There are two AIDS pandemics in the world: one in humans and the other in cats.
In their quest for ways to combat AIDS in humans, scientists have been studying feline immunodificiency virus (FIV) for insight into the human virus.
Afflicting mostly feral cats and big cats such as lions, FIV causes AIDS in cats the same way HIV causes AIDS in people -- by causing the loss of infection-fighting T cells.
Now, a group of researchers mostly from the Mayo Clinic report in the journal Nature Methods that they have genetically engineered three cats so they potentially have resistance to AIDS -- and so they glow in the dark.
Previous genetically engineered cats had to be cloned through delicate surgery. As New Scientist says,
The first cloned cat, born in 2001, was the only one to survive from 200 embryos, each created by taking an ear cell from cats, removing the nucleus and fusing it with a cat egg cell emptied of its own nucleus.
The new technique allows scientists to genetically modify the egg cells directly using viruses and is much simpler and more efficient than the previous method. Out of 22 implantations, three genetically modified cats were born.
Live Science reports,
The amount of genetic material they implanted within the cats was tiny — if the entire string of DNA that is the cat genome were unraveled and depicted as a highway reaching across the United States from New York to Los Angeles, the inserted material would be equal in length to one of the dashed yellow lines in the middle of the highway somewhere out in Nebraska, [Eric Poeschla, a molecular biologist and infectious disease specialist at the Mayo Clinic College of Medicine] said.
The reason the cats now glow in the dark is because they were given the green fluorescent protein (GFP) gene, which originates from jellyfish and has been used in a number of science experiments to make animals, including mice, fruit flies, rabbits and pigs, glow in the dark. Seeing the cats glow in the dark helps the researchers know that the genetic engineering was successful.
The cats were also given a monkey gene that protects rhesus monkeys from FIV. The team is hoping that this will protect them from FIV, and if so, that it could then lead to similar ways to protect humans from becoming infected with HIV.
So far, when white blood cells from the cats are cultured in the lab, those cells are protected from FIV. The scientists intend to give the virus to the cats to see whether they are also immune to it. Poeschla told New Scientist,
The animals clearly have the protective gene expressed in all their tissues including the lymph nodes, thymus and spleen. That's crucial because that's where the disease really happens, and where you see destruction of T-cells targeted by HIV in humans.
One male has already sired eight kittens with three non-genetically modified females, and each of the offspring had the implanted genes.
But the question remains whether this FIV research will ultimately prove helpful to the fight against HIV/AIDS.
Theodora Hatziioannou of the Aaron Diamond AIDS Research Center told New Scientist, "It's fantastic they've created GM cats. But what makes research in monkeys so much better is that SIV in monkeys is much more closely related to HIV, so it's more straightforward to draw conclusions than it would be with FIV."
photos: Mayo Clinic