Boost for AIDS research: Glowing cats 'created'

A team at Mayo Clinic College of Medicine in Minnesota says the genetically modified cats, prosaically named TgCat1, TgCat2 and TgCat3, glow ghostly green under ultraviolet light as they have been given the green fluorescent protein (GFP) geneMovie Camera originating from jellyfish.

The cats also carry an extra monkey gene, called TRIMCyp, which protects rhesus macaques from infection by FIV, responsible for cat AIDS, say the scientists.

By giving the gene to the cats, the team hopes to offer the animals protection from FIV; the research could help the scientists develop and test similar approaches to protecting humans from infection with HIV, the 'New Scientist' reported.

Already, the scientists have demonstrated that laboratory cultures of white blood cells from the cats are protected from FIV, and they now hope to give the virus to the three felines to check whether they are immune to it.

"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," said Eric Poeschla, who led the team.

The technique used by the team to create the cats has already been used successfully to make GM mice, pigs, cows and monkeys. They loads genes of interest into a lentivirus, which they then introduce directly into a cat oocyte, or egg cell. The oocyte loaded with the new genes is then fertilised and placed in the womb of a foster mother.

From 22 implantations, the scientists achieved 12 fetuses in five pregnancies, and three live births. And out of the 12 fetuses, 11 successfully incorporated the new genes, demonstrating how efficient the method is.

One surviving male kitten, TgCat1, has already mated with three normal females, siring eight healthy kittens that all carry the implanted genes as well, showing that they are inheritable, say the scientists.

But experts say that there are doubts about whether cats will replace monkeys as the staples of HIV research.

"It's fantastic they have 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," says Theodora Hatziioannou of Aaron Diamond AIDS Research Center, New York