Under a microscope, the two-color tag--called Dendra because it is derived from the sea coral Dendronephthya--first shows up as a green glow, highlighting the otherwise invisible protein to which it is attached. The green turns to red when the tags are zapped with an intense pulse of visible blue light.
The dramatic color change "makes it possible to precisely label an object, such as a cell, organelle, or protein, with a flash of light and then to follow the object's movement over time," said Konstantin Lukyanov, whose group conducted the Dendra research in the lab of his brother, Sergey Lukyanov, a Howard Hughes Medical Institute (HHMI) international research scholar at the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences in Moscow. "This tool opens new possibilities for studying protein and organelle dynamics in living cells, cell migration during embryogenesis, inflammation, and other pathological and normal processes," he said.
Unlike other green-to-red fluorescent markers, Dendra can be activated by visible blue light, which is less harmful to living cells and does not require special laser equipment, Konstantin Lukyanov explained. In fact, the light source of the laser-scanning confocal microscopes that researchers commonly use to peer into living cells can activate the tag, which should make the new tool useful to many scientists, said Sergey Lukyanov, whose lab reports on the Dendra tag in the April 2006 issue of Nature Biotechnology, published in advance online on March 19, 2006.
Importantly, Dendra is small enough to highlight proteins without interfering with their folding or function. And the resea
Source:Howard Hughes Medical Institute