Discovery of proteins associated with a predefined genomic locus via dCas9–APEX-mediated proximity labeling

Regulation of gene expression is primarily controlled by changes in the proteins that occupy genes’ regulatory elements. We developed genomic locus proteomics (GLoPro), in which we combine CRISPR-based genome targeting, proximity labeling, and quantitative proteomics to discover proteins associated with a specific genomic locus in native cellular contexts. After CRISPR-mediated targeting of the peroxidase APEX2 to a genomic locus of interest, the proteins at that locus are labeled, enriched and identified via quantitative proteomics.