The significance of peroxisome function in chronological aging of Saccharomyces cerevisiae.
Bottom Line: We show that intact peroxisomes are an important factor in yeast chronological aging because all pex mutants showed a reduced chronological lifespan.The strongest reduction was observed in Δpex5 cells.Our data indicate that this is related to the complete inactivation of the peroxisomal β-oxidation pathway in these cells due to the mislocalization of thiolase.
Affiliation: Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, P.O. Box 11103, 9700CC, Groningen, The Netherlands.Show MeSH
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Mentions: Unlike cultures of Δpex3 and Δpex6 cells, Δpex5 cultures showed a partial growth defect on glucose. Analysis of the genomic region of PEX5 revealed that PRP28 and MNN10 are flanking the PEX5 gene (Fig. 2A). PRP28 encodes an essential RNA helicase involved in RNA isomerization at the 5′ splice site (Strauss & Guthrie, 1991; Staley & Guthrie, 1999). MNN10 encodes a subunit of a Golgi mannosyltransferase complex the deletion of which affects growth (Karpova et al., 1993; Mondesert & Reed, 1996). In the used Δpex5 strain of the Euroscarf collection, the PEX5 gene is deleted from start to stop codon. The short distance between PRP28/MNN10 and PEX5 does not exclude that this deletion strategy may have shortened the promoter region of one or both of the flanking genes and affect their transcription. To test this, we complemented the Euroscarf PEX5 deletion strain by reintroducing the deleted PEX5 gene on a plasmid (Δpex5/PEX5 strain). As shown in Fig. 2B, reintroduction of the PEX5 gene did not result in restoration of the glucose growth defect. We also constructed a new PEX5 deletion strain preserving at least 500 bps in front of the start codon of PRP28 and MNN10 to avoid truncation of the promoter regions of these two genes (Fig. 2A). This strain is named Δ3'pex5.
Affiliation: Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, P.O. Box 11103, 9700CC, Groningen, The Netherlands.