Blog | Tuesday, September 13, 2011

QD: News Every Day--Glowing like cats and dogs

Scientists have added a new species to the menagerie of animals that glow, after introducing jellyfish genes into cats that can now glow green.

Photo courtesy of the Mayo ClinicScientists report that they transferred genes from monkeys (and jellyfish) into cats in order to study feline immunodeficiency virus (FIV), the cat equivalent of HIV. In cats and in people, immunodeficiency viruses deplete infection-fighting T-cells. Key proteins called restriction factors that would normally defend against the viruses are ineffective. The research appears in the September issue of Nature Methods.

To research potential treatments, physicians, virologists, veterinarians and gene therapy researchers from the Mayo Clinic and in Japan sought to mimic the way evolution would generate protective protein versions, according to a Mayo Clinic press release. They inserted monkey versions of a gene into the cat genome using gamete-targeted lentiviral transgenesis. This is done by inserting genes into feline eggs before sperm fertilization.

The monkey restriction factor, TRIMCyp, blocks FIV by attacking and disabling the virus as it tries to invade a cell. In the lab, the transgenic cat lymphocytes resisted FIV replication. The scientists said that they can now test the potential of various restriction factors for HIV gene therapy, as well as apply the gene transfer methods to build models of other infectious and noninfectious diseases.

The glowing doesn't have anything to do with preventing FIV; it just makes the cells easier to study. The cats glow green under a blue light (485 nM) as a side effect.

And, the cats with the protective genes have produced kittens whose cells make the proteins, thus proving that the inserted genes remain active in successive generations.

A similar feat was done in April 2009 to create "Ruppy," the ruby puppy who glowed red. In order to study cancer, South Korean scientists used retroviral integration to transfer a fluorescent gene normally expressed by sea anemones into dog fibroblast cell nuclei. These nuclei were introduced into egg cells, which developed into cloned embryos. A litter of puppies were born with a fluorescent protein that glows red under ultraviolet light.