How could a glowing jellyfish help three people win the Nobel Prize and help thousands of others in their quest to find a cure for cancer? The Nobel Prize, the most prestigious award in science, is presented once a year to recognize extraordinary achievements in physics, chemistry, and physiology or medicine. In 2008, the Nobel Prize for chemistry was awarded to Osamu Shimomura, Martin Chalfie, and Roger Tsien for their work on a series of fluorescent proteins that were originally discovered in the jellyfish Aequorea Victoria.
Did you know? The green fluorescent protein they discovered is now so widely used in scientific research that it is now simply referred to by its acronym GFP.
To understand why a protein from the humble jellyfish could be so important we must first look at what makes this fluorescent protein unique. There are many examples of organisms throughout the world that are bioluminescent, or give off visible light. Many of these organisms live deep in the ocean, too deep for sunlight to penetrate, so they must produce their own light through a series of chemical reactions. Potentially, the bioluminescent proteins of any of these organisms could be used by scientists, but what makes GFP so special is that it is capable of giving off light all on its own. Many other proteins require a complex series of reactions, and other protein partners, to produce light, whereas GFP only requires oxygen, which is present in almost every living cell. This means that GFP can be put into almost any cell type, from bacteria to human stem cells, causing them to glow a brilliant green.
The simplest use of GFP is to find and track a glowing cell when it is among many non-glowing cells. This has been especially useful in cancer and stem cell research. If researchers want to know how cancer cells spread throughout the body they must first be able to find there are cancer cells in the sea of normal body cells. This is extremely difficult unless your cancer cells are glowing bright green, while the other cells remain dark! Similarly, if you want to follow the offspring of a brain stem cell, you need to be able to pick these cells out of the millions of surrounding cells, a task quickly accomplished if the cells you are interested in are glowing brightly.
Did you know? GFP is used for research purposes only. The majority of work with GFP has been done with bacteria or small animals like fish and mice. GFP labelled cells are not injected into human patients.
Scientists are not content with just one color though. Modifications to the original green fluorescent protein has produced an incredible array of new fluorescent proteins allowing researchers to choose, and often combine fluorescent proteins to suit their purpose. The most stunning example of this was the creation of the 'brainbow' mouse, a mouse whose brain cells are labelled with all the different colors of the rainbow. This incredibly feat has allowed scientists to track how the millions of brains cells are connected, from one glowing neuron to the next!
The discovery and understanding of the green fluorescent protein has made a huge impact on nearly every field in biology, so much in fact that the next time you hear of a great scientific breakthrough you should thank the humble jellyfish.
Did you know? Although GFP is used to answer some serious and perplexing biology questions, it often receives the most notice when it is used to create "glowing" pets. News media have often reported the generation and potential sale of GFP expressing fish, mice and rabbits, which will glow brightly under an ultraviolet light.
By Kevin Graham
Article first published October 18, 2008