RNA templates preferred by the BVDV NS5B for RNA synthesis and binding. (A) Template preference for RNA synthesis. Four RNA template-primer pairs, poly(U)-oligo(dA), poly(A)-oligo(dT), poly(C)-oligo(G), and poly(G)-oligo(dC), were used to measure primer-dependent RNA synthesis by SPA. (B) RNA bandshift assay to measure the relative affinities of different RNAs bound by BVDV NS5B.