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Sengupta A, Carlson BA, Labunskyy VM, Gladyshev VN, Hatfield DL. Selenoprotein T deficiency alters cell adhesion and elevates selenoprotein W expression in murine fibroblast cells. Biochem Cell Biol 2010; 87:953-61. [PMID: 19935881 DOI: 10.1139/o09-064] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mammalian selenoproteins have diverse functions, cellular locations, and evolutionary histories, but all use the amino acid selenocysteine (Sec), often present in the enzyme's active site. Only about half of mammalian selenoproteins have been functionally characterized, with most being oxidoreductases. The cellular role of selenoprotein T (SelT), manifesting a CxxU motif in a thioredoxin-like fold and localized to Golgi and the endoplasmic reticulum, is not known. To examine its biological function, we knocked down SelT expression in mouse fibroblast cells and found that SelT deficiency alters cell adhesion and enhances the expression of several oxidoreductase genes, while decreasing the expression of genes involved in cell structure organization, suggesting the involvement of SelT in redox regulation and cell anchorage. Furthermore, we found that the loss of SelT elevates expression of another selenoprotein, selenoprotein W (SepW1). SelT and SepW1 belong to the same protein family, suggesting that SepW1 may functionally compensate for SelT.
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Shim MS, Kim JY, Jung HK, Lee KH, Xu XM, Carlson BA, Kim KW, Kim IY, Hatfield DL, Lee BJ. Elevation of glutamine level by selenophosphate synthetase 1 knockdown induces megamitochondrial formation in Drosophila cells. J Biol Chem 2009; 284:32881-94. [PMID: 19755423 PMCID: PMC2781704 DOI: 10.1074/jbc.m109.026492] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 09/11/2009] [Indexed: 11/06/2022] Open
Abstract
Although selenophosphate synthetase 1 (SPS1/SelD) is an essential gene in Drosophila, its function has not been determined. To elucidate its intracellular role, we targeted the removal of SPS1/SelD mRNA in Drosophila SL2 cells using RNA interference technology that led to the formation of vacuole-like globular structures. Surprisingly, these structures were identified as megamitochondria, and only depolarized mitochondria developed into megamitochondria. The mRNA levels of l(2)01810 and glutamine synthetase 1 (GS1) were increased by SPS1/SelD knockdown. Blocking the expression of GS1 and l(2)01810 completely inhibited the formation of megamitochondria induced by loss of SPS1/SelD activity and decreased the intracellular levels of glutamine to those of control cells suggesting that the elevated level of glutamine is responsible for megamitochondrial formation. Overexpression of GS1 and l(2)01810 had a synergistic effect on the induction of megamitochondrial formation and on the synthesis of glutamine suggesting that l(2)01810 is involved in glutamine synthesis presumably by activating GS1. Our results indicate that, in Drosophila, SPS1/SelD regulates the intracellular glutamine by inhibiting GS1 and l(2)01810 expression and that elevated levels of glutamine lead to a nutritional stress that provides a signal for megamitochondrial formation.
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Wirth EK, Conrad M, Winterer J, Wozny C, Carlson BA, Roth S, Schmitz D, Bornkamm GW, Coppola V, Tessarollo L, Schomburg L, Köhrle J, Hatfield DL, Schweizer U. Neuronal selenoprotein expression is required for interneuron development and prevents seizures and neurodegeneration. FASEB J 2009; 24:844-52. [PMID: 19890015 DOI: 10.1096/fj.09-143974] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Cerebral selenium (Se) deficiency is associated with neurological phenotypes including seizures and ataxia. We wanted to define whether neurons require selenoprotein expression and which selenoproteins are most important, and explore the possible pathomechanism. Therefore, we abrogated the expression of all selenoproteins in neurons by genetic inactivation of the tRNA[Ser](Sec) gene. Cerebral expression of selenoproteins was significantly diminished in the mutants, and histological analysis revealed progressive neurodegeneration. Developing interneurons failed to specifically express parvalbumin (PV) in the mutants. Electrophysiological recordings, before overt cell death, showed normal excitatory transmission, but revealed spontaneous epileptiform activity consistent with seizures in the mutants. In developing cortical neuron cultures, the number of PV(+) neurons was reduced on combined Se and vitamin E deprivation, while other markers, such as calretinin (CR) and GAD67, remained unaffected. Because of the synergism between Se and vitamin E, we analyzed mice lacking neuronal expression of the Se-dependent enzyme glutathione peroxidase 4 (GPx4). Although the number of CR(+) interneurons remained normal in Gpx4-mutant mice, the number of PV(+) interneurons was reduced. Since these mice similarly exhibit seizures and ataxia, we conclude that GPx4 is a selenoenzyme modulating interneuron function and PV expression. Cerebral SE deficiency may thus act via reduced GPx4 expression.-Wirth, E. K., Conrad, M., Winterer, J., Wozny, C., Carlson, B. A., Roth, S., Schmitz, D., Bornkamm, G. W., Coppola, V., Tessarollo, L., Schomburg, L., Köhrle, J., Hatfield, D. L., Schweizer, U. Neuronal selenoprotein expression is required for interneuron development and prevents seizures and neurodegeneration.
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Carlson BA, Yoo MH, Sano Y, Sengupta A, Kim JY, Irons R, Gladyshev VN, Hatfield DL, Park JM. Selenoproteins regulate macrophage invasiveness and extracellular matrix-related gene expression. BMC Immunol 2009; 10:57. [PMID: 19863805 PMCID: PMC2774298 DOI: 10.1186/1471-2172-10-57] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Accepted: 10/28/2009] [Indexed: 11/10/2022] Open
Abstract
Background Selenium, a micronutrient whose deficiency in diet causes immune dysfunction and inflammatory disorders, is thought to exert its physiological effects mostly in the form of selenium-containing proteins (selenoproteins). Incorporation of selenium into the amino acid selenocysteine (Sec), and subsequently into selenoproteins is mediated by Sec tRNA[Ser]Sec. Results To define macrophage-specific selenoprotein functions, we generated mice with the Sec tRNA[Ser]Sec gene specifically deleted in myeloid cells. These mutant mice were devoid of the "selenoproteome" in macrophages, yet exhibited largely normal inflammatory responses. However, selenoprotein deficiency led to aberrant expression of extracellular matrix-related genes, and diminished migration of macrophages in a protein gel matrix. Conclusion Selenium status may affect immune defense and tissue homeostasis through its effect on selenoprotein expression and the trafficking of tissue macrophages.
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Carlson BA, Yoo MH, Tsuji PA, Gladyshev VN, Hatfield DL. Mouse models targeting selenocysteine tRNA expression for elucidating the role of selenoproteins in health and development. Molecules 2009; 14:3509-27. [PMID: 19783940 PMCID: PMC3459062 DOI: 10.3390/molecules14093509] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Revised: 09/03/2009] [Accepted: 09/07/2009] [Indexed: 01/31/2023] Open
Abstract
Selenium (Se) deficiency has been known for many years to be associated with disease, impaired growth and a variety of other metabolic disorders in mammals. Only recently has the major role that Se-containing proteins, designated selenoproteins, play in many aspects of health and development begun to emerge. Se is incorporated into protein by way of the Se-containing amino acid, selenocysteine (Sec). The synthesis of selenoproteins is dependent on Sec tRNA for insertion of Sec, the 21st amino acid in the genetic code, into protein. We have taken advantage of this dependency to modulate the expression of Sec tRNA that in turn modulates the expression of selenoproteins by generating transgenic, conditional knockout, transgenic/standard knockout and transgenic/conditional knockout mouse models, all of which involve the Sec tRNA gene, to elucidate the intracellular roles of this protein class.
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81
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Xu XM, Yoo MH, Carlson BA, Gladyshev VN, Hatfield DL. Simultaneous knockdown of the expression of two genes using multiple shRNAs and subsequent knock-in of their expression. Nat Protoc 2009; 4:1338-48. [PMID: 19713955 DOI: 10.1038/nprot.2009.145] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Small hairpin RNA (shRNA) is a powerful tool for inhibiting gene expression. One limitation has been that this technique has been used primarily to target a single gene. This protocol expands upon previous methods by describing a knockdown vector that facilitates cloning of multiple shRNAs; this allows targeted knockdown of more than one gene or of a single gene that may otherwise be difficult to knockdown using a single shRNA. The targeted gene(s) can be readily re-expressed by transfecting knockdown cells with a knock-in vector, containing an shRNA-refractive cDNA that will express the protein-of-interest even in the presence of shRNAs. The constructed knockdown and knock-in vectors can be easily used concurrently to assess possible interrelationships between genes, the effects of gene loss on cell function and/or their restoration by replacing targeted genes one at a time. The entire knockdown or knock-in procedure can be completed in approximately 3-4 months.
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Downey CM, Horton CR, Carlson BA, Parsons TE, Hatfield DL, Hallgrímsson B, Jirik FR. Osteo-chondroprogenitor-specific deletion of the selenocysteine tRNA gene, Trsp, leads to chondronecrosis and abnormal skeletal development: a putative model for Kashin-Beck disease. PLoS Genet 2009; 5:e1000616. [PMID: 19696890 PMCID: PMC2721633 DOI: 10.1371/journal.pgen.1000616] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 07/24/2009] [Indexed: 01/09/2023] Open
Abstract
Kashin-Beck disease, a syndrome characterized by short stature, skeletal deformities, and arthropathy of multiple joints, is highly prevalent in specific regions of Asia. The disease has been postulated to result from a combination of different environmental factors, including contamination of barley by mold mycotoxins, iodine deficiency, presence of humic substances in drinking water, and, importantly, deficiency of selenium. This multifunctional trace element, in the form of selenocysteine, is essential for normal selenoprotein function, including attenuation of excessive oxidative stress, and for the control of redox-sensitive molecules involved in cell growth and differentiation. To investigate the effects of skeletal selenoprotein deficiency, a Cre recombinase transgenic mouse line was used to trigger Trsp gene deletions in osteo-chondroprogenitors. Trsp encodes selenocysteine tRNA[Ser]Sec, required for the incorporation of selenocysteine residues into selenoproteins. The mutant mice exhibited growth retardation, epiphyseal growth plate abnormalities, and delayed skeletal ossification, as well as marked chondronecrosis of articular, auricular, and tracheal cartilages. Phenotypically, the mice thus replicated a number of the pathological features of Kashin-Beck disease, supporting the notion that selenium deficiency is important to the development of this syndrome. Kashin-Beck disease (KBD) is a severe, chronic, and deforming musculoskeletal disease affecting millions of individuals in specific regions of Asia. Starting in childhood, the disorder leads to joint and limb deformities, short stature, and delayed skeletal development. Articular cartilage damage due to chondronecrosis and limb deformities then lead to secondary osteoarthritis and severe disability. Factors proposed to cause KBD include selenium deficiency, iodine deficiency, contamination of grain with toxic molds, and humic substances in well water. Soil and water deficiency in selenium (and iodine) are a consistent feature of KBD endemic areas, and affected individuals show profound deficiencies of these two elements. Thus far, there have been no convincing rodent models of KBD based on selenium (and/or iodine) deficiency achieved through dietary manipulation. Our manuscript describes a conditional gene mutation approach in mice that, in effect, mimics severe selenium deficiency, achieving this specifically within skeletal progenitor cells. By deleting selenocysteine tRNA (required for normal selenoprotein activity) in osteo-chondroprogenitors, we found that mice develop post-natal impairment of skeletal growth, dwarfism, delayed ossification, impaired endochondral bone formation, as well as severe chondronecrosis. Our mutant mouse supports the idea that selenium deficiency is key to the skeletal pathology of KBD.
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83
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Kehr S, Malinouski M, Finney L, Vogt S, Labunskyy VM, Kasaikina MV, Carlson BA, Zhou Y, Hatfield DL, Gladyshev VN. X-ray fluorescence microscopy reveals the role of selenium in spermatogenesis. J Mol Biol 2009; 389:808-18. [PMID: 19379757 DOI: 10.1016/j.jmb.2009.04.024] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 04/01/2009] [Accepted: 04/11/2009] [Indexed: 11/17/2022]
Abstract
Selenium (Se) is a trace element with important roles in human health. Several selenoproteins have essential functions in development. However, the cellular and tissue distribution of Se remains largely unknown because of the lack of analytical techniques that image this element with sufficient sensitivity and resolution. Herein, we report that X-ray fluorescence microscopy (XFM) can be used to visualize and quantify the tissue, cellular, and subcellular topography of Se. We applied this technique to characterize the role of Se in spermatogenesis and identified a dramatic Se enrichment specifically in late spermatids, a pattern that was not seen in any other elemental maps. This enrichment was due to elevated levels of the mitochondrial form of glutathione peroxidase 4 and was fully dependent on the supplies of Se by selenoprotein P. High-resolution scans revealed that Se concentrated near the lumen side of elongating spermatids, where structural components of sperm are formed. During spermatogenesis, maximal Se associated with decreased phosphorus, whereas Zn did not change. In sperm, Se was primarily in the midpiece and colocalized with Cu and Fe. XFM allowed quantification of Se in the midpiece (0.8 fg) and head (0.2 fg) of individual sperm cells, revealing the ability of sperm cells to handle the amounts of this element well above its toxic levels. Overall, the use of XFM allowed visualization of tissue and cellular Se and provided important insights in the role of this and other trace elements in spermatogenesis.
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84
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Yoo M, Xu X, Carlson BA, Gladyshev VN, Hatfield DL. Increased sensitivity of thioredoxin reductase 1 deficient breast cancer cells against TNF‐α induced apoptosis. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.338.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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85
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Xu X, Ganichkin OM, Carlson BA, Gladyshev VN, Wahl M, Hatfield DL. Catalytic Mechanism of Eukaryotic Selenocysteine Synthase. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.338.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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86
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Carlson BA, Lee BJ, Hatfield DL. Ribosomal frameshifting in response to hypomodified tRNAs in Xenopus oocytes. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.847.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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87
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Carlson BA, Yoo M, Kim JY, Shrimali RK, Irons R, Park JM, Hatfield DL. Knockout of the selenocysteine tRNA
[Ser]Sec
gene (
Trsp
) in mouse macrophages. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.346.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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88
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Sengupta A, Carlson BA, Labunskyy V, Gladyshev VN, Hatfield DL. Knocking down selenoprotein T (SelT) alters cell adhesion and elevates selenoprotein W (SelW) expression in murine fibroblast cells. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.728.8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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89
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Hatfield DL, Yoo MH, Carlson BA, Gladyshev VN. Selenoproteins that function in cancer prevention and promotion. Biochim Biophys Acta Gen Subj 2009; 1790:1541-5. [PMID: 19272412 DOI: 10.1016/j.bbagen.2009.03.001] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 02/27/2009] [Accepted: 03/01/2009] [Indexed: 01/16/2023]
Abstract
Of the many health benefits attributed to selenium, the one that has received the most attention is its role in cancer prevention. Selenium-containing proteins (selenoproteins) have been shown in recent years to have roles in cancer prevention. However, selenoproteins have diverse functions and their view as antioxidants is oversimplified. Some selenoproteins appear to have a split personality in having roles both in preventing and promoting cancer. The contrasting roles of one selenoprotein, thioredoxin reductase 1, in cancer are discussed in detail, but as also noted, at least one other selenoprotein may also have such a dual function. In addition, we discuss examples of inhibition of cancer development by selenoprotein deficiency in mouse models. These studies highlight the complex nature of selenium in relation to cancer.
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90
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Fomenko DE, Novoselov SV, Natarajan SK, Lee BC, Koc A, Carlson BA, Lee TH, Kim HY, Hatfield DL, Gladyshev VN. MsrB1 (methionine-R-sulfoxide reductase 1) knock-out mice: roles of MsrB1 in redox regulation and identification of a novel selenoprotein form. J Biol Chem 2008; 284:5986-93. [PMID: 18990697 DOI: 10.1074/jbc.m805770200] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Protein oxidation has been linked to accelerated aging and is a contributing factor to many diseases. Methionine residues are particularly susceptible to oxidation, but the resulting mixture of methionine R-sulfoxide (Met-RO) and methionine S-sulfoxide (Met-SO) can be repaired by thioredoxin-dependent enzymes MsrB and MsrA, respectively. Here, we describe a knock-out mouse deficient in selenoprotein MsrB1, the main mammalian MsrB located in the cytosol and nucleus. In these mice, in addition to the deletion of 14-kDa MsrB1, a 5-kDa selenoprotein form was specifically removed. Further studies revealed that the 5-kDa protein occurred in both mouse tissues and human HEK 293 cells; was down-regulated by MsrB1 small interfering RNA, selenium deficiency, and selenocysteine tRNA mutations; and was immunoprecipitated and recognized by MsrB1 antibodies. Specific labeling with (75)Se and mass spectrometry analyses revealed that the 5-kDa selenoprotein corresponded to the C-terminal sequence of MsrB1. The MsrB1 knock-out mice lacked both 5- and 14-kDa MsrB1 forms and showed reduced MsrB activity, with the strongest effect seen in liver and kidney. In addition, MsrA activity was decreased by MsrB1 deficiency. Liver and kidney of the MsrB1 knock-out mice also showed increased levels of malondialdehyde, protein carbonyls, protein methionine sulfoxide, and oxidized glutathione as well as reduced levels of free and protein thiols, whereas these parameters were little changed in other organs examined. Overall, this study established an important contribution of MsrB1 to the redox control in mouse liver and kidney and identified a novel form of this protein.
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91
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Glass RS, Berry MJ, Block E, Boakye HT, Carlson BA, Gailer J, George GN, Gladyshev VN, Hatfield DL, Jacobsen NE, Johnson S, Kahakachchi C, Kamiński R, Manley SA, Mix H, Pickering IJ, Prenner EJ, Saira K, Skowrońska A, Tyson JF, Uden PC, Wu Q, Xu XM, Yamdagni R, Zhang Y. Insights into the Chemical Biology of Selenium. PHOSPHORUS SULFUR 2008. [DOI: 10.1080/10426500801898366] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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92
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Carlson BA, Lee BJ, Hatfield DL. Ribosomal frameshifting in response to hypomodified tRNAs in Xenopus oocytes. Biochem Biophys Res Commun 2008; 375:86-90. [PMID: 18675785 DOI: 10.1016/j.bbrc.2008.07.118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Accepted: 07/23/2008] [Indexed: 11/19/2022]
Abstract
We used Xenopus oocytes as an intracellular system to study ribosomal frameshifting. Microinjection of oocytes with a construct encoding the naturally occurring UUU or AAC codon at the frameshift site demonstrated that the level of frameshifting was similar or lower than found normally in retroviral frameshifting in mammalian cells, suggesting that oocytes are a reliable system to study this event. Phenylalanine (Phe) or asparagine (Asn) tRNAs with and without the highly modified wyebutoxine (Y) or queuosine (Q) base, respectively, were microinjected to assess their ability to promote frameshifting. tRNAPhe+Y inhibited the level of frameshifting, while tRNAPhe-Y promoted frameshifting providing evidence that the hypomodified form does not act only to enhance frameshifting, but is an essential requirement. Both tRNAAsn+Q and tRNAAsn-Q were used indiscriminately in frameshifting, whether the frameshift site contained the wild-type AAC, or the mutant AAU codon, suggesting that Q base modification status does not influence this process.
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93
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Blauwkamp MN, Yu J, Schin MA, Burke KA, Berry MJ, Carlson BA, Brosius FC, Koenig RJ. Podocyte specific knock out of selenoproteins does not enhance nephropathy in streptozotocin diabetic C57BL/6 mice. BMC Nephrol 2008; 9:7. [PMID: 18647412 PMCID: PMC2494546 DOI: 10.1186/1471-2369-9-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Accepted: 07/22/2008] [Indexed: 11/24/2022] Open
Abstract
Background Selenoproteins contain selenocysteine (Sec), commonly considered the 21st genetically encoded amino acid. Many selenoproteins, such as the glutathione peroxidases and thioredoxin reductases, protect cells against oxidative stress by functioning as antioxidants and/or through their roles in the maintenance of intracellular redox balance. Since oxidative stress has been implicated in the pathogenesis of diabetic nephropathy, we hypothesized that selenoproteins protect against this complication of diabetes. Methods C57BL/6 mice that have a podocyte-specific inability to incorporate Sec into proteins (denoted in this paper as PodoTrsp-/-) and control mice were made diabetic by intraperitoneal injection of streptozotocin, or were injected with vehicle. Blood glucose, body weight, microalbuminuria, glomerular mesangial matrix expansion, and immunohistochemical markers of oxidative stress were assessed. Results After 3 and 6 months of diabetes, control and PodoTrsp-/- mice had similar levels of blood glucose. There were no differences in urinary albumin/creatinine ratios. Periodic acid-Schiff staining to examine mesangial matrix expansion also demonstrated no difference between control and PodoTrsp-/- mice after 6 months of diabetes, and there were no differences in immunohistochemical stainings for nitrotyrosine or NAD(P)H dehydrogenase, quinone 1. Conclusion Loss of podocyte selenoproteins in streptozotocin diabetic C57BL/6 mice does not lead to increased oxidative stress as assessed by nitrotyrosine and NAD(P)H dehydrogenase, quinone 1 immunostaining, nor does it lead to worsening nephropathy.
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Shrimali RK, Irons RD, Carlson BA, Sano Y, Gladyshev VN, Park JM, Hatfield DL. Selenoproteins mediate T cell immunity through an antioxidant mechanism. J Biol Chem 2008; 283:20181-5. [PMID: 18487203 PMCID: PMC2459287 DOI: 10.1074/jbc.m802559200] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 05/07/2008] [Indexed: 11/06/2022] Open
Abstract
Selenium is an essential dietary element with antioxidant roles in immune regulation, but there is little understanding of how this element acts at the molecular level in host defense and inflammatory disease. Selenium is incorporated into the amino acid selenocysteine (Sec), which in turn is inserted into selenoproteins in a manner dependent on Sec tRNA([Ser]Sec). To investigate the molecular mechanism that links selenium to T cell immunity, we generated mice with selenoprotein-less T cells by cell type-specific ablation of the Sec tRNA([Ser]Sec) gene (trsp). Herein, we show that these mutant mice exhibit decreased pools of mature T cells and a defect in T cell-dependent antibody responses. We also demonstrate that selenoprotein deficiency leads to oxidant hyperproduction in T cells and thereby suppresses T cell proliferation in response to T cell receptor stimulation. These findings offer novel insights into immune function of selenium and physiological antioxidants.
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95
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Kurotani R, Tomita T, Yang Q, Carlson BA, Chen C, Kimura S. Role of secretoglobin 3A2 in lung development. Am J Respir Crit Care Med 2008; 178:389-98. [PMID: 18535256 DOI: 10.1164/rccm.200707-1104oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Secretoglobin 3A2 (SCGB3A2) was originally identified as a downstream target in lung for the homeodomain transcription factor NKX2-1, whose null mutation resulted in severely hypoplastic lungs. A very low level of SCGB3A2 is expressed in lungs at Embryonic Day (E) 11.5 during mouse development, which markedly increases by E16.5, the time when lung undergoes dramatic morphologic changes, suggesting that SCGB3A2 may be involved in lung development in addition to a known role in lung inflammation. OBJECTIVES To determine whether SCGB3A2 plays a role in lung development. METHODS To assess a potential role for SCGB3A2 during early lung development, wild-type and Nkx2-1-null fetal lungs of early developmental stages were subjected to ex vivo organ culture in the presence of SCGB3A2. Nkx2-1-null fetuses were exposed to SCGB3A2 during early organogenesis period through intravenous administration of this protein to Nkx2-1-heterozygous pregnant females carrying these null fetuses. Cultured lungs and fetal lungs were subjected to histologic and immunohistochemical analyses. To assess a role for SCGB3A2 in late lung development, SCGB3A2 was administered to pregnant wild-type females during mid- to late organogenesis stages, and the preterm pups and/or their lungs were evaluated for extent of maturity using breathing motion, gross morphology and histology of lungs, expression of gestational stage-specific genes, and phospholipid profiles. MEASUREMENTS AND MAIN RESULTS SCGB3A2 significantly promoted both early and late stages of lung development. CONCLUSIONS SCGB3A2 is a novel growth factor in lung.
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96
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Turanov AA, Kehr S, Carlson BA, Hatfield DL, Gladyshev VN. Mammalian thioredoxin reductases: roles in redox homeostasis and analysis of cellular targets. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.156.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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97
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Yoo M, Patterson AD, Xu X, Carlson BA, Gladyshev VN, Hatfield DL. Functional analysis of phospholipid hydroperoxide glutathione peroxidase by targeting its expression. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.156.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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98
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Sengupta A, Lichti UF, Carlson BA, Yuspa SH, Hatfield DL. Targeted removal of the selenocysteine tRNA gene (
trsp
) in epidermis modulates skin function and development. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.156.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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99
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Xu X, Carlson BA, Zhang Y, Berry MJ, Gladyshev VN, Hatfield DL. Functional analysis of mammalian selenocysteine synthase. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.696.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Carlson BA, Xu X, Lee BJ, Gladyshev VN, Hatfield DL. The adaptor for stress‐related selenoprotein synthesis does not require aminoacylation for its maturation. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.156.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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