Inducible gene expression from the plastid genome by a synthetic riboswitch

I think this is a really cool paper. Currently very few synthetic riboswitches exist in eukaryotic systems. This is because eukaryotic transcription and translation is a lot more complex than a prokaryotic system and hence harder to manipulate. The author is able to get around this problem by targeting the chloroplast (plastids) in plants. Chloroplasts have their own transcription/ translation machinery which is largely prokaryotic. Therefore, the author is able to screen these riboswitches in E. coli and then transfer them to the chloroplasts. In this article, the author feels that this would be a great tool for synthetic biology and the manufacture of natural products. This is because chloroplasts have the ability to store large amounts of products with out becoming toxic to the cell. The picture above shows six different riboswitches expressed in the presence or the absence of their ligand. As you can see the only switch that worked was the synthetic theophylline switch.