CRISPR/Cas9: high throughput genome editing molecular tool

Targeted genome editing by RNA-guided nucleases is a high throughput and facile approach which not only provides modifications, gene editing and functional studies for researchers, but also develops their knowledge about molecular basis of diseases and stablishes novel targeted therapies. Several platforms for molecular scissors that enable targeted genome engineering have been developed, including zinc-finger nucleases (ZFNs), transcription activation-like effector nucleases (TALENs) and clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated-9 (Cas9). Indeed CRISPR/Cas9 system is bacterial defensive system against viral invasions. Cas9 protein can be targeted to DNA sequences by accompanying single-strand RNA guide which base-pairs directly with target DNA to introduce modifications. Improvements are urgently needed for various aspects of system, including delivery and control over the outcome of the repair process. CRISPR/Cas9 holds enormous therapeutic potential for the treatment of genetic disorders by directly correcting disease causing mutations. Although the Cas9 protein has been shown to bind and cleave DNA at off-target sites the field of Cas9 specificity is rapidly progressing with marked improvements in guide RNA selection, novel enzymes and off-target detection methods. In this review we discuss history and different aspects of CRISPR/Cas9 including advances in specificity strategies for genome engineering, system delivery and control optimization on repair processes along with its implication for the future of biological researches and gene therapy.