Attreed M et al. (2010) Neuronal Development, Synaptic Function and Behavior, Madison, WI "Visualizing Heparan Sulfate Domains in Living C. elegans"

Attreed M, Buelow H

[Neuronal Development, Synaptic Function and Behavior, Madison, WI, 2010]

Heparan sulfate (HS) are unbranched, highly modified polysaccharide chains of the extracellular space. These chains are attached to proteins forming proteoglycans. HS modifications occur non-randomly and non-uniformly thereby creating specific, functional domains believed to mediate protein-protein interactions. We have previously shown that these HS modifications can serve specific and instructive functions during neural development. However, the dynamics of these sugar molecules in vivo are not known. While in vivo imaging of genetically encoded molecules is routine since the introduction of green fluorescent protein, in vivo visualization of molecules with defined covalent modifications and/or non-genetically encoded molecules in the extracellular space is at best difficult or not possible at all. Using single chain variable fragment (scFv) antibodies, which recognize domains of modified HS, we have developed a tool that allows for the imaging of HS sugar domains in vivo. We find specific HS motifs associated with distinct anatomical structures throughout development of C. elegans. From late embryonic stages, HS is associated with the nervous system and pharyngeal muscle as well as select basement membranes. Additionally, the same HS motif is also found associated with body wall muscle. Using genetic analyses we demonstrate that the recognized HS structures associated with the nerve ring are (1) attached to the syndecan core protein and (2) contain both HS-3O-sulfated and HS-6O-sulfated sugar residues. In conclusion, we have developed a novel tool for the visualization of HS sugar domains in vivo. This tool should allow for investigation of the dynamics of HS domain formation and remodeling. Our approach is in principle applicable to visualize any type of molecule (genetically encoded or not) in the extracellular space.

Tecle E et al. (2010) Neuronal Development, Synaptic Function and Behavior, Madison, WI "The Role of 3-O Sulfation of Heparan Sulfate in Neuronal Development and Connectivity in C. elegans"

Tecle E, Buelow H

[Neuronal Development, Synaptic Function and Behavior, Madison, WI, 2010]

Our lab is interested in how Heparan Sulfate (HS) modifications regulate neuronal connectivity and patterning in C. elegans. HS is a highly modified un-branched glycosaminoglycan exhibiting substantial molecular diversity of modifications, including sulfation, epimerization and acetylation. HS modifications have been documented to have specific and instructive roles (Bülow and Hobert, 2004; Bülow et al., 2008) in neuronal development leading to the hypothesis of a HS code which regulates the patterning of the nervous system. However, the role of HS 3-O sulfation, the most rare HS modification has not been established. Vertebrate genomes code for at least seven members of the HST-3 gene family that are grouped into two distinct classes. We have identified one gene coding for a predicted HST-3 of each class in the C. elegans genome: hst-3.1 and hst-3.2. Analysis of null mutants of hst-3.1 shows that 3-O sulfation is required for synaptic branch formation and axon termination in a subset ofneurons. Some of the identified phenotypes are shared by mutations in rpm-1, a conserved regulator of pre-synaptic maturation (Schaefer et al., 2000; Zhen et al., 2000). Double mutant analyses indicate that rpm-1 and 3-O sulfation act in parallel genetic pathways suggesting that 3-O sulfation may be involved in a novel pathway and may be a crucial determinant in the establishment of neuronal connectivity. Reporter analyses of hst-3.2 reveal expression in multiple tissues including select neurons and hypodermal tissues.We will report on our progress to understand the role of 3-O sulfation in neuronal development.

Thomas JH et al. (1994) Worm Breeder's Gazette "lin-36, a Class B Synthetic Multivulva Gene, Encodes a Novel Protein"

Thomas JH, Horvitz HR

[Worm Breeder's Gazette, 1994]

lin-36, a Class B Synthetic Multivulva Gene, Encodes a Novel Protein Jeffrey H. Thomas and H. Robert Horvitz, HHMI, Dept. Biology, MIT, Cambridge, MA 02139, USA

Trivedi, M. et al. (2019) International Worm Meeting "Characterizing Novel Pathways for Dendritic Tiling in C. elegans."

Hernandez, L., Buelow, H., Trivedi, M.

[International Worm Meeting, 2019]

Neurons rely on dendrites for the acquisition of sensory and synaptic input from their particular receptive fields. Findings of aberrant dendritic morphology in disorders such as autism spectrum disorder (ASD) and schizophrenia highlight the importance of understanding how complex dendritic arbors are developed and maintained. During development, one of the goals of dendritic outgrowth is non-redundant coverage of a receptive field, which requires the avoidance of other dendrites both from the same neuron (self-avoidance) and from others (tiling). While tiling is a conserved property of many nervous systems, the molecular mechanisms by which it is established remain unclear. The goal of this project is to characterize the mechanisms of dendritic tiling using the multi-dendritic FLP and PVD mechanosensory neurons of C. elegans as a model. The dendritic arbor of FLP covers the head of the worm while the arbor of PVD covers the body. The mechanism by which these neurons establish distinct non-overlapping receptive fields remains unknown. Using an unbiased forward genetic approach, we isolated a mutant allele in unc-33, which displays altered FLP and PVD receptive field sizes. Unc-33 encodes a member of the Collapsin Response Mediator Protein (CRMP) family, which regulates axon outgrowth and morphology by binding and organizing tubulin heterodimers. We have shown that unc-33 acts cell-autonomously to regulate FLP and PVD field size. We hypothesize that unc-33/CRMP acts to define the border between FLP and PVD by organizing microtubules in outgrowing dendrites. Furthermore, we hypothesize that unbiased forward genetic approaches will uncover additional regulators of FLP and PVD tiling.

Sun J et al. (2013) Exp Parasitol "Parasitism of secondary-stage juvenile of Heterodera glycines and four larva stages of Caenorhabditis elegans by Hirsutella spp."

Sun J, Xie H, Xiang M, Liu X, Qiu J

[Exp Parasitol, 2013]

The fungi Hirsutella rhossiliensis and Hirsutella minnesotensis generally parasitize only plant-parasitic nematodes in nature but parasitize the bacterivorous nematode Caenorhabditis elegans on agar plates. To establish a model system for studying the interaction between fungi and nematodes, we compared the parasitism of the first- to fourth-stage larvae (L1-L4) of C. elegans and second-stage juvenile (J2) of Heterodera glycines by twenty isolates of Hirsutella spp. Although parasitism differed substantially among isolates, both H. minnesotensis and H. rhossiliensis parasitized a higher percentage of H. glycines J2s than of C. elegans larvae. Parasitism of C. elegans L1s was correlated with parasitism of H. glycines J2s. Parasitism of C. elegans by H. rhossiliensis and H. minnesotensis was negatively correlated with larva size and motility, i.e., parasitism was higher for the younger stages. The C. elegans L1 is recommended for studying parasitism of nematodes by H. rhossiliensis and H. minnesotensis.

Fei YJ et al. (2000) J Biol Chem "A novel H(+)-coupled oligopeptide transporter (OPT3) from Caenorhabditis elegans with a predominant function as a H(+) channel and an exclusive expression in neurons."

Leibach FH, Romero MF, Krause MW, Huang W, Ganapathy V, Fei YJ, Liu JC

[J Biol Chem, 2000]

We have cloned and functionally characterized a novel, neuron-specific, H(+)-coupled oligopeptide transporter (OPT3) from Caenorhabditis elegans that functions predominantly as a H(+) channel. The opt3 gene is approximately 4.4 kilobases long and consists of 13 exons. The cDNA codes for a protein of 701 amino acids with 11 putative transmembrane domains. When expressed in mammalian cells and in Xenopus laevis oocytes, OPT3 cDNA induces H(+)-coupled transport of the dipeptide glycylsarcosine. Electrophysiological studies of the transport function of OPT3 in Xenopus oocytes show that this transporter, although capable of mediating H(+)-coupled peptide transport, functions predominantly as a H(+) channel. The H(+) channel activity of OPT3 is approximately 3-4-fold greater than the H(+)/peptide cotransport activity as determined by measurements of H(+) gradient-induced inward currents in the absence and presence of the dipeptide using the two-microelectrode voltage clamp technique. A downhill influx of H(+) was accompanied by a large intracellular acidification as evidenced from the changes in intracellular pH using an ion-selective microelectrode. The H(+) channel activity exhibits a K(0.5)(H) of 1.0 microM at a membrane potential of -50 mV. At the level of primary structure, OPT3 has moderate homology with OPT1 and OPT2, two other H(+)-coupled oligopeptide transporters previously cloned from C. elegans. Expression studies using the opt3::gfp fusion constructs in transgenic C. elegans demonstrate that opt3 gene is exclusively expressed in neurons. OPT3 may play an important physiological role as a pH balancer in the maintenance of H(+) homeostasis in C. elegans.

Imadzu H et al. (1994) Worm Breeder's Gazette "Two Tropomyosins Expressed in Body Wall and the Third Did In Pharynx of Caenorhabditis elegans"

Kagawa H, Sakube Y, Imadzu H

[Worm Breeder's Gazette, 1994]

TWO TROPOMYOSINS EXPRBSSBD IN BODY WALL AND THE THIRD DID IN PHARYNX OF CAENORHABDDITIS ELEGANS. H. Imadzu, Y. Sakube and H. gagawa. Department of Biology, Faculty of Science, Okayama University, Okayama, 700 Japan.

Wilson PA et al. (1982) Parasitology "Strongyloides ratti (homogonic): the time-course of early migration in the generalized host deduced from experiments in lactating rats."

Steven GE, Simpson NE, Wilson PA

[Parasitology, 1982]

Unsuckled mother rats given a 1 h suckling stimulus 3 h after subcutaneous injection of an exact dose of homogonic Strongyloides ratti allow fewer worms to develop in their intestines by day 9 than nulliparous rats (Wilson & Simpson, 1981). This effect is studied in more detail in terms of the length of time between weaning and stimulus (W leads to S) and injection and stimulus (I leads to S). It was observable with a W leads to S of 30 h but this and a period of 5 h were less effective than 24 h. With W leads to S constant at 24 h, significantly more worms developed in mothers when I leads to S was 24 h compared to 3 h and 10 h (P less than 0.005). The data, combined with those from nulliparous controls, are presented as a measure of the change with time of numbers of larvae in that compartment of the system which gives access to the stimulated mammary gland. It is argued that the particular compartment is the local lymph node draining the injection site and that the kinetics deduced are applicable to migration in the rat in general.

Miller DL et al. (2007) Proc Natl Acad Sci U S A "Hydrogen sulfide increases thermotolerance and lifespan in Caenorhabditis elegans."

Miller DL, Roth MB

[Proc Natl Acad Sci U S A, 2007]

Hydrogen sulfide (H(2)S) is naturally produced in animal cells. Exogenous H(2)S has been shown to effect physiological changes that improve the capacity of mammals to survive in otherwise lethal conditions. However, the mechanisms required for such alterations are unknown. We investigated the physiological response of Caenorhabditis elegans to H(2)S to elucidate the molecular mechanisms of H(2)S action. Here we show that nematodes exposed to H(2)S are apparently healthy and do not exhibit phenotypes consistent with metabolic inhibition. Instead, animals exposed to H(2)S are thermotolerant and long-lived. These phenotypes require SIR-2.1 activity but are genetically independent of the insulin signaling pathway, mitochondrial dysfunction, and caloric restriction. These studies suggest that SIR-2.1 activity may translate environmental change into physiological alterations that improve survival. It is interesting to consider the possibility that the mechanisms by which H(2)S increases thermotolerance and lifespan in nematodes are conserved and that studies using C. elegans may help explain the beneficial effects observed in mammals exposed to H(2)S.

Sakube Y et al. (1994) Worm Breeder's Gazette "The Genome Structure and Expression of Promoter/lacZ Fusion Genes of C. elegans Ryanodine Receptor"

Imadzu H, Sakube Y, Kagawa H

[Worm Breeder's Gazette, 1994]

The Genome Structure and Expression of Promoter/lacZ Fusion Genes of the C. elegans Ryanodine Receptor Y. Sakube, H. Imadzu and H. Kagawa, Laboratory of Molecular Biology, Faculty of Science, Okayama University, Okayama, 700 Japan C51918@JPNKUDPC