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  • 1. Arkblad, Eva L
    et al.
    Tuck, Simon
    Umeå University, Faculty of Science and Technology, Umeå Centre for Molecular Pathogenesis (UCMP).
    Pestov, Nikolay B
    Dmitriev, Ruslan I
    Kostina, Maria B
    Stenvall, Jörgen
    Tranberg, Mattias
    Rydström, Jan
    A Caenorhabditis elegans mutant lacking functional nicotinamide nucleotide transhydrogenase displays increased sensitivity to oxidative stress.2005In: Free Radic Biol Med, ISSN 0891-5849, Vol. 38, no 11, 1518-25 p.Article in journal (Refereed)
  • 2.
    Chen, Changchun
    et al.
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Byström, Anders S
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Defects in tRNA modification associated with neurological and developmental dysfunctions in Caenorhabditis elegans elongator mutants2009In: PLoS genetics, ISSN 1553-7404, Vol. 5, no 7, e1000561- p.Article in journal (Refereed)
    Abstract [en]

    Elongator is a six subunit protein complex, conserved from yeast to humans. Mutations in the human Elongator homologue, hELP1, are associated with the neurological disease familial dysautonomia. However, how Elongator functions in metazoans, and how the human mutations affect neural functions is incompletely understood. Here we show that in Caenorhabditis elegans, ELPC-1 and ELPC-3, components of the Elongator complex, are required for the formation of the 5-carbamoylmethyl and 5-methylcarboxymethyl side chains of wobble uridines in tRNA. The lack of these modifications leads to defects in translation in C. elegans. ELPC-1::GFP and ELPC-3::GFP reporters are strongly expressed in a subset of chemosensory neurons required for salt chemotaxis learning. elpc-1 or elpc-3 gene inactivation causes a defect in this process, associated with a posttranscriptional reduction of neuropeptide and a decreased accumulation of acetylcholine in the synaptic cleft. elpc-1 and elpc-3 mutations are synthetic lethal together with those in tuc-1, which is required for thiolation of tRNAs having the 5'methylcarboxymethyl side chain. elpc-1; tuc-1 and elpc-3; tuc-1 double mutants display developmental defects. Our results suggest that, by its effect on tRNA modification, Elongator promotes both neural function and development.

  • 3. Chotard, Laëtitia
    et al.
    Mishra, Ashwini K
    Sylvain, Marc-André
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Lambright, David G
    Rocheleau, Christian E
    TBC-2 regulates RAB-5/RAB-7-mediated endosomal trafficking in Caenorhabditis elegans2010In: Molecular Biology of the Cell, ISSN 1059-1524, E-ISSN 1939-4586, Vol. 21, no 13, 2285-2296 p.Article in journal (Refereed)
    Abstract [en]

    During endosome maturation the early endosomal Rab5 GTPase is replaced with the late endosomal Rab7 GTPase. It has been proposed that active Rab5 can recruit and activate Rab7, which in turn could inactivate and remove Rab5. However, many of the Rab5 and Rab7 regulators that mediate endosome maturation are not known. Here, we identify Caenorhabditis elegans TBC-2, a conserved putative Rab GTPase-activating protein (GAP), as a regulator of endosome to lysosome trafficking in several tissues. We show that tbc-2 mutant animals accumulate enormous RAB-7-positive late endosomes in the intestine containing refractile material. RAB-5, RAB-7, and components of the homotypic fusion and vacuole protein sorting (HOPS) complex, a RAB-7 effector/putative guanine nucleotide exchange factor (GEF), are required for the tbc-2(-) intestinal phenotype. Expression of activated RAB-5 Q78L in the intestine phenocopies the tbc-2(-) large late endosome phenotype in a RAB-7 and HOPS complex-dependent manner. TBC-2 requires the catalytic arginine-finger for function in vivo and displays the strongest GAP activity on RAB-5 in vitro. However, TBC-2 colocalizes primarily with RAB-7 on late endosomes and requires RAB-7 for membrane localization. Our data suggest that TBC-2 functions on late endosomes to inactivate RAB-5 during endosome maturation.

  • 4. Elle, Ida C
    et al.
    Simonsen, Karina T
    Olsen, Louise C B
    Birck, Pernille K
    Ehmsen, Sidse
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Le, Thuc T
    Færgeman, Nils J
    Tissue- and paralogue-specific functions of acyl-CoA-binding proteins in lipid metabolism in Caenorhabditis elegans2011In: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 437, no 2, 231-241 p.Article in journal (Refereed)
    Abstract [en]

    ACBP (acyl-CoA-binding protein) is a small primarily cytosolic protein that binds acyl-CoA esters with high specificity and affinity. ACBP has been identified in all eukaryotic species, indicating that it performs a basal cellular function. However, differential tissue expression and the existence of several ACBP paralogues in many eukaryotic species indicate that these proteins serve distinct functions. The nematode Caenorhabditis elegans expresses seven ACBPs: four basal forms and three ACBP domain proteins. We find that each of these paralogues is capable of complementing the growth of ACBP-deficient yeast cells, and that they exhibit distinct temporal and tissue expression patterns in C. elegans. We have obtained loss-of-function mutants for six of these forms. All single mutants display relatively subtle phenotypes; however, we find that functional loss of ACBP-1 leads to reduced triacylglycerol (triglyceride) levels and aberrant lipid droplet morphology and number in the intestine. We also show that worms lacking ACBP-2 show a severe decrease in the β-oxidation of unsaturated fatty acids. A quadruple mutant, lacking all basal ACBPs, is slightly developmentally delayed, displays abnormal intestinal lipid storage, and increased β-oxidation. Collectively, the present results suggest that each of the ACBP paralogues serves a distinct function in C. elegans.

  • 5. Furuta, T
    et al.
    Tuck, S
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Kirchner, J
    Koch, B
    Auty, R
    Kitagawa, R
    Rose, A M
    Greenstein, D
    EMB-30: an APC4 homologue required for metaphase-to-anaphase transitions during meiosis and mitosis in Caenorhabditis elegans.2000In: Mol Biol Cell, ISSN 1059-1524, Vol. 11, no 4, 1401-19 p.Article in journal (Refereed)
  • 6. Gaur, Rahul
    et al.
    Björk, Glenn
    Umeå University, Faculty of Science and Technology, Molecular Biology (Faculty of Science and Technology).
    Tuck, Simon
    Umeå Centre for Molecular Pathogenesis (UCMP).
    Varshney, Umesh
    Diet-dependent depletion of queuosine in tRNAs in Caenorhabditis elegans does not lead to a developmental block.2007In: J Biosci, ISSN 0250-5991, Vol. 32, no 4, 747-54 p.Article in journal (Refereed)
    Abstract [en]

    Queuosine (Q), a hypermodified nucleoside,occurs at the wobble position of transfer RNAs (tRNAs)with GUN anticodons. In eubacteria, absence of Q affects messenger RNA (mRNA) translation and reduces the virulence of certain pathogenic strains. In animal cells,changes in the abundance of Q have been shown to correlate with diverse phenomena including stress tolerance, cell proliferation and tumour growth but the function of Q in animals is poorly understood. Animals are thought to obtain Q (or its analogues) as a micronutrient from dietary sources such as gut micro flora. However,the difficulty of maintaining animals under bacteria-free conditions on Q-deficient diets has severely hampered the study of Q metabolism and function in animals. In this study,we show that as in higher animals, tRNAs in the nematode Caenorhabditis elegans are modified by Q and its sugar derivatives. When the worms were fed on Q-deficient Escherichia coli, Q modification was absent from the worm tRNAs suggesting that C.elegans lacks a de novo pathway of Q biosynthesis. The inherent advantages of C.elegans as a model organism, and the simplicity of conferring a Q-deficient phenotype on it make it an ideal system to investigate the function of Q modification in tRNA.

  • 7.
    Kao, Gautam
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine). Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Surgery.
    Nordenson, Cecilia
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Surgery.
    Still, Maria
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences.
    Rönnlund, Agneta
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Naredi, Peter
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Surgery.
    ASNA-1 positively regulates insulin secretion in C. elegans and mammalian cells.2007In: Cell, ISSN 0092-8674, Vol. 128, no 3, 577-87 p.Article in journal (Refereed)
  • 8.
    Kao, Gautam
    et al.
    Department of Genetics, University of Pennsylvania, Philadelphia, USA.
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Baillie, David
    Department of Biological Sciences, Simon Fraser University, Canada.
    Sundaram, Meera V.
    Department of Genetics, University of Pennsylvania, Philadelphia, USA.
    C. elegans SUR-6/PR55 cooperates with LET-92/protein phosphatase 2A and promotes Raf activity independently of inhibitory Akt phosphorylation sites2004In: Development, ISSN 0950-1991, E-ISSN 1477-9129, Vol. 131, no 4, 755-765 p.Article in journal (Refereed)
    Abstract [en]

    Protein phosphatase 2A (PP2A) can both positively and negatively influence the Ras/Raf/MEK/ERK signaling pathway, but its relevant substrates are largely unknown. In C. elegans, the PR55/B regulatory subunit of PP2A, which is encoded by sur-6, positively regulates Ras-mediated vulval induction and acts at a step between Ras and Raf. We show that the catalytic subunit (C) of PP2A, which is encoded by let-92, also positively regulates vulval induction. Therefore SUR-6/PR55 and LET-92/PP2A-C probably act together to dephosphorylate a Ras pathway substrate. PP2A has been proposed to activate the Raf kinase by removing inhibitory phosphates from Ser259 from Raf-1 or from equivalent Akt phosphorylation sites in other Raf family members. However, we find that mutant forms ofC. elegans LIN-45 RAF that lack these sites still require sur-6. Therefore, SUR-6 must influence Raf activity via a different mechanism. SUR-6 and KSR (kinase suppressor of Ras) function at a similar step in Raf activation but our genetic analysis suggests that KSR activity is intact in sur-6 mutants. We identify the kinase PAR-1 as a negative regulator of vulval induction and show that it acts in opposition to SUR-6 and KSR-1. In addition to their roles in Ras signaling, SUR-6/PR55 and LET-92/PP2A-C cooperate to control mitotic progression during early embryogenesis.

  • 9. Korta, Dorota Z
    et al.
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Hubbard, E Jane Albert
    S6K links cell fate, cell cycle and nutrient response in C. elegans germline stem/progenitor cells.2012In: Development, ISSN 0950-1991, E-ISSN 1477-9129, Vol. 139, no 5, 859-870 p.Article in journal (Refereed)
    Abstract [en]

    Coupling of stem/progenitor cell proliferation and differentiation to organismal physiological demands ensures the proper growth and homeostasis of tissues. However, in vivo mechanisms underlying this control are poorly characterized. We investigated the role of ribosomal protein S6 kinase (S6K) at the intersection of nutrition and the establishment of a stem/progenitor cell population using the C. elegans germ line as a model. We find that rsks-1 (which encodes the worm homolog of mammalian p70S6K) is required germline-autonomously for proper establishment of the germline progenitor pool. In the germ line, rsks-1 promotes cell cycle progression and inhibits larval progenitor differentiation, promotes growth of adult tumors and requires a conserved TOR phosphorylation site. Loss of rsks-1 and ife-1 (eIF4E) together reduces the germline progenitor pool more severely than either single mutant and similarly to reducing the activity of let-363 (TOR) or daf-15 (RAPTOR). Moreover, rsks-1 acts in parallel with the glp-1 (Notch) and daf-2 (insulin-IGF receptor) pathways, and does not share the same genetic dependencies with its role in lifespan control. We show that overall dietary restriction and amino acid deprivation cause germline defects similar to a subset of rsks-1 mutant phenotypes. Consistent with a link between diet and germline proliferation via rsks-1, loss of rsks-1 renders the germ line largely insensitive to the effects of dietary restriction. Our studies establish the C. elegans germ line as an in vivo model to understand TOR-S6K signaling in proliferation and differentiation and suggest that this pathway is a key nutrient-responsive regulator of germline progenitors.

  • 10.
    Larsen, Morten K
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Centre for Molecular Pathogenesis (UCMP).
    Tuck, Simon
    Umeå University, Faculty of Science and Technology, Umeå Centre for Molecular Pathogenesis (UCMP).
    Faergeman, Nils J
    Knudsen, Jens
    MAA-1, a novel acyl-CoA-binding protein involved in endosomal vesicle transport in Caenorhabditis elegans.2006In: Mol Biol Cell, ISSN 1059-1524, Vol. 17, no 10, 4318-29 p.Article in journal (Refereed)
  • 11.
    Nilsson, L
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Li, X
    Tiensuu, T
    Auty, R
    Greenwald, I
    Tuck, S
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Caenorhabditis elegans lin-25: cellular focus, protein expression and requirement for sur-2 during induction of vulval fates.1998In: Development, ISSN 0950-1991, Vol. 125, no 23, 4809-19 p.Article in journal (Refereed)
  • 12. Nilsson, L
    et al.
    Tiensuu, T
    Tuck, S
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Caenorhabditis elegans lin-25: a study of its role in multiple cell fate specification events involving Ras and the identification and characterization of evolutionarily conserved domains.2000In: Genetics, ISSN 0016-6731, Vol. 156, no 3, 1083-96 p.Article in journal (Refereed)
  • 13.
    Nilsson, Lars
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Centre for Molecular Pathogenesis (UCMP).
    Conradt, Barbara
    Ruaud, Anne-Françoise
    Chen, Carlos Chih-Hsiung
    Hatzold, Julia
    Bessereau, Jean-Louis
    Grant, Barth
    Tuck, Simon
    Umeå University, Faculty of Science and Technology, Umeå Centre for Molecular Pathogenesis (UCMP).
    Caenorhabditis elegans num-1 negatively regulates endocytic recycling2008In: Genetics, Vol. 179, 375-387 p.Article in journal (Refereed)
    Abstract [en]

    Much of the material taken into cells by endocytosis is rapidly returned to the plasma membrane by the endocytic recycling pathway. Although recycling is vital for the correct localization of cell membrane receptors and lipids, the molecular mechanisms that regulate recycling are only partially understood. Here we show that in C. elegans, endocytic recycling is inhibited by NUM-1A, the nematode Numb homologue. NUM-1A::GFP fusion protein is localized to the baso-lateral surfaces of many polarized epithelial cells including the hypodermis and the intestine. We show that increased NUM-1A levels cause morphological defects in these cells similar to those caused by loss-of-function mutations in rme-1, a positive regulator of recycling both in C. elegans and mammals. We describe the isolation of worms lacking num-1A activity and show that, consistent with a model in which NUM-1A negatively regulates recycling in the intestine, loss of num-1A function bypasses the requirement for RME-1. Genetic epistasis analysis with rab-10, which is required at an early part of the recycling pathway, suggests that loss of num-1A function does not affect the uptake of material by endocytosis but rather inhibits baso-lateral recycling downstream of rab-10.

  • 14.
    Nilsson, Lars
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Jonsson, Eva
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Caenorhabditis elegans Numb Inhibits Endocytic Recycling by Binding TAT-1 Aminophospholipid Translocase2011In: Traffic: the International Journal of Intracellular Transport, ISSN 1398-9219, E-ISSN 1600-0854, Vol. 12, no 12, 1839-1849 p.Article in journal (Refereed)
    Abstract [en]

    Numb regulates endocytosis in many metazoans, but the mechanism by which it functions is not completely understood. Here we report that the Caenorhabditis ele-gans Numb ortholog, NUM-1A, a regulator of endocytic recycling, binds the C isoform of transbilayer amphipath transporter-1 (TAT-1), a P4 family adenosine triphosphatase and putative aminophospholipid translocase that is required for proper endocytic trafficking. We demonstrate that TAT-1 is differentially spliced during development and that TAT-1C-specific splicing occurs in the intestine where NUM-1A is known to function. NUM-1A and TAT-1C colocalize in vivo. We have mapped the binding site to an NXXF motif in TAT-1C. This motif is not required for TAT-1C function but is required for NUM-1A's ability to inhibit recycling. We demonstrate that num-1A and tat-1 defects are both suppressed by the loss of the activity of PSSY-1, a phosphatidylserine (PS) synthase. PS is mislocalized in intestinal cells with defects in tat-1 or num-1A function. We propose that NUM-1A inhibits recycling by inhibiting TAT-1C's ability to translocate PS across the membranes of recycling endosomes.

  • 15.
    Nyström, Josefin
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Shen, Zai-Zhong
    Aili, Margareta
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Flemming, Anthony J
    Leroi, Armand
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Increased or decreased levels of Caenorhabditis elegans lon-3, a gene encoding a collagen, cause reciprocal changes in body length.2002In: Genetics, ISSN 0016-6731, E-ISSN 1943-2631, Vol. 161, no 1, 83-97 p.Article in journal (Refereed)
  • 16. Rocheleau, Christian E
    et al.
    Rönnlund, Agneta
    Tuck, Simon
    Umeå University, Faculty of Science and Technology, Umeå Centre for Molecular Pathogenesis (UCMP).
    Sundaram, Meera V
    Caenorhabditis elegans CNK-1 promotes Raf activation but is not essential for Ras/Raf signaling.2005In: Proc Natl Acad Sci U S A, ISSN 0027-8424, Vol. 102, no 33, 11757-62 p.Article in journal (Refereed)
  • 17. Ruaud, Anne-Françoise
    et al.
    Nilsson, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM). Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Richard, Fabrice
    Krog Larsen, Morten
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Bessereau, Jean-Louis
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    The C. elegans P4-ATPase TAT-1 regulates Lysosome Biogenesis and Endocytosis2009In: Traffic: the International Journal of Intracellular Transport, ISSN 1398-9219, E-ISSN 1600-0854, Vol. 10, no 1, 88-100 p.Article in journal (Refereed)
  • 18. Schumacher, B
    et al.
    Schertel, C
    Wittenburg, N
    Tuck, S
    Umeå University, Faculty of Science and Technology, Umeå Centre for Molecular Pathogenesis (UCMP).
    Mitani, S
    Gartner, A
    Conradt, B
    Shaham, S
    C. elegans ced-13 can promote apoptosis and is induced in response to DNA damage.2005In: Cell Death Differ, ISSN 1350-9047, Vol. 12, no 2, 153-61 p.Article in journal (Refereed)
  • 19.
    Sheng, Ming
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Hosseinzadeh, Ava
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Muralidharan, Somsundar Veppil
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Gaur, Rahul
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Selstam, Eva
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Aberrant Fat Metabolism in Caenorhabditis elegans Mutants with Defects in the Defecation Motor Program2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 4, e0124515Article in journal (Refereed)
    Abstract [en]

    The molecular mechanisms by which dietary fatty acids are absorbed by the intestine, and the way in which the process is regulated are poorly understood. In a genetic screen for mutations affecting fat accumulation in the intestine of Caenorhabditis elegans, nematode worms, we have isolated mutations in the aex-5 gene, which encodes a Kex2/subtilisinfamily, Ca2+-sensitive proprotein convertase known to be required for maturation of certain neuropeptides, and for a discrete step in an ultradian rhythmic phenomenon called the defecation motor program. We demonstrate that aex-5 mutants have markedly lower steadystate levels of fat in the intestine, and that this defect is associated with a significant reduction in the rate at which labeled fatty acid derivatives are taken up from the intestinal lumen. Other mutations affecting the defecation motor program also affect steady-state levels of triglycerides, suggesting that the program is required per se for the proper accumulation of neutral lipids. Our results suggest that an important function of the defecation motor program in C. elegans is to promote the uptake of an important class of dietary nutrients. They also imply that modulation of the program might be one way in which worms adjust nutrient uptake in response to altered metabolic status.

  • 20.
    Stenvall, Jörgen
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Fierro-González, Juan Carlos
    Swoboda, Peter
    Saamarthy, Karunakar
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Cheng, Qing
    Cacho-Valadez, Briseida
    Arnér, Elias S J
    Persson, Olof P
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Miranda-Vizuete, Antonio
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Selenoprotein TRXR-1 and GSR-1 are essential for removal of old cuticle during molting in Caenorhabditis elegans2011In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 108, no 3, 1064-1069 p.Article in journal (Refereed)
    Abstract [en]

    Selenoproteins, in particular thioredoxin reductase, have been implicated in countering oxidative damage occurring during aging but the molecular functions of these proteins have not been extensively investigated in different animal models. Here we demonstrate that TRXR-1 thioredoxin reductase, the sole selenoprotein in Caenorhabditis elegans, does not protect against acute oxidative stress but functions instead together with GSR-1 glutathione reductase to promote the removal of old cuticle during molting. We show that the oxidation state of disulfide groups in the cuticle is tightly regulated during the molting cycle, and that when trxr-1 and gsr-1 function is reduced, disulfide groups in the cuticle remain oxidized. A selenocysteine-to-cysteine TRXR-1 mutant fails to rescue molting defects. Furthermore, worms lacking SELB-1, the C. elegans homolog of Escherichia coli SelB or mammalian EFsec, a translation elongation factor known to be specific for selenocysteine in E. coli, fail to incorporate selenocysteine, and display the same phenotype as those lacking trxr-1. Thus, TRXR-1 function in the reduction of old cuticle is strictly selenocysteine dependent in the nematode. Exogenously supplied reduced glutathione reduces disulfide groups in the cuticle and induces apolysis, the separation of old and new cuticle, strongly suggesting that molting involves the regulated reduction of cuticle components driven by TRXR-1 and GSR-1. Using dauer larvae, we demonstrate that aged worms have a decreased capacity to molt, and decreased expression of GSR-1. Together, our results establish a function for the selenoprotein TRXR-1 and GSR-1 in the removal of old cuticle from the surface of epidermal cells.

  • 21. Tiensuu, Teresa
    et al.
    Larsen, Morten Krog
    Vernersson, Emma
    Tuck, Simon
    Umeå University, Faculty of Science and Technology, Umeå Centre for Molecular Pathogenesis (UCMP).
    lin-1 has both positive and negative functions in specifying multiple cell fates induced by Ras/MAP kinase signaling in C. elegans.2005In: Dev Biol, ISSN 0012-1606, Vol. 286, no 1, 338-51 p.Article in journal (Refereed)
  • 22.
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    Extracellular vesicles: budding regulated by a phosphatidylethanolamine translocase2011In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 21, no 24, R988-R990 p.Article in journal (Refereed)
    Abstract [en]

    Recent work on a Caenorhabditis elegans transmembrane ATPase reveals a central role for the aminophospholipid phosphatidylethanolamine in the production of a class of extracellular vesicles

  • 23.
    Tuck, Simon
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Medicine (UCMM).
    The control of cell growth and body size in Caenorhabditis elegans2014In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 321, no 1, 71-76 p.Article, review/survey (Refereed)
    Abstract [en]

    One of the most important ways in which animal species vary is in their size. Individuals of the largest animal ever thought to have lived, the blue whale (Balaenoptera musculus), can reach a weight of 190 t and a length of over 30 m. At the other extreme, among the smallest multicellular animals are males of the parasitic wasp, Dicopomorpha echmepterygis, which even as adults are just 140 mu m in length. In terms of volume, these species differ by more than 14 orders of magnitude. Since size has such profound effects on an organism's ecology, anatomy and physiology, an important task for evolutionary biology and ecology is to account for why organisms grow to their characteristic sizes. Equally, a full description of an organism's development must include an explanation of how its growth and body size are regulated. Here I review research on how these processes are controlled in the nematode, Caenorhabditis elegans. Analyses of small and long mutants have revealed that in the worm, DBL-1, a ligand in the TGF beta superfamily family, promotes growth in a dose-dependent manner. DBL-1 signaling affects body size by stimulating the growth of syncytial hypodermal cells rather than controlling cell division. Signals from chemosensory neurons and from the gonad also modulate body size, in part, independently of DBL-1-mediated signaling. Organismal size and morphology is heavily influenced by the cuticle, which acts as the exoskeleton. Finally, I summarize research on several genes that appear to regulate body size by cell autonomously regulating cell growth throughout the worm. 

  • 24.
    Vaitkevicius, Karolis
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Lindmark, Barbro
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Ou, Gangwei
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Song, Tianyan
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Toma, Claudia
    Division of Bacterial Pathogenesis, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.
    Iwanaga, Masaaki
    Division of Bacterial Pathogenesis, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.
    Zhu, Jun
    Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia.
    Andersson, Agneta
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Hammarström, Marie-Louise
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Tuck, Simon
    Umeå University, Faculty of Science and Technology, Umeå Centre for Molecular Pathogenesis (UCMP).
    Wai, Sun Nyunt
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    A Vibrio cholerae protease needed for killing of Caenorhabditis elegans has a role in protection from natural predator grazing2006In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 103, no 24, 9280-9285 p.Article in journal (Refereed)
    Abstract [en]

    Vibrio cholerae is the causal bacterium of the diarrheal disease cholera, and its growth and survival are thought to be curtailed by bacteriovorous predators, e.g., ciliates and flagellates. We explored Caenorhabditis elegans as a test organism after finding that V. cholerae can cause lethal infection of this nematode. By reverse genetics we identified an extracellular protease, the previously uncharacterized PrtV protein, as being necessary for killing. The killing effect is associated with the colonization of bacteria within the Caenorhabditis elegans intestine. We also show that PrtV is essential for V. cholerae in the bacterial survival from grazing by the flagellate Cafeteria roenbergensis and the ciliate Tetrahymena pyriformis. The PrtV protein appears to have an indirect role in the interaction of V. cholerae with mammalian host cells as judged from tests with tight monolayers of human intestinal epithelial cells. Our results demonstrate a key role for PrtV in V. cholerae interaction with grazing predators, and we establish Caenorhabditis elegans as a convenient organism for identification of V. cholerae factors involved in host interactions and environmental persistence.

  • 25. Yochem, J
    et al.
    Tuck, S
    Umeå University, Faculty of Medicine, Umeå Centre for Molecular Pathogenesis (UCMP) (Faculty of Medicine).
    Greenwald, I
    Han, M
    A gp330/megalin-related protein is required in the major epidermis of Caenorhabditis elegans for completion of molting.1999In: Development, ISSN 0950-1991, Vol. 126, no 3, 597-606 p.Article in journal (Refereed)
1 - 25 of 25
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