Molecular Biology and Genetics / Moleküler Biyoloji ve Genetik

Permanent URI for this collectionhttps://hdl.handle.net/11147/9

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Subject: search.filters.subject.MitochondriaWoS Q: search.filters.wosQuartile.Q1

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  • Article
    Citation - WoS: 12
    Citation - Scopus: 12
    Identification of Respiratory Chain Gene Mutations That Shorten Replicative Life Span in Yeast
    (Elsevier Ltd., 2012) Hacıoğlu, Elise; Demir, Ayşe Banu; Koç, Ahmet
    Aging is the progressive accumulation of alterations in cells that elevates the risk of death. The mitochondrial theory of aging postulates that free radicals produced by the mitochondrial respiratory system contribute to the aging process. However, the roles of individual electron transfer chain (ETC) components in cellular aging have not been elucidated. In this study, we analyzed the replicative life span of 73 yeast deletion mutants lacking the genes of the mitochondrial electron transfer chain system, and found that nine of these mutants (δ nde1, δ tcm62, δ rip1, δ cyt1, δ qrc8, δ pet117, δ cox11, δ atp11, δ fmc1) had significantly shorter life spans. These mutants had lower rates of respiration and were slightly sensitive to exogenous administration of hydrogen peroxide. However, only two of them, δ nde1 and δ fmc1, produced higher amounts of intrinsic superoxide radicals in the presence of glucose compared to that of wild type cells. Interestingly, there were no significant alterations in the mitochondrial membrane potentials of these mutants. We speculate that the shorter life spans of ETC mutants result from multiple mechanisms including the low respiration rate and low energy production rather than just a ROS-dependent path. © 2011 Elsevier Inc.
  • Article
    Citation - WoS: 59
    Citation - Scopus: 60
    Effects of Deleting Mitochondrial Antioxidant Genes on Life Span
    (John Wiley and Sons Inc., 2007) Ünlü, Ercan Selçuk; Koç, Ahmet
    Reactive oxygen species (ROS) damage biomolecules, accelerate aging, and shorten life span, whereas antioxidant enzymes mitigate these effects. Because mitochondria are a primary site of ROS generation and also a primary target of ROS attack, they have become a major focus area of aging studies. Here, we employed yeast genetics to identify mitochondrial antioxidant genes that are important for replicative life span. In our studies, it was found that among the known mitochondrial antioxidant genes (TTR1, CCD1, SOD1, GLO4, TRR2, TRX3, CCS1, SOD2, GRX5, PRX1), deletion of only three genes, SOD1 (Cu, Zn superoxide dismutase), SOD2 (Manganese-containing superoxide dismutase), and CCS1 (Copper chaperone), shortened the life span enormously. The life span decreased 40% for Δsod1 mutant, 72% for Δsod2 mutant, and 50% for Δccs1 mutant. Deletion of the other genes had little or no effect on life span.