Nature Methods Release New Crispr / cas9 Technology

SHIRLEY, N.Y. - Nov. 23, 2015 - PRLog -- Scientists at University of Massachusetts Medical School had developed a kind of new CRISPR / cas9 technology which can edit accurately in almost all the genomic sites like an surgery on DNA, avoiding some of the potentially harmful off-target changes in standard CRISPR editing techniques (Read more about the standard Crispr/cas9 genome editing at http://www.creative-animodel.com/Animal-Model-Development/CRISPR-Cas9). By pairing the CRISPR/Cas9 system with a programmable DNA binding domain (CRISPR/Cas9-pDBD), the researchers created an additional proofing step to improve the accuracy of this gene editing system, thus opening the door for potential clinical and gene therapeutic applications. The research was published in the journal of Nature Methods.

"Although the standard CRISPR/Cas9 system is good for the use of a single directed RNA in vitro, this technique is not suitable for most gene therapy applications because gene therapy involves editing a large number of cells that minimize the collateral damage to the genome. So we added an extra step to this system. By having a zinc finger DNA binding domain to the CRISPR/Cas9 system, it can verify another genetic feature of the target site before cutting the genome. We have already confirmed that this can improve the accuracy of CRISPR/Cas9 nearly 100 times."

Researchers at the University of Massachusetts School of Medicine had developed this nucleic acid enzyme platform to remove the latent HIV virus in the infected cell genome and had the potential to correct the genetic mutations that caused chronic granuloma disease, which causes immune cells can not form the active compounds that kill certain bacteria and fungi. (Reference: Methods for CRISPR-Cas9 Specific Knockout and sgRNA for Specific Targeting CCR5 Gene http://www.creative-animodel.com/blog/methods-for-crispr-...)

CRISPR/Cas9 is a kind of adaptive immune system used by bacteria to protect itself against phage and other kinds of exogenous genetic material. It contains two components: molecular scissors Cas9 can effectively cut DNA, but is limited in its natural state; RNA guided complexes can open this pair of scissors when finding the matched genetic sequence and determining the exact cleavage site. These directed RNA are generated by the CRISPR sequence, and the CRISPR sequence contains the genomic remnants of previous viral infections. The CRISPR/Cas9 system provides adaptive immune defense against bacterial cells.

Although the CRISPR/Cas9 system is very powerful, it is not perfect. Sometimes guide RNA will disposal the cutting enzyme into the genome in the correct position, or will also let the cutting enzyme locate to other similar but not identical sequence target sites. Sometimes cutting the mismatch can cause unexpected damage.

"What we do is like creating a GPS for CRISPR/Cas9. By combining the DNA binding domain with the CRISPR/Cas9, we construct an exciting new technology platform that will be required to minimize the potential risk of patients undergoing gene therapy", a researcher at University of Massachusetts Medical School said.