Figure 10.

Pre-rRNA processing defects and polysome profile of the rh57 mutants. (a) Total RNA was isolated from 9-day-old seedlings of WT,rh57-1 and rh57-3 mutant plants that were incubated with shaking in sugar-free MS with or without 4.5% Glc for 30 min before harvest. The isolated total RNA (5 μg) was fractionated and blotted onto hybridization membranes for analysis. The 45S/35S pre-rRNA (indicated by an arrowhead) is represented in Figure9 with the position of selected oligonucleotides used as probes: 18S + 25S, 5′ETS, and ITS1. The abnormal pre-rRNA precursors are indicated by an asterisk. The box in the left panel indicates the18S image of reduced intensity for easier comparison. Data were obtained from two biologically independent experiments. (b). Polysome profile of the WT and rh57-1 plants. The 9-day-old seedlings of WT Col-0 and rh57-1 mutants were transferred to medium solutions supplemented with or without 4.5% Glc, and incubated for 30 min before harvest. Equivalent amounts of polysome extracts were analyzed by sucrose gradients in each case. The positions of 40S and 60S subunits are indicated as well as the monosome (80S) and polysome peaks. Data were obtained from three biologically independent experiments.