Fine tuning upstream open reading frames allow graded protein downregulation in plants

Regulatory components called upstream open reading frames (uORFs) are commonly found in eukaryotic mRNA molecules. These uORFs regulate the translation rate of downstream coding sequences. Xue et al. edited uORFs added or edited uORFs in several genes to investigate the effects of adding or extending uORFs. Using dual-luciferase assays, they showed that protein expression is significantly reduced when uORFs were extended in 5′ UTRs of different Arabidopsis and Oryza genes. With the same assay, they inserted de novo uORFs of different sizes (4-30 amino acid-long) into 5′ UTRs and graded their downregulation abilities. This allowed subtle changes via incremental inhibition of gene translation, and this was reflected in the phenotypic effects when endogenous genes were engineered. uORF editing to reduce protein translation could avoid adverse cellular consequences of gene knockouts. This paper is an exciting addition showing how precision genome editing can help crop breeding in the future. (Summary by Yen Peng (Apple) Chew @_applechew) Nature Biotechnol. 10.1038/s41587-023-01707-w