Contact: Peter Iglinski
University of Rochester
Better protein creation may be secret of longevity for the world’s
Naked mole rats have a unique mechanism for building proteins
IMAGE: Naked mole rats are small, hairless, subterranean rodents
native to eastern Africa.
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Naked mole rats have what any animal would want. They live long
lives—about 30 years—and stay healthy until the very end. Now
biologists at the University of Rochester have new insights into
the animal’s longevity—better-constructed proteins.
Proteins are involved in nearly all functions of an animal cell,
and consequently, are essential to all organisms. But before
proteins can do their job, they must fold into the appropriate
shapes that allow them to connect to and interact with other
structures in the cell. In a paper published this week in the
Proceedings of the National Academy of Sciences, Vera Gorbunova and
Andrei Seluanov describe their discovery of the process in naked
mole rats that leads to virtually perfect proteins.
“While this is basic research,” said Gorbunova, “we hope our
findings encourage further studies on better protein synthesis.”
Their work focused on naked mole rat ribosomes—the site of protein
creation in the animal’s cells—and began by happenstance. Gorbunova
and Seluanov were working with ribosome RNA (rRNA) when they made a
discovery. After applying a dye to a sample, they studied it under
ultraviolet light only to find three dark bands—representing
concentrations of different rRNA molecules—not the two bands that
are characteristic of all other animals, suggesting that there is a
“hidden break” in the naked mole rat rRNA. Since rRNA is an
essential part of the protein-creation mechanism, the two
biologists decided to see if the broken rRNA affects the quality of
naked mole rat proteins.
Ribosome RNA strands act as scaffolds on the ribosome, a protein
synthesis machine. Changing the shape of the scaffold can have a
profound effect on the organization of the ribosome parts.
Gorbunova and Seluanov discovered that the naked mole rat’s rRNA
scaffold is indeed unique. The rRNA strands split at two specific
locations and discard the intervening segment. Instead of floating
off on their own, the two remaining pieces from each strand stay
close to each other and act as a scaffold on which ribosomal
proteins are assembled to create a functional ribosome—a molecular
machine that puts amino acids together to create proteins. And the
results are impressive.
When the ribosome connects amino acids together to create a protein
a mistake is occasionally introduced when an incorrect amino acid
is inserted. Gorbunova and Seluanov found that the proteins made by
naked mole rat cells are up to 40 times less likely to contain such
mistakes than the proteins made by mouse cells.
“This is important because proteins with no aberrations help the
body to function more efficiently,” said Seluanov.
The next step for the biologists is to split mouse rRNA in the same
way to see if it would lead to improved protein creation.
The two biologists hope their work will eventually result in
pharmaceutical treatments that modulate protein synthesis in
humans, though any medical solution is a long way off.