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Selection-dependent and Independent Generation of CRISPR/Cas9-mediated Gene Knockouts in Mammalian Cells
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CRISPR-Cas12a exhibits metal-dependent specificity switching
Giang T Nguyen1,2, Michael A Schelling1,2, Kathryn A Buscher1,3
1Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, USA.
Biorxiv : the Preprint Server for Biology
|December 11, 2023
Summary
Magnesium ion concentration significantly alters Cas12a specificity, impacting its use in genome editing and CRISPR-Cas systems. Understanding these shifts is crucial for optimizing biotechnology tools and cellular immunity applications.
Area of Science:
- Molecular Biology
- Biotechnology
- Microbial Immunity
Background:
- Cas12a is a key enzyme in CRISPR-Cas systems, widely used in genome editing.
- Previous specificity studies often used non-physiological magnesium concentrations.
- Cellular magnesium levels are critical for CRISPR-Cas effector function.
Approach:
- Investigated Cas12a ortholog specificity across varying magnesium ion (Mg2+) concentrations.
- Analyzed cleavage efficiency and binding kinetics with different target mismatches.
- Compared specificity switching mechanisms in three distinct Cas12a variants.
Key Points:
- Cas12a specificity is dynamically regulated by Mg2+ concentration.
- Low Mg2+ favors binding to seed-mismatched targets but hinders PAM-distal mismatches.
- Mg2+-dependent specificity switching influences phage resistance mechanisms.
Conclusions:
- Physiological Mg2+ concentrations are essential for accurate Cas12a specificity profiling.
- Cas12a's utility in biotechnology requires consideration of cellular ion environments.
- Understanding Mg2+ effects enhances the development of precise CRISPR-based tools.
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