“Base editing” and “prime editing” are two advanced genome-editing techniques used in molecular biology and genetic engineering to make precise changes to an organism’s DNA. These techniques offer advantages over traditional methods like CRISPR-Cas9 regarding precision and reducing unintended mutations.
Base Editing: Base editing is a molecular biology technique that allows scientists to directly convert one DNA base pair into another without causing double-strand breaks in the DNA. It was developed to address some of the limitations of traditional CRISPR-Cas9 editing, which can introduce unwanted insertions, deletions, or mutations in the DNA.
In base editing, a modified version of the CRISPR system is used. Instead of cutting the DNA, it uses a fusion protein that combines a DNA-editing enzyme (usually a cytidine deaminase or adenine deaminase) with a guide RNA that targets the specific location in the genome where the edit is desired. The deaminase enzyme chemically modifies the targeted base pair, converting one base into another. For example, it can change a C-G (cytosine-guanine) pair to a T-A (thymine-adenine) pair or vice versa.
Base editing is handy for making point mutations, which are changes to a single base pair. This technique can potentially correct genetic mutations associated with diseases or create specific genetic changes for research purposes with high precision and reduced risk of introducing unintended mutations.
Prime Editing: Prime editing is another genome-editing technique with even greater precision than base editing. It allows scientists to make precise changes to the DNA sequence by directly writing new genetic information into the genome without causing double-strand breaks. Prime editing was developed to overcome some of the limitations of base editing, such as its inability to insert or delete longer sequences.
In prime editing, a prime editor protein is used, a fusion of a modified CRISPR-Cas9 protein and a reverse transcriptase enzyme. The prime editor is guided to the target DNA sequence by a specially designed guide RNA (sgRNA) that contains information about the desired edit. The prime editor then uses the reverse transcriptase to copy the edited genetic information from the sgRNA into the DNA strand.
This approach allows for the precise insertion, deletion, or replacement of DNA sequences with minimal errors or unintended mutations. Prime editing can potentially correct a broader range of genetic mutations and is considered one of the most precise genome-editing techniques.
Both base editing and prime editing hold great promise for applications in genetic medicine, agriculture, and basic research, as they enable scientists to make targeted changes to the genome with unprecedented accuracy and minimal off-target effects.
