FIG. 5.

Effect of dl-La on poliovirus RNA translation in RRL. (A) Effect of recombinant La protein on cell-free translation. Template RNA (0.5 μg) was incubated in RRL containing [³⁵S]methionine and 1 μg of N′-La, 0.7 μg of dl-La, 0.7 μg of La, or 50 μg of HeLa S100 extract as described in Materials and Methods. The mixture was boiled in SDS sample buffer for the immunoblot as described in the legend to Fig. 3. (B) Purities of recombinant La-related proteins. La-related proteins (lane 1, La; lane 2, dl-La; lane 3, N′-La) were purified as described in Materials and Methods and separated by SDS-PAGE. The results of silver staining of the gel (a) and immunoblot analysis with MAb La4B6 (b) are shown. Arrows on the right side of each figure indicate the positions of La protein, dl-La, and N′-La.