Figure 4.

Enhancement of translation of ribosomal protein mRNAs in the rpl24b mutant. (A) Changes in translation state (Δlog₂ TL) were plotted onto Arabidopsis biochemical pathways and functional categories using MapMan v3.5.1R2. Each square represents a single gene, and each gene occupies equivalent positions in each set. The log-scale indicates overtranslation (red) or undertranslation (blue) in rpl24b or eif3h or pab2 pab8 compared to wild-type. Ribosome occupancy of ribosomal protein mRNAs is stimulated in rpl24b, which is enhanced in eif3h (middle). The similarity does not extend to histones, which are shown as a representative comparison group. It also does not extend to pab2 pab8. Also note that transcript levels (Δlog₂ TC _rpl24b/WT) for cytosolic r-proteins tend to be elevated in the rpl24b mutant. Data are for selected gene classes from all A. thaliana probe sets (genes) on the GeneChip® Arabidopsis ATH1 Genome Array (n = 22,746). (B) Scatterplot showing the translational codependence of cytosolic (black filled circles) and organellar (red and green filled circles) r-protein mRNAs on RPL24B and eIF3h. Genes encoding organellar r-protein mRNAs are further subdivided into nuclear-encoded (nuc) and chloroplast-encoded or mitochondrion-encoded (chl/mit). Pearson correlation coefficients (R²) for cytosolic (C), organellar (O) and all (All) r-protein mRNAs are indicated. Dashed lines (blue and red) represent 1.5-fold changes. The number of mRNAs (n) for each class of r-protein is also indicated.