The Minimum Open Reading Frame, AUG-Stop, Induces Boron-Dependent Ribosome Stalling and mRNA Degradation

• Published in: The Plant cell Vol. 28; no. 11; pp. 2830 - 2849
• Main Authors: Tanaka, Mayuki, Sotta, Naoyuki, Yamazumi, Yusuke, Yamashita, Yui, Miwa, Kyoko, Murota, Katsunori, Chiba, Yukako, Hirai, Masami Yokota, Akiyama, Tetsu, Onouchi, Hitoshi, Naito, Satoshi, Fujiwara, Toru
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Biologists 01-11-2016
• Subjects: Aquaporins - genetics; Aquaporins - metabolism; Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Boron - metabolism; Gene Expression Regulation, Plant; Membrane Glycoproteins - genetics; Membrane Glycoproteins - metabolism; Open Reading Frames - genetics; Open Reading Frames - physiology; Ribosomes - genetics; Ribosomes - metabolism; RNA Stability - genetics; RNA Stability - physiology; Transcription Factors - genetics; Transcription Factors - metabolism
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.16.00481

Upstream open reading frames (uORFs) are often translated ahead of the main ORF of a gene and regulate gene expression, sometimes in a condition-dependent manner, but such a role for the minimum uORF (hereafter referred to as AUG-stop) in living organisms is currently unclear. Here, we show that AUG-stop plays an important role in the boron (B)-dependent regulation of NIP5;1, encoding a boric acid channel required for normal growth under low B conditions in Arabidopsis thaliana. High B enhanced ribosome stalling at AUG-stop, which was accompanied by the suppression of translation and mRNA degradation. This mRNA degradation was promoted by an upstream conserved sequence present near the 5′-edge of the stalled ribosome. Once ribosomes translate a uORF, reinitiation of translation must take place in order for the downstream ORF to be translated. Our results suggest that reinitiation of translation at the downstream NIP5;1 ORF is enhanced under low B conditions. A genome-wide analysis identified two additional B-responsive genes, SKU5 and the transcription factor gene ABS/NGAL1, which were regulated by B-dependent ribosome stalling through AUG-stop. This regulation was reproduced in both plant and animal transient expression and cell-free translation systems. These findings suggest that B-dependent AUG-stop-mediated regulation is common in eukaryotes.