Upstream open reading frames (uORFs) are DNA sequences preceding the main gene sequences. Previous studies have shown that ORFs play a role in regulating gene expression, particularly by controlling the amount of protein synthesized from a particular gene. 

Scientist Huawei Zhang and colleagues from the State Key Laboratory of Plant Cell and Chromosome Engineering in China use genome editing to control the expression of four genes involved in the development or antioxidant biosynthesis in plants. The team targeted uORFs of these genes using a single-guide RNA to produce multiple types of mutations. 

After uORF editing, they observed varying amounts of proteins from the targeted genes. They particularly noted that editing the uORF of LsGGP2, a gene encoding a key enzyme in lettuce vitamin C biosynthesis, resulted to increased oxidation stress tolerance and increased ascorbate content. The study emphasized the usefulness of gene editing in the discovery of biological mechanisms and improvement of crops.

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