In this paper Endoh and Sugimoto are able to insert a working theophylline riboswitch into HeLa cells. By blocking the ability of Tat to bind to the thTAR-RNA they are able to suppress transactivation of transcription. This is controlled through the use of theophylline. Without theophylline the Tat is able to properly bind, but in the presence of theophylline a conformational change prevents Tat binding.
Take a look at the small molecule concentration and the activity of the switch: at a 1 mM (!) theophylline concentration they see only a 3-fold reduction in reporter gene expression. Although I am a big fan of RNA-based switches, I don't think they really work in mammalian cells.
ReplyDeleteYa, I noticed that. I was not too impressed with the paper overall, but it was interesting to see that it is possible (though impractical) to use artificial riboswitches in HeLa cells.
ReplyDeleteIt is interesting to see different gene regulation machinery on the UTR regions of the mRNA. How is this indirect artificial regulation affective compared to direct gene regulation?
ReplyDeleteUnfortunately, riboswitches are "leaky". There are ways of making them less leaky, and I'm sure they could optimize this a little more. However, I think this is a good proof of principle that artificial riboswitches could be put in mammalian cells. I can primarily see this being used for elucidating functions of proteins, especially proteins that you don't want to or can't completely stop gene expression of.
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