CRISPR-powered RNA sensing in vivo.

RNA sensing in vivo evaluates past or ongoing endogenous RNA disturbances, which is crucial for identifying cell types and states and diagnosing diseases. Recently, the CRISPR-driven genetic circuits have offered promising solutions to burgeoning challenges in RNA sensing. This review delves into the cutting-edge developments of CRISPR-powered RNA sensors in vivo, reclassifying these RNA sensors into four categories based on their working mechanisms, including programmable reassembly of split single-guide RNA (sgRNA), RNA-triggered RNA processing and protein cleavage, miRNA-triggered RNA interference (RNAi), and strand displacement reactions. Then, we discuss the advantages and challenges of existing methodologies in diverse application scenarios and anticipate and analyze obstacles and opportunities in forthcoming practical implementations.