A “nonsense mutation” in our junk DNA that is.
A group of scientists led by Nitya Venkataraman and Alexander Colewhether wanted to try a new approach to fighting HIV – one that worked with the body’s own immune system. They knew Old World monkeys had a built-in immunity to HIV: a protein called retrocyclin, which can prevent HIV from entering cell walls and starting an infection. So they began poring over the human genome, looking to see if humans had a latent gene that could manufacture retrocyclin too. It turned out that we did, but a “nonsense mutation” in the gene had turned it off at some point in our evolutionary history.
Nonsense mutations are caused when random DNA code shows up in the middle of a gene, preventing it from beginning the process of manufacturing proteins in the cell. Venkataraman and her team decided to investigate this gene further, doing a series of tests to see if the retrocyclin it produced would keep HIV out of human cells. It did.
At last, they knew that if they could just figure out a way to reawaken the “junk” gene that creates retrocyclin in humans, they might be able to stop HIV infections. The researchers just needed to figure out a way to remove that nonsense mutation and get the target gene to start manufacturing retrocyclin again.
Here’s where things really get interesting. The team found a way to use a compound called aminoglycosides, which itself can cause errors when RNA transcribes information from DNA to make proteins. But this time, the aminoglycoside error would work in their favor: It would cause that RNA to ignore the nonsense mutation in the junk gene, and therefore start making retrocyclin again. In preliminary tests, their scheme worked. The human cells made retrocyclin, fended off HIV, and effectively became AIDS-resistant. And it was done entirely using the latent potential in the so-called junk DNA of the human genome….