Jellyfish Protein GFP in Biomedical Research
Nobel Prize for developing a New Way to Study Biological Processes
Oct 14, 2008
The Crystal Jelly (Aequorea victoria) is not unusual because it can emit light (bioluminescence) – it is unusual because the exact mechanism has been studied intensively, and the chemicals it uses are now widely used in medical and biological research.
Bioluminescence
Many marine animals can produce light, and they do so for a variety of reasons.
- Lights Confuse Predators – Flashes of light can confuse predators, and bioluminescence helps many small creatures in the plankton avoid being eaten by fish.
- Lights Attract Prey – Some deep-water anglerfish use light to attract other fish within range of their gulping mouth. The small wiggling light seems irresistible!
- Lights Contribute to Countershading - Many fish are dark above and silvery below. This makes them difficult to see from above (against a dark background), and similarly from below against the light. Species that live some way below the surface often use bioluminescence to ‘brighten up’ their undersides – making them even more difficult to see.
- Lights Help Communication – squid are probably the experts here. Some species flash complex patterns in order to communicate effectively with others of their kind.
- Lights to See the Way – very large bioluminescent organs are sometimes found on the head of deep-water fish. They probably function as ‘headlights’ and allow the animal to see in the murky depths.
Bioluminescence in The Crystal Jelly (Aequorea victoria)
The Crystal Jelly produces many small spots of green light around the margins of its ‘bell’. Like most jellyfish it is a predator, and it is likely that these small lights attract small fish (who presumably mistake the tiny lights for planktonic organisms in distress!). In 1961 Shimomura and Johnson were able to extract the chemicals involved in this light production, and this led to intensive study of ‘Green Fluorescent Protein’ (GFP).
Nobel Prize for Shimomura, Chalfie and Tsien in 2008
Shimomura first isolated GFP, Chalfie continued to study it, and Tsien went on to develop a range of slightly different GFPs that produce a range of colours. (Some of these colours are shown in the article iillustration. Bacteria – ‘tagged’ with some of these bioluminescent chemicals - were grown in a Petri dish and then put under UV light to produce the image. The artwork was by Nathan Shaner, the photography by Paul Steinbach, and it was created in the lab of Roger Tsien in 2006.). For their combined work Osamu Shimomura, Martin Chalfie and Roger Tsien recently won the Nobel Chemistry Prize.
How GFP is Used
GFP is inserted into the precise tissues that are being studied (using techniques borrowed from genetic engineering) and they can be made to glow to allow researchers to see exactly what is happening. As early as 1967 Ridgeway and Ashley had put GFP into single muscle fibres of barnacles in order to study the details of muscle contraction, and subsequently the technique became ‘a standard tool for thousands of researchers all over the world’ (Nobel panel). Two good examples are the way it has been used to look at the how nerve cells are destroyed in Alzheimer's disease, and to see exactly how certain tumors develop.
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