The methyltransferase domain of the Sudan ebolavirus L protein specifically targets internal adenosines of RNA substrates, in addition to the cap structure

Martin, Baptiste; Coutard, Bruno; Guez, Théo; Paesen, Guido C; Canard, Bruno; Debart, Françoise; Vasseur, Jean-Jacques; Grimes, Jonathan M; Decroly, Etienne

Infections by Ebola virus can cause severe to fatal haemorrhagic fevers. The outbreak in West Africa in 2015 was unprecedentedly devastating causing more than 11,000 deaths (1) . Despite huge efforts and investment in research for the development of countermeasures and for understanding the viral life cycle, Ebola is still a priority disease for the WHO, due to the risk of re-emergence and lack of efficient vaccines or antivirals. The genus Ebolavirus is comprised of five species: Zaire ebolavirus (Ebola virus, EBOV), Sudan ebolavirus (Sudan virus, SUDV), Tai Forest ebolavirus (Tai Forest virus, TAFV), Bundibugyo ebolavirus (Bundibugyo virus, BDBV) and Reston ebolavirus (Reston virus, RESTV) (2, 3) . They belong to the Filoviridae family together with other filamentous viruses such as Marburg marburgvirus (Marburg virus, MARV), which also causes acute haemorrhagic fevers. Having a non-segmented negative strand RNA genome (NNS), the Filoviridae are part of the Mononegavirales order, which also contains the well-characterized non-pathogenic vesicular stomatitis virus (VSV), as well as important human pathogens such as measles, Hendra and rabies viruses (4) .