Nishikori, K. et al. (2017) International Worm Meeting "RNAi screening of genetic factors required for the biogenesis of intestinal granular organelles in C. elegans - Involvement of intestinal proton transporters."

Hosoda, A., Tanji, T., Kawano, K., Aoyama, R., Shiraishi, H., Ohashi-Kobayashi, A., Nishikori, K.

[International Worm Meeting, 2017]

The cytosol of the intestinal cells of C. elegans was apparently occupied by superficially indistinguishable granular organelles (intestinal granules), which consist of at least three types of organelles: acidified lysosome-related gut granules, lipid droplets, and HEBE (HAF-4/HAF-9-enriched body evanescent with age) granules. Although the former two types of organelles were studied well, HEBE granules have been largely overlooked. HAF-4 and HAF-9 are homologous to mammalian lysosomal peptide transporter ABCB9 and localize to the membrane of HEBE granules. Population of HEBE granules changes dynamically by aging and food conditions. Although characters we found suggest roles of HEBE granules in nutritional resource allocation in response to physiologic changes during the young adult stage, regulatory mechanisms of the organelle dynamics have yet to be determined. To reveal the genetic mechanisms underlying the biogenesis of HEBE granules, we performed RNAi screening according to the following scheme: synchronized L1 larvae were fed with RNAi feeding library clones (Open Biosystems) on 12-well plates. Worms at adult day 1, when HEBE granules are most prominent in the control condition, were directly observed using digital microscopes to efficiently evaluate the presence of intestinal granules. Positive clones were then subjected to the second screening by differential interference contrast microscopy. We previously reported the progress of the screening with preliminary analyses of genes for pentose phosphate pathway (PPP) and vacuolar proton transporter (V-ATPase) subunits (Shiraishi et al., and Nishikori et al., 19th and 20th International C. elegans Meeting). In this meeting, we will present results of the whole screening, in which worms fed with 11,263 out of 11,479 RNAi clones reached adulthood and 142 positive clones were obtained. The gene ontology analysis revealed enrichment of genes associated with metabolic processes including PPP and vacuolar proton transport. In view of proton transport, we found a Na+/H+ exchanger NHX-2 and its regulator PBO-1 among the positive clones. Since V-ATPase and NHX-2 are assumed to play a role in nutritional uptake via acidification of the intestinal lumen in C. elegans, we examined involvement of H+/oligopeptide symporter PEPT-1 in the biogenesis of HEBE granules using pept-1 mutant. These results suggest that oligopeptide uptake is responsible for the biogenesis of HEBE granules.

Noble, Daniel et al. (2013) International Worm Meeting "FOG-1 and FOG-3, their mRNA targets and the sperm/oocyte fate decision."

Ortiz, Marco, Aoki, Scott, Kim, Kyung Won, Noble, Daniel, Kimble, Judith

[International Worm Meeting, 2013]

A major unsolved question in development is how germ cells are specified as sperm or oocyte. The C. elegans terminal regulators of sperm fate specification are FOG-1, a CPEB family member, and FOG-3, a Tob/BTG protein (1). Vertebrate CPEB and Tob/BTG proteins can function as post-transcriptional regulators and have recently been shown to interact (2). We provide evidence that FOG-1 and FOG-3 proteins physically bind to each other and likely work together to specify sperm fate. Epitope-tagged FOG-1 and FOG-3 co-immunoprecipitate in a mammalian cell culture expression system and do so via the FOG-1 RNA binding region and FOG-3 Tob domain. In addition, we have found that FOG-1 and FOG-3 may regulate a common battery of mRNAs. We used a rescuing epitope-tagged fog-3::3xFLAG mosSCI transgene to immunoprecipitate FOG-3 associated mRNAs from spermatogenic L4 larvae, and identified 1616 transcripts by microarray analysis. Most of these putative FOG-3 mRNA targets were germline enriched, with 37% annotated as spermatogenic and 29% as oogenic. We performed similar immunoprecipitation and microarray analyses with a rescuing bombarded fog-1::3xFLAG transgene to determine 133 likely FOG-1 bound mRNAs. Remarkably, 109 of these FOG-1 mRNAs were also associated with FOG-3. Moreover, these common target mRNAs were enriched for genes involved in oogenesis or embryogenesis. Our complementary lines of evidence strongly suggest that FOG-1 and FOG-3 work together to regulate a common battery of mRNAs involved in the oogenic program. Our working model supports a conserved function of Tob proteins as CPEB protein adaptors to inhibit target transcripts. For sperm fate specification, we suggest that FOG-1 and FOG-3 work together to inhibit a battery of oogenesis mRNAs. (1) Ellis, R. and T. Schedl (2007) in WormBook, doi:10.1895/wormbook.1.82.2. (2) Hosoda, N. et al. (2011) EMBO J 30: 1311-1323..

Quartey MO et al. (2021) Sci Rep "The A(1-38) peptide is a negative regulator of the A(1-42) peptide implicated in Alzheimer disease progression."

Pennington PR, Heistad RM, Nyarko JNK, Barnes JR, Bolanos MAC, Parsons MP, Knudsen KJ, De Carvalho CE, Leary SC, Mousseau DD, Buttigieg J, Maley JM, Quartey MO

[Sci Rep, 2021]

The pool of -Amyloid (A) length variants detected in preclinical and clinical Alzheimer disease (AD) samples suggests a diversity of roles for A peptides. We examined how a naturally occurring variant, e.g. A(1-38), interacts with the AD-related variant, A(1-42), and the predominant physiological variant, A(1-40). Atomic force microscopy, Thioflavin T fluorescence, circular dichroism, dynamic light scattering, and surface plasmon resonance reveal that A(1-38) interacts differently with A(1-40) and A(1-42) and, in general, A(1-38) interferes with the conversion of A(1-42) to a -sheet-rich aggregate. Functionally, A(1-38) reverses the negative impact of A(1-42) on long-term potentiation in acute hippocampal slices and on membrane conductance in primary neurons, and mitigates an A(1-42) phenotype in Caenorhabditis elegans. A(1-38) also reverses any loss of MTT conversion induced by A(1-40) and A(1-42) in HT-22 hippocampal neurons and APOE 4-positive human fibroblasts, although the combination of A(1-38) and A(1-42) inhibits MTT conversion in APOE 4-negative fibroblasts. A greater ratio of soluble A(1-42)/A(1-38) [and A(1-42)/A(1-40)] in autopsied brain extracts correlates with an earlier age-at-death in males (but not females) with a diagnosis of AD. These results suggest that A(1-38) is capable of physically counteracting, potentially in a sex-dependent manner, the neuropathological effects of the AD-relevant A(1-42).

Danielle Thierry-Mieg et al. (2003) Worm Breeder's Gazette "www.wormgenes.org , a new gene centered database"

Vahan Simonyan, Michel Potdevin, Mark Sienkiewicz, Yuji KOHARA, Jean Thierry-Mieg, Danielle Thierry-Mieg, Tadasu SHIN-I

[Worm Breeder's Gazette, 2003]

Wormgenes is a new resource for C.elegans offering a detailed summary about each gene and a powerful query system.

Tangrodchanapong T et al. (2020) Front Pharmacol "Frondoside A Attenuates Amyloid- Proteotoxicity in Transgenic Caenorhabditis elegans by Suppressing Its Formation."

Tangrodchanapong T, Sobhon P, Meemon K

[Front Pharmacol, 2020]

Oligomeric assembly of Amyloid- (A) is the main toxic species that contribute to early cognitive impairment in Alzheimer's patients. Therefore, drugs that reduce the formation of A oligomers could halt the disease progression. In this study, by using transgenic <i>Caenorhabditis elegans</i> model of Alzheimer's disease, we investigated the effects of frondoside A, a well-known sea cucumber <i>Cucumaria frondosa</i> saponin with anti-cancer activity, on A aggregation and proteotoxicity. The results showed that frondoside A at a low concentration of 1 M significantly delayed the worm paralysis caused by A aggregation as compared with control group. In addition, the number of A plaque deposits in transgenic worm tissues was significantly decreased. Frondoside A was more effective in these activities than ginsenoside-Rg3, a comparable ginseng saponin. Immunoblot analysis revealed that the level of small oligomers as well as various high molecular weights of A species in the transgenic <i>C. elegans</i> were significantly reduced upon treatment with frondoside A, whereas the level of A monomers was not altered. This suggested that frondoside A may primarily reduce the level of small oligomeric forms, the most toxic species of A. Frondoside A also protected the worms from oxidative stress and rescued chemotaxis dysfunction in a transgenic strain whose neurons express A. Taken together, these data suggested that low dose of frondoside A could protect against A-induced toxicity by primarily suppressing the formation of A oligomers. Thus, the molecular mechanism of how frondoside A exerts its anti-A aggregation should be studied and elucidated in the future.

Hodgkin JA (1998) International Journal of Developmental Biology "Seven types of pleiotropy."

Hodgkin JA

[International Journal of Developmental Biology, 1998]

Pleiotropy , a situation in which a single gene influences multiple phenotypic tra its, can arise in a variety of ways. This paper discusses possible underlying mechanisms and proposes a classification of the various phenomena involved.

Tuck S (2011) Curr Biol "Extracellular vesicles: budding regulated by a phosphatidylethanolamine translocase."

Tuck S

[Curr Biol, 2011]

Recent work on a Caenorhabditis elegans transmembrane ATPase reveals a central role for the aminophospholipid phosphatidylethanolamine in the production of a class of extracellular vesicles.

Viney ME et al. (2004) Naturwissenschaften "Is dauer pheromone of Caenorhabditis elegans really a pheromone?"

Viney ME, Franks NR

[Naturwissenschaften, 2004]

Animals respond to signals and cues in their environment. The difference between a signal (e.g. a pheromone) and a cue (e.g. a waste product) is that the information content of a signal is subject to natural selection, whereas that of a cue is not. The model free-living nematode Caenorhabditis elegans forms an alternative developmental morph (the dauer larva) in response to a so-called 'dauer pheromone', produced by all worms. We suggest that the production of 'dauer pheromone' has no fitness advantage for an individual worm and therefore we propose that 'dauer pheromone' is not a signal, but a cue. Thus, it should not be called a pheromone.

Schaeffer JM et al. (1990) J Antibiot (Tokyo) "Cochlioquinone A, a nematocidal agent which competes for specific [3H]ivermectin binding sites."

Williamson JM, Schaeffer JM, Bergstrom AR, Liesch JM, Goetz MA, Frazier EG

[J Antibiot (Tokyo), 1990]

Cochlioquinone A, isolated from the fungus Helminthosporium sativum, was found to have nematocidal activity. Cochlioquinone A is a competitive inhibitor of specific [3H]ivermectin binding suggesting that cochlioquinone A and ivermectin interact with the same membrane receptor.

Desta IT et al. (2016) J Lab Autom "Detecting and Trapping of a Single C. elegans Worm in a Microfluidic Chip for Automated Microplate Dispensing."

Giakoumidis N, Mustafa N, AlGharibeh N, Orozaliev A, Al-Sharif A, Song YA, Desta IT, Gunsalus KC

[J Lab Autom, 2016]

Microfluidic devices offer new technical possibilities for a precise manipulation of Caenorhabditis elegans due to the comparable length scale. C. elegans is a small, free-living nematode worm that is a popular model system for genetic, genomic, and high-throughput experimental studies of animal development and neurobiology. In this paper, we demonstrate a microfluidic system in polydimethylsiloxane (PDMS) for dispensing of a single C. elegans worm into a 96-well plate. It consists of two PDMS layers, a flow and a control layer. Using five microfluidic pneumatic valves in the control layer, a single worm is trapped upon optical detection with a pair of optical fibers integrated perpendicular to the constriction channel and then dispensed into a microplate well with a dispensing tip attached to a robotic handling system. Due to its simple design and facile fabrication, we expect that our microfluidic chip can be expanded to a multiplexed dispensation system of C. elegans worms for high-throughput drug screening.