Abstract
UV crosslinking and immunoprecipitation (CLIP) coupled with high-throughput sequencing is the most state-of-the-art technology to characterize protein-RNA interactions, yet only a small portion of RNA-binding proteins (RBPs) have been studied by CLIP due to its complex procedures and high level of false-positive signals. Herein, we report a SpyCLIP method that employs a covalent linkage formed between the RBP-fused SpyTag and SpyCatcher, which can withstand the harshest washing conditions for removing nonspecific interactions. Moreover, SpyCLIP circumvents the radioactive labeling and PAGE-membrane purification steps, and the whole procedure can be performed on beads and is readily amenable to automation. We investigated multiple RBPs by SpyCLIP and generated high-quality RNA binding maps with significantly improved reproductivity and accuracy. Therefore, the small tag size and convenient protocol of SpyCLIP provides a robust method for both routine characterization and high-throughput studies of protein-RNA interactions.