A mRNA is a stretch of letters, which contains genetic information to build proteins. Similar to the “text translation”, the process of using mRNA sequence information to produce proteins is called “mRNA translation” in biology. Thus, “translation initiation” mechanism, which controls where, when, and how translation events start along a mRNA, plays a critical role of shaping proteomes and controlling gene expressions for plant stress response/adaptation. However, the translating potential of mRNAs, the determinants of translation initiation sites, as well as the stress-responsive regulations remains obscure.
Dr. Ming-Jung Liu and her group at the Agricultural Biotechnology Research Center, Academia Sinica, systemically pinpointed “in vivo” translation initiation sites on transcriptome across plant species and discovered a number of novel AUG and non-AUG initiation sites, which were under appreciated in previous studies. The similarity of initiation codon usage between plant species further revealed the evolutionary conservation of initiation mechanisms. These novel initiation sites were associated with mRNA translation repression and also contribute to the expression of protein isoforms with different N-terminal ends, which consequently affected protein organelle localizations. Intriguingly, while these initiation sites were generally found in orthologous gene pairs, the sequences of initiation sites were not conserved, suggesting the conservation of initiation mechanisms but the flexibility in employing TISs. These findings uncovered the hidden coding potential of plant genomes and, importantly, the constraint and flexibility of translation initiation mechanisms in the regulation of gene expression across plant species. flexibility of translation initiation mechanisms in the regulation of gene expression across plant species.
Article link: https://genome.cshlp.org/content/30/10/1418
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