(A) Schematic of the truncations in M6 plus-strand RNA used as competitors in EMSA. Three fragments, M6a (nt 1–868), M6b (nt 449–1352, M6c (868–1769) were used. (B) EMSA data. The identity of the M6 truncation used as competitor for binding of the full-length probe is shown above each panel. Lane 1 contains 1× 10−9 M 32P-labeled full-length M6 probe only; lane 2, 32P-labeled probe and NS2 and lanes 3–8 contain 32P-labeled probe and NS2 and unlabeled competitor in molar ratio of probe: competitor of 1:10, 1:100, 1:300, 1:600, 1:1000 and 1:10,000 respectively.