Does the Fountain of Youth only contain one protein?
Japanese scientists have genetically engineered mice to have many of the ailments that humans develop in old age. What is special is that all the symptoms are caused by the failure of a single gene. And the mice can be made young again. Decreased life expectancy, loss of fertility, hair loss, shortness of breath, hardening of the arteries, bone problems and discoloration of the skin are some of the many signs of advanced human age. But also the consequences of a single gene case in genetically modified mice, reported by Makoto Kuro-o and his colleagues from the National Institute of Neuroscience in Tokyo in Nature (November 6, 1997 issue). They claim to have discovered the first gene responsible for a variety of aging symptoms.
Scientists have named the gene klotho - after the Greek goddess of fate who spins the threads of life for us all. klotho encodes a protein that may be involved in ceramide metabolism. Ceramide is known to play a role in cell death and the cessation of cell growth and division.
The discovery of a gene that causes many of the symptoms of old age when it is defective does not mean that it is the aging gene. Many other genes are known to cause various symptoms of aging, processes that are exceedingly complicated. This is also supported by the fact that klotho mice do not develop some striking features of human aging, such as amyloid plaques in the brain, which are common in Alzheimer's disease.
Interestingly - and provocatively - the researchers were able to cure their experimental mice by injecting them with the he althy klotho protein. The mice reverted to a juvenile appearance. Wouldn't that be an elegant form of the genetically engineered fountain of youth? But, again, any extrapolation of the results to humans is pure speculation.
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