Visualizing the Central Dogma:
Researchers Create First Movie Starring DNA, RNA, and Protein
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In 1958, five years after he helped discover the
double helix structure of DNA, Francis Crick coined the term "Central
Dogma" to characterize the all-important cellular processes
whereby DNA is "transcribed" into RNA and RNA is "translated" into
protein. Since then, researchers have typically examined individual
aspects of the Central Dogma in isolation, by developing separate
systems for studying transcription or translation. Now, researchers
at Cold Spring Harbor Laboratory have developed the first system
for viewing how the Central Dogma unfolds in its entirety, from
DNA to RNA to protein, within living cells. The study appears
in the March 5 issue of the journal Cell.
The researchers, led by Dr. David Spector, developed a multi-component,
fluorescence microscopy imaging system in which the DNA near
an inducible gene can be visualized, the messenger RNA (mRNA)
encoded by the gene is labeled yellow, and the protein encoded
by the mRNA is labeled blue. In short, the system’s DNA,
RNA, and proteins are labeled so that they glow different colors
and can be seen with a microscope. The scientists then captured
time-lapse images as the inducible gene was switched on (view
movie below): First, the gene's tightly coiled DNA adopted a
more relaxed, open shape. Next, RNA could be seen accumulating
and being spliced in the nucleus and exported to the cytoplasm.
Finally, the proteins appeared
Although scientists have known that the production of proteins
based on the information stored in DNA involves dynamic interactions
among many molecules that carry out gene transcription, RNA splicing
and export, and translation, they have never before been able
to simultaneously track all of the products of transcription
and translation as they are produced and move throughout living
cells.
Spector and his colleagues have used the method to detect specific
events that transform the architecture of chromosomes from a
transcriptionally silent state to an actively transcribed state.
These findings have revealed fundamental information about how
genes are switched on and off in the context of living cells.
The method is likely to be used by many researchers interested
in studying how a variety of dynamic processes involving DNA,
RNA, and protein unfold and are coordinated in normal cells,
as well as how those processes or their coordination might be
altered in cancerous or other diseased cells.
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