Zhao C et al. (1993) Worm Breeder's Gazette "Cloning of the lin-32 Gene"

Emmons SW, Zhao C

[Worm Breeder's Gazette, 1993]

Cloning of the lin-32 gene Connie Zhao and Scott W. Emmons, Department of Molecular Genetics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461

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

Yeon, Jihye et al. (2021) International Worm Meeting "Mechanosensitive Piezo Channel, PEZO-1, regulates food deglutition in C. elegans."

Yeon, Jihye, Kim, Kyuhyung, Golden, Andy, Xiaofei, Bai, Kim, Do-Young, Lee, Kyungeun, Hwang, Hyeonjeong, Jun, Seoyoung, Park, YeonJi, Heo, Woojung

[International Worm Meeting, 2021]

The PIEZO ion channel is an evolutionarily conserved mechanosensitive channel (Coste et al., 2010). Mammalian genomes encode two PIEZO genes, Piezo1 and Piezo2, of which functions have been shown to be involved in mechanosensation (Woo et al., 2014, Nonomura et al., 2017, Li et al., 2014, Rode et al., 2017). C. elegans genome has a single PIEZO gene, pezo-1, which encodes 14 isoforms (Bai et al., 2020). The molecular function of PEZO-1 in C. elegans has yet to be fully determined. To examine pezo-1 function, we grouped 14 isoforms depending on the mRNA length and observed their expression patterns. The promoter region of long isoforms is specifically expressed in the pharyngeal-intestinal valve, which is predicted to mediate food swallowing (Avery and Thomas, 1997). Next, to examine whether pezo-1 has a role in food swallowing, we fed animals with OP50-sized GFP-microsphere and found that pezo-1 mutant animals show excess accumulation of GFP-microsphere in the anterior part of the intestine lumen. Expression of long isoform PEZO-1 or mouse PIEZO1 under the control of valve cell-specific promoter restores the food swallowing defect of pezo-1 mutant animals. We also observed that when GFP-microspheres are fully accumulated at the anterior part of the intestine, the pharynx is pulled posteriorly to push GFP-microspheres down into the posterior intestine. We named this a pharyngeal plunge. We next found that the pharyngeal-intestinal valve exhibits calcium transient during pharyngeal plunge and the optogenetic activation of valve cells induces the pharyngeal plunge. Moreover, elevated pressure in the anterior part of the intestinal lumen by microinjecting buffer solution causes pharyngeal plunge, not in pezo-1 mutant but wild-type animals. Moreover, two gap junction genes, inx-2 and inx-20, which have been shown to connect the valve cells to the pharyngeal muscles, appear to mediate pharyngeal plunge. Currently, we are investigating whether PEZO-1 is activated upon pressure by performing electrophysiology in a heterologous system. These results demonstrate that the C. elegans PIEZO channel regulates pharyngeal plunge and provides insights to understand the function of the mammalian PIEZO channel shown to be expressed in the esophagus.

Liu J et al. (1995) International C. elegans Meeting "Suppression of A Channel Defect By A Mutation In A Basement Membrane Collagen"

Waterston RH, Liu J

[International C. elegans Meeting, 1995]

Semidominant mutations in unc-105 cause hyper- contraction and paralysis of body-wall muscles. Molecular analysis of unc-105 by B. Schrank in this laboratory showed that the unc-105 gene product is a member of the degenerin family and shares homology with amiloride- sensitive sodium channels in mammalian tissues. Thus, UNC-105 protein may be part of a sodium channel that functions in muscle. Significantly, the hyper-contraction and paralysis phenotype of unc-105 mutants can be completely suppressed by mutations in sup-20. Early work by Park and Horvitz showed that these suppressor mutations are special alleles of the gene, and that null alleles of sup-20 cause embryonic lethality (E. -C. Park and H. R. Horvitz, 1986). We have obtained several lines of evidence that suggest sup-20 mutations are allelic to mutations in let-2, a gene encoding the a2 chain of the basement membrane-specific type IV collagen (M. H. Sibley, J. J. Johnson, C. C. Mello, and J. M. Kramer, 1993). First, both genes map to the same interval and mutations in sup-20 and let-2 show non-complementation. Second, sup-20 mutations can be rescued by a cosmid carrying the wildtype let-2 gene. Third, a mutational change in let-2 sequence has been identified in sup-20 mutants. These data suggest a functional link between a potential membrane sodium channel and the extracellualr matrix surrounding the membrane. It is plausible that the gating of this channel involves interaction with the basement membrane, and such interaction may serve as a 'stretch receptor' to transduce external mechanical signals to regulate muscle contraction.

Petzold, Bryan C. et al. (2011) International Worm Meeting "Influence of Body Mechanics on Force Thresholds for Touch Sensation in C. elegans."

Park, Sung-Jin, Pruitt, Beth L., Goodman, Miriam B., Petzold, Bryan C.

[International Worm Meeting, 2011]

We assessed the interplay between body mechanics and touch sensitivity by modulating muscle tone with Channelrhodopsin-2 and measuring force thresholds with a novel force-clamp metrology. Touch sensation is poorly understood despite the prevalence of disrupted touch and associated pain in pervasive diseases like diabetes. C. elegans is an ideal model for touch with its six touch receptor neurons (TRNs) and behavioral response to gentle touch. Force applied to the body results in stress/strain of nearby TRNs, triggering opening of force-gated ion channels, cellular depolarization, and an avoidance response for sufficiently large forces. Previously, we developed a behavioral force-clamp metrology capable of applying nN-mN forces to moving L4/young adult animals (Park et al, Rev Sci Instr, in press). Using this metrology, we showed that wild-type (N2) animals respond to forces ³ 100 nN, revealing unprecedented mechanical sensitivity. Previously, we showed that the three-layered outer shell (cuticle, hypodermis, and body wall muscle) plays a crucial role in filtering and transmitting applied forces (Park et al, PNAS 104:17376, 2007) and that body wall muscle tone regulates body mechanics (Petzold et al, Biophys J, in press). Now, we are testing the hypothesis that changes in body mechanics modulate touch sensitivity. To do this, we compare force-response curves in un-stimulated and hyper-contracted animals. Preliminary results show that larger forces are needed to evoke avoidance responses in hyper-contracted animals. We used light to manipulate body wall muscle contraction in transgenic animals expressing ChR2 under the control of a body wall muscle-specific promoter. This study provides a way to study the interplay between body mechanics and touch sensitivity in C. elegans and will further our understanding of the role of the outer shell in filtering and transmitting loads to the TRNs.

Cherniak C (1995) Trends Neurosci "Neural component placement."

Cherniak C

[Trends Neurosci, 1995]

A range of neuroanatomical results supports the idea that 'save wire' is an organizing principle of brain structure: that the theory of combinatorial optimization of networks applies to the anatomy of the nervous system. In particular, optimization of the placement of components operates at several hierarchical levels in the nervous system, from gross to microscopic anatomy, and from invertebrates to primates. That is, when anatomical positioning of interconnected neural components is treated like a problem of wire minimization in microchip layout, a hypothesis of 'best of all possible brains' is consistent with the observed siting of brains, ganglia, and even somata of individual neurons that minimizes the length of interconnections. In the case of the positioning of ganglia of Caenorhabditis elegans, optimization predictions of one-in-a-million precision can be verified.AD - Committee on History and Philosophy of Science, University of Maryland, College Park 20742, USA.FAU - Cherniak, CAU - Cherniak CLA - engPT - Journal ArticlePT - ReviewPT - Review, TutorialCY - ENGLANDTA - Trends NeurosciJID - 7808616SB - IM

Park, Sang-Kyu et al. (2009) International Worm Meeting "Novel Pathways Mediating Dietary-Restriction-Induced Longevity in C. elegans: NLP-7 Signaling and Endocytosis by Coelomocytes."

Park, Sang-Kyu, Johnson, Thomas

[International Worm Meeting, 2009]

Dietary restriction (DR) is the most widely used intervention to promote longevity in a diverse range of organisms. Despite this, the mechanisms underlying efficacy of dietary restriction still remain elusive. The SKN-1 transcription factor mediates life extension under DR in Caenorhabditis elegans. We identified downstream targets of SKN-1 using genomic transcriptional profiling (Park et al., in press). Two SKN-1-dependent genes, nlp-7 and cup-4, were required for both resistance to oxidative stress and normal longevity. nlp-7 encodes a neuropeptide-like protein and cup-4 encodes a coelomocyte-specific ion-channel. Here, we report that nlp-7 and cup-4 are specifically required for DR-induced longevity in C. elegans. RNAi of nlp-7 or cup-4 significantly reduces the lifespan of a genetic model of DR, the eat-2 mutant, but has no effect on the lifespan of long-lived mutants having reduced insulin/IGF-1 signaling or dysfunctional mitochondrial electron transport chain. There are several methods for imposing DR in the worm and we found that bacterial dilution also fails to increase the lifespan of nlp-7 or cup-4 mutants. RNAi of genes encoding candidate receptors of NLP-7 and genes involved in coelomocyte endocytosis also specifically shortens the extended lifespan of eat-2 mutant. Based on these results, we conclude that two novel pathways, NLP-7 signaling and endocytosis in coelomocytes, are required for life extension under dietary restriction in C. elegans (supported by grants from the NIA).

Schroeder, Frank et al. (2021) International Worm Meeting "Carboxyesterases and intestinal granules in the biosynthesis of novel families of nematode small molecule signals"

Wrobel, Chester, Schroeder, Frank, Sternberg, Paul, Cohen, Sarah

[International Worm Meeting, 2021]

Signaling molecules derived from attachment of diverse primary metabolic building blocks to ascarosides play a central role in the life history of C. elegans and other nematodes; however, the extent to which various inter- and intra-organismal signaling pathways are controlled by small molecules is unclear. Using comparative metabolomics, we show that a pathway mediating formation of intestinal lysosome-related organelles (LROs) is required for biosynthesis of a large library of small molecules, including most modular ascarosides as well as previously undescribed modular glucosides (1). Similar to modular ascarosides, the modular glucosides are derived from highly selective assembly of moieties from nucleoside, amino acid, neurotransmitter, and lipid metabolism. We further show that a family of carboxylesterases (CEST's) that localize to intestinal organelles are required for the assembly of both modular ascarosides and glucosides, suggesting that modular glucosides, like the ascarosides, serve signaling functions. For example, biosynthesis of some modular glucosides is starkly upregulated in long-lived daf-2 mutants, suggesting that insulin signaling is modulated by small molecules produced in a lysosome-dependent manner. Parallel studies in C. briggsae and other nematode species indicate that assembly of modular metabolites via CEST enzymes is widely conserved in nematodes. Further exploration of LRO function and cest homologs in C. elegans and other animals may reveal additional new compound families and signaling paradigms. (1) H. H. Le, C. J. J. Wrobel, S. M. Cohen, J. Yu, H. Park, M. J. Helf, B. J. Curtis, P. R. Rodrigues, P. W. Sternberg, F. C. Schroeder. Modular metabolite assembly in C. elegans depends on carboxylesterases and formation of lysosome-related organelles. eLife, 9, e61886, 2020.

Sabnis S et al. (1991) International C. elegans Meeting "THE CHARACTERIZATION OF UNC-1."

Sabnis S, Sedensky MM, Morgan PG

[International C. elegans Meeting, 1991]

The mechanism of action of volatile anesthetics is as yet unknown. However, it appears that they disrupt neurophysiologic function in a manner conserved throughout nervous systems of different complexities. We are interested in understanding the molecular aspects of this process; a process that seems to be very fundamental to most nervous systems. Mutations in two genes, unc-79 (III) and unc-80 (V) cause altered responses to different groups of volatile anesthetics. This makes it very likely that there are multiple sites at which volatile anesthetics act, and that such sites are separable by mutation. Double mutant studies have indicated that other mutations such as unc-l (X), unc-7 (X), unc-9 (X) and unc-24 (IV) act as suppressors of unc- 79 and unc-80. Of all of these, we are most interested in further characterization of unc-l. There are four classes of unc-l alleles ( Park and Horvitz, 1986); two dominant coilers and two recessive kinkers. Only those alleles that show the recessive kinked phenotype act as suppressors of unc-79 and unc-80. By itself, an unc-l mutant shows an increased sensitivity to diethylether. In an attempt to clone the unc-l gene by transposon tagging, we are currently using the following methods for isolating spontaneous unc-l mutants. 1.) Brute- force screening for the kinky phenotype in the mutator strain RW7097 ( mut-6). 2.) Screening mut-2 (or mut-6); unc-79 double mutants for the suppression of sensitivity to halothane. 3.) Screening mut-2 (or mut-6) ; unc-l (d) double mutants for the loss of the dominant coiled phenotype and gain of the recessive kinked phenotype. Should none of these efforts give us the mutation of interest, we will also search for polymorphisms close to unc-l and initiate a walk to the gene.

Buechner M et al. (2000) Japanese Worm Meeting "A faciogenital dysplasia gene homologue regulates the formation of organ structure in C. elegans"

Hisamoto N, Nishiwaki K, Matsumoto K, Suzuki N, Buechner M, Hall DH

[Japanese Worm Meeting, 2000]

The molecular controls governing the formation of organ structure in the development are less understood. The Caenorhabditis elegans excretory system, like the renal organs of other animals, is believed to regulate osmoregulation and water elimination1. The excretory cell extends tubular processes, called canals, along the basolateral surface of the epidermis. Mutations in the exc-5 gene cause tubulocystic defects in the excretory canal. Here we report that exc-5 encodes a protein homologous to guanine nucleotide exchange factors (GEFs). EXC-5 contains, in order, a Dbl/Plecstrin homology (DH/PH) domain, a cysteine-rich FYVE domain and a second PH element. This motif architecture is similar to that of FGD1 (ref. 2), which is responsible for faciogenital dysplasia or Aarskog-Scott syndrome. Ultrastructural results suggest that exc-5 is required for the proper placement of cytoskeleton at the apical epithelial surface. Furthermore, EXC-5 associates with KEL-2, a protein similar to the actin-associated protein Drosophila Kelch3,4. We speculate that EXC-5 controls structural organization of the excretory canal by linking between the actin cytoskeleton and a Rho family GTPase. References: 1. Nelson, F. K., Albert, T. S. & Riddle, D. L. Fine structure of the Caenorhabditis elegans secretory-excretory system. J. Ultrastruct. Res. 82, 156-171 (1983) 2. Broeks, A., Janssen, H. W., Calafat, J. & Plasterk, R. K. A P-glycoprotein protects Caenor ha bditis elegans against natural toxins. EMBO J. 14, 1858-1866 (1995) 3. Pasteris, N. G. et al. Isolation and characterization of the faciogenital dysplasia (Aarskog-scott syndrome) gene: a putative Rho/Rac guanine nucleotide exchange factor. Cell 79, 669-678 (1994) 4. Chitwood, M. B. & Chitwood, B. G. The excretory system. In Introduction to Nematology:(eds. Chitwood, B. G. & Chitwood, M. B.; University Park Press, Baltimore) 126-135 (1974)