Fig. 1.

Schematic of the workflow of CARIC. EU and 4SU were simultaneously taken up by cells and metabolically incorporated into RNAs. The 365-nm UV light irradiation activated 4SU and covalently cross-linked RNAs with direct binders. The cells were lysed and reacted with azide-biotin to tag EU. After enrichment with streptavidin beads, the eluted RNPs were digested with RNase A and the released RBPs were analyzed by quantitative proteomics using LC-MS/MS.