOI Listing |
Viruses
December 2024
Division of Infectious Diseases, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
Cytomegalovirus (CMV) infection in solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients may increase the risk of rejection or allograft dysfunction, other infection(s), and morbidity and mortality. Treatment can be challenging due to medication-associated toxicities. Maribavir (MBV) is a promising option for the treatment of resistant or refractory (R/R) CMV infection in lieu of foscarnet (FOS), which has long been the recommended therapy for (val)ganciclovir-resistant infection.
View Article and Find Full Text PDFVirus Evol
November 2024
Laboratory of Virology and Chemotherapy, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, KU Leuven, Herestraat 49 box 1043, Leuven 3000, Belgium.
The widespread use of antivirals in immunocompromised individuals has led to frequent occurrences of drug-resistant herpes simplex virus 1 (HSV-1) infections. Current antivirals target the viral DNA polymerase (DP), resulting in cross-resistance patterns that emphasize the need for novel treatment strategies. In this study, we assessed whether combining antivirals with different targets affects drug resistance emergence by passaging wild-type HSV-1 under increasing concentrations of acyclovir (ACV), foscarnet (phosphonoformic acid, PFA), or the helicase-primase inhibitor pritelivir (PTV), individually or in combination (ACV + PTV or PFA + PTV).
View Article and Find Full Text PDFVirologie (Montrouge)
October 2024
Institut toulousain des Maladies infectieuses et inflammatoires (Infinity), Université de Toulouse, Inserm, CNRS, UPS, Toulouse, France.
Human cytomegalovirus (HCMV) is one of the most important causes of complications in immunocompromised patients and congenital infections. HCMV could also represent an interesting target for treatment to limit the progression of glioblastoma, a highly aggressive tumor. Ganciclovir, foscarnet and cidofovir, which interfere with the activity of the viral polymerase pUL54, are widely used in the treatment of transplant patients.
View Article and Find Full Text PDFJ Ophthalmic Inflamm Infect
October 2024
Department of Ophthalmology, University of Colorado School of Medicine, 1675 Aurora Court, F731, Aurora, CO, 80045, USA.
Transplantation
September 2024
Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute, KU Leuven, Leuven, Belgium.
Background: Cytomegalovirus (CMV) infection poses a significant risk to immunosuppressed transplant recipients, manifesting through primary infection, reinfection, or reactivation.
Methods: We analyzed the emergence of drug resistance in CMV infection in 3 patients who were later found to have received an allograft from a shared, deceased donor. The seronegative transplant recipients developed symptomatic CMV infections after bowel/pancreas, kidney, or lung transplantation.
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