Bowerman BA et al. (1994) Worm Breeder's Gazette "The Maternal Gene skn-4 and the Specification of Ventral Blastomere Fates in the Early C. elegans Embryo"

Bowerman BA, Shelton CA, Thorpe CJ, Martin PR

[Worm Breeder's Gazette, 1994]

THE MATERNAL GENE SKN-4 AND THE SPECIFICATION OF VENTRAL BLASTOMERE FATES IN THE EARLY C. ELEGANS EMBRYO Bruce Bowerman, Paula R. Martin, Christopher J. Thorpe, and Christopher A. Shelton. The Institute of Molecular Biology, University of Oregon, Eugene, OR 97403.

Lynn C Hull et al. (2005) International Worm Meeting "DIG-1, a giant secreted member of the immunoglobulin superfamily, is involved in fasciculation of neuronal processes during development of C. elegans"

Patricia Berninsone, Lynn C Hull, Christopher Burket, Christina E Higgins, Elizabeth F Ryder

[International Worm Meeting, 2005]

Mutations in the gene dig-1 cause defects in the sensory processes of several types of ciliated head sensory neurons in C. elegans. Mutant processes deviate from their usual straight paths and sometimes fail to reach their normal destinations in the nose. Experiments with a temperature sensitive mutation showed that dig-1 acts during embryogenesis and first larval stages. This phenotype suggests that dig-1 plays an adhesive role during development and maintenance of the sensory nervous system. Recent analysis has shown that longitudinal processes of several additional types of neurons in the worms body also show abnormal fasciculation patterns in dig-1 mutants. In addition, maintenance of axon position of neurons in the ventral nerve cord is affected (See Abstract by Benard et al.) dig-1 maps to a region on chromosome III that contains K07E12.1, which is predicted to encode a giant secreted member of the immunoglobulin superfamily. We have shown that two dig-1 alleles have mutations in this gene. In addition, RNAi using K07E12.1 sequence generated animals with a mutant sensory process phenotype closely resembling that of dig-1 alleles. Finally, an array containing the complete K07E12.1 sequence (kind gift of R. Proenca and E. Hedgecock) rescued the sensory process defects of dig-1(n1321). Thus, we conclude that K07E12.1 is the dig-1 gene. The DIG-1 predicted protein has several similarities to hyalectan proteoglycans, including N-terminal immunoglobulin domains, a highly repetitive middle region, and C-terminal domains involved in adhesion. In vertebrates, glycosaminoglycans (GAGs) are attached to the repetitive core region of proteoglycans at serine residues that are part of a consensus sequence. One of the most severe dig-1 alleles is a missense mutation (Ser to Phe) in a sequence in the repetitive region similar to the vertebrate GAG attachment consensus. The severity of the missense mutation suggests that it may destroy an important glycosylation site in the protein.

Christopher J Cronin et al. (2005) International Worm Meeting "The Combined UC San Diego/Caltech Quantitative Behavior Analysis System"

William R Schafer, Zhaoyang Feng, Kuang-man Huang, Paul W Sternberg, Christopher J Cronin

[International Worm Meeting, 2005]

California Institute of Technology and University of California, San Diego have each developed practical, automated movement analysis systems to quantify aspects of worm behavior and morphology (see An imaging system for standardized quantitative analysis of C. elegans behavior, Zhaoyang Feng, et al, BMC Bioinformatics 2004, 5:115, An automated system for measuring parameters of nematode sinusoidal movement, Christopher J Cronin, et al, BMC Genetics 2005, 6:5, and previous meeting abstracts). We have consolidated our development efforts and merged our independent system designs to create a single, unified behavior analysis system. The combined system provides researchers with all of the quantification tools and database functionality of the individual UCSD and Caltech systems, but also establishes a common, open software and hardware foundation for continued development by Caltech, UCSD and the community. Current efforts include expanding system capabilities for the automated analysis of mating behavior with the challenge of tracking multiple moving individuals, both in contact with and separated from each other.

Pena-Gonzalez, I. et al. (2013) International Worm Meeting "Suppressors of TDP-1 toxicity in Caenorhadbitis elegans."

Link, CD., Pena-Gonzalez, I.

[International Worm Meeting, 2013]

Suppressors of TDP-1 toxicity in Caenorhadbitis elegans Ilana Pena-Gonzalez1 and Christopher D Link1, 2 1 Integrative Physiology, University of Colorado, Boulder, CO 80309, USA 2 Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309, USA RNA binding protein TDP-43 forms damaging aggregates in multiple neurodegenerative diseases. We have found that the deletion of tdp-1, the C. elegans ortholog of TDP-43, leads to increased accumulation of double stranded RNA. TDP-1 is not believed to bind to dsRNA itself; however the marked increase in dsRNA accumulation in worms deleted for tdp-1 implies TDP-1 normally participates in limiting the stability and structure of dsRNA. Although worms deleted for TDP-1 do not have a severe phenotype, overexpressed nuclear TDP-1 is toxic in worms. One possible explanation for this is that too much TDP-1 leads to excessive disruption of structured RNAs needed for normal RNA metabolism. Making use of this overexpression model we have established a heat shock induction system to help identify components associated with TDP-1's prevention of dsRNA accumulation. Identifying mutations that suppress the neurotoxic effects of overexpressed TDP-1 could help identify others factors contributing to the complex mechanism of disassembling dsRNA. A mutagenesis screen has identified four mutant strains that partially suppress the toxicity of overexpressed TDP-1. We have also tested suppressors of other toxic proteins. Further identifying the pieces of the mechanism regulating dsRNA breakdown could help better explain the pathogenic pathway of TDP-1 and consequently TDP-43 in disease.

Sze-Wah Tse et al. (2003) International Worm Meeting "Interactions of mig-10 and rac pathway genes in neuronal migration and excretory canal outgrowth."

Sze-Wah Tse, Elizabeth F Ryder

[International Worm Meeting, 2003]

The gene mig-10 is required for the embryonic migration of the neurons CAN, ALM, and HSN, as well as the development of posterior excretory canals (Manser and Wood, 1990). We have also observed that mig-10 is required for the formation or maintenance of the axons of the IL2 head sensory neurons (Burket et al., ECWM, 1998). mig-10 has been cloned, and was found to have homology to the Grb family of cytoplasmic signal transduction proteins (Manser et al., 1997). In addition, mig-10 contains a ras-associating (RA) domain, suggesting it may interact with genes of the ras superfamily of GTPases (Wojcik et al., 1999). The rac genes are members of the ras-related GTPases of the Rho family. They have been shown in a number of systems to be involved in axon guidance and cell migration. C. elegans contains three rac genes, ced-10 , mig-2 , and rac-2 , as well as two guanine nucleotide exchange factors (GEFs), unc-73 and exc-5 , which can activate rac GTPases by exchanging GTP for GDP. The three C. elegans rac genes have been shown to function somewhat redundantly in cell migration and axon pathfinding (Lundquist et al., 2001; Wu et al., 2002). To determine whether mig-10 might interact with any of the rac pathway genes, we constructed double mutants of mig-10 with the three rac and two GEF genes. We are analyzing both excretory canal development and the locations of CAN, ALM, and HSN in these mutants. Preliminary results suggest that double mutant phenotypes are more severe than those of single mutants for most of the double mutants we have constructed, suggesting that partially redundant pathways are being affected. One interpretation of these results is that mig-10 , like unc-73 , may interact with all three rac genes. SWT was partially supported by a WPI summer fellowship. EFR is supported by NSF CAREER Award IBN-9984662.

Bauer CC et al. (1998) West Coast Worm Meeting "a, b AND g-FILAGENIN - NEW PROTEINS IN THE CORE'S OF THICK FILAMENTS"

Schmid MF, Ortiz I, Epstein HF, Liu FZ, Bauer CC

[West Coast Worm Meeting, 1998]

The cores of muscle thick filaments are composed of an outer layer of paramyosin surrounding an inner tubular region containing additional core proteins. In order to study the structure of the thick filament core and the mechanisms and molecules involved in the formation of this length-regulated, multi-protein structural assemblage, we have isolated and characterized three novel proteins: a, b and g-filagenin. We obtained partial peptide sequences from each of the filagenin proteins and determined their predicted protein sequences from the C. elegans Genome Project's database and correlated this information with cDNA sequence obtained from RT-PCR or phage libraries. All three filagenins are novel proteins with no significant homologies to any known proteins (although homologues in parasitic nematodes have been found in the databases). All filagenins also possess the distinction of having calculated isoelectric points of over pH 10 and having a higher than average number of aromatic amino acids. Both b and g-filagenin are predicted to have secondary structures containing only beta strands and loops, whereas a-filagenin is composed of both alpha helices and beta strands. Structural studies of the core indicate that there are seven paramyosin subfilaments crosslinked by additional internal proteins. We tested our structural model with Western blotting using an affinity-purified antibody and have showed that a, b and g-filagenins are associated with the cores. All three filagenins were localized by immunofluorescence microscopy to the A bands of body wall muscles, but there was no detectable reaction with the pharynx, with the exception of a slight reaction with anti-a-filagenin antibody. b-Filagenin has been shown by immunoelectron microscopy to be assembled with paramyosin into the tubular cores of wild-type nematodes at the same periodicity of 72-nm as observed with paramyosin. In CB1214 paramyosin null mutants, b-filagenin assembles with myosin to form abnormal tubular filaments with a periodicity identical to that of wild type. These results verify that the filagenins are core proteins that co-assemble with either myosin or paramyosin in C. elegans to form tubular filaments. Further studies on nematode muscle thick filaments are intended to elucidate the mechanisms behind the formation and regulation of these stable assemblies of myosin and associated proteins. *Supported by grants from the Muscular Dystrophy Association, the National Science Foundation and a NRSA postdoctoral fellowship for Christopher Bauer.

Maegan V Rivard et al. (2001) International C. elegans Meeting "An expression pattern study of mig-10, a gene required for nervous system development in C. elegans"

Elizabeth F Ryder, James Manser, Maegan V Rivard, Diana Rusiecki

[International C. elegans Meeting, 2001]

The gene mig-10 was originally identified as being required for the embryonic migration of the neurons CAN, ALM, and HSN, as well as development of posterior excretory canals (Manser and Wood, 1990). mig-10 was subsequently cloned, and was found to have homology to the Grb family of cytoplasmic signal transduction proteins (Manser et al., 1997). Surprisingly, mosaic analysis revealed that mig-10 acts cell nonautonomously during excretory canal development. This suggests either that mig-10 is not acting in signal transduction, or that the signaling system is fairly complex. For example, mig-10 might transduce signals within migratory path or target cells rather than within migratory cells themselves. Recently, we observed that mig-10 is also required in the formation or maintenance of the axons of IL2 neurons. These are six symmetrically positioned head sensory neurons that form a topographic map onto the nerve ring. In particular, IL2 axons in mig-10(ct41) mutants often stop before reaching the nerve ring or simply branch at the nerve ring rather than first extending posteriorly past it as in wild-type animals (Burket et al., ECWM 1998). A number of genes have been found to have effects on both cell migration and axon guidance. We are interested in understanding whether mig-10 is a gene in this class, or whether the axon defect is secondary to a migration defect (for example, a target of the IL2 neurons might be mispositioned in mig-10 mutants). We would also like to know whether mig-10 is acting cell autonomously in the IL2s. To better understand the role of mig-10 in both cell migration and axon outgrowth or maintenance, we are looking at the expression pattern of mig-10 . A mig-10 promotor::GFP fusion construct was successfully microinjected into worms using dpy-20 as a co-transformation marker. The extrachromosomal array has been integrated, and we are currently in the process of characterizing the expression pattern. The construct is expressed in many cells embryonically, first coming on at about 270 minutes. In L1 animals, no expression is observed in the head, while in older larvae, we see expression in four cells in the head that we are currently attempting to identify. We are just beginning to analyze the expression pattern in the body. Using a PCR technique called SOEing (Splice by Overlap Extension), we have fused GFP to a mig-10 rescuing construct. Work on generating a transgenic strain containing this construct is in progress. EFR is supported by a NSF CAREER Award (IBN-9984662).