Switchable cas9 nucleases and uses thereof

摘要: Some aspects of this disclosure provide compositions, methods, systems, and kits for controlling the activity and/or improving specificity RNA-programmable endonucleases, such as Cas9. For example, provided are guide RNAs (gRNAs) that engineered to exist in an "on" or "off state, which control binding hence cleavage endonucleases. mRNA- sensing gRNAs modulate endonucleases based on presence absence a target mRNA. endonuclease extended DNA (xDNA).