David Madsen et al. (2004) West Coast Worm Meeting "Characterization of C. elegans Synapsin, SNN-1"

Michael Francis, A Villu Maricq, David Madsen

[West Coast Worm Meeting, 2004]

The synaptic protein, synapsin, with its many vertebrate isoforms has been a subject of intense study since it was first identified over 30 years ago. However, despite this effort, its function in regulating neurotransmitter release and its role in the synaptic vesicle cycle remain unclear. We have begun analysis of the C. elegans homolog, snn-1 , to further characterize synapsin function. The synapsins are a family of synaptic peripheral membrane proteins abundant in the presynaptic terminal. In vertebrates, 3 distinct genes and alternative splicing yield the five known synapsins. Characterization of the synapsins has benefited from studies of highly conserved domains. Invertebrate synapsin homologs share considerable sequence identity in these domains. Specific roles for these domains are now becoming clear. Domain A contains a single phosphorylation site for PKA and CaM Kinase I that regulates binding to synaptic vesicles. Domain C has several predicted ATP binding sites and suggests that synapsins are ATP dependent enzymes. Domain E has been shown to regulate the reserve pool of synaptic vesicles. In C. elegans , snn-1 has a similar domain organization and has the conserved PKA/CaMKI site in domain A, many of the ATP binding sites of domain C, and high homology to domain E at the C-terminus. We have shown via expression of the snn-1 promoter fused to the reporter molecule GFP, that snn-1 is expressed in most neurons. Using a Tc1 transposon mediated approach, we have generated predicted null alleles of the snn-1 gene. We are currently assessing their phenotype through a variety of behavioral assays as well as electrophysiological techniques in conjunction with certain genetic strategies. Through these studies we hope to gain a better insight into the roles synapsin plays in neurotransmission.

Zarkower D et al. (1994) Worm Breeder's Gazette "mab-3 YAC Rescue"

De Bono M, Hodgkin JA, Zarkower D

[Worm Breeder's Gazette, 1994]

mab-3 YAC rescue David Zarkower, Mario de Bono, and Jonathan Hodgkin MRC Laboratory of Molecular Biology, Cambridge, England

Weinkove D (2018) BMC Biol "On microbes, aging and the worm: an interview with David Weinkove."

Weinkove D

[BMC Biol, 2018]

David Weinkove is an associate professor at Durham University, UK, studying host-microbe interactions in the model organism Caenorhabditis elegans. David has been focusing on the way microbes affect the physiology of their hosts, including the process of aging. In this interview, he discusses the questions shaping his research, how they evolved over the years, and his guiding principles for leading a lab.

Miller DM et al. (1992) Worm Breeder's Gazette "unc-4 LacZ Expression in A-Type Motor Neurons"

Miller DM, Niemeyer CJ

[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

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.

Susan Poulson et al. (2001) International C. elegans Meeting "CAM-1/KIN-8 Receptor Tyrosine Kinase is Important for Coordinated Movement"

Susan Poulson, Villu Maricq, David Madsen

[International C. elegans Meeting, 2001]

The neuromuscular junction (NMJ) is critical for neuronal control of muscle movement and coordination. Work from our lab indicates a Ror-like receptor tyrosine kinase, CAM-1/KIN-8, is expressed at the NMJ, and may play an important role in the development and/or function of the NMJ. CAM-1/KIN-8 as an important player in V-cell polarity and CAN cell migration (Forrester et al. , 1999, Nature , 400(6747):881-5). CAM-1/KIN-8 can also act in the dauer formation pathway as a regulator of DAF-7/TGF- b expression (Koga et al ., 1999, Development (23):5387-98). Our lab independently generated a cam-1/kin-8 deletion mutant, ak37 , and found that CAM-1/KIN-8 may be necessary for proper function of the NMJ. Using cell-specific GFP markers, we have examined muscle arm morphology and synaptic density at the neuromuscular junction. cam-1/kin-8(ak37) mutants have significantly smaller muscle arms and decreased acetylcholine receptor (AChR) density at the neuromuscular junction. cam-1/kin-8(ak37) mutants also show a mild resistance to Aldicarb. We are planning to use electrophysiology and the AChR-specific drug levamisole to further characterize NMJ function in cam-1/kin-8(ak37) animals. Transgenic worms that overexpress the full-length CAM-1/KIN-8 protein under its native promoter appear wild type, but worms overexpressing the CAM-1/KIN-8 receptor under the myo-3 promoter have severe morphological and behavioral defects including spiny muscle outgrowths, deformed vulval muscles, and paralysis. Paralysis caused by this muscle-specific overexpression is unchanged in the cam-1/kin-8(ak37) background. Worms overexpressing a truncated form of CAM-1/KIN-8 (lacking the kinase domain and putative intracellular protein-binding domains) are also paralyzed. These data suggest the CAM-1/KIN-8 extracellular domain may act as a ligand or signaling molecule independent of CAM-1/KIN-8 kinase activity.

Sri Koduri et al. (2006) Neuronal Development, Synaptic Function, and Behavior Meeting "Role of Stargazin in Regulating Glutamate Gated Currents"

Sri Koduri, Andres Maricq, David Madsen, Craig Walker

[Neuronal Development, Synaptic Function, and Behavior Meeting, 2006]

The majority of excitatory neurotransmitter function in vertebrates is mediated by ionotropic glutamate receptors (iGluRs). Reconstitution of iGluRs from C. elegans in Xenopus oocytes requires the auxiliary subunits SOL-1 and STG-1 (see abstracts by Francis et al., and Walker et al.). STG-1 shares weak sequence identity with vertebrate stargazin - a member of the family of glutamate receptor regulatory proteins known as TARPs (Transmembrane AMPA Receptor Regulatory Proteins). We have cloned stargazin homologues from Apis mellifera and Drosophila and co-expressed them with ionotropic glutamate receptor subunits in Xenopus oocytes. We found that the kinetics of the glutamate gated current were dependent upon the combination of the glutamate receptor subunit and the stargazin homologue. Apis STG, when co expressed with vertebrate GluR1, caused the channels to become non-desensitizing. We are currently analyzing chimeras made from Apis STG and vertebrate stargazin to determine which domain of the protein modifies the desensitization kinetics.

Emmons SW et al. (1994) Worm Breeder's Gazette "Strain Names for non-C. elegans Species."

Emmons SW, Fitch DHA, Leroi AM

[Worm Breeder's Gazette, 1994]

Strain names for non-C. elegans species Scott W. Emmonst, Armand Leroit, and David Fitch, Department of Molecular Genetics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, Department of Biology, New York University, RmlOO9 Main Bldg., Washington Square, New York, NY 10003

Hall DH et al. (1994) Worm Breeder's Gazette "Cytology of Degenerin-Induced Cell Death in the PVM Neuron"

Driscoll MA, Chalfie M, Gu GQ, Hall DH, Gong L

[Worm Breeder's Gazette, 1994]

Cytology of degenerin-induced cell death in the PVM neuron David H. Hall, Guoqiang Gu+, Lei Gong#, Monica Driscoll#, and Martin Chalfie+, * Dept. Neuroscience, Albert Einstein College of Medicine, Bronx, N.Y. 10461 + Dept. Biological Sciences, Columbia University, New York, N.Y. 10027 # Dept. Molecular Biology and Biochemistry, Rutgers University, Piscataway, N.J. 08855

Nathalie Strutz et al. (2001) International C. elegans Meeting "Identification of functional ion channel domains of C. elegans glutamate receptor subunits"

Nathalie Strutz, David Madsen, Michael Hollmann, Andres V Maricq

[International C. elegans Meeting, 2001]

Glutamate receptors are not only abundant in the nervous system of vertebrates but also of invertebrates. In Caenorhabditis elegans , 10 putative ionotropic glutamate receptor subunits have been identified so far (Brockie et al. 2001, J. Neurosci. 21, 1510). Two of these, GLR-1 and GLR-2, have been expressed in Xenopus oocytes and failed to show ligand-activated currents. Therefore, we set out to investigate if the pore-forming domains of these two subunits are intrinsically functional ion conducting domains. We have previously shown that domain transplantation between different subtypes of glutamate receptors can generate functional chimeras that allow the characterization of those domains. To test for pore function, we transplanted the pore-forming region of GLR-1 or GLR-2 into either rat GluR1, as a representative of the AMPA receptor family, or rat GluR6, as a representative of the KA receptor family. The resulting chimeras GluR1-PGLR1, GluR1-PGLR2, GluR6-PGLR1, and GluR6-PGLR2, as well as the respective wildtypes GluR1, GluR6, GLR-1, and GLR-2 were expressed and characterized in Xenopus oocytes. Surprisingly, GluR1-PGLR1, GluR1-PGLR2, and GluR6-PGLR2 produced ligand-activated currents, despite the GLR-1 and GLR-2 wildtype receptor's apparent lack of ion channel function. The maximal current amplitudes of GluR6-PGLR2 were comparable to wildtype GluR6. GluR1-PGLR1 and GluR1-PGLR2 showed reduced current amplitudes in comparison to wildtype GluR1. The ion channel properties of the chimeras classify GLR-1 and GLR-2 into the group of non-NMDA receptor subunits, consistent with conclusions derived from sequence homology data.