Growing human skin in the laboratory has advanced to the point where it's used to create skin grafts for burn victims, but it hasn't been possible to do the same with non-mammals – until now. Scientists led by the United States Geological Survey (USGS) have successfully reconstructed the skin of a green sea turtle as part of a study to learn more about a virus infection that threatens the endangered reptile species.

The green turtle is a large sea turtle that is found throughout tropical and subtropical seas. It migrates for thousands of miles as it moves between its feeding and breeding grounds, and was once so common that ship's crews would gather them for food. They were even commercially farmed for products like tinned soup and leather. Today, the green turtle is endangered or threatened throughout its range, and hunting them or their eggs is illegal.

Unfortunately, man isn't the only threat that the green turtle faces. They're also susceptible to a virus associated with fibropapillomatosis (FP) called chelonid herpesvirus 5 (ChHV5). In turtles, especially around Hawaii, Florida, and Brazil, FP produces tumors on the skin, eyes, and mouth as well as internally. This is not only disfiguring, but also compromises the animal's immune system, making it susceptible to secondary infections, emaciation, and even death.

Microscopic image showing a sun-shaped area within turtle skin cells where chelonid herpesvirus 5 replicate(Credit: Thierry Work/USGS)

The problem over the past 20 years for scientists trying to understand and treat FP in green turtles is finding a way to reproduce the tumors under laboratory conditions. To do this, the USGS team used normal skin and tumor cells taken from turtles and used them to not just culture cells, but engineer them to create the complex three-dimensional structure of turtle skin.

According to Thierry Work, a USGS scientist, this new skin is much closer to what it's like inside a living turtle than previous methods, and it allows scientists to observe the virus replicating in unprecedented detail. This not only revealed things like sun-shaped virus replication centers inside the cells where the viruses form, but could also lead to blood tests to detect the virus and a better understanding of virus-induced diseases in reptiles.

"Fibropapillomatosis is the most common infectious disease affecting endangered green turtles," says Work. "Our findings provide a significant advancement in studying FP, and may eventually help scientists better understand other herpes virus-induced tumor diseases, including those of humans."

The study was published the Journal of Virology.

View gallery - 2 images