CRISPR-Cas Past and Present |
Posted: January 20, 2018 |
A city (bacteria) policeman, the first city was invaded to recognize the suspect's face (the sequence of the virus); the second time the suspect was found, he was found looking for someone with a crRNA (crRNA) Use nucleases) to cut people (literally "cut"). The CRISPR-Cas system is such a guardian! And last year (2017) "Science" in the annual "top ten scientific breakthroughs" there are CRISPR system version 2.0 - base editing and related gene therapy
The end of last century, genetic engineering began to rise, a variety of gene editing techniques have been improved, such as zinc finger, TALENs. However, both technologies have apparent limitations. For example, in Kaifeng dishes • Zinc fingers and gold arches • TALENs, you can only buy hamburgers that have been matched (base sequence); but in Northern Shaanxi • CRISPR, you can customize the burgers and enjoy how to mix sauces Can be. As early as 1987, Yoshizumi Ishino, a Japanese microbiologist, unexpectedly found DNA fragments interspersed with tandem repeats (5) at the time of sequencing of E. coli. Each of the repeats contained a unique structure(difficult to understand for most people). But at that time people did not know anything about this it.
In the 1990s, researchers of different countries discovered this special sequence, which is useless to ordinary people, in the genomes of various bacteria and archaea.
In 2001, Ruud Jansen of the University of Utrecht in the Netherlands named the structure officially, the CRISPR sequence. And he also found that many of the nucleases associated with it, collectively referred to as another familiar word - Cas, which identified the CRISPR-Cas system.
In 2011, the molecular mechanism of the CRISPR-Cas system was revealed: when the virus was first infected, the bacteria incorporated a sequence of foreign genes into its own CRISPR; when it was second intruded, CRISPR transcribed a sequence containing both foreign and foreign The crRNA, which matches the sequence of the source gene, mediates nuclease binding and cleavage after crRNA recognizes the virus and thus forms a self-protecting mechanism.
In 2013, Jennifer A. Doudna and Jillian F. Banfield of the University of California, Berkeley, discovered that the CRISPR-Cas system efficiently edits genes. Then Chinese scientists Zhang Feng CRISPR-Cas system technology successfully applied to mouse cells and human cells, and achieved gene editing.
In October 2017, Professor Zhang Feng introduced a new CRISPR system called "REPAIR" in "Science",which can effectively repair RNA and correct the wrong information on RNA to synthesize the correct protein to treat the disease effect. It brings new hope for the treatment of Parkinson's disease and other research.
In order to make CRISPR technology more efficient, the transformation of CRISPR is also a hot topic. Last October, at "Nature," Professor David Liu led a lab that led to the development of a new gene-editing system, the new adenine base editor (ABE), that enables DNA- Substitution of bases in DNA. This means that researchers can now try to correct more than half of human genetic disease! It is more efficient and less error-prone than the traditional CRISPR. (This is one of the annual breakthroughs scored by Science last year.)
Gene editing, in addition to its research in the laboratory, can also be put into practical use. ? 2% of the world's people are allergic to eggs, but eggs produce most of our vaccines. Eggs transformed with CRISPR will eliminate the four proteins that cause allergies; ? agricultural pharmaceutical (using domestic animal production of drugs): In 2006, the European Union, the FDA approved the adoption of a latex of goat secreting anti-coagulation protein; ? livestock reform: the production of anti-plague pigs; ? vector control: transformation of anti-malaria, dengue mosquitoes; ? pet improvement: cultivate a specific color, pattern of Koi
In addition to editing genes, the real power of the CRISPR-Cas system is to explore the mechanisms of action of the genome so that we can better understand the molecular mechanisms of developmental metabolism to treat diseases and even edit human embryos.
Something has to say: Gene editing makes the future full of possibilities!
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