A research team headed by Byeong-Chun Lee of Seoul National University have created the world’s first transgenic dog, 
‘Ruppy’ (short for Ruby puppy). Ruppy and four other beagles all produce a fluorescent protein that glows red under ultraviolent light. The dogs were created by cloning fibroblast cells that express a red fluorescent gene produced by sea anemones. Lee’s team created Ruppy by first infecting dog fibroblast cells with a virus that inserted the fluorescent gene into a cell's nucleus. They then transferred the fibroblast's nucleus to another dog's egg cell, with its nucleus removed. After a few hours dividing in a Petri dish, researchers implanted the cloned embryo into a surrogate mother.
Starting with 344 embryos implanted into 20 dogs, Lee's team ended up with only seven pregnancies. Five of the dogs are still alive, healthy and starting to spawn their own fluorescent puppies.
Besides the low efficiency of cloning, another challenge to creating transgenic dogs is controlling where in the nuclear DNA a foreign gene lands. Lee's team used a retrovirus to transfer the fluorescent gene to dog fibroblast cells, but they could not control where the virus inserted the gene. This would seem to prevent researchers from making dog "knockouts" (lacking a specific gene) or engineering dogs that produce mutant forms of a gene. These knockout procedures are commonly done in mice and rats in a method, called "gene targeting".
Researchers however, remain relatively optimistic that these problems can be overcome, saying that the long lifespan of dogs and their reproductive cycle would make them more relevant to human fertility than mice. They believe that this experiment could open the door for transgenic dog models of human disease.
Kunaal Maharaj (42042297)
