Optimization of Cas12a for multiplexed genome-scale transcriptional activation
Cas12a allows for easy multiplexing of guide RNAs in a single construct. CRISPRa, in which transactivation domains are used to overexpress endogenous genes, has been optimized using Cas9 but not Cas12a. Griffith et al. optimize Cas12a-based CRISPRa and demonstrate that recruitment using the ALFA tag and a corresponding nanobody enables potent gene activation across multiple genes simultaneously. Then, they perform genome-wide Cas12a-based CRISPRa screens, compare results with screens using other technologies, and derive guidelines for library design.