Wednesday, November 16, 2016

New Gene Editing

Back in the early 90's, a gene editing technique involved CRISPR. This technique of gene editing removes, adds, or edits the DNA of a dividing cells through the use of an enzyme and a piece of RNA (gRNA). The RNA binds to the desired DNA sequence and then the enzyme Cas9 cuts at that position.  The natural repair system in the cells repairs the cut which causes a mutation. Similarly, a new technique designed by Salk Institute allowed a gene editing technique in non-diving cells.
The DNA repair pathway targeted was the NHEJ, also known as the "non-homologous end-joining", that repairs routine DNA breaks by rejoining strand ends. The old technique involved an enzyme and piece of RNA while the new technique is a custom made insertion complex known as HITI. The complex is made up of a mass of nucleic acid. The nucleic acids in HITI are delivered using an immobile virus. The first time this was used, it was delivered to neurons which indicated that this method could deliver information to non-dividing cells. The picture below is a picture of the neurons of the mouse brain. The blue neurons are the original ones while the green ones are the gene-edited neurons.

The next challenge was testing other non-diving cells like the retinal cells. The study was performed in rats that suffered from reunites pigmentosa, which causes blindness. A functional copy of one of the genes responsible for the condition, Mertk, was inserted into the eyes of a mouse with the condition. The study found that the rats were able to respond to light and passed tests that indicated improved vision.

The new technique brings light to the number of possibilities that our science community as a whole has created. One of the ideas mentioned, blindness, started in mice but could hopefully work its way up to humans. I would like to see what this new gene editing technique can bring to many different non-dividing cells. I could not imagine how much happiness this could bring to those that struggle with conditions affecting non-diving cells.


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