1.A.95 The Ephemerovirus Viroporin (EVVP) Family
Koolpinyah virus (KOOLV) isolated from healthy Australian cattle and Yata virus (YATV) isolated from a pool of Mansonia uniformis mosquitoes in the Central African Republic are related antigenically to kotonkon virus, an ephemerovirus that has caused an ephemeral fever-like illness in cattle in Nigeria. The complete genome sequences of KOOLV (16,133 nt) and YATV (14,479 nt) revealed complex genome organisations, with multiple genes, including a viroporin (α1) gene, between the G and L genes as is characteristic of ephemeroviruses (Blasdell et al. 2014).
The 10.5-kDa α1 protein of bovine ephemerovirus is expressed in infected cells and has the properties of a viroporin (Joubert et al. 2014). Expression of a BEFV α1-maltose binding protein (MBP) fusion protein in Escherichia coli was observed to inhibit cell growth and increase membrane permeability to hygromycin B. Increased membrane permeability was also observed in BEFV-infected mammalian cells (but not cells infected with an α1-deficient BEFV strain) and in cells expressing a BEFV α1-green fluorescent protein (GFP) fusion protein, which was shown by confocal microscopy to localize to the Golgi complex. The full-length α1 interacts specifically with importin β1 and importin 7 but not with importin α3. These data suggest that, in addition to its function as a viroporin, BEFV α1 may modulate components of nuclear trafficking pathways (Joubert et al. 2014).