There are many images of petri dishes filled with glow in the dark drawings and writing created by researchers and postgraduate students from labs around the world. I happen to like this one because there is nowhere nicer to be during sunset than by the sea. Have you ever wondered where these scientists get their glow in the dark “ink” from? It isn’t by extracting the ink from Crayola Glow Explosion markers.
It started in 1962 when Osamu Shimomura extracted the green fluorescent protein, (GFP), and another protein, aequorin, from the jellyfish Aequorea victoria. When the aequorin comes in contact with calcium ions, (Ca+2), the blue light created is absorbed by GFP which then releases it as green light. Osamu Shimomura was surprised to see GFP glowing bright green under UV light.
Since then, GFP has become an important tool in biological research. In 1992, Martin Chalfie demonstrated the use of GFP as a marker for gene expression when he coloured six individual cells in the transparent roundworm, Caenorhabditis elegans. His research paper has become one of the most referenced papers in Molecular Biology and Genetics. In 1994, Roger Y. Tsien showed that the part of GFP that formed the green glow was due to a chemical reaction with oxygen and that no other proteins were involved.
By 1998, Roger Y. Tsien’s laboratory had tweaked the GFP by genetic manipulation and by changing the structure of GFP to create variants of GFP that glowed brightly or in different colours like yellow, red, blue and cyan. Pink and orange have also been added to the colour palette.
GFP has now become part of the toolkit for researchers worldwide and instead of it being extracted from jellyfish, it is made in the laboratory. It has shown researchers how nerve cells develop in the brain, mapped the spread of cancer cells and shed light on the roles of the tens of thousands of proteins in living organisms. This can show when and how a protein malfunctions which is important as this can be followed by illness and disease.
In one colourful experiment, researchers from Harvard University in the USA tagged different nerve cells in the brain of a mouse resulting in Brainbow of 2007.