CRISPR Gene Editing Allows for More Precise Prime Editing

Although the scientific community generally understands how gene editing could improve life for those with genetic disorders, the challenge has been figuring out the proper ways to get there.

Early attempts at this complex process haven’t proven precise enough to successfully cut into, replace, and repair DNA strands at the correct locations.  

However, one effort is moving toward a better solution, this time by looking deeper into the genetic code.

Using CRISPR gene editing, researchers are able to more precisely identify where in the DNA strand to make a cut. The process uses an item called guide RNA to look for a certain enzyme on a certain gene and eliminates a lot of the guesswork used in the past.

CRISPR gene editing is modeled after the natural system bacteria use to fight against viruses, where specific intruded viruses are remembered when the immune system sees it in the future. It’s also faster, more affordable and more efficient than past methods of genomic research and editing, including possible treatments for HIV/AIDS.

Some research is looking in a slightly different direction, by utilizing this editing process in what’s called prime editing. Here, genes can be repaired at their base level by re-ordering the pairings in their sequence.

Basic DNA tells us that every gene has four bases that form pairs with certain other bases. These create all sorts of combinations in the diverse genetic code.

For instance, thymine (T) is supposed to match with other Ts, along with guanine, G, cytosine, C, and adenine, A.

Various factors to sometimes cause these bases to match with the incorrect letter, a process casually called a “misspelling.” These errors can lead to mutations, birth defects, and even death. It can cause organisms to grow in unpredictable, often fatal, directions.

One recent example is Adalia Rose, a popular YouTube personality. She had a rare medical condition called progeria, where her body growth was greatly accelerated. By the time she was celebrating her 15th birthday, her biological body was in her 80s, so she encountered similar health problems from advanced aging that seniors deal with, not teens.

Her YouTube channel chronicled her final days where she tried to find the positive, as well as visits with many doctors and geneticists who were unable to help. Ultimately, she passed away recently, but many in the genetic field say they are inspired to continue their explorations, especially using the potential of CRISPR gene editing.

David Liu, director of the Merkin Institute of Transformative Technologies in Healthcare at Harvard University and a professor of chemical biology and chemistry, and his colleagues have been focusing on prime editing to repair mutations and other genetic errors.

Last year, they were able to work to alter the genes of mice that had progeria. Success in this front could lead to approval to create clinical trials to treat this condition in human children.  

Dr. Liu’s team also found that the base editors worked even better if one strand has a small cut into it, which, if “spelled” correctly, will be automatically duplicated to the other strand in the double helix. This also improves the speed of which DNA could be edited.

While conducting experiments with progeria, Dr. Liu is also working with researchers at St. Jude Research Hospital to reverse sickle cell disease, another dangerous genetic condition. They have been able to use base editors to reverse this condition in mice.

CRISPR gene editing has been approved by the FDA to be used in human trials for sickle cell disease research and other genetic conditions.