Figure 1From: Translation reinitiation and development are compromised in similar ways by mutations in translation initiation factor eIF3h and the ribosomal protein RPL24Both eIF3h and RPL24B are required for efficient translation of the uORF-containing AtbZip11 mRNA. Data are from transient dual-luciferase gene expression assays in ten day old seedlings. The respective 5' leader is fused to firefly luciferase and is expressed in the presence of a reference gene expressing Renilla luciferase as an internal control for transformation efficiency. Both genes are transcribed from a CaMV 35S promoter [13]. (A) Schematic of the 5' leader of the AtbZip11 mRNA. Boxes numbered 1 to 4 represent uORFs. In the Δ AtbZip11 mutant the five uAUGs are replaced with stop codons [13]. Bars denote standard error; n = 7 to 10; * P < 0.002 by Student's t-test when compared to wild type. The gel images below the graph show mRNA levels for FLUC and RLUC as determined by subsaturating RT-PCR. Gel lanes correspond to the bars in the graph above. (B) Recognition of the uAUG start codons in AtbZip11. Like eif3h [13], rpl24b is not defective in recognizing the weak start codons, uAUG1 and uAUG2a, nor a strong version of uAUG4. (C) Testing the dependence of translation on the uORF peptide sequence. Both rpl24b and eif3h are inhibited to a similar degree by uORFs encoding the original uORF2 and uORF3 peptide sequences (white box in the schematic) and alternative peptide sequences generated by site-directed mutagenesis and a pair of compensatory frame shift mutations (gray box). For details on plasmid construction see [13].Back to article page