Jellyfish Light Up Mice

Scientists in Japan have implanted into mice a gene responsible for making jellyfish luminesce. The procedure, they say, offers a valuable tool for marking genes and tracking various types of cellular activity in organisms.

Osaka University spermatologist Masaru Okabe and colleagues at Osaka's Research Institute for Microbial Diseases added a form of a gene for green fluorescent protein (GFP) from the jellyfish Aequorea victoria into mice, producing animals that are green through and through when exposed to blue light. "It's very beautiful," Okabe says. The gene had previously been transferred into fruit flies and zebrafish, but not mammals.

In other bioluminescent techniques, such as the use of luciferase from fireflies, a substance has to be added to "turn on" the affected cells. But that can produce undesired side effects, says Ken-ichi Yamamura, a professor of developmental genetics at Kumamoto University's School of Medicine. "With the GFP, it glows on its own" (Science, 27 June, p. 1989). A report on the achievement appeared in the 5 May issue of FEBS Letters, published by the Federation of European Biochemical Societies.

Scientists see a role for green mice in a wide range of research. GFP-marked cancer cells could be injected into normal mice (or unmarked cancer cells into green mice), and their fate tracked. Or GFP-marked bone marrow could help scientists watch how transplanted marrow interacts with the host's immune system.