Identification of a small molecule that compromises the structural integrity of viroplasms and rotavirus double-layered particles

Eichwald, C. et al. (2018) Identification of a small molecule that compromises the structural integrity of viroplasms and rotavirus double-layered particles. Journal of Virology, 92(3), e01943-17. (doi: 10.1128/JVI.01943-17) (PMID:29142132) (PMCID:PMC5774888)

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Abstract

Despite the availability of two attenuated vaccines, rotavirus (RV) gastroenteritis remains an important cause of mortality among children in developing countries, causing about 215,000 infant deaths annually. Currently, there are no specific antiviral therapies available. RV is a nonenveloped virus with a segmented double-stranded RNA genome. Viral genome replication and assembly of transcriptionally active double-layered particles (DLPs) take place in cytoplasmic viral structures called viroplasms. In this study, we describe strong impairment of the early stages of RV replication induced by a small molecule known as an RNA polymerase III inhibitor, ML-60218 (ML). This compound was found to disrupt already assembled viroplasms and to hamper the formation of new ones without the need for de novo transcription of cellular RNAs. This phenotype was correlated with a reduction in accumulated viral proteins and newly made viral genome segments, disappearance of the hyperphosphorylated isoforms of the viroplasm-resident protein NSP5, and inhibition of infectious progeny virus production. In in vitro transcription assays with purified DLPs, ML showed dose-dependent inhibitory activity, indicating the viral nature of its target. ML was found to interfere with the formation of higher-order structures of VP6, the protein forming the DLP outer layer, without compromising its ability to trimerize. Electron microscopy of ML-treated DLPs showed dose-dependent structural damage. Our data suggest that interactions between VP6 trimers are essential, not only for DLP stability, but also for the structural integrity of viroplasms in infected cells.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:De Lorenzo, Dr Giuditta
Authors: Eichwald, C., De Lorenzo, G., Schraner, E. M., Papa, G., Bollati, M., Swuec, P., de Rosa, M., Milani, M., Mastrangelo, E., Ackermann, M., Burrone, O. R., and Arnoldi, F.
College/School:College of Medical Veterinary and Life Sciences > School of Infection & Immunity
College of Medical Veterinary and Life Sciences > School of Infection & Immunity > Centre for Virus Research
Journal Name:Journal of Virology
Publisher:American Society for Microbiology
ISSN:0022-538X
ISSN (Online):1098-5514
Published Online:17 January 2018
Copyright Holders:Copyright © 2018 American Society for Microbiology
First Published:First published in Journal of Virology 92(3): e01943-17
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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