Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2015 Jul 21;112(29):9100-5. doi: 10.1073/pnas.1419225112. Epub 2015 Jul 2.

A novel mycovirus from Aspergillus fumigatus contains four unique dsRNAs as its genome and is infectious as dsRNA.

Author information

1
Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, United Kingdom;
2
Institute of Food Research, Norwich Research Park, Colney Lane, Norwich NR4 7UA, United Kingdom.
3
Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, United Kingdom; r.coutts@herts.ac.uk.

Abstract

We report the discovery and characterization of a double-stranded RNA (dsRNA) mycovirus isolated from the human pathogenic fungus Aspergillus fumigatus, Aspergillus fumigatus tetramycovirus-1 (AfuTmV-1), which reveals several unique features not found previously in positive-strand RNA viruses, including the fact that it represents the first dsRNA (to our knowledge) that is not only infectious as a purified entity but also as a naked dsRNA. The AfuTmV-1 genome consists of four capped dsRNAs, the largest of which encodes an RNA-dependent RNA polymerase (RdRP) containing a unique GDNQ motif normally characteristic of negative-strand RNA viruses. The third largest dsRNA encodes an S-adenosyl methionine-dependent methyltransferase capping enzyme and the smallest dsRNA a P-A-S-rich protein that apparently coats but does not encapsidate the viral genome as visualized by atomic force microscopy. A combination of a capping enzyme with a picorna-like RdRP in the AfuTmV-1 genome is a striking case of chimerism and the first example (to our knowledge) of such a phenomenon. AfuTmV-1 appears to be intermediate between dsRNA and positive-strand ssRNA viruses, as well as between encapsidated and capsidless RNA viruses.

KEYWORDS:

capping enzyme; infectious dsRNA; mycovirus; protoplast transfection; virus evolution

PMID:
26139522
PMCID:
PMC4517262
DOI:
10.1073/pnas.1419225112
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center