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[
Biochemistry,
1987]
The major intestinal esterase from the nematode Caenorhabditis elegans has been purified to essential homogeneity. Starting from whole worms, the overall purification is 9000-fold with a 10% recovery of activity. The esterase is a single polypeptide chain of Mr 60,000 and is stoichiometrically inhibited by organophosphates. Substrate preferences and inhibition patterns classify the enzyme as a carboxylesterase (EC 3.1.1.1), but the physiological function is unknown. The sequence of 13 amino acid residues at the esterase N- terminus has been determined. This partial sequence shows a surprisingly high degree of similarity to the N-terminal sequence of two carboxylesterases recently isolated from Drosophila mojavensis [Pen, J., van Beeumen, J., & Beintema, J. J. (1986) Biochem. J. 238, 691-699].
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[
Eur J Cell Biol,
2004]
Intestinal cells of C. elegans show an unexpectedly high complexity of cytoplasmic intermediate filament (IF) proteins. Of the 11 known IF genes six are coexpressed in the intestine, i.e. genes B2, C1, C2, D1, D2, and E1. Specific antibodies and GFP-promoter constructs show that genes B2, D1, D2, and E1 are exclusively expressed in intestinal cells. Using RNA interference (RNAi) by microinjection at 25 degreesC rather than at 20 degreesC we observe for the first time lethal phenotypes for C1 and D2. RNAi at 25 degreesC also shows that the known A1 phenotype occurs already in the late embryo after microinjection and is also observed by feeding which was not the case at 20 degreesC. Thus, RNAi at 25 degreesC may also be useful for the future analysis of other nematode genes. Finally, we show that triple RNAi at 20 degreesC is necessary for the combinations B2, D1, E1 and B2, D1, D2 to obtain a phenotype. Together with earlier results on genes A1, A2, A3, B1, and C2 RNAi phenotypes are now established for all 11 IF genes except for the A4 gene. RNAi phenotypes except for A2 (early larval lethality) and C2 (adult phenotype) relate to the late embryo. We conclude that in C. elegans cytoplasmic IFs are required for tissue integrity including late embryonic stages. This is in strong contrast to the mouse, where ablation IF genes apparently does not affect the embryo proper.
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[
Cytoskeleton (Hoboken),
2017]
The dimerisation properties of six intestine-expressed intermediate filament (IF) proteins (B2, C1, C2, D1, D2, E1) were analysed in blot overlay assay on membranes containing all of the eleven recombinant C. elegans IF proteins (A1, A2, A3, A4, B1, B2, C1, C2, D1, D2 and E1). The interactions detected in the blot assays exclusively comprise intestine-expressed IF proteins and the protein A4, which is found in the dauer larva intestine. 86% of these interactions are heterotypic, while the remaining interactions relate to C1, C2 and D2 homodimers. These multiple modes of interaction were also supported by calculations of the numbers of possible interchain ionic interactions derived from the individual rod sequences. The results predict that the six B2, C1, C2, D1, D2 and E1 IF proteins are able to form as many as eleven different heteropolymeric and three homopolymeric IFs in the C. elegans intestine. This simple model of the intestinal IF meshwork enables us to speculate that our previously reported triple RNAi worms arrested or decreased their growth because of feeding reduction due to morphological defects of the mechanically-compromised intestine. This article is protected by copyright. All rights reserved.
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[
J Mol Evol,
2019]
Our previous calculations of ionic interactions indicated that the Caenorhabditis elegans intermediate filament (IF) IFA proteins, in addition to IFA/IFB-1 heterodimers, may also form homodimers. In order to prove the significance of these calculations, we analysed the dimerization potential of the IFA chains in blot overlays. Unexpectedly, we found here that the dimerization of the IFA-1 protein was of both homotypic and heterotypic nature, and involved all proteins immobilized on the membrane (IFA-1, IFA-2, IFA-4, IFB-1, IFB-2, IFC-1, IFC-2, IFD-1, IFD-2 and IFP-1). A similar interaction profile, though less complex, was observed for two biotinylated proteins (IFA-2 and IFA-4). These and previous results indicate that the IFA proteins are able to form many different heteropolymeric and homopolymeric complexes in the C. elegans tissue, but that only those triggered by the IFA-specific IFB-1 protein result in mature IFs. Moreover, the calculations of the possible ionic interactions between the individual rod sequences as well as their various deletion variants indicated a special role in this process for the middle part of the C. elegans IF coil 1B segment that is deleted in all vertebrate cytoplasmic IFs. We hypothesized here, therefore, that the striking promiscuity of the C. elegans IFs originally involved a nuclear lamin which, due to a two-heptad-long rod deletion, prevented formation of a functional lamin/cIF dimer. This, in concert with an efficient dimerization and a strict tissue-specific co-expression, may allow expansion and maintenance of the multiple Caenorhabditis IFs. A possible implication for evolution of chordate IFs proteins is also discussed.
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[
Curr Biol,
1999]
In this Brief Communication, which appeared in the 14 September 1998 issue of Current Biology, the UV dose was reported erroneously. The dose reported was 20 J/m2 but the actual dose used was 0.4 J/cm2. Also, the gene formally referred to as
tkr-1 has since been renamed
old-1 (overexpression longevity determination).
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[
J Bacteriol,
2014]
Volume 195, no. 16, p. 35143523, 2013. A number of problems related to images published in this paper have been brought to our attention. Figure 1D contains duplicated images in lanes S and LE, and Fig. 4D and 6B contain images previously published in articles in this journal and in Microbiology and Microbial Pathogenesis, i.e., the following: C. G. Ramos, S. A. Sousa, A. M. Grilo, J. R. Feliciano, and J. H. Leitao, J. Bacteriol. 193:15151526, 2011. doi:10.1128/JB.01374-11. S. A. Sousa, C. G. Ramos, L. M. Moreira, and J. H. Leitao, Microbiology 156:896908, 2010. doi:10.1099/mic.0.035139-0. C. G. Ramos, S. A. Sousa, A. M. Grilo, L. Eberl, and J. H. Leitao, Microb. Pathog. 48:168177, 2010. doi: 10.1016/j.micpath.2010.02.006. Therefore, we retract the paper. We deeply regret this situation and apologize for any inconvenience to the editors and readers of Journal of Bacteriology, Microbial Pathogenesis, and Microbiology.
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Berynskyy M, Morimoto RI, Bukau B, Stengel F, Kirstein J, Szlachcic A, Arnsburg K, Stank A, Scior A, Nillegoda NB, Gao X, Guilbride DL, Aebersold R, Wade RC, Mayer MP
[
Nature,
2015]
Protein aggregates are the hallmark of stressed and ageing cells, and characterize several pathophysiological states. Healthy metazoan cells effectively eliminate intracellular protein aggregates, indicating that efficient disaggregation and/or degradation mechanisms exist. However, metazoans lack the key heat-shock protein disaggregase HSP100 of non-metazoan HSP70-dependent protein disaggregation systems, and the human HSP70 system alone, even with the crucial HSP110 nucleotide exchange factor, has poor disaggregation activity in vitro. This unresolved conundrum is central to protein quality control biology. Here we show that synergic cooperation between complexed J-protein co-chaperones of classes A and B unleashes highly efficient protein disaggregation activity in human and nematode HSP70 systems. Metazoan mixed-class J-protein complexes are transient, involve complementary charged regions conserved in the J-domains and carboxy-terminal domains of each J-protein class, and are flexible with respect to subunit composition. Complex formation allows J-proteins to initiate transient higher order chaperone structures involving HSP70 and interacting nucleotide exchange factors. A network of cooperative class A and B J-protein interactions therefore provides the metazoan HSP70 machinery with powerful, flexible, and finely regulatable disaggregase activity and a further level of regulation crucial for cellular protein quality control.
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[
Worm Breeder's Gazette,
1992]
unc-4 LacZ expression in A-type motor neurons David M. Miller and Charles J. Niemeyer, Dept. of Cell Biology, Duke Univ. Medical Ctr, Durham, NC 27710
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[
Worm Breeder's Gazette,
1994]
Evolution of vulva-formation: Part II: Species with a central vulva Ralf J. Sommer & Paul W. Sternberg, California Institute of Technology, Division of Biology 156-29, Pasadena, CA 91125
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[
International C. elegans Meeting,
2001]
Heparan sulfate binds and activates a large variety of growth factors, enzymes and extracellular matrix proteins. These interactions largely depend on the specific arrangement of sulfated moieties and uronic acid epimers within the chains. These oligosaccharide sequences are generated in a step-wise manner, initiated by the formation of a linkage tetrasaccharide which is then extended by copolymerization of alternating
a1,4GlcNAc and
b1,4GlcA residues. As the chains polymerize, they undergo a series of sulfation and epimerization reactions. The first set of modifications involves the removal of acetyl units from subsets of GlcNAc residues, and the addition of sulfate groups to the resulting free amino groups. These reactions are catalyzed by a family of enzymes designated as GlcNAc N-deacetylase/N-sulfotransferases (NDST), since they simultaneously. Four members of the family have been identified in vertebrates, with single orthologs present in Drosophila and C. elegans. We have revealed tissue-specific expression pattern and unique enzymatic properties of these four isozymes1,2). In fly, loss of NDST (sulfateless) results in unsulfated chains and defective signaling by multiple growth factors and morphogens. I reconstituted cDNA for worm NDST from EST clones and 5' RACE products. Enzymatic activities will be discussed. 1) Aikawa, J. & Esko, J. D J. Biol. Chem. 274, 2690-2695 (1999) 2) Aikawa, J., Grobe, K., Tsujimoto, M. & Esko, J. D J. Biol. Chem. 276, 5876-5882 (2001)