CRISPR-Cas9 Gene Editing

CRISPR-Cas9 Gene Editing

Sub: Sci

Sec: Biotech

Why in News

• The CRISPR-Cas9 gene-editing tool has been at the forefront of ground breaking research, including advancements in agriculture, healthcare, and genetic engineering.

What is Gene Editing?

• Gene editing involves altering the DNA sequence using specific enzymes to remove, add, or replace genetic material.
• The process is comparable to editing a document, where errors in the DNA code are corrected for desired outcomes.
• Early methods involved two enzymes:
  • One to cut DNA at a specific location.
  • Another to insert the desired genetic change.
• These methods were labour-intensive and lacked efficiency.

What is CRISPR-Cas9?

• CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats, while Cas9 refers to CRISPR-associated Protein 9.
• It is a revolutionary gene-editing tool that precisely cuts DNA strands to allow the insertion of new genetic material.
• Jennifer Doudna (University of California, Berkeley) and Emmanuelle Charpentier (Humboldt University, Germany) developed the CRISPR-Cas9 system, earning the Nobel Prize in 2012.
• Feng Zhang (Broad Institute) advanced its applications but was excluded from the Nobel recognition.

Applications in Plant Genome Engineering:

• Researchers like Holger Puchta (Karlsruhe Botanical Institute) have used CRISPR variants (Cas9, Cas12, Cas13) to modify plant genomes.
• Notable advancements: Gene ‘knockout’ in tomato plants, enhancing sweetness without affecting weight.

Breakthrough in Treating Eye Disorders:

• Scientists at LV Prasad Eye Institute, Hyderabad, in collaboration with IGIB, used CRISPR to correct genetic mutations in patient-specific stem cells.
• The mutation-corrected stem cells developed into retinal cells with restored protein expression.
• Opened pathways for autologous cell therapies for inherited eye disorders.

Cas12: A CRISPR-associated protein that targets and cleaves both double-stranded and single-stranded DNA, activated by DNA sequences, and utilized in gene editing and molecular diagnostics.

Cas13: A CRISPR-associated protein that specifically targets and cleaves single-stranded RNA, activated by RNA sequences, and applied in RNA research and antiviral strategies.