Notes on Genus: Ebolavirus

enveloped filaments

Type member: Zaire ebolavirus

General Description

The genus Ebolavirus is one of two genera in the family Filoviridae. It is named after the river Ebola in Zaire where the disease was first recognised. The virions are larger than those of the genus Marburgvirus and their are minor differences in genome organisation.

Morphology

Virions pleomorphic but usually filamentous or bacilliform, enveloped, about 80 nm in diameter and 970nm long (although they may appear longer because of aggregation), with small (10 nm) projections.

Genome

Monopartite single-stranded negative sense RNA of about 19 kb. There is no genome-linked protein (VPg) at the 5'-terminus nor a 3'-polyA tail.

Genus Genomic Organization

There are 7 major ORFs with the RNA polymerase at the 5'-end of the genome and the capsid nucleoprotein at the 3'-end.

Type Member Genomic Organization

There are 7 major ORFs translated from positive sense template RNAs. They are listed here in their order on the template strand - i.e. from 3' to 5' with respect to the virion strand:

1	NP	83 kDa	Coat protein (nucleocapsid)
2	VP35	37 kDa	Phosphoprotein
3	VP40	35 kDa	Matrix protein
4	GP	74 kDa	Glycoprotein precursor, consisting of two overlapping ORFs that are fused by transcriptional editing
5	VP30	32 kDa	Virion protein
6	VP24	28 kDa	Virion protein
7	L	253 kDa	Polymerase