White JG (2000) Int J Dev Biol "Worm tales."

White JG

[Int J Dev Biol, 2000]

1969 was a landmark year. But for me it was not Neil Armstrong's giant leap or Woodstock heralding the beginning of the end of the sixties that sticks in my mind. It was a visit I made to Cambridge to meet a "bloke who is starting a new project to study some sort of worm", as my head of department at the Medical Research Council's National Institute of Medical Research informed me...

Xu XM et al. (2009) Sheng Li Ke Xue Jin Zhan "[Physiological and molecular control of lipid accumulation in Caenorhabditis elegans]."

Wang DY, Xu XM

[Sheng Li Ke Xue Jin Zhan, 2009]

Fat storage is a complex physiological process, and model organism of Caenorhabditis elegans has already been explored as an important model to study lipid accumulation. The lipid particles or fatty acid can be stained or labeled with Sudan Black B or Neil Red. The metabolism pathways for fatty acid synthesis and breakdown in nematodes are almost identical to those in other organisms, and functions of many genes encoding the key regulation enzymes have been identified. At least four central regulation pathways are involved in the fat storage control in nematodes: insulin and TGF-beta signaling pathway, sbp-1/mdt-15 mediated pathway, nhr-49 mediated pathway, and TOR and hexosamine pathway. Moreover, neurotransmitters 5-HT, dopamine, and glutamate were found to participate in the control of lipid accumulation. In addition, involvement of tub-1 and bbs-1 in neuronal control of fat storage suggest the possibly important roles of amphid structure and sensory neurons in regulating lipid accumulation. The data obtained in C. elegans on fat storage control will contribute largely to the study on metabolism related diseases, such as obesity, in human beings.

Huang, Huiyan et al. (2021) International Worm Meeting "C. elegans modeling and human studies of a rare RAB5B patient variant reveal a novel role of RAB5B in regulated secretion of pulmonary surfactant"

Huang, Huiyan, Lindsey, Anika, Dawson, Zachary, Spielberg, David, Chen, Jian, Schedl, Tim, Mohammad, Ariz, Burrage, Lindsay, Kim, Hyori, Baldridge, Dustin, Pan, Jiehong, Rosenfeld, Jill, Scott, Daryl, Pak, Stephen, Hanchard, Neil, Murdock, David, Morrison, Stephanie, Dai, Hongzheng, Brody, Steven, Zhu, Alex, Tycksen, Eric, Silverman, Gary, Ramu, Avinash

[International Worm Meeting, 2021]

Many patients with severe, chronic diseases remain without a diagnosis despite extensive medical evaluation, including some cases with clinical exome sequencing. The goal of the NIH-funded Undiagnosed Diseases Network (UDN) is to provide a diagnosis for these challenging cases and to identify biological characteristics of newly discovered disease genes. The UDN uses a collaborative multidisciplinary approach that combines comprehensive medical workup, exome/genome sequencing, bioinformatic analysis, with functional studies in model organisms including zebrafish, Drosophila, and C. elegans. Through the UDN, we evaluated a child with interstitial lung disease suggestive of surfactant deficiency. Variants in known surfactant dysfunction disorder genes were not found in trio exome sequencing. Instead, a de novo heterozygous variant, p.Asp136His, in the Ras/Rab GTPases family nucleotide binding domain in RAB5B was identified. Functional studies were performed in the C. elegans Model Organism Screening Center at Washington University in St. Louis. We used CRISPR/Cas9 to knock the proband variant into the conserved position (Asp135) of the ortholog, rab-5. Analyses of organismal phenotypes such as locomotion and size demonstrated that rab-5[Asp135His] is damaging. We also show data indicating that rab-5[Asp135His] heterozygotes were defective in endocytosis and early endosome (EE) fusion. Dosage analysis by adding extra copies of wild type rab-5 transgene revealed that rab-5[D135H] has a strong dominant negative effect, requiring three wild type copies to suppress the variant's poisonous effect. Immunostaining studies of the proband's lung biopsy revealed that RAB5B and EE marker EEA1 were significantly reduced in type II pneumocytes, and mature SP-B and SP-C were significantly reduced, while ProSP-B and ProSP-C were normal. Furthermore, staining of normal lung showed co-localization of RAB5B and EEA1 with ProSP-B and ProSP-C. These findings indicate that dominant negative-acting RAB5B Asp136His and EE dysfunction cause a defect in processing/trafficking to produce mature SP-B and SP-C, inducing interstitial lung disease, and that RAB5B and EEs normally function in the regulated surfactant secretion pathway. Together, the data suggest a non-canonical function for RAB5B and identify RAB5B p.Asp136His as a genetic mechanism for surfactant dysfunction disorder.

James Dillon et al. (2006) European Worm Meeting "The Molecular, Cellular and Functional Organization of the C. elegans Metabotropic Glutamate Receptor, MGL-1"

Lindy Holden-Dye, James Dillon, Vincent O'Connor, Neil A. Hopper

[European Worm Meeting, 2006]

James Dillon, Neil A. Hopper, Lindy Holden-Dye and Vincent O''Connor. Metabotropic glutamate receptors (mGluRs) are G-protein coupled receptors that are responsible for the fine-tuning of glutamatergic signalling within neural networks that subserve complex brain functions and behaviours. The C. elegans mGluR, mgl-1, is selectively expressed in the nervous system, where it is distributed in neurons of the tail, the nerve ring and the pharynx. We have defined a role for MGL-1 in the modulation of pharyngeal function and feeding behaviour. In the presence of the mammalian mGluR agonists, trans-ACPD (500?M) and L-CCG-I (EC50: 3?M) pharyngeal pumping is inhibited. The basal pharyngeal pumping frequency of the mgl-1 mutant strain mgl-1(tm1811) is not significantly different to wild-type levels in the absence of drug and is not inhibited by drug application (trans-ACPD 500?M and L-CCG-I in the range 1-12.5?M). The inhibition by L-CCG-I was rescued in mgl-1(tm1811) by the re-introduction of the mgl-1 gene, suggesting MGL-1 is responsible for the agonist-mediated regulation of pharyngeal function. The intracellular C-terminals of the eight mammalian mGluR subtypes have been shown to be responsible for directing protein-protein interactions with accessory proteins that scaffold the receptors function. Scaffolding entails the targeting of the receptor to specific compartments of the neuron, anchoring within specialized subcellular domains and the organised assembly of the receptors intracellular signalling pathway. A yeast-2-hybrid screen was performed with the MGL-1 C-terminal to identify proteins that scaffold MGL-1 function. The multi-PDZ domain protein MPZ-1a was identified as a strong interactor in yeast. MPZ-1a is encoded by the gene mpz-1, which we have identified as being co-expressed with mgl-1 in neurons of the pharyngeal nervous system and the nerve ring. The inhibition of pharyngeal pumping by MGL-1 in response to the agonist L-CCG-I was used as a behavioural assay to assess the functional significance of the interaction between MGL-1 and MPZ-1 in this neural network. Pharyngeal pumping was recorded from the available mpz-1 mutant animals mpz-1(tm1136), mpz-1(gk273/+) and mpz-1(tm1136/gk273) trans-heterozygotes. In each case a wild-type response was recorded in the presence of L-CCG-I, suggesting the MGL-1 signalling complex is intact. Although our study provides the first evidence for the function of MGL-1 in worm behaviour the significance of the PDZ-domain dependent interaction of MGL-1 and MPZ-1a requires further investigation.

Neil A. Hopper et al. (2006) European Worm Meeting "Do ark-1, gap-1 and sli-1 Have synMuvB Activity?"

Paul W. Sternberg, Neil A. Hopper, Junho Lee, Anne D. Wooller

[European Worm Meeting, 2006]

?. Neil A. Hopper1, Junho Lee2,3, Paul W. Sternberg2 and Anne D. Wooller1. During wild-type hermaphrodite development, the gonadal anchor cell induces 3 from 6 vulva precursor cells (VPCs) to form the vulva. This inducing signal activates the Egfr/Ras/Map kinase pathway in a dose dependent manner in the proximal VPCs. Lateral signalling refines this to ensure that the VPC closest to the anchor cell adopts the primary fate and the two adjacent VPCs adopt the secondary fate. Activity of the synthetic multivulva (synMuv) genes ensures that the remaining VPCs adopt the tertiary (non-induced) fate. The synMuv genes broadly fall into two classes: class A and class B. Mutations in either class alone are superficially silent with respect to vulval induction. However, in animals carrying mutations in both classes, all six VPCs adopt vulval fates. A third class, the synMuvC genes act redundantly with both synMuv A and B genes. The synMuvA genes are novel. Many class B synMuv genes encode components of the Rb/Histone deacetylase complex signaling pathway that represses transcription and conversely the synMuvC genes encode transcriptional co-activators that include a histone acetyl transferase. At least some of the synMuv genes have been shown to act outside the VPCs.. ark-1, gap-1 and sli-1 were identified as negative regulators of Egfr/Ras/Map kinase signalling and interact with each other to produce a partially penetrant excessive vulval induction phenotype. We recovered lin-15A(pd3) in a screen for mutations that interact with ark-1 to produce excessive vulval induction. lin-15A(pd3) R27stop interacts with ark-1, gap-1 and sli-1 to produce a temperature sensitive Muv phenotype. This result is confirmed with additional lin-15A alleles and with a second synMuvA gene, lin-8(n111). Moreover, the ark-1; lin-15A Muv phenotype is partially gonad independent. In contrast, no interaction is seen between ark-1, gap-1 and sli-1 and the synMuvB genes. This suggests that ark-1, gap-1 and sli-1 may have weak synMuvB activity. An alternate possibility is that the synMuvA genes have a non-redundant activity that weakly antagonises Egfr/Ras/Map kinase signalling in the VPCs, and this synergises with ark-1, gap-1 and sli-1. Consistent with this latter possibility, null alleles of lin-15A display a partially penetrant excessive vulval induction phenotype at 25C by themselves and along with lin-8(n111) enhance the sos-1(pd10gf) and let-60(n1046gf) Muv phenotype. However, unlike the enhancement of ark-1, gap-1 and sli-1 by synMuvA genes, the enhancement of sos-1(pd10gf) and let-60(n1046gf) Muv is not synMuvA specific, as it is also seen by a sub-set of synMuvB genes. These and other related findings will be presented.

James Dillon et al. (2006) European Worm Meeting "Screening for Negative Regulators of Growth Factor Signalling"

Anne D. Wooller, Neil A. Hopper, James Dillon

[European Worm Meeting, 2006]

James Dillon, Anne D. Wooller and Neil A. Hopper. The Egfr/Ras/Map kinase pathway functions several times during C. elegans development to specify various hypodermal specialisations including the excretory duct cell and hermaphrodite vulva. Animals severely compromised for Egfr/Ras/Map kinase pathway signalling fail to produce the excretory duct cell and die as vacuolated L1s. The Fgfr/Ras/Map kinase pathway regulates the activity of the excretory system and certain cell migrations, including that of the sex myoblasts. Animals homozygous for the sem-5(n1619) mutation are maternal effect lethal due to a failure to induce the excretory duct cell and/or due to effects upon excretory system activity. We screened for suppressors of the sem-5(n1619) lethality and identified 13 suppressors. Nine of these suppressors also suppressed the vulvaless phenotype of sem-5(n1619) and were given allele names (pd8-pd16). All suppressed animals are egg laying defective, suggesting that the sex myoblast migration defect of sem-5(n1619) is not suppressed. Candidates for suppressors include loss/reduction of function alleles in ark-1, clr-1, gap-1 and sli-1 and gain of function alleles of components of the Ras/Map kinase pathway. The four suppressing mutations that have been cloned were such candidates and include two gain of function sos-1 alleles. We hypothesise that sos-1(pd9gf), which produces a C662Y substitution, increases the rate of SOS catalysed nucleotide exchange on RAS and are performing biochemical experiments to test this. In order to test whether the suppressors of sem-5(n1619) lethality we isolated were specific to the Egfr we also tested them for suppression of a weak daf-2/InsR allele, m577, using the dauer assay. The majority of sem-5(n1619) suppressors also suppressed the daf-2(m577) Daf-c phenotype. This included the sos-1gf alleles and also reference alleles of ark-1, clr-1 and sli-1, but not gap-1. However, gap-2 was found to weakly suppress the daf-2(m577) Daf-c phenotype. These findings may be explained by the finding that let-60/Ras is a positive regulator of DAF-2 signalling during dauer formation (see also Nanji, Hopper and Gems (2005) Aging Cell 4, 235-245). In a related screen, we sought to look for suppressors of the daf-2(m577) Daf-c phenotype. To distinguish those that may suppress due to the enhancement of Ras signalling from other suppressors, we performed the screen in a daf-2(m577); gap-1(n1691) background, with the logic that any suppressors that enhanced Ras signalling would also produce a multivulva phenotype in this backgound. >From a 10, 000 genome screen we isolated 16 suppressors of daf-2(m577) Daf-c, none of which produced a multivulva phenotype in combination with gap-1(n1691). Preliminary data from this screen will also be presented.