CRISPR/Cas9 screening with destabilized bicistronic fluorescent protein reporter revealed PABPN1 as a hub of regulators for alternative polyadenylation

Alternative polyadenylation (APA) is intricately intertwined with diverse biological processes. Efficient approaches for screening the regulatory factors of specific APA events are essential to elucidate their regulation mechanisms. Here, we first engineered a destabilized bicistronic fluorescent protein reporter (dBFPR) to enhance the sensitivity of APA detection. Then, we developed a robust high-throughput screening platform for APA regulators by integrating CRISPR/Cas9, dBFPR, and fluorescence-activated cell sorting. With this method, we successfully screened the library of RNA binding proteins and found that PTBP1, ELAVL1, and DDX3X play significant roles in regulating APA and promoting cell proliferation through interaction with PABPN1, suggesting that PABPN1 is an important hub for APA regulation.