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CRISPR/Cas9 Genome Editing

CRISPR/Cas9 Genome Editing

The CRISPR-Cas system serves as a bacterial defense mechanism against invading genetic elements such as viruses and plasmids, forming the foundation for its adaptation as a powerful genome-editing tool. Originally discovered in prokaryotes, this system has been repurposed to revolutionize genetic engineering across a wide range of organisms, including plants, animals, and humans. The core component, Cas9, is an endonuclease derived from Streptococcus pyogenes, capable of introducing...

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Bacteria and archaea are susceptible to viral infections just like eukaryotes; therefore, they have developed a unique adaptive immune system to protect themselves. Clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins (CRISPR-Cas) are present in more than 45% of known bacteria and 90% of known archaea.
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The Antiviral System of Bacteria and Archaea: CRISPR

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Related Experiment Video

Updated: Oct 7, 2025

Enhanced Genome Editing with Cas9 Ribonucleoprotein in Diverse Cells and Organisms

Enhanced Genome Editing with Cas9 Ribonucleoprotein in Diverse Cells and Organisms

Published on: May 25, 2018

Evolutionary plasticity and functional versatility of CRISPR systems.

Eugene V Koonin¹, Kira S Makarova¹

¹National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America.

|January 5, 2022

Summary

CRISPR systems provide bacterial and archaeal adaptive immunity against viruses. These versatile systems also have non-defense roles, showing significant evolutionary innovation and plasticity in cellular functions.

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Substrate Generation for Endonucleases of CRISPR/Cas Systems

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Published on: September 8, 2012

Area of Science:

Microbiology
Molecular Biology
Genetics

Background:

CRISPR-Cas systems are prokaryotic immune systems targeting foreign nucleic acids.
These systems exhibit diverse defense mechanisms, including direct elimination, programmed cell death, and dormancy induction.

Purpose of the Study:

To explore the evolutionary plasticity and functional versatility of CRISPR systems beyond their canonical immune functions.
To investigate the recruitment of CRISPR components for non-defense roles in various genetic elements.

Main Methods:

Comparative genomics analysis of CRISPR-Cas system evolution.
Functional characterization of CRISPR-associated non-defense mechanisms.
Bioinformatic identification of novel CRISPR variants and their associated functions.

Main Results:

CRISPR systems demonstrate significant adaptability, being repurposed for transposition, plasmid competition, and viral conflicts.
Diverged repeat variants outside CRISPR arrays are crucial for innovation and regulatory functions.
Multiple CRISPR variants with unknown functions have been identified, highlighting ongoing evolutionary processes.

Conclusions:

CRISPR systems display remarkable evolutionary plasticity, extending beyond adaptive immunity to encompass diverse cellular functions.
The interplay between defense and non-defense roles drives CRISPR system innovation and diversification.
Understanding CRISPR versatility is key to comprehending prokaryotic evolution and mobile genetic element dynamics.