M H G Verheijen et al. (2001) International C. elegans Meeting "The differentially expressed C. elegans RapGEF, pxf-1, is required for molting."

R H A Plasterk, M H G Verheijen, J L Bos, W van Berkel, G Jansen, F J T Zwartkruis, J de Rooij

[International C. elegans Meeting, 2001]

The Rap1-specific guanine nucleotide exchange factor (GEF), pxf-1, is the C. elegans orthologue of the mammalian PDZ-GEF. Differential promoter usage and alternative splicing result in the production of at least three different pxf-1 isoforms, which share a common catalytic domain. Green fluorescent protein (GFP) reporter construct demonstrate that pxf-1 is expressed in the hypodermis, gut, various neurons and somatic cells of the distal gonad. Particularly striking is the oscilating expression of the downstream promoter in the pharynx during the four molting stages L1 to L4. Worms homozygous for a mutation in pxf-1, that deletes part of the PDZ-domain and the complete catalytic domain, hatch normally but develop slower and move uncoordinated. They have severe problems in removing the old cuticle during molting. In addition, vesicles are frequently formed underneath the cuticle, indicating a defect in cell-matrix or cell-cell interaction. Most animals die before adulthood, but those that reach this stage are largely sterile. From these results we conclude that pxf-1 is not involved in processes directly related to cell proliferation or development, but plays an role in cell maintenance processes like cell adhesion and/or polarized secretion, which are essential for proper molting.

Ramos CG et al. (2014) J Bacteriol "Retraction for Ramos et al., MtvR is a global small noncoding regulatory RNA in Burkholderia cenocepacia."

Feliciano JR, da Costa PJ, Ramos CG, Grilo AM, Leitao JH

[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.

Liu W et al. (2011) Nucleic Acids Res "Structural basis for nematode eIF4E binding an m(2,2,7)G-Cap and its implications for translation initiation."

Darzynkiewicz E, Jones DN, Stepinski J, Jankowska-Anyszka M, Dickson L, Davis RE, Liu W, Piecyk K, Niedzwiecka A, Wallace A, Kieft J, Zhao R, Stolarski R

[Nucleic Acids Res, 2011]

Metazoan spliced leader (SL) trans-splicing generates mRNAs with an m(2,2,7)G-cap and a common downstream SL RNA sequence. The mechanism for eIF4E binding an mG-cap is unknown. Here, we describe the first structure of an eIF4E with an m(2,2,7)G-cap and compare it to the cognate mG-eIF4E complex. These structures and Nuclear Magnetic Resonance (NMR) data indicate that the nematode Ascaris suum eIF4E binds the two different caps in a similar manner except for the loss of a single hydrogen bond on binding the m(2,2,7)G-cap. Nematode and mammalian eIF4E both have a low affinity for m(2,2,7)G-cap compared with the mG-cap. Nematode eIF4E binding to the mG-cap, m(2,2,7)G-cap and the m(2,2,7)G-SL 22-nt RNA leads to distinct eIF4E conformational changes. Additional interactions occur between Ascaris eIF4E and the SL on binding the m(2,2,7)G-SL. We propose interactions between Ascaris eIF4E and the SL impact eIF4G and contribute to translation initiation, whereas these interactions do not occur when only the m(2,2,7)G-cap is present. These data have implications for the contribution of 5'-UTRs in mRNA translation and the function of different eIF4E isoforms.

(2014) J Bacteriol "Retraction for Ramos et al., The second RNA chaperone, Hfq2, is also required for survival under stress and full virulence of Burkholderia cenocepacia J2315."

[J Bacteriol, 2014]

Volume 193, no. 7, p.15151526, 2011. Problems related to images published in this paper have been brought to our attention. Figure 8 contains duplicated images as well as images previously published in articles in Microbiology and Microbial Pathogenesis, i.e., the following: S. A. Sousa, C. G. Ramos, L. M. Moreira, and J. H. Leitao, Microbiology 156:896908, 2010. http://dx.doi.org/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. http://dx.doi.org/10.1016 /j.micpath.2010.02.006. Therefore, we retract the paper.Wedeeply regret this situation and apologize for any inconvenience to the editors and readers of Journal of Bacteriology, Microbial Pathogenesis, and Microbiology.

Stachelska A et al. (2002) Acta Biochim Pol "Interaction of three Caenorhabditis elegans isoforms of translation initiation factor eIF4E with mono- and trimethylated mRNA 5' cap analogues."

Pietrzak M, Darzynkiewicz E, Jankowska-Anyszka M, Lamphear BJ, Stachelska A, Stolarski R, Wieczorek Z, Rhoads RE, Ruszczynska K

[Acta Biochim Pol, 2002]

Translation initiation factor eIF4E binds the m(7)G cap of eukaryotic mRNAs and mediates recruitment of mRNA to the ribosome during cap-dependent translation initiation. This event is the rate-limiting step of translation and a major target for translational control. In the nematode Caenorhabditis elegans, about 70% of genes express mRNAs with an unusual cap structure containing m(3)(2'2'7)G, which is poorly recognized by mammalian eIF4E. C. elegans expresses five isoforms of eIF4E (IFE-1, IFE-2, etc.). Three of these (IFE-3, IFE-4 and IFE-5) were investigated by means of spectroscopy and structural modelling based on mouse eIF4E bound to m(7) GDP. Intrinsic fluorescence quenching of Trp residues in the IFEs by iodide ions indicated structural differences between the apo and m(7)G cap bound proteins. Fluorescence quenching by selected cap analogues showed that only IFE-5 forms specific complexes with both m(7)G and m(3)(2,2,7)G-containing caps (K(as)2X10(6) M-1 to 7X10(6) M-1) wheras IFE-3 and IFE-4 discriminated strongly in favor of m(7)G-containing caps. These spectroscopic results quantitatively confirm earlier qualitative data derived from affinity chromatography. The dependence of K-as on pH indicated optimal cap binding of IFE-3, IFE-4 and IFE-5 at pH 7.2, lower by 0.4 pH units than that of eIF4E from human erythrocytes. These results provide insight into the molecular mechanism of recognition of structurally different caps by the highly homologous

Grenache DG et al. (1993) Worm Breeder's Gazette "Differential Effects of Dauer-Defective Mutations in L1-Specific Surface Antigen Switching"

Politz SM, Grenache DG

[Worm Breeder's Gazette, 1993]

DIFFERENTIAL EFFECTS OF DAUER-DEFECTIVE MUTATIONS ON L1- SPECIFIC SURFACE ANTIGEN SWITCHING. David G. Grenache and Samuel M. Politz, Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA.

Cao P et al. (2012) FASEB J "Light-sensitive coupling of rhodopsin and melanopsin to G(i/o) and G(q) signal transduction in Caenorhabditis elegans."

Palczewski K, Zheng M, Kramp K, Jastrzebska B, Sun W, Salom D, Cao P, Feng Z, Jin H

[FASEB J, 2012]

Activation of G-protein-coupled receptors (GPCRs) initiates signal transduction cascades that affect many physiological responses. The worm Caenorhabditis elegans expresses >1000 of these receptors along with their cognate heterotrimeric G proteins. Here, we report properties of 9-cis-retinal regenerated bovine opsin [(b)isoRho] and human melanopsin [(h)Mo], two light-activated, heterologously expressed GPCRs in the nervous system of C. elegans with various genetically engineered alterations. Profound transient photoactivation of G(i/o) signaling by (b)isoRho led to a sudden and transient loss of worm motility dependent on cyclic adenosine monophosphate, whereas transient photoactivation of G(q) signaling by (h)Mo enhanced worm locomotion dependent on phospholipase C. These transgenic C. elegans models provide a unique way to study the consequences of G(i/o) and G(q) signaling in vivo with temporal and spatial precision and, by analogy, their relationship to human neuromotor function.

Moorthy S et al. (2000) J Cell Biol "Caenorhabditis elegans beta-G spectrin is dispensable for establishment of epithelial polarity, but essential for muscular and neuronal function."

Bennett V, Chen LS, Moorthy S

[J Cell Biol, 2000]

The Caenorhabditis elegans genome encodes one alpha spectrin subunit, a beta spectrin subunit (beta-G), and a beta-H spectrin subunit. Our experiments show that the phenotype resulting from the loss of the C. elegans alpha spectrin is reproduced by tandem depletion of both beta-G and beta-H spectrins. We propose that alpha spectrin combines with the beta-G and beta-H subunits to form alpha/beta-G and alpha/beta-H heteromers that perform the entire repertoire of spectrin function in the nematode. The expression patterns of nematode beta-G spectrin and vertebrate beta spectrins exhibit three striking parallels including: (1) beta spectrins are associated with the sites of cell-cell contact in epithelial tissues; (2) the highest levels of beta-G spectrin occur in the nervous system; and (3) beta spectrin-G in striated muscle is associated with points of attachment of the myofilament apparatus to adjacent cells. Nematode beta-G spectrin associates with plasma membranes at sites of cell-cell contact, beginning at the two-cell stage, and with a dramatic increase in intensity after gastrulation when most cell proliferation has been completed. Strikingly, depletion of nematode beta-G spectrin by RNA-mediated interference to undetectable levels does not affect the establishment of structural and functional polarity in epidermis and intestine. Contrary to recent speculation, beta-G spectrin is not associated with internal membranes and depletion of beta-G spectrin was not associated with any detectable defects in secretion. Instead beta-G spectrin-deficient nematodes arrest as early larvae with progressive defects in the musculature and nervous system. Therefore, C. elegans beta-G spectrin is required for normal muscle and neuron function, but is dispensable for embryonic elongation and establishment of early epithelial polarity. We hypothesize that heteromeric spectrin evolved in metazoans in response to the needs of cells in the context of mechanically integrated tissues that can withstand the rigors imposed by an active organism.

Hu KJ et al. (1999) Nematology "Nematicidal metabolites produced by Photorhabdus luminescens (Enterobacteriaceae), bacterial symbiont of entomopathogenic nematodes."

Hu KJ, Li JX, Webster JM

[Nematology, 1999]

The secondary metabolites, 3,5-dihydroxy-4-isopropylstilbene (ST) and indole, from the culture filtrate of Photorhabdus luminescens MD, were shown to have nematicidal properties. ST caused nearly 100% mortality of 54 and adults of Aphelenchoides rhytium, Bursaphelenchus spp. and Caenorhabditis elegans at 100 mu g/ml, but had no effect on J2 of Meloidogyne incognita or infective juveniles (IJ) of Heterorhabditis megidis at 200 mu g/ml. Indole was lethal to several nematode species at 300 mu g/ml, and caused a high percentage of Bursaphelenchus spp. (54 and adults), M, incognita (J2) and Heterorhabditis spp. (IJ) to be paralysed at 300, 100 and 400 mu g/ml, respectively. Both ST and indole inhibited egg hatch of M, incognita. ST repelled IJ of some Steinernema spp. but not IJ of Heterorhabditis spp., and indole repelled IJ of some species of both Steinernema and Heterorhabditis. ST, but not indole, was produced in nematode-infected larval Galleria mellonella. after 24 h infection.

Masaomi Minaba et al. (2007) International Worm Meeting "Development of heterotrimeric G protein signalling manipulation by exogenous G-protein coupled receptors originated from evolutionarily distant animals using C. elegans model."

Masaomi Minaba, Yusuke Kato

[International Worm Meeting, 2007]

The GPCR-G protein signalling regulates various physiological functions in a wide variety of organisms including plants and animals. Therefore, such physiological functions can be affected by manipulation of the GPCR-G protein signal transduction. Our interest is in the use of GPCRs derived from evolutionarily distant organisms for the manipulation of G protein signalling. GPCRs recognise a wide variety of ligands. Although some ligands are conserved in many organisms (e.g. acetylcholine, dopamine, etc.), others are recognised only in few organisms (e.g. peculiar peptide hormones, biogenic amines, etc). The GPCRs recognising such unique ligands are often found in evolutionarily distant organisms. If such GPCRs can couple with the target G<font face=symbol>a</font>, we can manipulate the GPCR-G protein signalling of transgenic individuals by using specific ligands that do not activate any receptors in wild-type individuals. We are interested in developing such manipulation system using C. elegans model. To test the functional coupling of a GPCR from an evolutionarily distant organism and a C. elegans G protein, we selected the mammalian G<font face=symbol>a</font>_i/o coupled receptor, human muscarinic acetylcholine receptor M₂ subtype (M₂), and the nematode G<font face=symbol>a</font>_i/o orthologue, GOA-1, as a model. A fusion protein of M₂ and GOA-1 was expressed using a baculovirus expression system. The ligand binding properties of M₂ in the GOA-1 fusion protein agree with that of the G<font face=symbol>a</font>_i1 fusion protein, indicating that the M₂ is functional. The binding of GTP<font face=symbol>g</font>S was increased by stimulation with the agonist, carbamylcholine, in a dose-dependent manner. The increase of GTP<font face=symbol>g</font>S binding was completely inhibited by the antagonist, atropine, suggesting that carbamylcholine induced the substitution for GTP<font face=symbol>g</font>S in GOA-1. In addition, carbamylcholine caused the decrease of GDP affinity in GOA-1. These results indicate that M₂ functionally couples with GOA-1. The affinity of M₂ for agonists, but not for antagonists, decreases on interaction with G<font face=symbol>a</font>_i/o in the presence of guanine nucleotides. The affinity for carbamylcholine of the fusion protein decreased in the presence of GTP, whereas the affinity for atropine was not affected by GTP, suggesting that M₂ in the fusion protein interacts with GOA-1 as well as with G<font face=symbol>a</font>_i/o in a GTP-sensitive manner. In conclusion, the human M₂ can activate the nematode GOA-1. We are presently trying other mammalian GPCRs for coupling with various nematode G proteins.