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The researchers injected eggs from
ovaries left over after spaying proce-
dures with viruses containing genes for
a rhesus monkey version of the antiviral
protein and a green fluorescent protein.
The viruses inserted the genes into the
eggs’ DNA. After fertilizing the eggs, the
researchers transplanted the resulting
embryos into the wombs of feline sur-
rogate mothers. In the end, three trans-
genic kittens — meaning kittens carrying
foreign genes — survived past birth: two
males and one female. Because the cats
carry the foreign genes in every cell,
including eggs and sperm, the animals
have been able to pass the genes on to
their own kittens.
Poeschla and his colleagues don’t know
yet whether the monkey gene will pro-
tect the cats from getting FIV: The team
needs to do more genetic
experiments and breed
the cats to get enough
animals to test immunity
to the virus. If the experi-
ments are successful, the
cats could be the first of
a new breed immune to
the virus. The research-
ers also hope studying
the cats will show how
TRIM5alpha and related
proteins work, some-
thing that could be
important for protecting
humans from HIV.
These cats are the
first to carry two for-
eign genes, says Martha
Gomez, a reproductive biologist at the
Audubon Center for Research of Endan-
gered Species in New Orleans, who was
part of a team that created fluorescent
cats using cloning.
By Tina Hesman Saey
A new breed of glowing green kitties may
represent a first step in creating cats that
are resistant to feline AIDS, possibly giving clues about fighting HIV infections
in people.
The kittens are engineered with a gene
that makes an antiviral protein that scientists hope will combat feline immunodeficiency virus, or
FIV. (Another inserted
gene makes the cats glow
under fluorescent light
so scientists can readily
confirm the procedure’s
success.) Researchers at
the Mayo Clinic College
of Medicine in Rochester, Minn., and Yamagu-chi University in Japan
report the accomplishment online September
11 in Nature Methods.
3) carries genes for green
fluorescent protein, which
makes her glow under
fluorescent light, and also
for an antiviral protein.
It remains to be seen whether the
newly created cats will be able to pass
along any protection their foreign genes
might confer for more than one generation. Unpublished data from Gomez and
her colleagues suggest that foreign genes
are shut off before reaching a second generation of kittens. That could limit the
usefulness of the technique for making
multiple generations of transgenic cats. s
TgCat3 (for transgenic cat
HIV has killed millions of people worldwide and infects millions
more; FIV is causing a
similar worldwide epidemic within the feline population, says
study leader Eric Poeschla, a molecular
virologist at the Mayo Clinic.
Part of the reason cats fall prey to the
virus is their lack of a key immune protein called TRIM5alpha, which helps
fight viruses even before the rest of the
immune system knows an infection is
under way, Poeschla says. He and his colleagues decided to do “an evolutionary
experiment” to see if inserting this antiviral protein would protect cats from FIV.
Cats engineered
to resist disease
Genetic tweak may foster
immunity to HiV-like virus
NEWS BRIEFS
Heart light
Stanford University researchers
have created human heart cells
that beat in response to light.
The team genetically engineered
embryonic stem cells to contain
the light-activated protein channel-rhodopsin- 2, then grew the stem
cells into beating heart cells in lab
dishes. The heart cells naturally
beat to their own rhythm until
researchers turned on a flash of
blue light. Then the cells became
tuned to the rhythm of the flashing
light, the team reports in the Sept.
21 Biophysical Journal. Controlling
cells with flashes of light may help
researchers better understand
how hearts beat, and could lead
to light-based pacemakers.
— Tina Hesman Saey
Anti-aging proteins are no font
of longevity
Sirtuins, proteins once touted as
the answer to fighting aging, aren’t
all they were cracked up to be.
Previous research had shown that
making more of a sirtuin called
sir- 2. 1 could lengthen the lives
of roundworms and fruit flies.
But the life-extending properties
observed in those experiments
were probably due to genetic varia-
tions unrelated to sirtuins, report
researchers at University College
london and an international team
of collaborators in the Sept. 22
Nature. Mohan Viswanathan and
leonard Guarente, both of Mi T,
also show in the same issue that
the role of sirtuins in increasing
life span was overstated in reports
of earlier experiments. Guarente’s
lab was the first to discover a link
between sirtuins and longevity.
— Tina Hesman Saey
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october 22, 2011 | SCIENCE NEWS | 9
