Notes on Family: Rhabdoviridae

enveloped bacilliform

Contents

Members of this Family
General Description
Morphology
Genome
Genera in the Family
All Known Sequences
Curated Sequences

General Description

This family is characterised by its bullet-shaped or bacilliform, enveloped, particles which contain a monopartite negative sense ssRNA genome. It is classified in the order Mononegavirales with three other families of enveloped viruses with monopartite negative sense genomes, i.e. the Bornaviridae and Paramyxoviridae (both of which have spherical particles) and the Filoviridae (whose members have filamentous particles).

Morphology

Virions regular or pleomorphic in shape and size (in unfixed preparations). Plant virus members fixed prior to negative staining are bacilliform but other members appear bullet-shaped. All confirmed members of the family have enveloped virions, 100-430 nm long and 45-100 nm in diameter with distinct surface projections 5-10 nm long and about 3 nm in diameter. The projections consist of trimers of the virus glycoprotein and occur evenly over all the surface. Uncoiled nucleocapsids are filamentous, 700 nm long and 20 or 30-70 nm in diameter. Nucleocapsids show an obvious regular cross-banding pattern (spaced 4.5-5 nm, in negatively stained preparations and thin sections). They consist of an RNA and N protein complex together with NS (M1) proteins and are surrounded by a lipid envelope containing M (M2) protein.

Particles contain 1-2 % nucleic acid, 65-75 % (structural) protein, 15-25 % lipid and 3% carbohydrates. Generally phospholipids represent about 50-60%, and sterols and glycolipids about 35-40%, of the total lipids. G protein has a covalently associated fatty acid proximal to the lipid envelope. The carbohydrates are present as N-linked glycan chains on G proteins and as glycolipids.

Genome

Monopartite, with linear, single stranded negative sense, RNA. Total genome 11000-15000 nucleotides long. Nucleotide sequences of the 3'-terminus are inverted and complementary to similar regions on the 5' end. The 5' terminus has a triphosphate. There are 5 structural proteins in all members which are (from 3'- to 5'):
N Nucleoprotein: the major component of the coat protein
P Polymerase-associated phosphoprotein (sometimes named NS or M1)
M Matrix protein
G Glycoprotein that binds to host cell receptors
L Polyprotein with functions including RNA polymerase and transccription
Additional proteins are encoded in some genera (between the P and M or between the G and L genes).

Genera in the Family

Plant infecting genera are: Animal virus genera are: