Hi there! In this article, I will talk about Prime Editing. If Prime Editing sounds unfamiliar to you, that’s okay. Five days before writing this article, I didn’t know anything about Prime Editing either. We are here to learn something new. Together.
Before we dive into why Prime Editing is important, how it differs from CRISPR, and what might the future hold for Prime Editing, let’s first talk about what it is.
Are you ready? Here we go…
What is it Prime Editing?
Prime Editing is the newest gene-editing technique that helps prevent human genetic diseases caused by mutations. The invention of Prime Editing was led by David Liu, an American Chemist and Biologist who is a faculty member at the Broad Institute of Harvard and MIT, and postdoctoral fellow Andre Anzalone. They have performed a total of 175 edits on human and mouse cells, such as targeted insertions, deletions, and nucleotide substitutions. Liu estimates that Prime Editing has the potential to fix up to 89% of known genetic mutations in humans.
Why is it important?
Genetic diseases can be more common than you think. According to research, worldwide, around 1 in every 700 babies is born with down syndrome, an estimation of 1 in every 20,000 babies is born with albinism, and around 1 out of every 365 black individuals have sickle cell disease. However, Prime Editing can help repair genetic mutations with a high success rate, developing genome editing techniques to a higher level. If we can bring Prime Editing to clinical use in the future, 89 out of 100 individuals who have genetic diseases can be birthed as perfectly healthy babies. In addition, genome editing technologies allow scientists to make changes to DNA, which leads to changes in physical traits such as eye color and hair color.
*Genetic mutation mini crash course*
To form a strand of DNA, you need 4 types of nucleotides, aka code letters: Adenine (A), Thymine (T), Cytosine (C), Guanine (G). “A” is always paired with “T” and “C” is always paired with “G”. These pairs of letters get connected and become a “sentence” that contains genetic information. However, if the letters are sequenced incorrectly, it means that one of the four types of mutations has occurred.
How is it different from CRISPR?
Let’s start with a bit of background knowledge.
CRISPR, pronounced as “crisper”, stands for “Clustered Regularly Interspaced Short Palindromic Repeats”. Cas 9 is a protein and its main function is to cut DNA. Therefore, this genome-editing technology is often known as CRISPR-Cas 9.
Prime Editing is an “improved version” of CRISPR-Cas 9. Why is it so exciting?
While CRISPR-Cas 9 cuts both strands of DNA, Prime Editing only makes changes to one strand. CRISPR-Cas 9 relies on the cell’s repair system to correct the genome, but it is unreliable as it can insert or delete nucleotides during the process, which can result in abnormal development of the cell. Prime Editing inserts correctly-sequenced nucleotides into one strand of the DNA. The other strand will be able to repair itself to match the edited sequence. For example, if “C” is replaced with “T” on one strand, the other strand would repair itself from “G” to “A”. Prime Editing can replace any letters with any other ones and can also delete up to 80 nucleotides. Here’s an image that may help you understand the process of Prime Editing better:
What might the future hold for Prime Editing?
Prime Editing has the potential to decrease the risk of genetic diseases caused by mutations significantly. Scientists are hoping to optimize Prime Editing in as many different types of cells and organisms as possible in the future. I am looking forward to Prime Editing developing into a gene-editing technique that is ethical and economical, making it acceptable and accessible to everyone.