GFP also known as Green Fluorescent Protein has existed for approximately one hundred and sixty million years in one species of jellyfish. Sometime in 1994 studies showed that GFP has been cloned. Now GFP is found in laboratories all over the world where it is used in every conceivable plant and animal. Flatworms, algae, E. coli and pigs have all been made to fluoresce with GFP. To some scientist and researchers, GFP is considered as the microscope of the twenty-first century. Using GFP we can see when proteins are made and where they can go with the aid of a microscope. It is said that it is done by joining the GFP gene to the gene of the protein of interest so that when the protein is made it will have GFP hanging off it. One of these scientist said are Osamu Shimomura whom was the first person to isolate GFP and to find out which part of GFP was responsible for its fluorescence with the use of microscope. His meticulous research laid the solid foundations on which the GFP revolution was built. Shimomura started studying the bioluminescence of the crystal jellyfish, Aequorea Victoria which is now widely used for experiments and tests. This jellyfish produces green bioluminescence from small photoorgans located on its microscopic umbrella.
He has concluded that the rings of twenty to thirty jellyfish are squeezed through a rayon gauze, a faintly luminescent liquid called squeezate is obtained. He went to a lot of laboratories in Washington to collect this squeezate and to extract from it the substance responsible for its luminescence. In order to do his research Shimomura estimates that he collected over a million Aequorea specimens, cut off the rings, and produced squeezate under the use of equipments specifically the microscope. However another scientist and researcher, Douglas Prasher was one of the few people to realize the potential of GFP as a tracer molecule. In 1987 he got the idea that sparked the GFP revolution. He thought that GFP from a jellyfish could be used to report when a protein was being made in a cell. His studies showed that proteins are extremely small and cannot be seen, even under an electron microscope. However if one could somehow link GFP to a specific protein, such as the hemoglobin, we would be able to see the green fluorescence of the GFP that is attached to the hemoglobin that is according to Douglas Prasher. It would be a bit like attaching a light bulb to the hemoglobin molecule he says. Hemoglobin is defined as a vital protein found in the body, since it carries the oxygen in our blood, our bodies are continuously making new hemoglobin. Encoded in the DNA is some type of index that directs the molecular machinery to the start of the hemoglobin gene. When new hemoglobin is required protein production is activated. The gene is read and the protein is manufactured. At the end of the gene is a message called a stop codon, which also ends protein. production. The manufacture of proteins using the instructions from the gene is called protein expression.
Doug Prasher envisioned that it would be possible to use biomolecular techniques to insert the GFP gene at the end of the hemoglobin gene, right before the stop codon. When the cell needed to make hemoglobin, it would go to the hemoglobin gene, use the information encoded in the gene to make it, but instead of stopping when the hemoglobin was made, this cell would carry on making GFP until it reached the stop codon at the end of the GFP gene. As a result, the cell would produce a hemoglobin molecule with a GFP attached to it, see below.
