Optical Control of Endogenous Mammalian Transcription

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Silvana Konermann, Mark D. Brigham, Alexandro Trevino, Matthias Heidenreich, Le Cong, Patrick D. Hsu, George M. Church, and Feng Zhang

United States

The ability to engineer synthetic transcriptional circuits holds enormous potential for applications from basic science and biotechnology to medical engineering. Spatiotemporal and quantitative bimodal control is necessary for the precise construction of artificial transcriptional circuits in vivo. Here, we describe the development of Light-Inducible Transcriptional Effectors (LITEs), a novel optogenetic tool capable of bimodally modulating gene expression from the endogenous mammalian genome. LITEs are a two-component system integrating the programmable TALE DNA-binding domain with the light-sensitive cryptochrome 2 protein and its interacting partner CIB1 from Arabidopsis thaliana. They can be engineered to mediate positive and negative regulation of endogenous mammalian gene expression in a reversible manner, with changes in mRNA levels occurring within minutes following optical illumination. We have applied this system in mammalian cell lines, primary neurons, and within the brain of awake, behaving mice in vivo. The LITE system offers bidirectional gene regulation and quantitative control of gene expression through adjustment of light intensity. In addition, it enables programming of biological processes with a high degree of spatiotemporal precision. Finally, LITEs are amenable to multiplexing with other optogenetic technologies through wavelength discrimination. Taken together, LITEs hold great promise for the construction of complex transcriptional circuits in vivo.