Oxygen metabolism and reactive oxygen species cause chromosomal rearrangements and cell death

Abstract

The absence of Tsa1, a key peroxiredoxin that functions to scavenge H2O2 in Saccharomyces cerevisiae, causes the accumulation of a broad spectrum of mutations including gross chromosomal rearrangements (GCRs). Deletion of TSA1 also causes synthetic lethality in combination with mutations in RAD6 and several key genes involved in DNA double-strand break repair. In the present study we investigated the causes of GCRs and cell death in these mutants. tsa1-associated GCRs were independent of the activity of the translesion DNA polymerases , , and Rev1. Anaerobic growth reduced substantially GCR rates of WT and tsa1 mutants and restored the viability of tsa1 rad6, tsa1 rad51, and tsa1 mre11 double mutants. Anaerobic growth also reduced the GCR rate of rad27, pif1, and rad52 mutants, indicating a role of reactive oxygen species in GCR formation in these mutants. In addition, deletion of TSA1 or H 2O2 treatment of WT cells resulted in increased formation of Rad52 foci, sites of repair of multiple DNA lesions. H 2O2 treatment also induced the GCRs. Our results provide in vivo evidence that oxygen metabolism and reactive oxygen species are important sources of DNA damages that can lead to GCRs and lethal effects in S. cerevisiae.dsDNA break ͉ gross chromosomal rearrangement ͉ translesion DNA synthesis ͉ peroxiredoxin M aintaining genome stability is crucial for cell growth and cell survival. Different genetic disorders, including most human cancers, are associated with different forms of genome instability (1-3). One type of genomic instability observed frequently in many cancers is gross chromosomal rearrangements (GCRs), such as translocations, deletions of chromosome arms, interstitial deletions, inversions, amplifications, chromosome fusions, and aneuploidy. Multiple genes and pathways that suppress GCRs have been characterized by using the yeast Saccharomyces cerevisiae as a model system (4-6). These include genes involved in DNA replication, recombination, and repair, cell-cycle checkpoints that function during DNA replication and repair, and pathways involved in telomere maintenance, chromatin assembly, and detoxification of reactive oxygen species (ROS) (refs. 7 and 8 and references therein). The importance of these pathways for suppressing genome instability is further emphasized by their roles in preventing the development of human cancer (7, 9, 10).Although many pathways that function in the suppression of GCRs have been discovered, little is known about the causes and origin of GCRs. It is generally thought that a major cause of DNA damage that leads to mutations is ROS, which are generated as a normal part of oxygen metabolism but are also produced by ionizing radiation, metabolism of exogenous compounds, and pathological processes such as infection and inflammation (11,12). ROS, such as the superoxide radical, H 2 O 2 , and the hydroxyl radical, can attack almost all cell components and can induce many types of DNA damage, including single-stranded DNA breaks and dsDNA breaks (DSB), base and sugar modificat...

Peroxiredoxins, gerontogenes linking aging to genome instability and cancer

“…In support of this view, Tsa1 deficiency combined with deficiencies in Ogg1, a glycosylase that removes 7,8-dihydro-8-oxo-29-deoxyguanosine (8-oxo-dG; a major, mutagenic product of DNA oxidation) results in markedly elevated mutation rates (Huang and Kolodner 2005). Furthermore, the increased mutation rate in tsa1 cells is suppressed by anaerobiosis (Ragu et al 2007). However, in contrast to Ogg1-deficient cells, where the mutation rate returns to wild-type levels in the absence of oxygen (Northam et al 2010), a tsa1 mutant has a somewhat higher mutation rate than wild-type cells also in the absence of oxygen (Ragu et al 2007).…”

“…Furthermore, the increased mutation rate in tsa1 cells is suppressed by anaerobiosis (Ragu et al 2007). However, in contrast to Ogg1-deficient cells, where the mutation rate returns to wild-type levels in the absence of oxygen (Northam et al 2010), a tsa1 mutant has a somewhat higher mutation rate than wild-type cells also in the absence of oxygen (Ragu et al 2007).…”

Smc5–Smc6 complex suppresses gross chromosomal rearrangements mediated by break-induced replications

“…Several studies using this approach have demonstrated that there are eight pathways for suppressing these chromosomal aberrations, while six pathways promote GCR formation. The suppression mechanisms include cell cycle checkpoints [7][8][9][10][11][12], post-replication [13,14] and mismatch repair [15,16], recombination pathways, an anti-de novo telomere addition mechanism [17,18], chromatin assembly factors [11,19], mechanisms that prevent end-to-end chromosome fusions [17,18,20] and a pathway detoxifying reactive oxygen species [14,21,22]. In contrast, the promoters of GCRs include telomerase-related factors [17,23], a mitotic checkpoint network [24], the Rad1-Rad10 endonuclease [25], non-homologous end-joining proteins including Lig4 and Nej1 [17], a pathway generating inappropriate recombination via sumoylation and the Srs2 helicase [13] and the Bre1 ubiquitin ligase [13].…”

Two Distinct Translesion Synthesis Pathways across a Lipid Peroxidation-derived DNA Adduct in Mammalian Cells

“…Endogenous reactive chemicals such as reactive oxygen species and certain lipid peroxidation products are thought to contribute significantly to aging, age-related degenerative diseases, and cancer (1)(2)(3)(4). Cellular DNA is one of their targets, and replication of un-repaired DNA damage introduces mutations into the genome, thereby contributing to the aforementioned biological effects.…”