Glow-in-the-Dark Kittens Lend a Paw to AIDS Fight

A genetically engineered cat glows. — Here one of the cats that was genetically engineered to have genes that code for a fluorescent jellyfish protein, which produces the green color, as well as an antiviral restriction factor from a rhesus macaque.

(Image credit: Mayo Clinic)

Cats that can glow in the dark from a new genetic engineering technique are helping scientists study molecules that could stop AIDS, researchers announced today (Sept. 11).

So far, the researchers have created three genetically engineered kittens that can glow green and pass this gene onto their offspring. They explained that cats are much better models for AIDS viruses than are mice and other animals. [See Images of the Glowing Kittens]

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As such, researchers have long wanted to genetically experiment with cats to better understand how to combat AIDS. To create genetically modified animals, scientists insert genes into their genomes, often using benign viruses as the delivery vehicles. Investigators commonly target the earliest possible stages in an animal's development so the gene gets installed into all of its cells — any later, and the gene can end up in some tissues but not others.

At first scientists created genetically engineered cats using cloning, which meant injecting a gene into one cell — from the skin, for instance — and then implanting the modified nucleus of that cell into an egg cell that had its nucleus removed; the resulting cell then develops into an embryo much like a fertilized egg would. In this manner, researchers generated felines that were either fluorescent red or green, a glow-in-the-dark cat being visible proof of the genetic engineering succeeding.

Now scientists have developed a new way to create genetically engineered domestic cats where they modify egg cells directly with viruses. 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, Poeschla said.

The researchers stress their work could also help cats themselves, not just humans. Since FIV afflicts feral cats the most, the virus causes a lot of unwitnessed, unattended and unrelieved feline suffering, with millions of cats dying annually worldwide from AIDS, often painfully and alone. "Millions more suffer with chronic illness from the virus," Poeschla added. "Supporting this research can help cats as much as people."

"Some feline organs, such as the eye, are much more similar to humans than the same organs in mice," Poeschla explained. "The cat brain, particularly the cerebral cortex and vision-processing parts, is the best understood of any species." As such, transgenic cats "might be of help in understanding the workings of the brain and neurological diseases such as Alzheimer's, or with genetic illnesses and major eye diseases such as glaucoma or macular degeneration," he added.

Charles Q. Choi is a contributing writer for Live Science and Space.com. He covers all things human origins and astronomy as well as physics, animals and general science topics. Charles has a Master of Arts degree from the University of Missouri-Columbia, School of Journalism and a Bachelor of Arts degree from the University of South Florida. Charles has visited every continent on Earth, drinking rancid yak butter tea in Lhasa, snorkeling with sea lions in the Galapagos and even climbing an iceberg in Antarctica.