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NSF PR 96-56 - October 7, 1996
Media contact: |
Cheryl Dybas |
(703) 306-1070 |
cdybas@nsf.gov |
Program contact: |
Kamal Shukla |
(703) 306-1444 |
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This material is available primarily for archival purposes. Telephone
numbers or other contact information may be out of date; please see current
contact information at media
contacts.
Green Glow: Not Only for Halloween
New Fluorescent Protein Useful
in Gene Therapy
More than two millennia ago, the Roman natural philosopher
Pliny the Elder wrote of a "slime" that could be obtained
from marine creatures and used to make objects glow
green. Now, molecular and cellular biologists have
turned this marvel into a powerful research tool used
to illuminate the workings of genes and follow the
wanderings of protein molecules inside a living cell.
The source of the green glow is a unique protein,
called green fluorescent protein (GFP), found in a
Pacific Northwest jellyfish.
National Science Foundation-supported biologists James
Remington of the University of Oregon and Roger Tsien
of the University of California at San Diego have
determined the structure of an altered form of the
protein and revealed the source of the green glow.
"The unusual molecule responsible for the glow resembles
a chinese finger puzzle: a barrel-shaped structure
with a coil of amino acids corked in the center,"
explains Kamal Shukla, program director in NSF's division
of molecular and cellular biosciences, which funded
the research. "The green color results from the collapse
of one turn of the coil to form a ring of three amino
acids." The researchers chose to study the modified
GFP because it is more useful for cell biologists,
glowing much more brightly than the natural variant.
In a second experiment, the researchers deliberately
changed one amino acid in contact with the green pigment,
in hopes that change would make GFP glow yellow, rather
than the green of the original protein. It worked,
giving biologists a new tool to track the location
in a living cell of two proteins simultaneously, and
to determine whether two genes are "turned on" at
the same time. The researchers hope to make more colors,
including orange and red, by introducing other mutations
into the protein.
The uses for GFP are almost unlimited, they say. In
gene therapy, doctors could inject GFP along with
the therapy substance, and by checking for fluorescence,
determine whether the therapy had been properly delivered.
By "tuning" the green dye to different colors, scientists
studying vision may be able to gain insight into how
the human eye is able to respond to so many different
colors. Says Kamal Shukla, "Pliny the Elder probably
never would have guessed where his original observations
would lead."
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