Document Type : Review Article



The clustered regularly interspaced short palindromic repeats / (CRISPR) associated protein system is an adaptive immune system in bacteria and archaea. This system mimics eukaryotic RNA interference (RNAi) system and can play an important role in gene regulation and immune system. CRISPR interference (CRISPRi) defends the bacteria against invader agents, such as phages and plasmids. As a result, it can provide a genetic interference pathway depending on the integration of a small stretch of invader DNA of the bacterial or archaeal genome, which acts as a heritable genetic memory to defense against viruses or phages.