FIG. 8.

Purification of complementing activity by RNA affinity chromatography. Partially purified complementing activity was incubated with the triple-mutant (Mu) RNA affinity resin. After this preclearing step, the unbound fraction was loaded onto the wild-type (WT) RNA affinity resin. Bound proteins were eluted with 0.5 M-salt-containing buffer. (A) The unbound fractions and the 0.5 M-salt-eluted fraction were assayed for complementing activity. (B) An aliquot of the affinity-purified fraction was also resolved by SDS–8% PAGE and analyzed by silver staining.