CRISPR as a Versatile Technology for Gene Activation and Genome Editing

CRISPR/Cas system, a microbial adaptive immune system, has rapidly transformed the ways researchers can interrogate the genome. CRISPR has many advantages over traditional methods such as Transcription activator-like effector nucleases (TALEN) and Zinc-finger nucleases (ZFN). Since CRISPR discovery as an adaptive immune system used by bacterial against viruses, it has been repurposed to help in many different genome-related studies such as gene knocking in and out, gene expression upregulation and downregulation. Also CRISPR holds vast therapeutic potential for the management of genetic disorders by straight modifying disease-causing mutations. Although the Cas9 protein has been revealed to attach and cleave DNA at off-target sites, the field of Cas9 specificity is quickly progressing, with marked modifying in guide RNA choice, protein and guide engineering, innovative enzymes, and off-target recognition methods. In current review we mostly focus on CRISPR unique ability in gene activation/ upregulation, which has wide applications in different aspects such as gene studies, stem cell differentiation, and trans-differentiation. Compared to other gene activation methods such as viral gene overexpression, TALEN and ZFN, CRISPR offers many benefits such as easy designing and high precision.