How CRISPR lets you edit DNA - Andrea M. Henle

Summary

CRISPR, a natural bacterial immune system, has revolutionized gene editing with its precision and affordability. It works by using guide RNA to direct the Cas9 protein to target genes, enabling scientists to edit DNA with ease. Applications range from curing genetic diseases to enhancing crops and even reprogramming cancer cells. However, the technology raises ethical concerns due to its potential for unintended changes and long-term impacts.

Takeaways

• 🧬 Genes define every living organism and their DNA acts as an instruction manual for cells, with traits determined by sequences of four bases.
• 🛠️ Gene editing tools, such as CRISPR, allow scientists to alter an organism's fundamental features rapidly and precisely.
• 🍎 Scientists can use gene editing to create beneficial modifications like drought-resistant crops and apples that don't brown.
• 🏥 Potential applications of gene editing include preventing infectious diseases and developing cures for genetic disorders.
• 🔍 CRISPR is a natural process that functions as a bacterial immune system against viruses, using CRISPR sequences and Cas proteins.
• 🔑 The CRISPR-Cas system captures viral DNA and uses it to create RNA that guides the immune response against future invasions.
• 🧬 In 2012, scientists discovered how to repurpose CRISPR for gene editing, targeting any DNA sequence in almost any organism.
• 🧬 The CRISPR-Cas9 complex can be directed to specific genes using guide RNA, allowing for precise DNA cutting and editing.
• 🛠️ DNA repair mechanisms, such as nonhomologous end joining and homology directed repair, are leveraged by CRISPR for gene editing.
• 💡 CRISPR has the potential to treat genetic diseases like cystic fibrosis or sickle cell anemia by correcting DNA errors.
• 🌱 Beyond human applications, CRISPR can be used to enhance plants, modify mosquitoes to prevent disease transmission, and reprogram cancer cells.
• 🔬 CRISPR is a powerful tool for genomic research, enabling the study of gene function through targeted gene activation or deactivation.
• ⚠️ Despite its potential, CRISPR editing is not without risks, as it may introduce unintended changes and raises ethical concerns.

Q & A

What is the primary function of DNA in living organisms?

DNA acts like an instruction manual for cells, with sequences of four building blocks called bases that tell the cell how to behave and form the basis for every trait.

What recent advancements have allowed scientists to change an organism’s fundamental features quickly?

Recent advancements in gene editing tools, such as CRISPR, have allowed scientists to change an organism’s fundamental features in record time.

What are some practical applications of gene editing using CRISPR?

Gene editing using CRISPR can engineer drought-resistant crops, create apples that don’t brown, prevent the spread of infectious outbreaks, and develop cures for genetic diseases.

Where does the CRISPR technology originally come from?

CRISPR is a natural process that originally functions as a bacterial immune system, defending single-celled bacteria and archaea against invading viruses.

What are the two main components of naturally occurring CRISPR?

The two main components of naturally occurring CRISPR are short snippets of repetitive DNA sequences called CRISPRs (clustered regularly interspaced short palindromic repeats) and Cas (CRISPR-associated) proteins.

How do Cas proteins contribute to the CRISPR immune response in bacteria?

Cas proteins cut out a segment of the viral DNA and stitch it into the bacterium’s CRISPR region, capturing a chemical snapshot of the infection. If the virus invades again, Cas9 swiftly destroys the viral DNA.

How did scientists in 2012 advance the use of CRISPR technology?

In 2012, scientists figured out how to hijack CRISPR to target any DNA in almost any organism, transforming it into a precise gene-editing tool.

What is the key to CRISPR's power in gene editing?

The key to CRISPR’s power is the ability to design a guide RNA to match the gene they want to edit, attach it to Cas9, and use the protein’s molecular scissors to snip the DNA, allowing for precise editing.

What are the two types of DNA repair processes mentioned in the script, and how do they differ?

The two types of DNA repair processes are nonhomologous end joining, which is prone to mistakes and can lead to unusable genes, and homology directed repair, which uses a template DNA to guide the rebuilding process, allowing for precise corrections or insertions.

What potential medical advancements could CRISPR bring?

CRISPR could potentially create new treatments for diseases linked to specific genetic errors, like cystic fibrosis or sickle cell anemia, and even reprogram drug-resistant cancer cells.

What are some of the ethical considerations surrounding the use of CRISPR technology?

CRISPR raises ethical questions because it doesn’t always make just the intended changes, and it’s difficult to predict the long-term implications of a CRISPR edit, making it important to decide the best course forward.