Editing DNA With Molecular Scissors – Cure For HIV
More groundbreaking research is underway as scientists and researchers are working on the cure for AIDS/HIV. It is believed that Molecular Editing of DNA could be the answer we have been waiting for. The human body has a hereditary material called DNA (deoxyribonucleic acid) in nearly every cell of the body. The DNA itself is located in the cell nucleus and in the mitochondria. Everything that determines the body’s make-up is stored as a code in the DNA. Four chemical bases namely adenine (A), guanine (G), cytosine (C) and thymine (T), form 3 billion bases of pairs, attached to a sugar molecule and a phosphate molecule, called a nucleotide. Two strands of nucleotides form a double helix spiral that looks like a ladder. The combination of A’s, G’s, C’s and T’s varies in each human, but 99% of those bases are the same in all people. What makes us different is the combination and sequences these chemical bases will take on in each human.
Scientist are comparing the DNA to a Word Document in a latest study where a tiny scissors called a TALEN will serve as an editing tool to mend and cut broken genes in cells. With this tool it might be possible to “cut” out genetic diseases and hopefully viruses like the HIV virus, from the body’s “document”. Other illnesses it could potentially target is cell anemia and cystic fibrosis. Although it would appear that curing complicated diseases like cancer (where there are more genes affected by the disease, than say for example in cell anemia, where only one cell is broken) might be more difficult to achieve due to the fact that a scissors for each cell will have to be made, scientist’s are working hard on eliminating HIV from the DNA of immune cells and permanently inactivating its replication. But similar to the conundrum scientists are facing with the amount of cells that needs to be targeted in cancer, it will require multiple insertions of these scissors TALEN’s to get to each cell that has been infected by the HIV virus.
So how would you utilise this tool? The scissors is called a TALEN – protein TAL + bacterial gene endonucleases EN = TALEN. The TALEN has to find the broken or defective gene, this is done by using a protein called TAL that will recognize the DNA sequences of A’s, G’s, C’s and T’s. Once the tool has found the broken genes the bacterial gene called endonucleases EN will chop off the invading DNA that causes the disease. After this the DNA needs to be repaired. A copy of the working gene has to replace or “pasted” into the old DNA and this is done by adding the right DNA sequence, leaving the cell to do the rest of the repair work by using a process called homologous recombination.
All of this has been tested in the lab, but not yet on humans. It will take five to ten years before this technology will be ready to use in patients. However researchers at Lewis Katz School of Medicine at Temple University Philadelphia in the US, are confident that they will be able to start human trials within three years. “The fact that, for the first time, we have been able to completely eliminate segments of the viral genome in the laboratory demonstrates that we should be able to eliminate it in the human body,” said lead researcher Kamel Khalili.
“The system can protect cells from reinfection and the technology has no toxic effects. Replacing only 20% of immune cells with the genetically altered cells would probably cure HIV.” It has been proven that gene editing with TALEN’s are more effective than gene therapy. Sickle cell disease (SCD), the cause of strokes in humans, is also a great candidate for TALEN treatment.
