Aging of the Other Genome: A Decisive but Ambitious Solution
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by Jay, 13 years ago
Google Tech Talks
December, 19 2007
The DNA in our cells consists of not only the well-known 46
chromosomes currently receiving such avid attention from specialists
in sequencing technology, but also a large number of copies of a
relatively tiny, circular DNA molecule inside the "powerhouse of the
cell," the mitochondrion. Among other things, mitochondria perform
the chemistry of breathing - they extract energy from nutrients by
exquisitely regulated chemical reactions that consume oxygen and
create CO2. This vital function depends on the 13 proteins encoded by
the mitochondrial DNA (mtDNA), as well as on hundreds of proteins
that are encoded in our more famous genome and imported across the
mitochondrial surface after construction in the body of the cell. The
mtDNA accumulates mutant, non-functional variants far faster than our
main genome, so 20 years ago scientists began looking at the idea of
putting copies of the 13 genes of interest into the nucleus after
making modifications that would cause them to be processed by the
same "protein import" machinery that processes the mitochondrion's
many other proteins, thus making the mtDNA itself superfluous and
mutations in it harmless. I will discuss this concept in detail in my
talk. Progress has been very erratic in the meantime but is now very
rapid, partly because of Methuselah Foundation-funded research.
However, this approach may still prove impossible, so many other,
ostensibly simpler ideas - some more promising than others - have
been proposed, and I will describe some of these too.
Speaker: Dr Aubrey de Grey
Aubrey de Grey is a biomedical gerontologist based in Cambridge, UK,
and is the Chairman and Chief Science Officer of the Methuselah
Foundation, a 501(c)(3) non-profit charity dedicated to combating the
aging process. He is also Editor-in-Chief of "Rejuvenation Research",
the world's only peer-reviewed journal focused on intervention in
aging. His research interests encompass the etiology of all the
accumulating and eventually pathogenic molecular and cellular
side-effects of metabolism ("damage") that constitute mammalian aging
and the design of interventions to repair and/or obviate that damage.
He has developed a possibly comprehensive plan for such repair, termed
Strategies for Engineered Negligible Senescence (SENS), which breaks the
aging problem down into seven major classes of damage and identifies
detailed approaches to addressing each one. A key aspect of SENS is
that it can potentially extend healthy lifespan without limit, even
though these repair processes will never be perfect, as the repair only
needs to approach perfection rapidly enough to keep the overall level
of damage below pathogenic levels. de Grey has termed this required
rate of improvement of repair therapies "longevity escape velocity".