Release date: 2017-04-17 Researchers from the Korea Institute of Basic Science, IBS, published an article entitled "Genome-wide target specificities of CRISPR RNA-guided programmable deaminases", confirming the accuracy of recently developed genetic editing methods. The research was published in the April 10 issue of Nature Biotechnology. The author of the article is KIM Jin-Soo, a big man in the field of genetic editing. His research group has published many articles in top journals such as Nature, and put forward many innovative ideas in the field of CRISPR technology. For example, they have designed the smallest ones. CRISPR-Cas9, which is delivered to the eyes of muscle cells and mice by adeno-associated virus (AAV) to edit the genes that cause blindness. For the latest study, Kim said, "This is the first time that the accuracy of this base editing has been verified at the entire genome level." The rapid development of gene editing tools has made the whole biological research field crazy. The main character of the third generation DNA scissors is CRISPR, which is a faster and cheaper tool than its predecessor. CRISPR-Cas9 and CRISPR-Cpf1 silence or reduce the expression of erroneous genes by excising small DNA sequences. However, last year's new method of base editing: instead of causing random DNA deletions and insertions, it replaced a DNA gene and attracted the attention of biologists. This method of genetic correction is critical because some diseases are caused by errors in one of the four basic components of DNA (adenine (A), cytosine (C), guanine (G), and thymine (T)). . Single nucleotide errors in DNA are called point mutations, and diseases caused by point mutations include cystic fibrosis, sickle cell anemia, and color blindness. Unlike the existing third-generation DNA scissors, the single-base editing method consists of a variant of CRISPR-Cas9 (nCas9, nickase) and another called cytosine deaminase, replaced by T. C, directing the correct DNA position by targeting RNA. But so far, it is not known whether this base editor works only in the wrong gene region, or can be replaced (off-target) in other regions. Last month, IBS researchers changed the dystrophin gene (Dmd) and a single nucleotide in the tyrosinase gene (Tyr) to test the fusion of CRISPR-nCas9 cytidine deaminase. The study achieved two successes: mouse embryos carrying a single nucleotide mutation in the Dmd gene resulted in the inability to produce dystrophin protein in mouse muscle; the other was a mouse carrying the Tyr mutation, which showed an albino trait. Dystrophin protein is associated with muscle muscular dystrophy disease, and tyrosinase controls melanogenesis. In the latest study, they verified the accuracy of this method in the genome range and modified individual nucleotides in the dystrophin and tyrosinase genes. To determine the correctness of gene editing across the genome, the researchers modified a false detection technique: Digenome-seq, which detects CRISPR/Cas9 off-target effects in human cells across the genome (new method ends CRISPR-CAS9) debate). It also improved the computer program (Digenome 2.0) to more fully identify off-targets and compare different targeting RNAs to find RNA that reduces malfunction and increases specificity. Using this technique, the researchers verified the correctness of the base-editor technique and found it to be more accurate than the current third-generation CRISPR-Cas9. Base-editing technology can induce C-to-T conversion in 1-67 loci in the human genome, while CRISPR-Cas9 can cleave at 30-241 loci, which means that the base editor is reducing off-target changes. "Therefore, these base editors are expected to become popular CRISPR technology," Kim said. Source: Biopass China Extract Powder For Use As Dietary Supplement Extract Powder, Extract Powder Manufacturer Shaanxi Kang New Pharmaceutical co., Ltd. , https://www.anabolicsteriod.com