Protein dimerization systems that can be controlled by red light with increased tissue penetration depth are a highly needed optogenetic tool for clinical applications such as cell and gene therapies. However, existing red light-induced dimerization systems are all based on phytochrome photoreceptors and naturally occurring binding partners with complex structures and suboptimal in vivo performance, limiting mammalian applications. Here, we introduce an efficient, generalizable method (COMBINES-LID) for creating highly specific light-induced dimerization systems. Proof-of-principle was provided by creating nanobody-based, red light-induced dimerization (nanoReD) systems comprising a truncated bacterial phytochrome sensory module using a mammalian endogenous chromophore, biliverdin, and light-form specific nanobodies. Selected nanoReD systems were biochemically characterized and exhibited low dark activity and high induction specificity for in vivo activation of gene expression. Overall, COMBINES-LID opens new opportunities for creating genetically encoded actuators for the optical manipulation of biological processes.

中文翻译：

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创建红光控制的蛋白质二聚系统，作为具有高特异性的基因编码致动器

可以通过红光控制并具有增加的组织穿透深度的蛋白质二聚化系统是临床应用（如细胞和基因疗法）急需的光遗传学工具。然而，现有的红光诱导的二聚化系统全部基于植物色素感光剂和具有复杂结构且体内性能欠佳的天然存在的结合伴侣，从而限制了哺乳动物的应用。在这里，我们介绍一种有效的，可概括的方法（COMBINES-LID），用于创建高度特定的光诱导二聚系统。通过使用哺乳动物内源性发色团，胆绿素和轻型特异性纳米抗体，创建基于纳米抗体的红光诱导的二聚化（nanoReD）系统，提供了原理证明，该系统包含截短的细菌植物色素感觉模块。对选定的nanoReD系统进行了生化鉴定，显示出低的暗活性和高的诱导特异性，可在体内激活基因表达。总体而言，COMBINES-LID为创建用于光学处理生物过程的基因编码致动器提供了新的机会。