Abstract
Protein degradation technologies represent a powerful functional genomics tool, allowing fast and controllable target protein depletion. Establishing these systems requires a knock-in of the degradation tag into both endogenous target gene alleles. Here, we provide a step-by-step protocol for the efficient generation of biallelic degradation tag knock-ins in mouse and human cell lines using CRISPR-Cas9. We use knockin of an endogenous Kansl3 degradation tag in mouse embryonic stem (ES) cells as an example but provide modifications for application in other cell types. For complete details on the use and execution of this protocol, please refer to Radzisheuskaya et al. (2021).