In recent years, genetic engineering has had various advancements. Due to this, genetic engineers are expanding their study in fields ranging from agriculture to biomedical science. One interesting and rather popular tool for gene editing is the “clustered regularly interspaced short palindromic repeats” or simply, CRISPR technology. Let’s learn more about it in this blog!
What is gene editing?
Simply out, gene editing is a group of technologies you to edit an organism’s DNA. Scientists can now add, remove, or alter genetic material at any desired location in the genome (which is an organism’s complete set of DNA, including all of its genes) of their choice. Out of several gene editing approaches, a recent one is known as CRISPR-Cas9.
What is CRISPR-Cas9?
The CRISPR-Cas9 system is popular because it is quicker, low cost, precise, and more efficient than other existing genome editing methods. Cas9 stands for CRISPR-associated protein 9. CRISPRs are particularly designed stretches of DNA. The protein Cas9 is an enzyme that cuts strands of DNA. Bacteria make use of Cas9 or a similar enzyme to cut the DNA of a virus apart, which disables the virus during an attack.
How does CRISPR-Cas9 work in labs?
A small piece of RNA is designed with a “guide” sequence that attaches to a desired target sequence of DNA in a genome.
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The RNA also binds to the Cas9 enzyme.
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Along with the modified RNA, Cas9 enzyme cuts the DNA at the desired location.
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Once the DNA is cut, researchers can make changes to the DNA by replacing an existing segment with a customized DNA sequence of their choice.
Image courtesy: Wikipedia
Voila! You get a genetically modified/engineered DNA that has many, many applications!
What are the applications of gene editing?
Genome editing has a big role to play in the prevention and treatment of human diseases. Since most research in genetic engineering is done on animal models first, scientists are still trying to determine if such methods will be safe and effective in humans too. CRISPR-Cas9 and other techniques can also be helpful in research on single-gene disorders such as cystic fibrosis, hemophilia, and sickle cell disease. The treatment and prevention of more complex diseases, such as cancer, heart disease, mental illness, and human immunodeficiency virus (HIV) infection can also be explored by gene editing.
What are some recent findings of CRISPR-Cas9?
- CRISPR molecule programmed to find strains of viruses, e.g. Zika, in blood serum, urine and saliva.
- Using CRISPR to eliminate a heart disease defect in an embryo
- Upgrading CRISPR to edit thousands of genes simultaneously
CRISPR-Cas9 does give rise to some ethical concerns. The technique creates synthetic changes in the somatic and egg and sperm cells. Unlike somatic cells, but changes in egg and sperm cells can be passed down in generations. Editing such cells thus brings many ethical challenges questioning the extent of these synthetic changes. Therefore, germline cell and embryo genome editing are currently illegal in many countries.
Despite the concerts, CRISPER and allied techniques are exciting and will play a huge role in the future. Best to keep an eye out for their results!
REFERENCES:
1. Broeders M, Herrero-Hernandez P, Ernst MP, van der Ploeg AT, Pijnappel WP. Sharpening the molecular scissors: advances in gene-editing technology. Iscience. 2020 Jan 24;23(1):100789.
2. What are genome editing and CRISPR-Cas9? Available from: https://ghr.nlm.nih.gov/primer/genomicresearch/genomeediting. Accessed on 21 July 2020.
3. CRISPR gene editing. Available from: https://en.wikipedia.org/wiki/CRISPR_gene_editing. Accessed on 21 July 2020.
4. What Is CRISPR? Available from: https://www.livescience.com/58790-crispr-explained.html. Accessed on 21 July 2020.