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Dendra is the latest addition to the growing family of photoactivatable fluorescent proteins (PAFPs), innovative imaging tools first made possible by Douglas Prasher, who isolated the gene for green fluorescent protein (GFP) from a species of bioluminescent jellyfish in 1992, and Martin Chalfie, who first used GFP for labeling in 1994, said Marc Zimmer, a computational chemist at Connecticut College and author of Glowing Genes: A Revolution in Biotechnology (2005). Since then, HHMI investigator Roger Tsien has developed a veritable rainbow of refined high-performance GFP mutants.

A major breakthrough in fluorescent protein applications came when Sergey Lukyanov first found GFP-like proteins in corals, Zimmer said. Before Lukyanov, no one had looked for GFP-like proteins in corals because they do not glow in the dark like fireflies and jellyfish. The corals' native green and red fluorescent proteins give off light only when stimulated by higher intensity light. Lukyanov's findings resulted in the discovery of many new GFP-like proteins in non-bioluminescent and sometimes even non-fluorescent marine organisms, Zimmer said.

Meanwhile, Sergey Lukyanov and other researchers had discovered that certain wavelengths of light could cause striking spectral changes in some proteins, which could convert from dark to light or change colors. Later, the Russian scientist and his colleagues discovered that the GFP-like protein they isolated from Dendronephthya had this capacity to change color, but it was too big to be useful for many research applications.

So the Lukyanovs and colleagues set out to create a smaller and more versatile version of their fluorescent protein. They systematically mutat
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Source:Howard Hughes Medical Institute