Fluorescent Cats Aid Research

Tiny, adorable and…green? Glowing kittens may answer questions about neurobiology and disease.

Sep 13, 2011
Rachel Nuwer

This glow-in-the-dark kitten has a unique set of genes.MAYO CLINIC

Cats come in all sorts of colors—tabby, orange, and calico—but scientists are most interested in the fluorescent variety. Eric Poeschla, a molecular virologist at the Mayo Clinic, used a technique called transgenesis to bestow kittens with a heightened immune system as well as an unearthly green glow, which allows researchers to track the expression of genes of interest.

Poeschla and colleagues used a modified virus to transfer the green fluorescent protein gene into cat egg cells. The green marker allowed them to visualize their real target: a monkey-derived protein called TRIMCyp. This protective protein, found in some primates but not in cats, prevents organisms from becoming infected with an HIV-like disease called feline immunodeficiency virus (FIV).

The transduced cat eggs were then fertilized and injected into adult female cats. Of the 11 successfully-implanted embryos, 10 contained the TRIMCyp and GFP genes. “Almost all the offspring [carried the new genes], so you’re not screening hundreds of animals to find the transgenic ones,” Poeschla told told ScienceNOW. After about two months, five kittens were born, three of which survived.

More importantly, Poeschla and colleagues report in Nature Methods, when the scientists exposed blood samples from the transgenic kittens to FIV, the virus didn’t replicate well, suggesting the TRIMCyp protein was offering some level of protection to the cats.

The experiment marks the first time GFP has been successfully expressed in a carnivore. The researchers suggest the same method can be used to test whether other antiviral proteins may aid cats against FIV, as well as study other aspects of cat physiology. Cats’ visual cortexes are also more closely related to humans than those of mice, for example, suggesting cats may serve as a better model system for studying that part of the brain. It seems there’s a glowing future in cat research.

Correction: This story has been updated from its original version to clarify the success of the technique, and indicate that some primates, but not humans, have the TRIMCyp gene. The Scientist regrets the error.