Eastman CL et al. (1999) J Neurosci "Coordinated transcriptional regulation of the unc-25 glutamic acid decarboxylase and the unc-47 GABA vesicular transporter by the Caenorhabditis elegans UNC-30 homeodomain protein."

Horvitz HR, Eastman CL, Jin YS

[J Neurosci, 1999]

An important aspect of the specification of neuronal fate is the choice of neurotransmitter. In Caenorhabditis elegans the neurotransmitter GABA is synthesized by the UNC-25 glutamic acid decarboxylase (GAD) and packaged into synaptic vesicles by the UNC-47 transporter. Both unc-25 and unc-47 are expressed in 26 GABAergic neurons of five different types. Previously, we have identified that the unc-30 homeobox gene controls the fate of 19 type D GABAergic neurons. We report here that the UNC-30 homeodomain protein transcriptionally regulates the expression of unc-25 and unc-47 in the 19 type D neurons. UNC-30 bound to the unc-25 and unc-47 promoters sequence-specifically. Mutations in the UNC-30 binding sites of the unc-25 and unc-47 promoters abolished the expression of reporter genes in the D neurons. The ectopic expression of UNC-30 induced the ectopic expression of reporter genes driven by the wild-type unc-25 and unc-47 promoters. Our data establish a mechanism for cell type-specific transcriptional coregulation of genes required for the synthesis and packaging of the neurotransmitter GABA.

Krieser RJ et al. (2000) Gene "Deoxyribonuclease II: structure and chromosomal localization of the murine gene, and comparison with the genomic structure of the human and three C. elegans homologs."

Eastman A, Krieser RJ

[Gene, 2000]

Deoxyribonuclease II (DNase II) has been implicated in diverse functions including degradation of foreign DNA, genomic instability, and in mediating the DNA digestion associated with apoptosis. The production of a mouse deleted for DNase II would clearly help to discriminate these functions. We have cloned and sequenced the mouse gene encoding DNase II. It was found to have a similar intron/exon structure to the human gene, although introns 3 and 5 are considerably shorter. The gene is located on mouse chromosome 8. The order of genes at this locus is mGCDH, mEKLF, mDNase II, mSAST, which is the same order that these genes are found on human chromosome 19. The GenBank database contains incorrect expressed sequence tags (ESTs) for the 3' end of the mouse mRNA. Furthermore, the gene structure of two of the three homologs in C. elegans is also incorrectly predicted in the database. We have established the correct intron/exon structure for these genes and show the conserved sequence and structure of the C. elegans, murine and human genes.

DeGroot MS et al. (2018) Genetics "The Caenorhabditis elegans SMOC-1 Protein Acts Cell Non-autonomously To Promote Bone Morphogenetic Protein Signaling."

Shi H, McKillop AN, Eastman A, DeGroot MS, Liu J

[Genetics, 2018]

Bone morphogenetic protein (BMP) signaling regulates many different developmental and homeostatic processes in metazoans. The BMP pathway is conserved in <i>Caenorhabditis elegans</i>, and is known to regulate body size and mesoderm development. We have identified the <i>C. elegans smoc-1</i> (Secreted MOdular Calcium binding protein-1) gene as a new player in the BMP pathway. <i>smoc-1(0)</i> mutants have a small body size, while overexpression of <i>smoc-1</i> led to a long body size and increased expression of the RAD-SMAD BMP reporter, suggesting that SMOC-1 acts as a positive modulator of BMP signaling. Using double mutant analysis, we showed that SMOC-1 antagonizes the function of the glypican LON-2 and acts through the BMP ligand DBL-1 to regulate BMP signaling. Moreover, SMOC-1 appears to specifically regulate BMP signaling without significant involvement in a TGF-like pathway that regulates dauer development. We found that <i>smoc-1</i> is expressed in multiple tissues, including cells of the pharynx, intestine, and posterior hypodermis, and that the expression of <i>smoc-1</i> in the intestine is positively regulated by BMP signaling. We further established that SMOC-1 functions cell non-autonomously to regulate body size. Human SMOC1 and SMOC2 can each partially rescue the <i>smoc-1(0)</i> mutant phenotype, suggesting that SMOC-1's function in modulating BMP signaling is evolutionarily conserved. Together, our findings highlight a conserved role of SMOC proteins in modulating BMP signaling in metazoans.

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).

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.

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.

Ailion M et al. (2017) Curr Biol "Genetics: Master Regulator or Master of Disguise?"

Malik HS, Ailion M

[Curr Biol, 2017]

The pha-1 gene of Caenorhabditis elegans was originally heralded as a master regulator of organ differentiation. A new study suggests instead that pha-1 actually serves no role in development and instead is a component of a selfish genetic element.

Gokul G et al. (2020) Curr Biol "Extracellular Proteostasis: Laying Siege to Pathogens."

Singh J, Gokul G

[Curr Biol, 2020]

How protein homeostasis is maintained in the extracellular space remains poorly studied. A recent study employed a Caenorhabditis elegans model to carry out a systematic analysis of the extracellular proteostasis network and uncovered its role in combating a pathogenic attack.