The Nobel Prize for chemistry is shared this year by three US-based scientists, one of them Japanese and two American, each of whom had a contributing part in the discovery and application of GFP – green fluorescent protein – which may be used to better observe and study certain cells.

The protein found in certain jellyfish is bioluminescent, it glows. But the main difference between GFP and others like luciferase, which is found in Fireflies, is that unlike the latter, the GFP’s ability to glow is not dependent on a specific chemical that gets used up in the process.

When a cell produces this protein, some amino acids that comprise the protein’s core undergo a series of changes which require only oxygen, and which form a structure that can absorb ultraviolet light and emit a green-shaded glow. Almost any cell can be made to produce GFP, from bacterial cells to those found in humans.

There is enormous potential here for biological study. Unlike most methods biologists use today to look at cells, having a glowing cell to look at could let scientists directly study living cells. Therefore you could get a moving picture of cell activity, which will offer a much better look at biological processes.

The winners who share this prize are 80 year old Osamu Shimomura, who is an emeritus professor with the Marine Biological Laboratory in Woods Hole, Massachusetts and Boston University Medical School; Martin Chalfie, who is 61, and a biological sciences professor at Columbia University; and 56 year old Roger Y. Tsien, a pharmacology professor with the University of California in San Diego.

Shimomura is the one who started the research at Princeton in 1969, when he studied extracts from jellyfish he collected in Friday Harbor in the San Juan Islands of Washington State. He found a blue luminescent protein called aequorin, and the green-glowing GFP. It’s then that he discovered the unique property of GFP of only required oxygen.

In 1988, Chalfie, who had heard about GFP, decided to use it to study the transparent roundworm, Caenorhabditis elegans, and study the path of proteins in its visible internal organs. Douglas Prasher of the Woods Hole Oceanographic Institution then inserted the gene into the bacterium E. coli, and produced green-glowing bacteria. Chalfie applied the same process to the roundworm’s touch neurons, which started to glow bright green.

Finally Tsien is the one who because of the fact that for technical reasons green is not the best suited color for such a luminous marker, isolated the color producing part of GFP and altered it to produce cyan and yellow glowing versions of the protein. Scientists eventually produced a whole spectrum of colours, and in one notable experiment altered proteins in a mouse’s brain to yellow, cyan and red, producing a brain in all the colours of the rainbow – a “brainbow.”

GFP is applied today in technologies to detect heavy metals (in mining) and explosives, in children’s toys, and even in art.