Figure 5. NS3 proteases from distantly related GB viruses inhibit human MAVS.
(A) Phylogram made using NS3 sequence from the indicated viruses. Bootstrap values are indicated for each branch. Scale represents 0.1 amino acid substitutions per site. Bovine viral diarrheal virus (BVDV) and Yellow fever virus (YFV) are representative pesti- and flaviviruses, respectively. We refer to GBV-C and GBV-A viruses as hepaciviruses, although they have not been formally assigned to a particular genus within the Flaviviridae family. GBV-C is also known as Hepatitis G virus (HGV). CHV stands for canine hepacivirus [17]. Corresponding hosts that can be naturally infected by each virus are indicated on the right. (B) IFN-β induction, as determined by luciferase firefly activity upon expression of human MAVS in the presence of NS3 protease from the corresponding virus in (A). IFN-β induction is normalized as being 100% in absence of any protease. Experiments were performed in triplicate with error bars indicating standard deviation.