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Ludwig CLM, Bohleber S, Lapp R, Rebl A, Wirth EK, Langhammer M, Schweizer U, Weitzel JM, Michaelis M. Alterations in gonadotropin, apoptotic and metabolic pathways in granulosa cells warrant superior fertility of the Dummerstorf high fertility mouse line 1. J Ovarian Res 2023; 16:32. [PMID: 36739419 PMCID: PMC9898973 DOI: 10.1186/s13048-023-01113-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 01/29/2023] [Indexed: 02/06/2023] Open
Abstract
The development and maturation of ovarian follicles is a complex and highly regulated process, which is essential for successful ovulation. During recent decades, several mouse models provided insights into the regulation of folliculogenesis. In contrast to the commonly used transgenic or knockout mouse models, the Dummerstorf high-fertility mouse line 1 (FL1) is a worldwide unique selection experiment for increased female reproductive performance and extraordinary high fertility. Interactions of cycle-related alterations of parameters of the hypothalamic pituitary gonadal axis and molecular factors in the ovary lead to improved follicular development and therefore increased ovulation rates in FL1 mice. FL1 females almost doubled the number of ovulated oocytes compared to the unselected control mouse line. To gain insights into the cellular mechanisms leading to the high fertility phenotype we used granulosa cells isolated from antral follicles for mRNA sequencing. Based on the results of the transcriptome analysis we additionally measured hormones and growth factors associated with follicular development to complement the picture of how the signaling pathways are regulated. While IGF1 levels are decreased in FL1 mice in estrus, we found no differences in insulin, prolactin and oxytocin levels in FL1 mice compared to the control line. The results of the mRNA sequencing approach revealed that the actions of insulin, prolactin and oxytocin are restricted local to the granulosa cells, since hormonal receptor expression is differentially regulated in FL1 mice. Additionally, numerous genes, which are involved in important gonadotropin, apoptotic and metabolic signaling pathways in granulosa cells, are differentially regulated in granulosa cells of FL1 mice.We showed that an overlap of different signaling pathways reflects the crosstalk between gonadotropin and growth factor signaling pathways, follicular atresia in FL1 mice is decreased due to improved granulosa cell survival and by improving the efficiency of intracellular signaling, glucose metabolism and signal transduction, FL1 mice have several advantages in reproductive performance and therefore increased the ovulation rate. Therefore, this worldwide unique high fertility model can provide new insights into different factors leading to improved follicular development and has the potential to improve our understanding of high fertility.
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Affiliation(s)
| | - Simon Bohleber
- grid.10388.320000 0001 2240 3300Institut für Biochemie und Molekularbiologie (IBMB), Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Rebecca Lapp
- grid.418188.c0000 0000 9049 5051Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Alexander Rebl
- grid.418188.c0000 0000 9049 5051Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Eva Katrin Wirth
- grid.6363.00000 0001 2218 4662Department of Endocrinology and Metabolism, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany ,grid.452396.f0000 0004 5937 5237DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Martina Langhammer
- grid.418188.c0000 0000 9049 5051Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Ulrich Schweizer
- grid.10388.320000 0001 2240 3300Institut für Biochemie und Molekularbiologie (IBMB), Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Joachim M. Weitzel
- grid.418188.c0000 0000 9049 5051Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Marten Michaelis
- grid.418188.c0000 0000 9049 5051Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
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Bohleber S, Fradejas-Villar N, Zhao W, Reuter U, Schweizer U. High-Resolution Ribosome Profiling Reveals Gene-Specific Details of UGA Re-Coding in Selenoprotein Biosynthesis. Biomolecules 2022; 12:biom12101504. [PMID: 36291713 PMCID: PMC9599142 DOI: 10.3390/biom12101504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/11/2022] [Accepted: 10/14/2022] [Indexed: 11/16/2022] Open
Abstract
Co-translational incorporation of selenocysteine (Sec) into selenoproteins occurs at UGA codons in a process in which translational elongation competes with translational termination. Selenocysteine insertion sequence-binding protein 2 (SECISBP2) greatly enhances Sec incorporation into selenoproteins by interacting with the mRNA, ribosome, and elongation factor Sec (EFSEC). Ribosomal profiling allows to study the process of UGA re-coding in the physiological context of the cell and at the same time for all individual selenoproteins expressed in that cell. Using HAP1 cells expressing a mutant SECISBP2, we show here that high-resolution ribosomal profiling can be used to assess read-through efficiency at the UGA in all selenoproteins, including those with Sec close to the C-terminus. Analysis of ribosomes with UGA either at the A-site or the P-site revealed, in a transcript-specific manner, that SECISBP2 helps to recruit tRNASec and stabilize the mRNA. We propose to assess the effect of any perturbation of UGA read-through by determining the proportion of ribosomes carrying UGA in the P-site, pUGA. An additional, new observation is frameshifting that occurred 3′ of the UGA/Sec codon in SELENOF and SELENOW in SECISBP2-mutant HAP1 cells, a finding corroborated by reanalysis of neuron-specific Secisbp2R543Q-mutant brains.
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Affiliation(s)
- Simon Bohleber
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Noelia Fradejas-Villar
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Wenchao Zhao
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
- Department Medical Biochemistry and Biophysics, Karolinska Institute, SE-171 77 Stockholm, Sweden
| | - Uschi Reuter
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
- Correspondence: ; Tel.: +49-228-73-4444
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Braun D, Bohleber S, Vatine GD, Svendsen CN, Schweizer U. Sodium Phenylbutyrate Rescues Thyroid Hormone Transport in Brain Endothelial-Like Cells. Thyroid 2022; 32:860-870. [PMID: 35357974 DOI: 10.1089/thy.2021.0643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Background: Monocarboxylate transporter 8 (MCT8) deficiency is a rare genetic disease leading to a severe developmental delay due to a lack of thyroid hormones (THs) during critical stages of human brain development. Some MCT8-deficient patients are not as severely affected as others. Previously, we hypothesized that these patients' mutations do not affect the functionality but destabilize the MCT8 protein, leading to a diminished number of functional MCT8 molecules at the cell surface. Methods: We have already demonstrated that the chemical chaperone sodium phenylbutyrate (NaPB) rescues the function of these mutants by stabilizing their protein expression in an overexpressing cell system. Here, we expanded our previous work and used iPSC (induced pluripotent stem cell)-derived brain microvascular endothelial-like cells (iBMECs) as a physiologically relevant cell model of human origin to test for NaPB responsiveness. The effects on mutant MCT8 expression and function were tested by Western blotting and radioactive uptake assays. Results: We found that NaPB rescues decreased mutant MCT8 expression and restores transport function in iBMECs carrying patient's mutation MCT8-P321L. Further, we identified MCT10 as an alternative TH transporter in iBMECs that contributes to triiodothyronine uptake, the biological active TH. Our results indicate an upregulation of MCT10 after NaPB treatment. In addition, we detected an increase in thyroxine (T4) uptake after NaPB treatment that was not mediated by rescued MCT8 but an unidentified T4 transporter. Conclusions: We demonstrate that NaPB is suitable to stabilize a pathogenic missense mutation in a human-derived cell model. Further, it activates TH transport independent of MCT8. Both options fuel future studies to investigate repurposing the Food and Drug Administration-approved drug NaPB in selected cases of MCT8 deficiency.
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Affiliation(s)
- Doreen Braun
- Institut für Biochemie und Molekularbiologie, Medizinische Fakultät, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Simon Bohleber
- Institut für Biochemie und Molekularbiologie, Medizinische Fakultät, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Gad D Vatine
- The Department of Physiology and Cell Biology, Faculty of Health Sciences, The Regenerative Medicine and Stem Cell (RMSC) Research Center and the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel
- Department of Biomedical Sciences, The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Clive N Svendsen
- Department of Biomedical Sciences, The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Medizinische Fakultät, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
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Ludwig CLM, Bohleber S, Rebl A, Wirth EK, Venuto MT, Langhammer M, Schweizer U, Weitzel JM, Michaelis M. Endocrine and molecular factors of increased female reproductive performance in the Dummerstorf high-fertility mouse line FL1. J Mol Endocrinol 2022; 69:285-298. [PMID: 35388794 PMCID: PMC9175557 DOI: 10.1530/jme-22-0012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 04/06/2022] [Indexed: 11/25/2022]
Abstract
The Dummerstorf high-fertility mouse line FL1 is a worldwide unique selection experiment for increased female reproductive performance. After more than 190 generations of selection, these mice doubled the amount of offspring per litter compared to the unselected control line. FL1 females have a superior lifetime fecundity and the highest Silver fecundity index that has been described in mice, while their offspring show no signs of growth retardation. The reasons for the increased reproductive performance remained unclear. Thus, this study aims to characterize the Dummerstorf high-fertility mouse line FL1 on endocrine and molecular levels on the female side. We analyzed parameters of the hypothalamic pituitary gonadal axis on both hormonal and transcriptional levels. Gonadotropin-releasing hormone and follicle-stimulating hormone (FSH) concentrations were decreased in FL1 throughout the whole estrous cycle. Luteinizing hormone (LH) was increased in FL1 mice in estrus. Progesterone concentrations were decreased in estrus in FL1 mice and not affected in diestrus. We used a holistic gene expression approach in the ovary to obtain a global picture of how the high-fertility phenotype is achieved. We found several differentially expressed genes in the ovaries of FL1 mice that are associated with different female fertility traits. Our results indicate that ovulation rates in mice can be increased despite decreased FSH levels. Cycle-related alterations of progesterone and LH levels have the potential to improve follicular maturation, and interactions of endocrine and molecular factors lead to enhanced follicular survival, more successful folliculogenesis and therefore higher ovulation rates in female FL1 mice.
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Affiliation(s)
| | - Simon Bohleber
- Institut für Biochemie und Molekularbiologie (IBMB), Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Alexander Rebl
- Institute of Genome Biology, Fish Genetics Unit, Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Eva Katrin Wirth
- Department of Endocrinology and Metabolism, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Marzia Tindara Venuto
- Institute of Reproductive Biology, Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Martina Langhammer
- Institute of Genetics and Biometry, Service Group Model Laboratory Animals, Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie (IBMB), Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Joachim M Weitzel
- Institute of Reproductive Biology, Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
- Correspondence should be addressed to J M Weitzel or M Michaelis: or
| | - Marten Michaelis
- Institute of Reproductive Biology, Research Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
- Correspondence should be addressed to J M Weitzel or M Michaelis: or
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Fradejas-Villar N, Zhao W, Reuter U, Doengi M, Ingold I, Bohleber S, Conrad M, Schweizer U. Missense mutation in selenocysteine synthase causes cardio-respiratory failure and perinatal death in mice which can be compensated by selenium-independent GPX4. Redox Biol 2021; 48:102188. [PMID: 34794077 PMCID: PMC8605217 DOI: 10.1016/j.redox.2021.102188] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/26/2021] [Accepted: 11/11/2021] [Indexed: 12/16/2022] Open
Abstract
Selenoproteins are a small family of proteins containing the trace element selenium in form of the rare amino acid selenocysteine (Sec), which is decoded by the UGA codon. In humans, a number of pathogenic variants in genes encoding distinct selenoproteins or selenoprotein biosynthesis factors have been identified. Pathogenic variants in selenocysteine synthase (SEPSECS), which catalyzes the last step in Sec-tRNA[Ser]Sec biosynthesis, were reported in children suffering from progressive cerebello-cerebral atrophy. To understand the pathomechanism associated with SEPSECS deficiency, we generated a novel mouse model recapitulating the respective human pathogenic p.Y334C variant in the murine Sepsecs gene (SepsecsY334C). Unlike in patients, pups homozygous for the p.Y334C variant died perinatally with signs of cardio-respiratory failure. Perinatal death is reminiscent of the Sedaghatian spondylometaphyseal dysplasia disorder in humans, which is caused by pathogenic variants in the gene encoding the selenoprotein and key ferroptosis regulator glutathione peroxidase 4 (GPX4). Protein expression levels of distinct selenoproteins in SepsecsY334C/Y334C mice were found to be generally reduced in brain and isolated cortical neurons, while transcriptomics analysis uncovered an upregulation of NRF2-regulated genes. Crossbreeding of SepsecsY334C/Y334C mice with mice harboring a targeted mutation of the catalytically active Sec to Cys in GPX4 rescued perinatal death of SepsecsY334C/Y334C mice, showing that the cardio-respiratory defects of SepsecsY334C/Y334C mice were caused by the lack of GPX4. Like in SepsecsY334C/Y334C mice, selenoprotein expression levels remained low and NRF2-regulated genes remained highly expressed in these compound mutant mice, indicating that selenium-independent GPX4, along with a sustained antioxidant response are sufficient to compensate for dysfunctional Sec-tRNA[Ser]Sec biosynthesis. Our findings imply that children with pathogenic variants in SEPSECS or GPX4 may even benefit from treatments that incompletely compensate for impaired GPX4 activity.
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Affiliation(s)
| | - Wenchao Zhao
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Bonn, Germany
| | - Uschi Reuter
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Bonn, Germany
| | - Michael Doengi
- Institut für Physiologie, Universitätsklinikum Bonn, Bonn, Germany
| | - Irina Ingold
- Helmholtz Zentrum München, Institute of Metabolism and Cell Death, 85764, Neuherberg, Germany
| | - Simon Bohleber
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Bonn, Germany
| | - Marcus Conrad
- Helmholtz Zentrum München, Institute of Metabolism and Cell Death, 85764, Neuherberg, Germany; Pirogov Russian National Research Medical University, Laboratory of Experimental Oncology, Moscow, 117997, Russia
| | - Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Bonn, Germany.
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Fradejas-Villar N, Bohleber S, Zhao W, Reuter U, Kotter A, Helm M, Knoll R, McFarland R, Taylor RW, Mo Y, Miyauchi K, Sakaguchi Y, Suzuki T, Schweizer U. The Effect of tRNA [Ser]Sec Isopentenylation on Selenoprotein Expression. Int J Mol Sci 2021; 22:ijms222111454. [PMID: 34768885 PMCID: PMC8583801 DOI: 10.3390/ijms222111454] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 12/22/2022] Open
Abstract
Transfer RNA[Ser]Sec carries multiple post-transcriptional modifications. The A37G mutation in tRNA[Ser]Sec abrogates isopentenylation of base 37 and has a profound effect on selenoprotein expression in mice. Patients with a homozygous pathogenic p.R323Q variant in tRNA-isopentenyl-transferase (TRIT1) show a severe neurological disorder, and hence we wondered whether selenoprotein expression was impaired. Patient fibroblasts with the homozygous p.R323Q variant did not show a general decrease in selenoprotein expression. However, recombinant human TRIT1R323Q had significantly diminished activities towards several tRNA substrates in vitro. We thus engineered mice conditionally deficient in Trit1 in hepatocytes and neurons. Mass-spectrometry revealed that hypermodification of U34 to mcm5Um occurs independently of isopentenylation of A37 in tRNA[Ser]Sec. Western blotting and 75Se metabolic labeling showed only moderate effects on selenoprotein levels and 75Se incorporation. A detailed analysis of Trit1-deficient liver using ribosomal profiling demonstrated that UGA/Sec re-coding was moderately affected in Selenop, Txnrd1, and Sephs2, but not in Gpx1. 2′O-methylation of U34 in tRNA[Ser]Sec depends on FTSJ1, but does not affect UGA/Sec re-coding in selenoprotein translation. Taken together, our results show that a lack of isopentenylation of tRNA[Ser]Sec affects UGA/Sec read-through but differs from a A37G mutation.
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Affiliation(s)
- Noelia Fradejas-Villar
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, D-53115 Bonn, Germany; (N.F.-V.); (S.B.); (W.Z.); (U.R.); (R.K.)
| | - Simon Bohleber
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, D-53115 Bonn, Germany; (N.F.-V.); (S.B.); (W.Z.); (U.R.); (R.K.)
| | - Wenchao Zhao
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, D-53115 Bonn, Germany; (N.F.-V.); (S.B.); (W.Z.); (U.R.); (R.K.)
| | - Uschi Reuter
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, D-53115 Bonn, Germany; (N.F.-V.); (S.B.); (W.Z.); (U.R.); (R.K.)
| | - Annika Kotter
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University of Mainz, Staudingerweg 5, D-55128 Mainz, Germany; (A.K.); (M.H.)
| | - Mark Helm
- Institute of Pharmacy and Biochemistry, Johannes Gutenberg University of Mainz, Staudingerweg 5, D-55128 Mainz, Germany; (A.K.); (M.H.)
| | - Rainer Knoll
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, D-53115 Bonn, Germany; (N.F.-V.); (S.B.); (W.Z.); (U.R.); (R.K.)
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Clinical and Translational Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK; (R.M.); (R.W.T.)
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial Research, Clinical and Translational Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK; (R.M.); (R.W.T.)
| | - Yufeng Mo
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; (Y.M.); (K.M.); (Y.S.); (T.S.)
| | - Kenjyo Miyauchi
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; (Y.M.); (K.M.); (Y.S.); (T.S.)
| | - Yuriko Sakaguchi
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; (Y.M.); (K.M.); (Y.S.); (T.S.)
| | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; (Y.M.); (K.M.); (Y.S.); (T.S.)
| | - Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, D-53115 Bonn, Germany; (N.F.-V.); (S.B.); (W.Z.); (U.R.); (R.K.)
- Correspondence:
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Bohleber S, Zhao W, Fradejas Villar N, Schweizer U. High resolution ribosome profiling reveals gene‐specific details of UGA re‐coding in selenoproteins. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Schweizer U, Bohleber S, Zhao W, Fradejas-Villar N. The Neurobiology of Selenium: Looking Back and to the Future. Front Neurosci 2021; 15:652099. [PMID: 33732108 PMCID: PMC7959785 DOI: 10.3389/fnins.2021.652099] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/08/2021] [Indexed: 12/18/2022] Open
Abstract
Eighteen years ago, unexpected epileptic seizures in Selenop-knockout mice pointed to a potentially novel, possibly underestimated, and previously difficult to study role of selenium (Se) in the mammalian brain. This mouse model was the key to open the field of molecular mechanisms, i.e., to delineate the roles of selenium and individual selenoproteins in the brain, and answer specific questions like: how does Se enter the brain; which processes and which cell types are dependent on selenoproteins; and, what are the individual roles of selenoproteins in the brain? Many of these questions have been answered and much progress is being made to fill remaining gaps. Mouse and human genetics have together boosted the field tremendously, in addition to traditional biochemistry and cell biology. As always, new questions have become apparent or more pressing with solving older questions. We will briefly summarize what we know about selenoproteins in the human brain, glance over to the mouse as a useful model, and then discuss new questions and directions the field might take in the next 18 years.
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Affiliation(s)
- Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Medizinische Fakultät, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Simon Bohleber
- Institut für Biochemie und Molekularbiologie, Medizinische Fakultät, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Wenchao Zhao
- Institut für Biochemie und Molekularbiologie, Medizinische Fakultät, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Noelia Fradejas-Villar
- Institut für Biochemie und Molekularbiologie, Medizinische Fakultät, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
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Zhao W, Bohleber S, Schmidt H, Seeher S, Howard MT, Braun D, Arndt S, Reuter U, Wende H, Birchmeier C, Fradejas-Villar N, Schweizer U. Ribosome profiling of selenoproteins in vivo reveals consequences of pathogenic Secisbp2 missense mutations. J Biol Chem 2019; 294:14185-14200. [PMID: 31350336 DOI: 10.1074/jbc.ra119.009369] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 07/08/2019] [Indexed: 01/31/2023] Open
Abstract
Recoding of UGA codons as selenocysteine (Sec) codons in selenoproteins depends on a selenocysteine insertion sequence (SECIS) in the 3'-UTR of mRNAs of eukaryotic selenoproteins. SECIS-binding protein 2 (SECISBP2) increases the efficiency of this process. Pathogenic mutations in SECISBP2 reduce selenoprotein expression and lead to phenotypes associated with the reduction of deiodinase activities and selenoprotein N expression in humans. Two functions have been ascribed to SECISBP2: binding of SECIS elements in selenoprotein mRNAs and facilitation of co-translational Sec insertion. To separately probe both functions, we established here two mouse models carrying two pathogenic missense mutations in Secisbp2 previously identified in patients. We found that the C696R substitution in the RNA-binding domain abrogates SECIS binding and does not support selenoprotein translation above the level of a complete Secisbp2 null mutation. The R543Q missense substitution located in the selenocysteine insertion domain resulted in residual activity and caused reduced selenoprotein translation, as demonstrated by ribosomal profiling to determine the impact on UGA recoding in individual selenoproteins. We found, however, that the R543Q variant is thermally unstable in vitro and completely degraded in the mouse liver in vivo, while being partially functional in the brain. The moderate impairment of selenoprotein expression in neurons led to astrogliosis and transcriptional induction of genes associated with immune responses. We conclude that differential SECISBP2 protein stability in individual cell types may dictate clinical phenotypes to a much greater extent than molecular interactions involving a mutated amino acid in SECISBP2.
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Affiliation(s)
- Wenchao Zhao
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Simon Bohleber
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Henrik Schmidt
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Sandra Seeher
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Michael T Howard
- Department of Genetics, University of Utah, Salt Lake City, Utah 84112
| | - Doreen Braun
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Simone Arndt
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Uschi Reuter
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Hagen Wende
- Max Delbrück Center of Molecular Medicine, 13125 Berlin, Germany
| | | | - Noelia Fradejas-Villar
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
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Abstract
Base 37 in tRNA, 3′-adjacent to the anticodon, is occupied by a purine base that is thought to stabilize codon recognition by stacking interactions on the first Watson-Crick base pair. If the first codon position forms an A.U or U.A base pair, the purine is likely further modified in all domains of life. One of the first base modifications found in tRNA is N6-isopentenyl adenosine (i6A) present in a fraction of tRNAs in bacteria and eukaryotes, which can be further modified to 2-methyl-thio-N6-isopentenyladenosine (ms2i6A) in a subset of tRNAs. Homologous tRNA isopentenyl transferase enzymes have been identified in bacteria (MiaA), yeast (Mod5, Tit1), roundworm (GRO-1), and mammals (TRIT1). In eukaryotes, isopentenylation of cytoplasmic and mitochondrial tRNAs is mediated by products of the same gene. Accordingly, a patient with homozygous mutations in TRIT1 has mitochondrial disease. The role of i6A in a subset of tRNAs in gene expression has been linked with translational fidelity, speed of translation, skewed gene expression, and non-sense suppression. This review will not cover the action of i6A as a cytokinin in plants or the potential function of Mod5 as a prion in yeast.
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Affiliation(s)
- Ulrich Schweizer
- a Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn , Bonn , Germany
| | - Simon Bohleber
- a Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn , Bonn , Germany
| | - Noelia Fradejas-Villar
- a Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn , Bonn , Germany
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