Figure 6. Channeling of aminoacyl-tRNA in permeabilized CHO cells.

WT, Mut2 and Mut1 cells (grown at 40°C to inactivate any endogenous ArgRS activity) were harvested, permeabilized, and incubated for protein synthesis as described in “Experimental Procedures”. At each time point, two 100 μl portions were taken, cooled on ice and precipitated with TCA. One portion, left on ice, measured aminoacyl-tRNA plus protein synthesized. The other portion was heated for 10 min at 95°C to solubilize labeled aminoacyl-tRNA. This portion was used to measure protein synthesis (■). The difference between the two samples represents aminoacyl-tRNA (□). Each data point represents ∼ 2 × 10⁶ cells. Panels on the left were incubated with [³H] amino acids, those on the right with the corresponding [¹⁴C] aminoacyl-tRNAs.