FIG 8.

Polysomes do not accumulate in the absence of RAC/Ssb. (A and B) Ribosome profiles of wild-type (A) and Δssb1 Δssb2 (B) strains in the absence (−) or presence (+) of cycloheximide (CHX). Strains were grown at 30°C and then shifted to 20°C for 2.5 h prior to harvest. The temperature shift was performed to enhance effects due to the absence of RAC/Ssb. The Δssb1 Δssb2 mutation causes severe cold sensitivity (33). Cells were then harvested in the presence or absence of cycloheximide (CHX) as indicated. Lysates were separated on 15 to 55% sucrose gradients and subsequently fractionated monitoring A₂₅₄. The polysome/80S ratio represents the mean of 3 independent experiments, and the standard error of the mean is indicated. Quantifications were performed using ImageJ software.