Oxidative
stress and mother cell-specific aging in Saccharomyces cerevisiae.
Gino Heeren (1),
Peter Laun (1), Stefanie Jarolim (1), Gabriel Perrone (2), Nazif Alic (2), Ian
Dawes (2), Michael Breitenbach (1)
(1) Genetics and General Biology, University of Salzburg, HelbrunnerstraBe,
Salzburg, 5020, Austria (gino.heeren@sbg.ac.at); (2) School of Biochemistry and
Molecular biology, UNSW, Sydney, Australia
In Saccharomyces cerevisiae the aging process is mother cell-specific. Only the mother cell ages while the biological clock of each daughter is reset to zero. In the work presented here, we isolated old and young yeast cells by centrifugal elutriation. RNA isolated from these cells was hybridised to polypropylene filters. This way we achieved a list of about 60 genes that are differentially expressed in old and young yeast cells. Because cells were not stressed during isolation, these genes are good candidates to be relevant in the ageing process. Since lifespan determination of Saccharomyces cerevisiae is not possible for 60 strains, we had to make an extra selection in the obtained data. Since we know from previous publications, that mitochondria of old cells contain reactive oxygen species as shown by dihydrorhodamine staining [1], we chose to test the deletion strains corresponding to the under-and over expressed genes for sensitivity and resistance to four different oxidants (hydrogen peroxide, t-BHP, thiol oxidizing diamide, superoxide generating menadione). Also some other phenotypes that could be important to the aging process (N-starvation survival, resistance to heath shock, ...) were tested. [1] Laun P., Pichova A., Madeo F., Fuchs J., Ellinger A., Kohlwein S., Dawes I., Frohlich K.U., Breitenbach M.: Mol Microbiol, Mar; 39(5): 1166-73 (2001)