Recent progress in technological improvement and biomedical applications of the clustered regularly interspaced short palindromic repeats/cas system

The adaptive immune systems of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated genes (Cas) selectively destroy nonnative DNA and defend almost all archaea and about half of the bacteria against infections. In the past years, the system has been genetically engineered to a powerful genome editing tool for a wide variety of organisms. Recently, many progresses have been made in the CRISPR-Cas systems. These improvements include applications in editing multiple genes, correcting mutation genes with one base difference, targeting nondividing cells, reducing off-target, and editing RNAs. The biomedical applications of the technology are to edit not only cells but also embryos in clinical settings. In this review, we briefly introduce the improvements of CRISPR-Cas9 gene editing methods and summarize the recent advances of this technology.