High level expression of transgenes by use of 5′-untranslated region of the Arabidopsis thaliana arabinogalactan-protein 21 gene in dicotyledons

Abstract

For higher expression of a foreign gene in plant cells, it is important to optimize nucleotide sequences corresponding to 5′-untranslated region (5′-UTR), because it usually has great impacts on the expression of the gene mainly at the translational level. In this study, with an aim to find useful 5′-UTRs, thirty nine 5′-UTRs derived from Arabidopsis thaliana genes were tested by transient expression of firefly luciferase (Fluc), and that of A. thaliana arabinogalactanprotein 21 (AtAGP21) gene was selected for further analyses. Its activity was either equaling or surpassing that of known translational enhancer, A. thaliana alchol dehydrogenase (AtADH) 5′-UTR in dicotyledons, and was further improved by the optimizing sequence context of the initiating codon (-3 to -1 of AUG). Finally, we also found that the modified AtAGP21 5′-UTR was useful in recombinant expression of horseradish peroxidase (HRP) in tobacco cultured cells, and the yield was as much as 23 mg l -1 culture medium in seven days. © 2012 The Japanese Society for Plant Cell and Molecular Biology.