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  1. Article: Regulation of gene expression by stop codon recoding: selenocysteine.

    Copeland, Paul R

    Gene

    2003  Volume 312, Page(s) 17–25

    Abstract: ... of selenocysteine (Sec) into protein, the UGA codon is transformed from one that signals translation termination ... The regulation of gene expression at the translational level not only allows for rapid changes ... in specific protein levels but also provides an opportunity to alter codon specificity. For the incorporation ...

    Abstract The regulation of gene expression at the translational level not only allows for rapid changes in specific protein levels but also provides an opportunity to alter codon specificity. For the incorporation of selenocysteine (Sec) into protein, the UGA codon is transformed from one that signals translation termination to one specific for Sec. This review provides a look at Sec incorporation from the perspective of the individual steps involved in protein synthesis: initiation, elongation and termination. The roles of the factors known to be required for Sec incorporation are considered in the context of each step in translation including structural modeling of the differences between the standard elongation factor eEF1A and the Sec-specific counterpart, eEFSec.
    MeSH term(s) Amino Acid Sequence ; Animals ; Codon, Terminator/genetics ; Gene Expression Regulation/genetics ; Humans ; Models, Genetic ; Molecular Sequence Data ; Protein Biosynthesis/genetics ; Proteins/genetics ; Proteins/metabolism ; Selenocysteine/genetics ; Selenocysteine/metabolism ; Selenoproteins ; Sequence Homology, Amino Acid
    Chemical Substances Codon, Terminator ; Proteins ; Selenoproteins ; Selenocysteine (0CH9049VIS)
    Language English
    Publishing date 2003-07-17
    Publishing country Netherlands
    Document type Journal Article ; Review
    ZDB-ID 391792-7
    ISSN 1879-0038 ; 0378-1119
    ISSN (online) 1879-0038
    ISSN 0378-1119
    DOI 10.1016/s0378-1119(03)00588-2
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 1357: Show issues Location:
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  2. Article ; Online: A homozygous mutation in the human selenocysteine tRNA gene impairs UGA recoding activity and selenoproteome regulation by selenium.

    Vindry, Caroline / Guillin, Olivia / Wolff, Philippe / Marie, Paul / Mortreux, Franck / Mangeot, Philippe E / Ohlmann, Théophile / Chavatte, Laurent

    Nucleic acids research

    2023  Volume 51, Issue 14, Page(s) 7580–7601

    Abstract: ... by the recoding of a UGA codon, typically used as a stop codon. A homozygous point mutation (C65G) in the human ... The selenocysteine (Sec) tRNA (tRNA[Ser]Sec) governs Sec insertion into selenoproteins ... recoding activities. Overall, this study demonstrates the pleiotropic effect of a single C65G mutation ...

    Abstract The selenocysteine (Sec) tRNA (tRNA[Ser]Sec) governs Sec insertion into selenoproteins by the recoding of a UGA codon, typically used as a stop codon. A homozygous point mutation (C65G) in the human tRNA[Ser]Sec acceptor arm has been reported by two independent groups and was associated with symptoms such as thyroid dysfunction and low blood selenium levels; however, the extent of altered selenoprotein synthesis resulting from this mutation has yet to be comprehensively investigated. In this study, we used CRISPR/Cas9 technology to engineer homozygous and heterozygous mutant human cells, which we then compared with the parental cell lines. This C65G mutation affected many aspects of tRNA[Ser]Sec integrity and activity. Firstly, the expression level of tRNA[Ser]Sec was significantly reduced due to an altered recruitment of RNA polymerase III at the promoter. Secondly, selenoprotein expression was strongly altered, but, more surprisingly, it was no longer sensitive to selenium supplementation. Mass spectrometry analyses revealed a tRNA isoform with unmodified wobble nucleotide U34 in mutant cells that correlated with reduced UGA recoding activities. Overall, this study demonstrates the pleiotropic effect of a single C65G mutation on both tRNA phenotype and selenoproteome expression.
    MeSH term(s) Humans ; Codon, Terminator ; Mutation ; Selenium/pharmacology ; Selenium/metabolism ; Selenocysteine/genetics ; Selenocysteine/metabolism ; Selenoproteins/genetics ; Proteome
    Chemical Substances Codon, Terminator ; Selenium (H6241UJ22B) ; Selenocysteine (0CH9049VIS) ; Selenoproteins ; Proteome
    Language English
    Publishing date 2023-05-31
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 186809-3
    ISSN 1362-4962 ; 1362-4954 ; 0301-5610 ; 0305-1048
    ISSN (online) 1362-4962 ; 1362-4954
    ISSN 0301-5610 ; 0305-1048
    DOI 10.1093/nar/gkad482
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    Zs.A 1067: Show issues Location:
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  3. Article ; Online: Selective up-regulation of human selenoproteins in response to oxidative stress.

    Touat-Hamici, Zahia / Legrain, Yona / Bulteau, Anne-Laure / Chavatte, Laurent

    The Journal of biological chemistry

    2014  Volume 289, Issue 21, Page(s) 14750–14761

    Abstract: Selenocysteine is inserted into selenoproteins via the translational recoding of a UGA codon ... regulation of UGA-selenocysteine recoding efficiency and relocalization of SBP2, selenocysteine-specific ... normally used as a stop signal. This process depends on the nature of the selenocysteine ...

    Abstract Selenocysteine is inserted into selenoproteins via the translational recoding of a UGA codon, normally used as a stop signal. This process depends on the nature of the selenocysteine insertion sequence element located in the 3' UTR of selenoprotein mRNAs, selenium bioavailability, and, possibly, exogenous stimuli. To further understand the function and regulation of selenoproteins in antioxidant defense and redox homeostasis, we investigated how oxidative stress influences selenoprotein expression as a function of different selenium concentrations. We found that selenium supplementation of the culture media, which resulted in a hierarchical up-regulation of selenoproteins, protected HEK293 cells from reactive oxygen species formation. Furthermore, in response to oxidative stress, we identified a selective up-regulation of several selenoproteins involved in antioxidant defense (Gpx1, Gpx4, TR1, SelS, SelK, and Sps2). Interestingly, the response was more efficient when selenium was limiting. Although a modest change in mRNA levels was noted, we identified a novel translational control mechanism stimulated by oxidative stress that is characterized by up-regulation of UGA-selenocysteine recoding efficiency and relocalization of SBP2, selenocysteine-specific elongation factor, and L30 recoding factors from the cytoplasm to the nucleus.
    MeSH term(s) Cell Nucleus/metabolism ; Cytoplasm/metabolism ; Gene Expression/drug effects ; Glutathione Peroxidase/genetics ; Glutathione Peroxidase/metabolism ; HEK293 Cells ; Humans ; Hydrogen Peroxide/pharmacology ; Immunoblotting ; Membrane Proteins/genetics ; Membrane Proteins/metabolism ; Microscopy, Fluorescence ; Oxidants/pharmacology ; Oxidative Stress ; Phospholipid Hydroperoxide Glutathione Peroxidase ; Reactive Oxygen Species/metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Selenium/metabolism ; Selenium/pharmacology ; Selenocysteine/genetics ; Selenocysteine/metabolism ; Selenoproteins/genetics ; Selenoproteins/metabolism ; Up-Regulation/drug effects
    Chemical Substances Membrane Proteins ; Oxidants ; Reactive Oxygen Species ; SELENOS protein, human ; Selenoproteins ; Selenocysteine (0CH9049VIS) ; Hydrogen Peroxide (BBX060AN9V) ; glutathione peroxidase GPX1 (EC 1.11.1.-) ; Phospholipid Hydroperoxide Glutathione Peroxidase (EC 1.11.1.12) ; Glutathione Peroxidase (EC 1.11.1.9) ; Selenium (H6241UJ22B)
    Language English
    Publishing date 2014-04-04
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2997-x
    ISSN 1083-351X ; 0021-9258
    ISSN (online) 1083-351X
    ISSN 0021-9258
    DOI 10.1074/jbc.M114.551994
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  4. Article ; Online: Epitranscriptomic regulation of the response to the air pollutant naphthalene in mouse lungs: from the perspectives of specialized translation and tolerance linked to the writer ALKBH8

    Leonardi, Andrea / Kovalchuk, Nataliia / Yin, Lei / Endres, Lauren / Evke, Sara / Nevins, Steven / Martin, Samuel / Dedon, Peter C. / Melendez, J. Andres / Winkle, Laura Van / Zhang, Qing-Yu / Ding, Xinxin / Begley, Thomas J.

    bioRxiv

    Abstract: ... via stop codon recoding, of proteins that contain selenocysteine. Corresponding selenoproteins play ... methyltransferase that modifies the wobble uridine of selenocysteine tRNA to promote the specialized translation ... gene expression, molecular markers of damage, viability and tolerance to NA. Results Under basal conditions, lungs ...

    Abstract Background The epitranscriptomic writer Alkylation Repair Homolog 8 (ALKBH8) is a tRNA methyltransferase that modifies the wobble uridine of selenocysteine tRNA to promote the specialized translation, via stop codon recoding, of proteins that contain selenocysteine. Corresponding selenoproteins play critical roles in protecting against reactive oxygen species and environmental stress. Using a novel animal model deficient in Alkbh8, we have investigated the importance of epitranscriptomic systems in the response to naphthalene (NA), an abundant polycyclic aromatic hydrocarbon, glutathione depleter and lung toxicant found in tobacco smoke, gasoline and mothballs. Objectives Our goal was to define the molecular reprogramming of Alkbh8 deficient (Alkbh8def) mice and evaluate the roles that the epitranscriptomic writer ALKBH8 and selenoproteins play in mitigating NA-induced toxicity and lung dysfunction. Methods We performed basal lung analysis and NA exposure studies using WT, Alkbh8def and Cyp2abfgs-null mice, the latter of which lack the cytochrome P450 enzymes required for NA bioactivation. We characterized gene expression, molecular markers of damage, viability and tolerance to NA. Results Under basal conditions, lungs from Alkbh8def mice have increased oxidation-reduction potential (ORP) and 8-isoprostane levels, and have reprogrammed at the molecular level to display increased stress response transcripts. In addition, the ALKBH8 writer deficient lungs have a decreased GSH/GSSG ratio. Alkbh8def mice are more sensitive to NA than WT, showing higher susceptibility to lung damage both at the cellular and molecular levels. WT mice develop a tolerance to NA after 3 days, defined as resistance to a high challenging dose after repeated exposures, which is absent in Alkbh8def mice, with writer deficient not surviving NA exposure. Discussion We conclude that the epitranscriptomic writer ALKBH8 plays a protective role against NA-induced lung dysfunction and promotes NA tolerance. Our work provides an early example of how epitranscriptomic systems can regulate the response to environmental stress in vivo.
    Keywords covid19
    Publisher BioRxiv
    Document type Article ; Online
    DOI 10.1101/727909
    Database COVID19

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