gene editing as one of the emerging techniques of genetic engineering, its essence is to artificially change the natural selection. The current widespread use of“gene scissors”is a CRISPR-Cas9, the technology in a range of gene therapy applications show great prospects, but too much of the protein molecule become a CRISPR future applications the most important bottleneck one.
recently, from the University of California at Berkeley and the Innovative Genomics Institute of the researchers found a new gene editing tools-CasΦ, it is a function of the minimum CRISPR-Cas system, by the 170 KD CasΦ protein and a CRISPR array, and only in the macrophages of the genome encoding, the volume of which is the CRISPR-Cas 9 that this study results in 7, on 16, published in “Science” magazine.
DOI: 10.1126/science. abb1400
CasΦ （Cas12j is macrophage Mycobacterium encoding the Cas protein family, and macrophages use it to induce bacterial resistance to itself and not itself a virus. It uses a single active site for CRISPR RNA（crRNA processing and crRNA guide the DNA-cutting, in order to target foreign nucleic acids.
researchers first to determine CasΦ whether as real the CRISPR-Cas system. They found that CasΦ in its natural environment is a functional phage protein and the the true of the CRISPR-Cas effector, capable of cleavage of the crRNA-complementary DNA. In addition, this single RNA system other than the activity of the CRISPR-Cas system is much more compact. span>
next, the research team need to understand CasΦ in vitro on DNA recognition and cleavage requirements. The results showed that CasΦ cleavage activity only in the identification of CIS-DNA can be observed, and requires only a minimum of PAM condition, which may be beneficial in more extensive nucleic acid detection.
finally, in order to study the CasΦ whether for human genome editing, the researchers in the HEK293 cells used in the crRNA Co-expressed CasΦ carried out gene disruption assay. They found that CasΦ-2 and CasΦ-3-induced genomic integration of the enhanced green fluorescent protein（EGFP）gene of the directional damage. Wherein, with a single guide RNA CasΦ-2 to be able to edit up to 33% of the cells, which with the previously reported CRISPR-Cas9, CRISPR-Cas12a and CRISPR-CasX levels quite a bit.
macrophages coded CasΦ in which a host of Super-infection in case of a functional schematic diagram
actually, this is not CasΦ debut. It was first used by this study, another main author-IGI a PhD student Basem Al-Shayeb found, this study to this year 2 month 12, published in the Nature of on. At the time, Al-Shayeb is the University of California, Berkeley Earth and Planetary Science Professor Jillian F. Banfield of the laboratory work. They believe that this contains CasΦ the macrophage is a macrophage, a member of, and present in a variety of environments.
this latest discovery reveals CasΦ huge gene editing potential, so as to the cell transfer provides the advantage of expanding the gene editing Toolbox. More importantly, CasΦ protein the macrophages toward human health discovery and biotechnology applications of the frontier. But for the optimization CasΦ for gene editing, as well as exploring used to design targeted gene-specific guide RNA is the best method, the researchers still have a long way to go.
