Expression and characterization of RNA-dependent RNA polymerase of Ectropis obliqua virus

Replication of positive-strand RNA virus is mediated by a virus-encoded RNA-dependent RNA polymerase (RdRp). To study the replication of Ectropis obliqua virus (EoV), a newly identified insect virus belonging to the family Iflaviradae, we expressed the RNA polymerase domain in Escherichia coli and purified it on a Ni-chelating HisTrap affinity column. It is demonstrated that EoV RdRp initiated RNA synthesis in a primer- and poly (A)-dependent manner in vitro. Furthermore, the effect of primer concentration, temperature, metal ions (Mg(2+), Mn(2+), and K(+)) on enzymatic activity were determined. Our study represented a first step towards understanding the mechanism of EoV replication. [BMB reports 2010; 43(4): 284-290]