CRISPR‐Cas13: Biology, Mechanism, and Applications of RNA‐Guided, RNA‐Targeting CRISPR Systems

Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR associated (CRISPR-Cas) proteins have quickly become a focus of intense interest, both for their function as adaptive immune systems in their native contexts and for their numerous applications in biotechnology. This chapter discusses the expanding set of Cas13 and type VI systems, their mechanisms of action and how they differ from other RNA targeting CRISPR systems, and the myriad applications of Cas13 for eukaryotic manipulation and nucleic acid diagnostics. A central component of CRISPR's adaptive immunity, acquisition of sequences that guide targeting, is a peculiar circumstance in type VI systems, as there are multiple uncertainties around how RNA targets can be incorporated as DNA spacers. The unique RNA-programmed RNA-targeting characteristics of Cas13 enable multiple applications, both for measuring and manipulating RNA in cells and for detecting nucleic acids sensitively in vitro .