CRISPR/dCas9 Approaches for Engineering Gene Expression

CRISPR is a powerful technology and the CRISPR-Cas9 system has provided a new tool for simple, precise, selective and easy to use genetic engineering of any different DNA targets of the genome. This ability is essential for understanding gene function, engineering cell behaviors, and developing therapies. The type II CRISPR-Cas9 system is the most commonly used for genome editing. This ribonucleoprotein complex consists of a DNA endonuclease (Cas9) and two RNAs, CRISPR RNA (crRNA) and transacting RNA (tracrRNA). Subsequently, the discovery of nuclease-dead Cas molecules (dCas9) provided a platform for precise control of genome function without gene editing. In this review article, the advances of CRISPR/dCas9 technique and its applications in the field of genome engineering and gene expression, as well as the improvement of its methods, have been discussed.