Precise Interference of RNA-Protein Interaction by CRISPR-Cas13-Mediated Peptide Competition

RNA-protein interactions are essential nodes of cellular regulatory circuits and play critical roles in normal physiology and disease. However, the precise roles of individual RNA-protein interactions remain elusive. Here we report a method for precise interference of endogenous RNA interacting with the RNA binding protein (RBP). TTP is an RBP that recognizes the AU-rich element (ARE) of mRNA via the binding domain TZF and represses gene expression. We engineer Cas13b, a class 2 type VI CRISPR-Cas endonuclease that exclusively targets RNA, to direct the peptide of TZF to the binding site and compete with endogenous TTP. We show that this tool specifically interferes with TTP interacting with the PIM1 and IL-2 3' UTR under the guidance of the gRNA specific for the AREs. Further, precise interference with the TTP-PIM1 interaction exerts a distinct effect on cell proliferation compared to transcriptome-wide interference. Thus, our work establishes a tool for deep understanding of RNARBP interactions.