GM fish explain motor
neurone disease
ABC Science Online Friday, 26 March 2004
Associate Professor Surindar
Cheema hopes his zebra fish will mimic the human disease
Thousands of stripey aquarium fish are helping Australian researchers learn
more about a degenerative disease of the human nervous system.
The zebra fish have been genetically modified to carry a human gene for a
type of motor neurone disease.
Associate Professor Surindar Cheema, from the Howard Florey Institute at the
University of Melbourne, hopes that if
the fish develop diseased motor neurones, they could become a model for the
human disease.
That would allow Cheema and his U.K. collaborators to test drugs against
motor neurone disease, for which there is currently no known cure.
Motor neurone disease affects the nerves that provide the stimulus to the
muscles through which we move, breathe, eat and drink.
Scientist don't know what causes the disease and doctors can't diagnose it
early. Everybody with the disease dies, usually within five years of being
diagnosed. Cheema said one person dies from the disease each day in
Australia.
Cheema's group is researching a type of motor neurone disease called
amyotrophic lateral sclerosis (ALS).
That's the disease U.K. actor David Niven and Chinese Communist Party
leader, Mao Zedong suffered from and Professor Stephen Hawking, the U.K.
theoretical physicist, has.
Cheema is working with the U.K. biotechnology company Daniolabs, in
Cambridge, to create transgenic zebra fish.
Together, they have injected a faulty gene that causes a particular type of
ALS, known as familial ALS, into zebra fish eggs minutes after they were
fertilised.
The SOD1 gene is faulty because it cannot code for a protein that protects
cells from free radicals, agents that can damage and kill cells.
Cheema said they could tell if the microinjection process worked and the
foreign gene was expressed because the injected gene also carried a piece of
DNA encoding a green fluorescent protein. If the faulty gene is expressed
the zebra fish will glow green under fluorescent light.
Zebra fish reproduce and develop quickly
"Now we are waiting to see if the microinjected zebra fish, which are now a
few months old, develop the disease," Cheema said. The group also hopes to
find out if the injected gene is passed on to future generations.
If the zebra fish develop ALS, Cheema's group will add drugs to their water
or inject the fish with drugs to see if they can cure ALS.
Cheema said that this sort of drug testing was not possible using rats or
mice as there are tens of thousands of drugs to be tested.
The advantage of using zebra fish is that they are cheaper than mice,
reproduce and develop quickly, and have a similar nervous system to humans,
he added.
The Cambridge group has already used zebra fish to develop a model to study
retinitis pigmentosa, a degenerative disease of the eye that leads to tunnel
vision. So Cheema's team is "hopeful that they can do the same for ALS".