Upstream open reading frame-mediated upregulation of ANAC082 expression in response to nucleolar stress in Arabidopsis.

Perturbations in ribosome biogenesis cause a type of cellular stress called nucleolar or ribosomal stress, which triggers adaptive responses in both animal and plant cells. The Arabidopsis ANAC082 transcription factor has been identified as a key mediator of the plant nucleolar stress response. The 5'-untranslated region (5'-UTR) of mRNA contains an upstream ORF (uORF) encoding an evolutionarily conserved amino acid sequence.

Genome-wide identification of Arabidopsis non-AUG-initiated upstream ORFs with evolutionarily conserved regulatory sequences that control protein expression levels.

This study identified four novel regulatory non-AUG-initiated upstream ORFs (uORFs) with evolutionarily conserved sequences in Arabidopsis and elucidated the mechanism by which a non-AUG-initiated uORF promotes main ORF translation. Upstream open reading frames (uORFs) are short ORFs found in the 5'-untranslated regions (5'-UTRs) of eukaryotic transcripts and can influence the translation of protein-coding main ORFs (mORFs). Recent genome-wide ribosome profiling studies have revealed that hundreds or thousands of uORFs initiate translation at non-AUG start codons.

Identification of Arabidopsis thaliana upstream open reading frames encoding peptide sequences that cause ribosomal arrest.

Specific sequences of certain nascent peptides cause programmed ribosomal arrest during mRNA translation to control gene expression. In eukaryotes, most known regulatory arrest peptides are encoded by upstream open reading frames (uORFs) present in the 5'-untranslated region of mRNAs. However, to date, a limited number of eukaryotic uORFs encoding arrest peptides have been reported.