Early embryonic lethality caused by targeted disruption of the mouse PHGPx gene

Imai, Hideki; Hirao, Fumi; Sakamoto, Taro; Sekine, Kanae; Mizukura, Yumi; Saito, Makoto; Kitamoto, Takeo; Hayasaka, Michiko; Hanaoka, Kazunori; Nakagawa, Yasuhito

doi:10.1016/s0006-291x(03)00734-4

Cited by 309 publications

(248 citation statements)

References 29 publications

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“…Genetic disruption of the entire GPx4 gene in the murine genome demonstrated that GPx4 is essential for viability. Homozygous GPx4 knockout mice die in utero at midgestation because of gastrulation failure (Imai et al, 2003;Yant et al, 2003). The apparent embryonic lethality has been related to increased apoptosis and cell death leading to malformation of embryonic and extraembryonic cavities.…”

Section: Developmental Regulation and Cellular Distribution In The Brainmentioning

confidence: 99%

“…For GPx4 the hypothesis that highly ranked selenoproteins are of major biological relevance is supported by functional inactivation of gpx4 in mice. Stem cell knockout of gpx4 leads to early embryonic lethality (Imai et al, 2003;Yant et al, 2003), whereas GPx1 knockout mice develop normally and are fully viable (Ho et al, 1997;de Haan et al, 1998). Interestingly, GPx4 shows a unique cellular distribution in brain compared to GPx1 (Ho et al, 1997;Schweizer et al, 2004;Savaskan et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Various aspects of GPx4 research are discussed in the current literature (Brigelius-Flohe, 1999;Kuhn and Borchert, 2002;Imai et al, 2003), but not the structural biology of GPx4 nor its role in the central nervous system. Recent advances in these fields, including elucidation of the crystal structure of various GPx isoforms and novel data on regulation in response to brain injury (Borchert et al, 2006;Savaskan et al, 2007), prompted us to critically discuss the state of the art in these fields.…”

Section: Introductionmentioning

confidence: 99%

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Molecular biology of glutathione peroxidase 4: from genomic structure to developmental expression and neural function

Savaskan

Ufer

Kühn

et al. 2007

BCHM

114

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Selenoproteins have been recognized as modulators of brain function and signaling. Phospholipid hydroperoxide glutathione peroxidase (GPx4/PHGPx) is a unique member of the selenium-dependent glutathione peroxidases in mammals with a pivotal role in brain development and function. GPx4 exists as a cytosolic, mitochondrial, and nuclear isoform derived from a single gene. In mice, the GPx4 gene is located on chromosome 10 in close proximity to a functional retrotransposome that is expressed under the control of captured regulatory elements. Elucidation of crystallographic data uncovered structural peculiarities of GPx4 that provide the molecular basis for its unique enzymatic properties and substrate specificity. Monomeric GPx4 is multifunctional: it acts as a reducing enzyme of peroxidized phospholipids and thiols and as a structural protein. Transcriptional regulation of the different GPx4 isoforms requires several isoform-specific cis-regulatory sequences and trans-activating factors. Cytosolic and mitochondrial GPx4 are the major isoforms exclusively expressed by neurons in the developing brain. In stark contrast, following brain trauma, GPx4 is specifically upregulated in non-neuronal cells, i.e., reactive astrocytes. Molecular approaches to genetic modification in mice have revealed an essential and isoform-specific function for GPx4 in development and disease. Here we review recent findings on GPx4 with emphasis on its molecular structure and function and consider potential mechanisms that underlie neural development and neuropathological conditions.

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Section: Developmental Regulation and Cellular Distribution In The Brainmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molecular biology of glutathione peroxidase 4: from genomic structure to developmental expression and neural function

Savaskan

Ufer

Kühn

et al. 2007

BCHM

114

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“…In contrast, when performed under competitive conditions, the hierarchy that we observed for both SECIS-binding and UGA recoding efficiency (PHGPx > Dio2 > GPx1) parallels the physiological importance of these selenoproteins. The disruption of the PHGPx gene in mice is embryonic lethal 23 whereas Dio2 knockout mice have a modest phenotype. 48,49 Conversely, GPx1 knockout mice do not have an observable phenotype unless stressed.…”

Section: Discussionmentioning

confidence: 99%

“…[17][18][19][20][21] In general, affected patients usually have a combination of heterozygous mutations that are not completely functionally null, resulting in a partial SBP2 deficiency. This is not surprising given that the mouse knockout model of SBP2 is embryonically lethal, 22 as are several selenoprotein knockouts 23,24 supporting the essential nature of some selenoproteins. The most common clinical phenotype is an unusual thyroid hormone profile, as the deiodinase proteins, which are integral to thyroid hormone signaling, are selenoproteins.…”

Section: Introductionmentioning

confidence: 98%

Characterization of the UGA-recoding and SECIS-binding activities of SECIS-binding protein 2

2014

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Selenium, a micronutrient, is primarily incorporated into human physiology as selenocysteine (Sec). The 25 Seccontaining proteins in humans are known as selenoproteins. Their synthesis depends on the translational recoding of the UGA stop codon to allow Sec insertion. This requires a stem-loop structure in the 3' untranslated region of eukaryotic mRNAs known as the Selenocysteine Insertion Sequence (SECIS). The SECIS is recognized by SECIS-binding protein 2 (SBP2) and this RNA:protein interaction is essential for UGA recoding to occur. Genetic mutations cause SBP2 deficiency in humans, resulting in a broad set of symptoms due to differential effects on individual selenoproteins. Progress on understanding the different phenotypes requires developing robust tools to investigate SBP2 structure and function. In this study we demonstrate that SBP2 protein produced by in vitro translation discriminates among SECIS elements in a competitive UGA recoding assay and has a much higher specific activity than bacterially expressed protein. We also show that a purified recombinant protein encompassing amino acids 517-777 of SBP2 binds to SECIS elements with high affinity and selectivity. The affinity of the SBP2:SECIS interaction correlated with the ability of a SECIS to compete for UGA recoding activity in vitro. The identification of a 250 amino acid sequence that mediates specific, selective SECIS-binding will facilitate future structural studies of the SBP2:SECIS complex. Finally, we identify an evolutionarily conserved core cysteine signature in SBP2 sequences from the vertebrate lineage. Mutation of multiple, but not single, cysteines impaired SECIS-binding but did not affect protein localization in cells.

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Glutathione peroxidase 4 plays an important role in oxidative homeostasis and wound repair in corneal epithelial cells

et al. 2016

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Oxidative stress is involved in the pathologies of corneal epithelial cells. However, the importance of specific antioxidant enzymes in corneal epithelial cells is not fully understood. The purpose of this study is to elucidate the role of glutathione peroxidase 4 ( GP x4) in corneal epithelial cells. For in vitro experiments, an immortalized human corneal epithelial cell line was used. Cytotoxicity measured through LDH activity, lipid peroxidation immunostained for 4‐hydroxynonenal, cell viability, and cell death were compared between cells transfected with either GP x4 si RNA or scrambled control si RNA . In addition, the rescue effects of α‐tocopherol and ferrostatin‐1, a ferroptosis inhibitor, were examined in the cells with deficient GP x4 expression. For in vivo experiments, we applied n‐heptanol on the cornea of GP x4 +/+ and GP x4 +/− mice to create corneal epithelial wound. The epithelial defect area size was measured up to 48 h after epithelial wound creation. Knockdown of GP x4 strongly induced cytotoxicity and cell death in human corneal epithelial cells. Cell death induced by GP x4 knockdown was characterized by positive staining for both annexin V and propidium iodide, nuclear translocation of AIF , and without activation of caspase 3, and was rescued by α‐tocopherol and ferrostatin‐1. The delayed wound healing of GP x4 si RNA ‐transfected cells were ameliorated by α‐tocopherol in vitro . In addition, loss of one GP x4 allele was sufficient to significantly delay the healing of experimental corneal epithelial wounds in vivo . Our results suggest that the antioxidant enzyme GP x4 plays an important role in oxidative homeostasis, cell survival, and wound healing in corneal epithelial cells.

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Early embryonic lethality caused by targeted disruption of the mouse PHGPx gene

Cited by 309 publications

References 29 publications

Molecular biology of glutathione peroxidase 4: from genomic structure to developmental expression and neural function

Molecular biology of glutathione peroxidase 4: from genomic structure to developmental expression and neural function

Characterization of the UGA-recoding and SECIS-binding activities of SECIS-binding protein 2

Glutathione peroxidase 4 plays an important role in oxidative homeostasis and wound repair in corneal epithelial cells

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