Figure 2.

Incorporation of [³²P]AMP into polysomal RNA in the presence or absence of postribosomal S100 supernatants. The experimental procedures are described in the text. Postribosomal extracts were made by centrifuging the lysed cells at 100,000 rpm for 2 hr. The supernatants (S100) were stored on ice overnight. PAP I⁺ is SK5667 (rna-19 thyA715) and PAP I⁻ is SK8964 (ΔpcnB rna-19 thyA715). Lanes 1 and 6 were sampled at 0 min, and all remaining lanes were sampled at 10 min. Lanes 1–5, polysomes from PAP I⁺ to which the postribosomal supernatant from PAP I⁻ was added at the indicated protein concentrations. Lanes 6–10, polysomes from PAP I⁻ with postribosomal supernatant from PAP I⁺ added at the indicated protein concentrations. Lanes 11 and 12, postribosomal supernatant from PAP I⁺ without (lane 11) and with (lane 12) 2 μg of added tRNA. Lanes 13 and 14, postribosomal supernatant from PAP I⁻ without (lane 13) and with (lane 14) 2 μg of added tRNA. Lane 15, polysomes from PAP I⁻ incubated with 1 unit of exogenous PAP I enzyme. RNA size markers in nucleotides are shown on the left.