Loading the protein researcher’s imaging toolbox with fluorophores
Over the past several years,
an increasing number of fluorescent probes — from both natural and laboratory
sources — have made possible noninvasive imaging of live cells and even whole
organisms. And, according to Roger Y. Tsien and colleagues at the University of
California, San Diego, in La Jolla, fluorescence techniques will remain a key part
of biological research for years to come.
In a review of the fluorescent tools
available to researchers, the authors note that fluorescent probes — such
as GFP and other proteins derived from Aequorea victoria or man-made inorganic
crystals, such as quantum dots — provide high spatial and temporal resolution
in most imaging applications. Furthermore, the power of fluorescence imaging continues
to expand, with improvements not only in the probes, but also in the instruments,
data analysis tools and strategies used to implement them.
Photo courtesy of National Center for Microscopy
and Imaging Research/Ben Giepmans.
The scientists discuss recent advancements
in fluorophores, including small organic dyes, fluorescent proteins and quantum
dots; immunolabeling and genetic tagging as a means of attaching fluorophores to
proteins of interest; and methods with which to study protein expression and localization
in primary cells and in fixed tissue samples. They also describe techniques using
fluorescent probes to observe protein synthesis and turnover, diffusion, conformational
changes and interactions with other proteins in live cells, as well as ways in which
to improve spatial resolution past the diffraction limit and depth of penetration
The authors report that further progress
in the development and use of small organic dyes is likely to be incremental, but
that there is no apparent limit to the variety of reporter molecules incorporating
fluorescent proteins to monitor cell biology. (Science, April 14, 2006, pp.
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