ENHANCED
GENOME-EDITING SYSTEM : SCIENCE & TECHNOLOGY
NEWS
:
Indian scientists build breakthroughgene-editor, are aiming for patent
WHAT’S
IN THE NEWS?
A CRISPR system built to use the FnCas9 enzyme was
found to edit genomes more efficiently and with less unintended damage than
existing technologies, researchers at CSIR-IGIB and the L.V. Prasad Eye
Institute have reported
Enhanced
Genome-Editing System by CSIR-IGIB
Background
on CRISPR
• CRISPR Definition: Clustered Regularly
Interspaced Short Palindromic Repeats; a natural defense mechanism found in
some bacteria to fend off viral infections.
• Scientific Breakthrough: Researchers
repurposed this bacterial system to edit genomes of higher-order organisms,
earning a Nobel Prize.
CRISPR-Cas9
System
• Functionality:
Allows precise addition, removal, or alteration of DNA sequences in the genomes
of animals and plants.
• Applications:
• Agriculture:
Enhances nutritional value and yield of crops.
• Healthcare:
Used for diagnosing diseases and treating genetic disorders.
Off-Target
Problem with CRISPR-Cas9
• SpCas9 Enzyme: Derived from
Streptococcus pyogenes; while effective, it often cuts unintended parts of the
genome, leading to off-target effects.
• High-Fidelity Versions: Engineered
to reduce off-target cuts but at the expense of editing efficiency.
Transition
to FnCas9
• Source: Francisella
novicida bacteria.
• Advantages:
More precise than SpCas9 but has lower efficiency.
Enhancing
FnCas9
• Research Team:
Led by Debojyoti Chakraborty at CSIR-IGIB.
• Modifications: Adjusted amino acids in
FnCas9 to improve recognition and interaction with the PAM sequence on the host
genome.
• Outcomes:
• Increased Binding Affinity:
Stronger bond with the PAM sequence, enhancing gene editing efficiency.
• Flexibility:
Engineered to access and edit harder-to-reach genome regions, broadening
potential applications.
Experimental
Validation
•
Enzyme Activity: Enhanced FnCas9 showed a higher rate of
DNA cutting compared to unmodified FnCas9.
• Diagnostic Potential:
Better at identifying specific single-nucleotide changes, crucial for detecting
genetic mutations associated with diseases.
Therapeutic
Applications
• Collaboration: With L.V. Prasad Eye
Institute, Hyderabad.
• Tests:
• Human Kidney and Eye Cells: Edited
genes with higher efficiency and minimal off-target effects.
• Inherited Blindness (LCA2):
• Condition: Caused by a
mutation in the RPE65 gene, leading to severe vision loss.
• Procedure: Isolated skin
cells from an LCA2 patient, reprogrammed them into iPSCs, corrected the
mutation using enhanced FnCas9, and differentiated iPSCs into retinal cells.
• Results: Corrected
mutation, restored normal levels of RPE65 protein, and high editing efficiency
with minimal off-target effects.
Advantages
of Enhanced FnCas9 for Therapy
• Safety: Editing
patient-specific stem cells and transplanting them back offers a safer approach
than direct injection of CRISPR into the body.
• Efficiency: High rate of
mutation correction and low off-target effects make it a promising tool for
treating genetic disorders.
Future
Directions
• Delivery Systems:
Focus on improving the precision of delivering enhanced FnCas9 to the nuclei of
target cells.
• Adaptation: Reducing the size of
enhanced FnCas9 for better delivery and efficiency.
• Patenting: Working with Indian
companies to secure an indigenous patent, making the technology more affordable
for low- and middle-income countries.
Significance
• Precision Editing: Crucial for reducing
off-target effects in CRISPR-based therapies, improving the safety and
effectiveness of genetic treatments.
• Cost-Effective Solutions: Indigenous
development and patenting of high-precision gene-editing tools can lower costs
and enhance accessibility in developing countries.
Source : https://epaper.thehindu.com/ccidist-ws/th/th_delhi/issues/93024/OPS/GAND4HFDT.1+GGFD4HG41.1.html