CRISPR Used for Gene Editing
Researchers have taken the CRISPR-Cas system and turned it into a gene-editing tool. The first mention of the CRISPR-Cas system being used for gene-editing was in ___ by a researcher called ___.
since then many researchers have taken CRISPR-Cas9 and used it in various fields ranging from blood disorders, eyesight, cancer, gene drives.. the list is actually never-ending because there are endless capabilities of CRISPR-Cas.
So how does CRISPR-Cas Gene Editing work?
Well firstly, the specific gene you want to target is recognised, for example, a sickle cell disease gene! Then you make specific guide RNA which is complementary to your target gene and then you can deliver guide RNA and a Cas protein inside the cells! The complementary guide RNA finds the target gene sequence and the Cas creates a cut in the DNA. Then two pathways can occur, one is homology-directed repair (HDR) and the other is called Non-homologous end joining (NHEJ). NHEJ causes indels, these are basically just random DNA base insertions or deletions. The other pathway which causes HDR can only occur if you supply donor DNA, this donor DNA which could be a specific gene to replace a faulty gene is inserted where the DNA was cut. The image below summarises the general gene-editing process.
What are the examples of gene editing?
CRISPR gene editing has been used in laboratory studies to correct various disease-causing mutations. For example, researchers were able to fix the