The Caribou genome editing technology platform is centered on Cas9, a protein derived from the CRISPR-Cas prokaryotic immune system. Cas9 is a programmable nuclease which acts as a type of molecular scissors. Cas9 uses short RNA molecules, known as guide RNAs, to target the protein to a specific sequence within cellular DNA. By changing the sequence of the guide RNA, Cas9 can be directed to almost any DNA sequence, enabling simple and flexible targeting of nearly any site in a given genome.
A precise cut in DNA is a critical step in editing DNA. A cell’s own machinery will repair the break, and the repair can be directed to introduce new DNA sequences or to create deletions. These activities can also be used to introduce specific edits to the genome.
Through the use of multiple guide RNAs, Cas9 can enable multiplexed engineering of many sites in parallel. Versions of Cas9 with altered or inactivated nuclease activity can be harnessed as DNA-binding proteins to activate or repress transcription, providing the potential to control gene expression and build synthetic cellular control networks.