Abstract
Upstream open reading frames (uORF) are small ORFs located in 5' leader region of certain eukaryotic genes. The presence of uORF can negatively modulate translational efficiency of the downstream main ORF. Although the effects of most uORFs are independent of their encoded peptide sequences, several uORFs have been shown to control translation of the main ORF in an amino acid sequence-dependent manner. In plants, so far only two genes regulated by such a uORF-encoded bioactive peptide have been reported. In order to further identify uORF peptides that control expression of the main ORF, we searched for Arabidopsis uORFs whose amino acid sequences are conserved beyond rosids group by using a comparative genomic approach. We found 14 novel uORFs conserved in a wide range of dicot plants. Next, we tested whether these uORFs affect expression of the downstream ORF in a uORF peptide sequence-dependent manner, and identified 5 novel genes whose expression is controlled by a uORF-encoded peptide.
