Micromonas pusilla reovirus: a new member of the family Reoviridae assigned to a novel proposed genus (Mimoreovirus).
Micromonas pusilla reovirus (MpRV) is an 11-segmented, double-stranded RNA virus isolated from the marine protist Micromonas pusilla. Sequence analysis (including conserved termini and presence of core motifs of reovirus polymerase), morphology and physicochemical properties confirmed the status of MpRV as a member of the family Reoviridae. Electron microscopy showed that intact virus particles are unusually larger (90-95 nm) than the known size of particles of viruses belonging to the family Reoviridae. Particles that were purified on caesium chloride gradients had a mean size of 75 nm (a size similar to the size of intact particles of members of the family Reoviridae), indicating that they lost outer-coat components. The subcore particles had a mean size of 50 nm and a smooth surface, indicating that MpRV belongs to the non-turreted Reoviridae. The maximum amino acid identity with other reovirus proteins was 21 %, which is compatible with values existing between distinct genera. Based on morphological and sequence findings, this virus should be classified as the representative of a novel genus within the family Reoviridae, designated Mimoreovirus (from Micromonas pusilla reovirus). The topology of the phylogenetic tree built with putative polymerase sequences of the family Reoviridae suggested that the branch of MpRV could be ancestral. Further analysis showed that segment 1 of MpRV was much longer (5792 bp) than any other reovirus segment and encoded a protein of 200 kDa (VP1). This protein exhibited significant similarities to O-glycosylated proteins, including viral envelope proteins, and is likely to represent the additional outer coat of MpRV.
Attoui
Houssam
H
Unité des Virus Emergents EA3292, EFS Alpes-Méditerranée and Faculté de Médecine de Marseille, 27 Boulevard Jean Moulin, 13005 Marseille cedex 5, France.
Jaafar
Fauziah Mohd
FM
Unité des Virus Emergents EA3292, EFS Alpes-Méditerranée and Faculté de Médecine de Marseille, 27 Boulevard Jean Moulin, 13005 Marseille cedex 5, France.
Belhouchet
Mourad
M
Unité des Virus Emergents EA3292, EFS Alpes-Méditerranée and Faculté de Médecine de Marseille, 27 Boulevard Jean Moulin, 13005 Marseille cedex 5, France.
de Micco
Philippe
P
Unité des Virus Emergents EA3292, EFS Alpes-Méditerranée and Faculté de Médecine de Marseille, 27 Boulevard Jean Moulin, 13005 Marseille cedex 5, France.
de Lamballerie
Xavier
X
Unité des Virus Emergents EA3292, EFS Alpes-Méditerranée and Faculté de Médecine de Marseille, 27 Boulevard Jean Moulin, 13005 Marseille cedex 5, France.
Brussaard
Corina P D
CPD
Department of Biological Oceanography, Royal Netherlands Institute for Sea Research, NL-1790 AB Den Burg, The Netherlands.
D000595:Amino Acid Sequence; D056890:Eukaryota / Q000821:virology*; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012087:Reoviridae / Q000737:chemistry / Q000145:classification* / Q000235:genetics / Q000648:ultrastructure; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014764:Viral Proteins / Q000235:genetics
D014764:Viral Proteins