“Genetic Scissors” Can Completely Eliminate HIV From Cells

Mar 22, 2016

Photo credit: NIH via Flickr, CC by 2.0

By Alexandra Ossola

Thanks to the cocktail of drugs that make up antiretroviral therapy, HIV is no longer a death sentence. But there are downsides to antiretroviral therapy—taking the treatment for many years is expensive, increases drug resistance, and could cause adverse reactions in a patient. And, because the virus stays in reservoirs in the body, the disease can continue to progress in patients if they stop taking their medication.

Now a team of German researchers has found an enzyme that can “cut” the viral DNA out of a cell’s genetic code, which could eradicate the virus from a patient’s body altogether. The proof-of-concept study, published this week in Nature Biotechnology and reported by Ars Technica, was done in mice, but the researchers believe that their conclusions show that this DNA-snipping enzyme could be used in clinical practice. And if it can cut HIV’s genetic code out of a patient’s body, the technique could be a cure for the disease.

The researchers created the DNA-snipping enzyme called Brec1 using directed evolution, an engineering technique that mimics proteins’ natural evolution process. They programmed the enzyme to cut DNA on either side of a sequence characteristic of HIV—a difficult task since the DNA of organisms and of the virus itself mutates often. Still, the researchers identified a well-conserved sequence, then they tested how reliably the enzyme could snip out that sequence in cells taken from HIV-positive patients, in bacteria, and in mice infected with the human form of HIV. After a number of tweaks, Brec1 would cut only that sequence of DNA, patching up the cell’s genetic code once the HIV sequence was cleaved out. After 21 weeks, the cells treated with Brec1 showed no signs of HIV.

Source: http://www.popsci.com/enzyme-can-snip-hiv-out-cell-dna

5 comments on ““Genetic Scissors” Can Completely Eliminate HIV From Cells

  • One other disadvantage of antiretrovirals. If the patient is not careful about taking every dose, the viral load can creep up and they can transmit it to others.

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  • @david-r-allen

    Not sure if I have this right but as I understand it, a retrovirus like HIV puts code into its host’s DNA which acts as a sort of template for creating new viruses even if the infection has been cleared out. So this technique would edit the genome of the host to take out the but of code inserted rather than attacking the virus itself.

    Need a scientist to come and put me straight though

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  • The idea of restriction endonucleases and their use has been around for decades. It would seem that finding the right one has proved elusive but it seems moderately likely that the molecular biology crew have constructed or repurposed the correct one at last. Great work.

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