scholarly journals The expression of essential selenoproteins during zebrafish development requires SECIS binding protein 2-like

2021 ◽  
Author(s):  
Nora T Kiledjian ◽  
Rushvi Shah ◽  
Michael B Vetick ◽  
Paul R Copeland
Keyword(s):  
Oxidative Stress ◽  
Amino Acid ◽  
Rna Structure ◽  
Insertion Sequence ◽  
Binding Protein ◽  
Zebrafish Development ◽  
Dietary Requirement ◽  
Stress Marker ◽  
Full Complement ◽  
Selenoprotein Mrnas

The dietary requirement for selenium is based on its incorporation into selenoproteins, which contain the amino acid selenocysteine (Sec). The Sec insertion sequence (SECIS) is an RNA structure found in the 3' UTR of all selenoprotein mRNAs, and it is required to convert in-frame UGA codons from termination to Sec-incorporating codons. There are two proteins that bind to SECIS elements, but only one, SECIS binding protein 2 (Sbp2), has been shown to be required for Sec incorporation. The Sbp2 paralogue, SECIS binding protein 2-like (Secisbp2l) is conserved in all vertebrates and shares many features with Sbp2, but its function is unknown. Here we set out to determine the relative roles of Sbp2 and Secisbp2l by introducing CRISPR mutations in both genes in zebrafish. By monitoring selenoprotein synthesis with 75Se labeling during embryogenesis, we found that sbp2-/- embryos still make a select subset of selenoproteins but secisbp2l-/- embryos retain the full complement. Abrogation of both genes completely prevents selenoprotein synthesis and juveniles die at 14 days post fertilization. Embryos lacking Sbp2 are sensitive to oxidative stress and express the stress marker Vtg1. We propose a model where Secisbp2l is required to promote essential selenoprotein synthesis during stress.

scholarly journals The polypyrimidine tract binding protein, PTBP1, regulates selenium homeostasis via the Selenoprotein P 3′ untranslated region

2020 ◽  
Author(s):  
Sumangala P. Shetty ◽  
Nora T. Kiledjian ◽  
Paul R. Copeland
Keyword(s):  
Untranslated Region ◽  
Insertion Sequence ◽  
Rna Binding ◽  
Binding Protein ◽  
Selenoprotein P ◽  
Polypyrimidine Tract ◽  
Secis Element ◽  
Polypyrimidine Tract Binding Protein ◽  
Considerable Length ◽  
Selenoprotein Mrnas

AbstractSelenoproteins contain the 21st amino acid, selenocysteine (Sec), which is incorporated at select UGA codons when the encoding mRNA contains a specialized hairpin sequence in its 3′ UTR. This hairpin, the so-called Sec insertion sequence (SECIS) element, is found in all selenoprotein mRNAs, but the sequence surrounding these elements is widely variable and in many cases of considerable length. In order to determine the function of one such SECIS context, we chose to focus on the plasma selenoprotein, SELENOP, that is required to maintain selenium homeostasis. It is unique in that its mRNA contains two SECIS elements that lie in the context of a highly conserved 843-nucleotide 3′ UTR. Prior work has attempted to examine the functions of the SECIS context but none were identified. Here we have used CRISPR/Cas9 genome editing to delete the region between the two SECIS elements. We found that this sequence is required to mediate an increase in SELENOP synthesis under conditions of peroxide stress. Using RNA affinity chromatography, we have identified PTBP1 as the major RNA binding protein that specifically interacts with this region.

scholarly journals A Zebrafish Model for Selenoprotein Synthesis and Function (OR11-01-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Paul Copeland ◽  
Michael Vetick
Keyword(s):  
Oxidative Stress ◽  
Rna Binding ◽  
Binding Protein ◽  
Model System ◽  
National Institutes Of Health ◽  
Zebrafish Model ◽  
Funding Sources ◽  
And Function ◽  
Selenoprotein Mrnas

Abstract Objectives We have established a zebrafish model system that will allow unprecedented access to the role of selenoprotein function during development. The work described here focuses on a poorly characterized RNA binding protein that is similar to SECIS binding protein 2 (SBP2), which is required for the co-translational insertion of selenocysteine at select UGA codons in selenoprotein mRNAs. This protein, SECISBP2L, shares many features with SBP2 but is has no known function. We hypothesize that the zebrafish model system will reveal a selenoprotein-synthesis related function for SECISBP2L. Methods Using CRISPR/Cas9, we generated zebrafish with a disruption in one of the conserved domains in SECISBP2L. When bred out to a homozygous mutant animal, we verified that SECISBP2L protein expression was eliminated. To analyze selenoprotein synthesis, we metabolically labeled wild-type and mutant embryos with radioactive selenium (Se-75). Results In terms of overt phenotypes in SECISBP2L null fish, we observed no defects in growth, mobility or fertility. However, we noticed a significant sensitivity to oxidative stress as measured by lethality associated with peroxide exposure. In order to detect changes in selenoprotein expression that may have resulted from SECISBP2L loss, we performed Se-75 labeling in embryos. We also began an investigation of the effect of oxidative stress on selenoprotein expression during development. As such, one set of embryos was treated for 24 hours with 100 nM Se-75 and the other with Se-75 plus 200 μM H2O2. In general, we did not observe an overall alteration of selenoprotein expression as a result of SECISBP2L loss. We did, however, observe a significant spike of expression for a 50 kDa selenoprotein that did not occur in the SECISBP2L null animals. Based on this molecular weight, we predict that this band corresponds to selenophosphate synthase (SEPHS2). In addition, subsequent labeling at later time points revealed a general reduction of selenoprotein expression that may result from reduced SEPHS2 expression because it is essential for selenocysteine-tRNA synthesis. Conclusions We conclude that SECISBP2L is required for optimal selenoprotein expression and its function may be induced by oxidative stress. We have also demonstrated the value of a zebrafish model system for studying the mechanism of selenoprotein synthesis. Funding Sources Funded by the National Institutes of Health.

Trace elements as an oxidative stress marker in women with gestational diabetes and their neonates

2017 ◽  
Author(s):  
Georgios Boutzios ◽  
Eleni Koukoulioti ◽  
Ioannis Papoutsis ◽  
Sotirios Athanaselis ◽  
Gerasimos Tsourouflis ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Trace Elements ◽  
Gestational Diabetes ◽  
Oxidative Stress Marker ◽  
Stress Marker

scholarly journals Amino Acid and Acylcarnitine Levels in Chronic Patients with Schizophrenia: A Preliminary Study

Metabolites ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
Irina A. Mednova ◽  
Alexander A. Chernonosov ◽  
Marat F. Kasakin ◽  
Elena G. Kornetova ◽  
Arkadiy V. Semke ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Amino Acids ◽  
Amino Acid ◽  
Chronic Schizophrenia ◽  
Integrated Approach ◽  
Serum Levels ◽  
Tandem Mass ◽  
Chronic Patients ◽  
Healthy Donors ◽  
Preliminary Study

Amino acids and acylcarnitines play an important role as substrates and intermediate products in most of pathways involved in schizophrenia development such as mitochondrial dysfunction, inflammation, lipid oxidation, DNA damage, oxidative stress, and apoptosis. It seems relevant to use an integrated approach with ‘omics’ technology to study their contribution. The aim of our study was to investigate serum amino acid and acylcarnitine levels in antipsychotics-treated patients with chronic schizophrenia compared with healthy donors. We measured serum levels of 15 amino acids and 30 acylcarnitines in 37 patients with schizophrenia and 36 healthy donors by means of tandem mass spectrometry. In summary, patients with chronic schizophrenia had an altered concentration of a few amino acids and acylcarnitines in comparison to the healthy probands. Further research is needed to assess and understand the identified changes.

scholarly journals The Functional Consequences of the Novel Ribosomal Pausing Site in SARS-CoV-2 Spike Glycoprotein RNA

2021 ◽  
Vol 22 (12) ◽  
pp. 6490
Author(s):  
Olga A. Postnikova ◽  
Sheetal Uppal ◽  
Weiliang Huang ◽  
Maureen A. Kane ◽  
Rafael Villasmil ◽  
...  
Keyword(s):  
Amino Acid ◽  
Insertion Sequence ◽  
Experimental Studies ◽  
Spike Protein ◽  
Spike Glycoprotein ◽  
Furin Cleavage ◽  
New Host ◽  
S Protein ◽  
Furin Cleavage Site ◽  
Ribosome Pausing

The SARS-CoV-2 Spike glycoprotein (S protein) acquired a unique new 4 amino acid -PRRA- insertion sequence at amino acid residues (aa) 681–684 that forms a new furin cleavage site in S protein as well as several new glycosylation sites. We studied various statistical properties of the -PRRA- insertion at the RNA level (CCUCGGCGGGCA). The nucleotide composition and codon usage of this sequence are different from the rest of the SARS-CoV-2 genome. One of such features is two tandem CGG codons, although the CGG codon is the rarest codon in the SARS-CoV-2 genome. This suggests that the insertion sequence could cause ribosome pausing as the result of these rare codons. Due to population variants, the Nextstrain divergence measure of the CCU codon is extremely large. We cannot exclude that this divergence might affect host immune responses/effectiveness of SARS-CoV-2 vaccines, possibilities awaiting further investigation. Our experimental studies show that the expression level of original RNA sequence “wildtype” spike protein is much lower than for codon-optimized spike protein in all studied cell lines. Interestingly, the original spike sequence produces a higher titer of pseudoviral particles and a higher level of infection. Further mutagenesis experiments suggest that this dual-effect insert, comprised of a combination of overlapping translation pausing and furin sites, has allowed SARS-CoV-2 to infect its new host (human) more readily. This underlines the importance of ribosome pausing to allow efficient regulation of protein expression and also of cotranslational subdomain folding.

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