GENET archive


5-Animals: GE animal news from Japan, the U.S., and Brazil

                                  PART I
-------------------------------- GENET-news -------------------------------

TITLE:  Japanese researchers develop novel method of introducing
        transgenes into animals
SOURCE: Medical News Today

DATE:   21 Jun 2004

------------------- archive: -------------------

Japanese researchers develop novel method of introducing transgenes into

Reproductive biologists at Kyoto University have succeeded in producing
the first animal offspring with transgenic material carried directly from
sperm stem cells "infected" by a retrovirus. Some of the resulting
transgenic mice reproduced and passed on the new genetic material to
their offspring.

 The team of researchers, headed by Dr. Takashi Shinohara, injected the
retrovirus into the seminiferous tubules in the testes of immature male
mice. The retrovirus was taken up by the sperm stem cells, which went on
to produce sperm with the transgene.

According to Dr. Shinohara and his colleagues Mito Kanatsu-Shinohara and
Shinya Toyokuni, 86 percent of the males injected with the retrovirus
became fertile. Eight of 31 of these males (26 percent) later mated
normally with wild-type female mice and sired offspring. An average of
about 3 percent of these offspring had the transgene.

The transgene remained stable and was detected in some offspring in the
next generation. When transgenic offspring from injected ("founder')
males were mated with wild-type mice, six of eight second-generation
offspring from a transgenic male mouse showed the presence of the
transgene, as did one of three offspring of a transgenic female mouse.

Because stem cells treated with retroviral transgenes can continuously
generate large numbers of transgenic sperm, many transgenic offspring can
be produced from a single "founder" male.

In a paper accepted for publication in the journal Biology of
Reproduction, the Japanese team notes that other methods have been
described for introducing transgenes into animals, including techniques
based on eggs or embryos from female animals. The rate of success for
these methods, however, is generally less than 1 percent.

The new method of using male sperm stem cells is simple and has a
relatively high rate of success. It should be directly applicable for
producing a wide range of animals, including pigs and cattle, with
modified germlines.

The same technique does not work with mature male mice, the scientists
point out. Apparently the retrovirus injected into seminiferous tubules
of immature mice is able to penetrate potential barriers and reach the
sperm stem cells.

Biology of Reproduction, published by the Society for the Study of
Reproduction, is the top-rated peer-reviewed journal in the field of
reproductive biology.

Contact: Dr. Takashi Shinohara
Society for the Study of Reproduction

                                  PART II
-------------------------------- GENET-news -------------------------------

TITLE:  GM mouse produces fish oil
SOURCE: Nature 427: 504, posted by checkbiotech / Syngenta
DATE:   22 Jun 2004

------------------- archive: -------------------

GM mouse produces fish oil

Fish oils known to help prevent heart attacks can now be made by land
animals for themselves, thanks to work by genetic engineers.

The researchers inserted a gene from a nematode worm into mice which
enables the mammals to make the omega-3 fatty acids. If the same feat can
be achieved in farm animals, meat, milk and eggs could all be directly
enriched with the oils.

This would not only benefit people, but could keep livestock healthier
too. "It's a double bonus," says Jing Kang, whose team produced the
altered mice at the Harvard Medical School in the US.

At present, meat and dairy produce from farm animals only contains the
omega-3 oils if farmers feed them with fishmeal, which is costly and can
waste scarce marine resources.

Improved circulation

Kang gave the mice a gene called fat-1, taken from the nematode
Caenorhabditis elegans. The gene makes omega-3 fatty acid saturase, an
enzyme which converts omega-6 fatty acids into their omega-3
counterparts, and humans and other animals already make the omega-6 oils.

As well as protecting hearts, omega-3 oils improve circulation, are
thought to dampen inflammatory conditions and could even combat cancer.
Fish such as mackerel, salmon and herring naturally contain omega-3 oils,
but many people do not eat the recommended amount. Other foods and
supplements containing the oils are available, but are expensive.

Engineering animals to make their own oils would be "a neat approach",
says Liz Lund of the Institute of Food Research in Norwich, England. "But
only if genetic modification of animals is more acceptable."

"The US market might be more tolerant, but the practicalities of getting
people to eat GM farm animals are extremely problematic, especially in
Europe," says Lund, who is investigating whether omega-3 oils can prevent
colon cancer in rats.

But Kang says the project is moving forward: "We're first going to do it
in chickens."

                                  PART III
-------------------------------- GENET-news -------------------------------

TITLE:  Brazil hails 'breakthrough' cow plan
SOURCE: South African Press Agency / Agence France Press
DATE:   30 Jun 2004

------------------- archive: -------------------

Brazil hails 'breakthrough' cow plan

Rio de Janeiro - Brazilian researchers are developing embryos to create a
transgenic cow whose milk could be used to produce drugs to treat blood
disorders, scientists said on Tuesday. Research began eight months ago
and is currently in its embryo production phase, said Jose Manuel Cabras
Dias, biotechnology and genetic resources chief at Embrapa, the
agriculture ministry's research arm. The cow's milk would contain a blood
thickener that can be extracted to create the drugs, Cabras Dias said.
"It's much easier to extract this type of material from milk," he said.
The transgenic cow should be born in three years, he said, and it would
take the pharmaceutical industry five years to develop the drugs. The
announcement came one day after Embrapa said one of Brazil's three cloned
cows had died. Vitoriosa, born on February 5, was a clone of Latin
America's first cloned cow, Vitoria. Scientists want to determine whether
Vitoriosa's death is related to being the clone of a clone. The cloned
cows Vitoria and Lenda, developed from the ovaries of a dead cow, are
doing well.


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