Locus-Specific Knock-In of a Degradable Tag for Target Validation Studies

: Small molecule-induced targeted protein degradation is a powerful approach for drug target validation given its selectivity, high kinetic resolution, dose dependency, and reversibility. Out of the several methods that have been reported so far, the 12 kDa degradation tag (dTAG) system has the advantage of hijacking a degradation machinery that is ubiquitously expressed in all human tissues. Therefore it is independent of expressing additional, exogenous factors and additionally permits target validation in vivo. Here, we describe the protocol for generation and validation of clones harboring knock-in of a selectable dTAG cassette at the endogenous locus of proteins of interest using the near-haploid cell line KBM7.