
Gene editing changes DNA sequences and RNA processing to modulate gene expression and protein function. Since 2013, CRISPR-Cas9 enabled precise edits, with applications in disease treatment, animal models, and agriculture.
Gene editing delivers a nuclease and guide RNA to target cells in vivo or ex vivo. DNA is cut and repaired to yield altered protein products.
Explore gene editing techniques developed over the last half century, including conventional homologous recombination, chemical systems, protein-based nucleus systems, and RNA-based CRISPR, with advances for clinical and laboratory applications.
Zinc finger nuclease uses engineered zinc finger binding domains to recognize specific DNA sequences and create double-strand breaks repaired by DNA repair machinery, enabling precise genome modification in higher organisms.
Left and right TALEN monomers recognize DNA with 34‑amino‑acid repeats and residues at 12 and 13; binding induces double‑strand break repaired by NHEJ or HDR, yielding insertions, deletions, or substitutions.
Explore CRISPR, an RNA-protein based gene editing system derived from ancient prokaryotic immunity, where CRISPR arrays store viral genomes and Cas proteins cleave invaders to defend the host.
Explore the general mechanism of CRISPR-Cas, including spacer acquisition with Cas1 and Cas2, crRNA biogenesis, and interference that cleaves foreign DNA.
Describe how type I CRISPR-Cas system uses spacer acquisition with Cas1 and Cas2, pre-crRNA processing in the Cascade by Cas6, and mature crRNA guiding Cas3 to nick and degrade DNA.
Trace the CRISPR-Cas mechanism in three steps: spacer acquisition, crRNA processing, and interference, leading to Cas9 guided cleavage of viral DNA at the PAM site.
Examine how the type iii CRISPR-Cas system processes pre-crRNA with Cas6, matures via Cas10, includes anti-crRNA steps, and uses iii-a for DNA cleavage and iii-b for RNA degradation.
Over the last half century after post-DNA helical structure discovery, the world has seen a continuous staircase outburst of various molecular technologies, which are now heading forward toward translation into clinical and laboratory practice. Given the availability of sequencing platforms, acquired wisdom about the micro-mechanics at work within the genetic apparatus, and the introduction of user-friendly nanotechnologies, it was possible for next-generation scientists to manipulate the genetic codes at various levels.
Principally, gene editing techniques can be interpreted as methods where DNA sequences are changed by deletions, mRNA processing, and post-transcriptional modifications to result in altered gene expression, leading to functional behavior of proteins
Gene editing is performed using enzymes, particularly nucleases that have been engineered to target a specific DNA sequence, where they introduce cuts into the DNA strands, enabling the removal of existing DNA and the insertion of replacement DNA.
The enormous knowledge and ongoing research have now been able to demonstrate methodologies that can alter DNA coding. The gene editing techniques evolved from the earlier attempts like nuclease technologies, homologous recombination, and certain chemical methods (peptide nucleic acid). Molecular techniques like meganuclease, transcription activator-like effector nucleases (TALENs), and zinc-finger nucleases (ZFNs) initially emerged as genome-editing technologies.
These initial technologies suffer from lower specificity due to their off-targets side effects. Moreover, from biotechnology’s perspective, the main obstacle was to develop simple but effective delivery methods for host cell entry. The latest discovery of CRISPR/Cas9 technology seems more encouraging by providing better efficiency, feasibility, and multi-role clinical application.
The significant leap in gene editing techniques brought new urgency to long standing discussions about the ethical concerns surrounding the genetic engineering. Many questions, such as whether genetic engineering should be used to treat human disease or to alter traits such as beauty or intelligence, had been asked in one form or another for decades.
This course generally discusses the various gene editing techniques in terms of the mechanisms of action, advantages, and side effects.
This course is a valuable resource for students and researchers related to molecular biology, forensic science, medical laboratory technology, biotechnology, and genetics.
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