Engineered UV-A light-responsive gene expression system for measuring sun cream efficacy in mammalian cell culture

• UV-A and blue light-inducible gene expression system.
• Mammalian synthetic light-dependent dimerization of CRY2 and C1BN.
• Cell-based evaluation of sun cream UV-A protection properties.

Light-dependent gene regulation systems are advantageous as they allow for precise spatio-temporal control of target gene expression. In this paper, we present a novel UV-A and blue-light-inducible gene control system that is based on the light-dependent heterodimerization of the CRY2 and C1BN domains. Upon their interaction, a transcription factor is released from the cell membrane and initiates target gene expression. Capitalizing on that, sun cream UV-A protection properties were measured intracellularly.