Reconstituting Arabidopsis CRY2 signaling pathway in mammalian cells reveals regulation of transcription by direct binding of CRY2 to DNA (Cell Rep)

Cryptochromes (CRYs) are blue-light receptors that were first identified in plants more than 20 years ago, but with modes of action that have remained obscure. Yang, Mo, and Yu, et al. reassembled this blue-light signaling module in mammalian cells in order to better understand CRY function. Previously, they showed that in this system CRY2 absorbs blue light, dimerizes in response to blue light, and forms blue-light specific photobodies. In this new study, the authors show that CRY2 binds DNA (specifically, the FT gene), that this binding is enhanced by blue light, and that blue-light enhances CRY2’s transcriptional activity, both directly and through its interaction with CIB1. (Summary by Mary Williams) Cell Reports 10.1016/j.celrep.2018.06.069