Gene editing technology works to remove deleterious DNA
sequences and replace with a correct sequence
Genome editing is a new therapeutics approach that enables to restore correct functions by eliminating a deleterious gene and replacing with the correct DNA sequence. Like gene therapy, genome editing approach employs virus vector to deliver editing machineries into target cells.
The only variable component in CRISPR-Cas9 is gRNA, which allows fast optimization and high throughput screening.
Early generations of genome editing technology employs proteins such as ZFN and TALEN, these proteins require considerable effort to design and produce against target DNA sequences. The proteins need to fuse with DNA cleaving enzyme, which requires dimerization to cleave the target DNA. Thus, two proteins need to bind to the target sequences at the same time, imposing stoichiometry requirement.
CRISPR technology employs Cas9 protein, which is applicable to any target DNA sequences. Cas9 protein recognizes target sequence using gRNA, which is easy to design and synthesize. One caveat is that there are several reports that indicate risk of cancer associated with cleaving DNA by these genome editing technologies.