Researchers Successfully Cut HIV DNA Out of Human Cells 64
mrspoonsi sends word that researchers from Temple University have managed to eliminate the HIV-1 virus from human cells for the first time. "When deployed, a combination of a DNA-snipping enzyme called a nuclease and a targeting strand of RNA called a guide RNA (gRNA) hunt down the viral genome and excise the HIV-1 DNA (abstract). From there, the cell's gene repair machinery takes over, soldering the loose ends of the genome back together – resulting in virus-free cells." While antiretroviral therapy can treat people who are infected with HIV, the immune system is incapable of actually removing the virus, so this is an important step in fighting it. The researchers still have to overcome the problem of delivering the the genetic "toolkit" to each affected cell in a patient's body, and also HIV's high mutation rate.
Re:soddering (Score:0, Informative)
Dialect's an interesting thing. In 10-20% of the US, calm is in fact pronounced as if the L is silent. In at least everywhere in the US I've lived (about a third of it), folk is most definitely pronounced with a silent L.
Here too, calm and solder are pronounced with the same vowel sound...
a tiny step.. (Score:3, Informative)
http://www.pnas.org/content/early/2014/07/17/1405186111.abstract
This isn't such a big deal. Cas9/CRISPR is being used for all sorts of applications. This is just one of them, and the actual challenge isn't editing the genome, it is delivering Cas9/CRISPR to all cells of the body and having them being specific. That is far, far more difficult.
The authors detected INDELS (insertion/deletions) within the HIV-1 targetted sequence, so that is good -- it's doing what it should be in that respect.
However, Cas9/CRISPR can go OT (off target) and edit non-targetted DNA. It is the most specific editing tool that anybody has ever found, and will no doubt be Nobel-Prize worthy one day. But if OT effects happen, this is bad, when you start deleting/editing bits of DNA randomly - things can go wrong, cells and tissues can do things they're not meant to. Although that is fairly rare with Cas9/CRISPR -- however when exposed to megabases of DNA even rare events can become frequent (I would consider 1 OT effect too many for me, if I was about to be injected with something that was going to edit my Genome).
The authors did detect some OT effects (from their paper published in PNAS). So they carefully use the phrasing "minimize" OT effects in their paper. Also, they say "The long-term expression of Cas9/LTR-A/B gRNAs did not adversely affect cell growth or viability, suggesting a low occurrence of off-target interference with the host genome or Cas9-induced toxicity in this model." while it's a golf-clap worthy assay for cells in a dish (where's the rest of the assays for motility, cilial function, cell cycle length, etc.?), that isn't good enough either when uttering the words 'therapy'.
It's kind of neat, but I can see why this is PNAS and not Nature or Nat Med.