Figure 1.
The CRISPR/Cas adaptive immunity system involves three stages: CRISPR adaptation, CRISPR RNA biogenesis, and CRISPR interference. In the adaptation stage, viruses trigger Cas1 and Cas2 modules, cleaving invading sequences. In the biogenesis stage, the CRISPR array is transcribed into mature crRNA molecules, forming effector complexes with Cas proteins.
