ROS not the cause of yeast aging
oberonNOSPAM at vcn.bc.ca
Fri Jun 11 06:55:56 EST 2004
Proc Natl Acad Sci U S A. 2004 May 12 [Epub ahead of print]
Methionine sulfoxide reductase regulation of yeast lifespan reveals
reactive oxygen species-dependent and -independent components of aging.
Aging is thought to be caused by the accumulation of damage, primarily
from oxidative modifications of cellular components by reactive oxygen
species (ROS). Here we used yeast methionine sulfoxide reductases MsrA
and MsrB to address this hypothesis. In the presence of oxygen, these
antioxidants could increase yeast lifespan and did so independent of the
lifespan extension offered by caloric restriction. However, under
ROS-deficient, strictly anaerobic conditions, yeast lifespan was shorter,
not affected by MsrA or MsrB, and further reduced by caloric restriction.
In addition, we identified changes in the global gene expression
associated with aging in yeast, and they did not include oxidative stress
genes. Our findings suggest how the interplay between ROS, antioxidants,
and efficiency of energy production regulates the lifespan. The data also
suggest a model wherein factors implicated in aging (for example, ROS) may
influence the lifespan yet not be the cause of aging.
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