I vividly remember the first time I saw some glowing jellyfish at the Monterey Bay Aquarium – they were absolutely fascinating! There is something about glowing creatures; they seem so surreal and attractive. Think of the effect that the soft glow of fireflies has on you, and you will know what I mean. While most of us are fascinated by luminescent creatures, this is a story about some whose curiosity went beyond fascination, resulting in a discovery that revolutionized biology.
In 1962, a scientist, Osamu Shimomura, isolated a ‘glowing protein’ called Green Fluorescent Protein (GFP) from a jellyfish (Aequorea victoria). As the name suggests, this protein fluoresces with a bright green light when a UV (blue) light is shone on it. In the years that followed, scientists realized that they had found the equivalent of a glowing hat; place it on anyone’s head to locate that person in dark. They could simply fuse the gene that coded for GFP with a gene coding for any other protein to make this protein visible because of its glowing neighbor. Martin Chalfie, for instance, fused this gene with a gene from a worm and produced a glowing worm.
Once the ball got rolling, there was no looking back. Roger Tsien questioned: why stop at one color? He tweaked around with the protein to make many versions with different colors. So, we could now see multiple proteins in the cell simultaneously. An excellent example of the use of the many colored proteins is the ‘Brainbow’ project. Different neurons (brain cells) are labeled with different colors to distinguish them and capture stunning (and informative) images!
Osamu Shimomura, Martin Chalfie, and Roger Tsien together won the Nobel Prize in 2008 for their discovery and development of the green fluorescent protein. Before this protein, coloring cells was only possible by killing them and then staining the dead cells with some dyes. The technology of lighting up proteins in living cells and visualizing them while actually performing their functions was revolutionary. It caught up so fast that it is now the most basic tool in every biology lab. So much so that we don’t really think much about it.
Recently, I casually showed a video of a moving cell, where the filaments that push the cell forward have been tagged with the colored proteins, to a 76 yr old guy, with a biology major about 50 yrs ago. The reaction that this video spurred in him – staring awestruck, muttering “this is amazing” a few times – was when I re-realized the achievements that we often take for granted. It was a reminder that inspite of researchers complaining about their glacially slow projects with little or no results, as a group we have progressed. Roger Tsien died last week, but his work glows on, giving us a hope that even when we know a lot, there are always some invisible parts waiting to light up. In closing, I am reminded of the movie scene in ‘The Great Gatsby’, where Gatsby stares across the bay each night because he ‘believes in the green light‘. So should we.