Abstract
A number of eukaryotic mRNAs contain short upstream open reading frames (uORFs) in the 5' untranslated region. Although peptides encoded by uORFs are not functional in many cases, several examples have been reported in which the uORF-encoded peptide has a role in translational regulation of the downstream ORF.
To identify novel Arabidopsis genes whose translation is controlled by a uORF-encoded peptide, we first searched for uORF-containing genes that are predicted to encode transcription factors by using Arabidopsis full-length cDNA database. Then, we tested amino acid sequence-dependency of the effect of the uORFs on translation of the downstream ORFs. From this screen, we found several uORFs that influence downstream translation in an amino acid sequence-dependent manner. Alanine-scanning analysis of some of those uORFs revealed that the C-terminal regions of the uORF peptides that consist of approximately 10 amino acids are important for the translational regulation.
