A HaloTag-Based Reporter System Enabling Two-Color Timestamped Gene Expression Monitoring

Abstract

Precise gene expression regulation is essential for cellular homeostasis, particularly in stress response pathways. In the endoplasmic reticulum, the unfolded protein response (UPR^ER) plays an important role in maintaining the protein folding capacity. We developed a chemigenetic gene expression reporter system for BiP/GRP78, a key regulator of the UPR^ER, based on co-expression of the self-labeling HaloTag protein. We designed a two-color sequential labelling strategy for improved readout sensitivity and applied our system in a high-content screening, identifying a promising novel activator of BiP/GRP78 expression.