Protein splicing elements and plants: from transgene containment to protein purification

Protein splicing elements, termed inteins, have been discovered in all the domains of life. Basic research on inteins has led to a greater understanding of how they mediate the protein splicing process. Because inteins are natural protein engineering elements they have been harnessed for use in a number of applications, including protein purification, protein semisynthesis, and in vivo and in vitro protein modifications. This review focuses on the use of inteins in plants. A split-gene technique utilizes inteins to reconstitute the activity of a transgene product with the goal of limiting the spread of transgenes from a genetically modified plant to a weedy relative. Furthermore, merging the intein tag for protein purification with the large protein yields possible with plants has the potential to produce pharmaceutically important proteins. Finally, relevant techniques that may be used in plants in the future are discussed.