Notes on Genus: Tenuivirus

branched filaments

Type member: Rice stripe virus

Contents

Members of this Genus
General Description
Morphology
Electron Micrograph
Genome
Genus Genomic Organization
Genome Map
Type Member Genomic Organization
All Known Sequences
Curated Sequences

General Description

The genus Tenuivirus is quite distinctive, having members with thin (3-10 nm diameter) filamentous particles and an ambisense genome strategy. It is named from the Latin tenui, meaning thin or weak. The viruses are transmitted by planthoppers in a persistent manner to hosts in the Gramineae.

Morphology

Virions filamentous and not enveloped (may appear to be spiral, branched or circular), 3-10 nm in diameter. There are four or five different lengths.

Genome

Multi- (4 to 6) partite, single stranded, positive sense RNA. Sizes of segments about 9000, 3400-3600, 2300-2500 and 2000-2200 nucleotides. Maize stripe virus contains a fifth RNA of 1300 nucleotides, while rice grassy stunt virus has six RNAs.

Genus Genomic Organization

The proteins are encoded in an ambisense arrangement. In most members, there appears to be a single protein (replicase) encoded in the negative (complementary) sense on RNA1 and two proteins, one each in the positive and negative sense, on the remaining three RNA segments. At least two members (EHBV and MSpV) have a fifth RNA encoding a single protein in the negative (complementary) sense. The coat protein is encoded in the complementary sense on RNA3. In rice grassy stunt virus, each of the six segments has two proteins, one each in the positive and negative sense and the coat protein is encoded in the complementary sense on RNA5.

Type Member Genomic Organization

The genome products are:
ORF    Segment     Sense   Size   Putative Function
1:  pC1RNA1 - 337 kDa Polymerase
2:  p2 RNA2 + 23 kDa membrane-associated protein
3:  pC2 RNA2 - 94 kDa membrane glycoprotein
4:  p3RNA3 + 24 kDa non-structural (cytoplasmic) protein
5:  pC3RNA3 - 35 kDa Coat protein (nucleocapsid)
6:  p4RNA4 + 20 kDaNon-capsid "S" protein (virus inclusion body protein)
7:  pC4RNA4 - 32 kDanon-structural protein