Resistance of HCMV to DHPG, HPMPC and HPMPA mapped to the viral DNA polymerase gene

Penciclovir is the active form of the orally available prodrug famciclovir, which is entering clinical use for herpesvirus infections. Like aciclovir, penciclovir is an acyclic guanosine analogue that is phosphorylated by viral thymidine kinase and whose triphosphate can inhibit viral DNA polymerase. We tested several well-characterized herpes simplex virus mutants with aciclovir-resistance mutations in the viral DNA polymerase gene for altered sensitivity to penciclovir. The mutants varied in their susceptibilities to penciclovir with one exhibiting 2-fold hypersensitivity, one marginal resistance and three about 3-fold resistance. Marker rescue and DNA sequencing analyses mapped the penciclovir-resistance mutation of one mutant, AraA r7, to a single base change that alters a glycine to a cysteine at residue 841 within conserved region III of α-like DNA polymerases. The results have implications for the mechanism of selective action of penciclovir, for the potential for development of resistance in the clinic, and for the substrate recognition properties of herpes simplex virus DNA polymerase.

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Molecular Characterization and Pathogenicity of an Indian Isolate of Duck Enteritis Virus Recovered From a Natural Outbreak

Indian Journal of Animal Research ◽

10.18805/ijar.b-4006 ◽

2020 ◽

Author(s):

Sivasankar Panickan ◽

Satyabrata Dandapat ◽

Jyoti Kumar ◽

Mahesh Mahendran ◽

Sukdeb Nandi ◽

...

Keyword(s):

Dna Polymerase ◽

Pcr Amplification ◽

Duck Enteritis Virus ◽

Polymerase Gene ◽

Viral Dna ◽

Its Sequence Analysis ◽

Dna Polymerase Gene ◽

Enteritis Virus ◽

Infected Duck ◽

Natural Outbreak

Background: Duck plague is a highly contagious viral disease reported in our country very often with significant economic loss. There are some bottlenecks with the currently used ‘Holland strain’ vaccine that involves cumbersome process of vaccine production in embryonated chicken eggs. With the future goal of development of an indigenous cell culture vaccine for duck plague, the present study is aimed at isolation of an Indian strain of DEV from a natural outbreak and its characterization for the seed virus purpose. Methods: Liver samples were collected from the suspected ducks died during a natural outbreak in Kerala and subjected to polymerase chain reaction (PCR) to confirm presence of viral DNA. The duck enteritis virus (DEV) was isolated by inoculation of PCR positive samples in embryonated duck eggs/ducklings and its pathogenicity was studied. Further, the DEV recovered from the infected duck embryo and duckling liver was confirmed by PCR amplification of the viral DNA polymerase gene and its sequence analysis. Result: Out of 12 liver samples tested eight (8) were found to be positive for duck plague by PCR. The DEV infected duck embryos and ducklings died showing typical signs and characteristic gross and microscopic lesions. PCR amplification of viral DNA targeting the DNA polymerase gene yielded amplicon of expected size of 446bp. The amplicon sequence showed 99-100% homology with other DEV isolates, thus confirming the new isolate as DEV, named as DEV/India/IVRI-2016 and the gene sequence has NCBI acc. no. KX511893.

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