Founded by Dr. Emmanuelle Charpentier and Dr. Jennifer Doudna, CRISPR is a gene-editing tool that has enabled medical breakthroughs and changed biomedical research. The goal of CRISPR is to treat diseases by developing advanced cell therapies designed to target specific genes that cause or progress the course of a disease. Although in the process of clinical trials, CRISPR could potentially be a treatment for sickle cell anemia.

The CRISPR gene-editing system is split into two parts: Cas9 and a guide RNA. Cas9 is an enzyme that unwinds and cuts two strands of DNA in a specific location in the genome so that DNA can be added or removed. Cas9 has a similar function to the helicase enzyme we studied earlier this year; however, unlike helicase, Cas9 unwinds DNA in an ATP-independent manner and uses the binding energy between the guide RNA and target strand to unzip the DNA. The guide RNA (gRNA) guides Cas9 to a target-specific sequence in the DNA where it should bind and where the edit should be made. This target-specific sequence has a similar function to an RNA primer, which guides the DNA polymerase to this binding site to initiate DNA replication.

Sickle cell anemia is a genetic blood disorder that affects hemoglobin. Sickle cell anemiaSickle cell disease (SCD) causes the body to produce hemoglobin S, an abnormal form of the molecule that lessens its function. Hemoglobin S has a distorted shape, which causes obstructions, pain, infections, and inhibits circulation. Sickle cell anemia is a monogenic, autosomal recessive trait, which means that sickle cell anemia can be passed down through generations if there is one mutated sickle cell hemoglobin S gene present, even though it is a recessive trait (a recessive trait usually indicates that there needs to be two mutated genes for the trait to be present in offspring). CRISPR is a perfect solution for sickle cell anemia, as CRISPR involves an ex vivo gene-edited cell therapy where, theoretically, hemoglobin stem cells can be extracted from the patient, edited and corrected, and then put back into the body. Scientists are still in the clinical trial phase of using CRISPR to treat sickle cell anemia, but wouldn’t it be amazing if it worked for thousands of people!

I hope you guys found this post as interesting as I did. Feel free to leave a comment and tell me what you think!

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