Notch signaling is highly conserved in most animals and plays critical roles during neurogenesis as well as embryonic development. Synthetic Notch-based systems, modeled from Notch receptors, have been developed to sense and respond to a specific extracellular signal. Recent advancement of synNotch has shown promise for future use in cellular engineering to treat cancers. However, synNotch from Morsut et al. (2016) has a high level of ligand-independent activation, which limits its application. Here we show that adding an intracellular hydrophobic sequence (QHGQLWF, named as RAM7) present in native Notch, significantly reduced ligand-independent activation. Our enhanced synthetic Notch receptor (esNotch) demonstrates up to a 14.6-fold reduction in ligand-independent activation, without affecting its antigen-induced activation efficiency. Our work improves a previously reported transmembrane receptor and provides a powerful tool to develop better transmembrane signaling transduction modules for further advancement of eukaryotic synthetic biology.

Notch信号在大多数动物中高度保守，在神经发生和胚胎发育中起关键作用。已开发出以Notch受体为模型的基于Notch的合成系统，以感应并响应特定的细胞外信号。synNotch的最新进展显示出有望在细胞工程中用于治疗癌症。但是，来自Morsut等人的synNotch。（2016）具有高水平的配体非依赖性激活，这限制了其应用。在这里我们表明，添加天然Notch中存在的细胞内疏水序列（QHGQLWF，称为RAM7）会显着降低配体非依赖性激活。我们增强的合成Notch受体（esNotch）在不影响配体诱导的激活效率的情况下，在配体依赖性激活方面最多降低了14.6倍。