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.

Wang, Guoqiang et al. (2015) International Worm Meeting "Probing the Mechanisms by Which Exercise Enhances Axon Regrowth."

Driscoll, Monica, Wang, Guoqiang, Song, Isaac, Reina, Christopher

[International Worm Meeting, 2015]

In mammalian neuronal injury models, exercise improves neuronal regeneration, although the cellular and molecular mechanisms operative remain largely unclear. We found that pre-axotomy swim training of young age Caenorhabditis elegans can enhance axon regrowth consequent to single neurite severing. Even more striking is that a short period of post-axotomy exercise can also significantly enhance regrowth. C. elegans is thus a novel model with which to define the genetic pathways that link exercise to neuronal regeneration capacity.We have initiated our studies with a focus on the classical signaling pathways that confer mammalian exercise adaptation, such as those involving Ca2+, AMPK, PGC-1alpha and p38 kinase. A common outcome of different activating pathways is enhanced mitochondrial biogenesis. We have found that increased mitochondrial biogenesis via limiting the activity of the gei-8/NCoR gene, which encodes a negative regulator of mitochondrial biogenesis, can significantly enhance axon regrowth. On the other hand, genetically uncoordinated animals exhibit basically wild type levels of axon regrowth after laser axotomy-so baseline crawling activity does not seem to induce any particular regeneration signal. Taken together, our results indicate exercise might potentiate regrowth by activating physiological stress responses to intensive exercise. We have found that aak-2/AMPK is normally required for exercise strength adaptation. Interestingly, an aak-2/AMPK mutation does not suppress the increased regrowth of severed ALM neurons in the post-axotomy exercise paradigm. This observation indicates that the AMPK signaling pathway is not essential for potentiating axon regrowth by post-injury exercise. An alternative hypothesis is that exercise enhances axon regrowth by increasing stimulation to the injured neuron. For example, the mec-4 mec-10 double mutant, defective for gentle and harsh touch responses, is strongly inhibited for axon regrowth of ALM neurons, although the effect of exercise on the mec-4 mec-10 mutant is waiting to be tested. In general, we will report on findings relevant to the cellular and molecular mechanisms of exercise-enhanced neuronal regeneration of individual axotomized neurons.

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.

Zugasti, Olivier et al. (2013) International Worm Meeting "Triggering antifungal innate immunity."

Schroeder, Frank, Bose, Neelanjan, Squiban, Barbara, Zugasti, Olivier, Pujol, Nathalie, Belougne, Jerome, Ewbank, Jonathan, Kurz, Leo

[International Worm Meeting, 2013]

Infection of worms by the fungus D. coniospora leads to the up-regulation of genes such as nlp-29, one of a cluster of six paralogous nlp antimicrobial peptide genes, via a PMK-1/p38 MAP kinase pathway. The worm genome, however, lacks orthologs of the receptors known to be important for pathogen recognition in other species. How D. coniospora triggers an immune response is an open question. For epidermal defenses, the p38 signaling cassette acts downstream of the Ga protein GPA-12, implicating a G-protein coupled receptor (GPCR) in the immune response. By RNAi, we knocked down individually three-quarters of the worm's >1,500 GPCR genes. Quantification with the COPAS Biosort of the effect of each RNAi clone on the expression of a nlp-29p::gfp reporter following infection allowed us to identify dcar-1 (dihydrocaffeic acid receptor) as a candidate innate immune receptor gene. dcar-1 mutants exhibit an almost complete block of nlp genes induction following infection and a heightened susceptibility to infection compared to wild-type worms. We found that dcar-1 is expressed in the major epidermal syncytium, hyp7, site of expression of the infection-inducible nlp genes. Restoring dcar-1 expression in the epidermis rescued nlp gene expression and the mutant's resistance to infection. DCAR-1 has been previously shown to have a high affinity for dihydrocaffeic acid (DHCA) a derivative of DOPA. We found that unlike DOPA, direct addition of DHCA or oxidized DOPA to worms triggers the expression of nlp genes but could not demonstrate the production in vivo of DHCA. This suggests that DHCA might not be the natural ligand of DCAR-1. Our current hypothesis is that a derivative of DOPA is rapidly produced upon infection and triggers an immune response via DCAR-1. We are currently applying genetic and biochemical techniques to identify the putative DCAR-1 ligand. Thanks to Christophe Melon, and Reina Aoki and Yoshio Goshima for reagents.

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.