Application of NanoLuc to monitor the intrinsic promoter activity of GRP78 using the CRISPR/Cas9 system.

In this study, we applied a highly sensitive small luciferase, NanoLuc, to establish a knock-in cell line using the CRISPR/Cas9 system and characterized the endogenous promoter activity of the glucose-regulated protein 78 (GRP78) gene. The N-terminal region of the human GRP78 gene was fused to the NanoLuc gene and aligned with the puromycin-resistant gene through the 2A peptide sequence and used as a knock-in vector. The selected cells responded to both pharmacological and genetic ER stress and show NanoLuc-based CRISPR/Cas9 system is a very useful tool to isolate gene-edited cells and to characterize the endogenous promoter activity for genes of interest.