The
genus Ebolavirus is a
virological taxon included in the family
Filoviridae, order
Mononegavirales. The members of this genus are called ebolaviruses. The five known
virus species are named for the region where each was originally identified:
Bundibugyo ebolavirus,
Reston ebolavirus,
Sudan ebolavirus,
Taï Forest ebolavirus (originally
Côte d'Ivoire ebolavirus), and
Zaire ebolavirus. The Ebola virus (EBOV) protein VP24 inhibits type I and II interferon (IFN) signaling by binding to NPI-1 subfamily karyopherin a (KPNA) nuclear import proteins, preventing their interaction with tyrosine-phosphorylated STAT1 (phospho-STAT1). This inhibits phospho-STAT1 nuclear import. A biochemical screen now identifies heterogeneous nuclear ribonuclear protein complex C1/C2 (hnRNP C1/C2) nuclear import as an additional target of VP24. Co-immunoprecipitation studies demonstrate that hnRNP C1/C2 interacts with multiple KPNA family members, including KPNA1. Interaction with hnRNP C1/C2 occurs through the same KPNA1 C-terminal region (amino acids 424–457) that binds VP24 and phospho-STAT1. The ability of hnRNP C1/C2 to bind KPNA1 is diminished in the presence of VP24, and cells transiently expressing VP24 redistribute hnRNP C1/C2 from the nucleus to the cytoplasm. These data further define the mechanism of hnRNP C1/C2 nuclear import and demonstrate that the impact of EBOV VP24 on nuclear import extends beyond STAT1.
[1] Each species of the genus
Ebolavirus has one member virus, and four of these cause
Ebola virus disease (EVD) in humans, a type of
hemorrhagic fever having a very high
case fatality rate; the fifth, Reston virus, has caused EVD in other primates.
Zaire ebolavirus is the
type species (reference or example species) for
Ebolavirus, and has the highest mortality rate of the ebolaviruses, and is also responsible for the largest number of
outbreaks of the five known members of the genus, including the 1976 Zaire outbreak and the
outbreak with the most deaths (2014).