echemi logo
Product
  • Product
  • Supplier
  • Inquiry
    Home > Biochemistry News > Biotechnology News > Science Long Article: Reveal the new toxin-antitoxin RNA system that guards CRISPR-Cas

    Science Long Article: Reveal the new toxin-antitoxin RNA system that guards CRISPR-Cas

    • Last Update: 2021-08-12
    • Source: Internet
    • Author: User
    Search more information of high quality chemicals, good prices and reliable suppliers, visit www.echemi.com

    In October 2020, the genome editing technology based on the CRISPR-Cas9 system won the "2020 Nobel Prize in Chemistry"


    The stability maintenance of the CRISPR-Cas system in the microbial genome is the key basis for the realization of its antiviral function


    On April 30, 2021, the top international journal Science published online the latest research results of the Xiang Hua/Li Ming team of the Institute of Microbiology of the Chinese Academy of Sciences in the form of a long article (Research Article) "Toxin-antitoxin RNA pairs safeguard CRISPR-Cas systems" ( Li M.


    As early as 2014, the Xiang Hua/Li Ming team used the Spanish saltbox bacteria (Haloarcula hispanica) and its virus to establish the first high-efficiency adaptation model of the type I CRISPR system in the world, revealing the need for the CRISPR system to efficiently adapt to the virus.


    The main innovative findings:

    1.


    The team first obtained by knocking out the 311 bp sequence of the intergenic region between cas6 and cas8? TA strain, and then successfully obtained Cascade single-gene deletion strains based on this strain


    In order to determine the specific sequence of CreT, the team found through truncation experiments that the toxicity of CreT comes from a 132bp sequence, which contains a typical promoter sequence that can initiate transcription to produce a 78nt small RNA


    2.


      The detailed sequence and structure analysis of CreT RNA shows that its 5'end has a strong translation signal SD (Shine-Dalgarno) sequence and AUG start codon, followed by two rare arginine codons AGA, This is followed by the stop codon UGA and a stem-loop structure


      3.


      In order to reveal the molecular mechanism of the Cascade protein's inhibition of CreT toxicity, the team first knocked out the only CRISPR array structure in the cell, thereby eliminating the possibility that crRNA derived from the CRISPR array could participate in toxicity inhibition


      4.


      The team further revealed that, like crRNA-mediated Cascade complex recognition of foreign target sequences, CreA-mediated Cascade precise recognition of the creT promoter


      In particular, the team’s early experiments have revealed the high plasticity of crRNA.


      5.


      By studying the destruction of cascade genes by the active movable element IS (insertion element) in the presence or absence of CreTA, the team further confirmed that CreTA as a minimal "addiction" element protects the physiological functions of the CRISPR-Cas system


      6.
    Reveal the ubiquity of CreTA homology or similar systems in different microorganisms and different CRISPR subtypes

      The team also digs into existing microbial genome data and cooperates with the team of Professor Eugene V Koonin, a well-known expert in the field of bioinformatics at NCBI in the United States, to further discover that there are CreTA analogues hidden in different types of archaea/bacteria in different types of CRISPR-Cas systems.
    , Suggesting that CRISPR-Cas may generally use the inherent gene regulation function of CRISPR effectors (such as inhibiting the transcription of a toxic RNA) to hedge its suitability costs
    .
    The discovery of this new mechanism explains the widespread distribution of CRISPR-Cas in microorganisms from a new perspective
    .


    It is worth emphasizing that the known toxin-antitoxin (TA) systems all encode a toxin protein, and the CreTA discovered in this work uses a minimalist small RNA (CreT) as the toxin component, and its antitoxin (CreA) It is also a small RNA and depends on the Cascade complex to function.
    Therefore, CreTA may define a new TA classification unit
    .
    More importantly, the new molecular mechanism of this type of system provides important elements and enlightenment for applications such as genetic engineering and gene editing.
    For example, the team has used CreT to develop a minimalist system that can be used in bacteria and archaea.
    The reverse selection markers provided by Gene Engineering provide new elements for genetic engineering; on the other hand, based on the molecular circuit of CreA regulating creT transcription, new technologies for simultaneous gene editing and gene regulation have been developed (both have applied for patents)
    .

      This discovery is not only a milestone in the biological research of CRISPR-Cas and its coupling system, but also opens a door for studying the "non-coding RNA dark matter world" of prokaryotic microorganisms
    .
    The paper pointed out that the CreTA analogs found in different types of CRISPR-Cas systems of different archaea and bacteria are rich in sequence diversity and may contain a large number of unknown toxicity mechanisms and functional elements
    .
    Therefore, the in-depth exploration of this kind of rich and diverse "dark matter" will further promote the development of biotechnology, including the development of small RNA drugs in the future, or will be instructive
    .

      Researcher Xiang Hua and Researcher Li Ming of the Institute of Microbiology of the Chinese Academy of Sciences are the co-corresponding authors of the paper.
    Researcher Li Ming, postdoctoral fellow of Xiang Hua's research group Gong Luyao and doctoral student Cheng Feiyue are the co-first authors
    .
    Professor Eugene Koonin and his team from the National Institutes of Health (NIH) Center for Biotechnology Information (NCBI) provided important help
    .

      Researcher Xiang Hua has been funded by the National Science Fund for Distinguished Young Scholars in 2009 and started cutting-edge research on the CRISPR-Cas system.
    He is currently the director of the State Key Laboratory of Microbial Resources Preliminary Development, the deputy director of the Institute of Microbiology, and the key project leader of the National Major Research Program , Chief Scientist of National Key R&D Program Project
    .
    Li Ming entered the Hua Lab in 2009 and focused on CRISPR research.
    He was funded by the National Outstanding Youth Project in 2020.
    He is currently the youth group leader of the Key Laboratory of Microbial Physiology and Metabolic Engineering of the Chinese Academy of Sciences
    .
    This work has been supported by the Chinese Academy of Sciences Strategic Pilot Research Program, National Key Research and Development Program, National Natural Science Foundation of China, National Genetically Modified Major Science and Technology Project, China Association for Science and Technology Young Talents Project, Chinese Academy of Sciences Youth Innovation Promotion Association and other projects
    .

      Paper link:

      https://science.
    sciencemag.
    org/content/372/6541/eabe5601

    This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to service@echemi.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

    Contact Us

    The source of this page with content of products and services is from Internet, which doesn't represent ECHEMI's opinion. If you have any queries, please write to service@echemi.com. It will be replied within 5 days.

    Moreover, if you find any instances of plagiarism from the page, please send email to service@echemi.com with relevant evidence.