Foster, Olivia et al. (2015) International Worm Meeting "Regulation of GLO-1 Rab GTPase activity in trafficking to gut granules."

Vo, My Van, Hermann, Greg, Foster, Olivia, Peloza, Kim

[International Worm Meeting, 2015]

Gut granules are C. elegans intestinal cell restricted lysosome-related organelles (LROs). Protein trafficking to LROs utilizes factors that mediate trafficking through conventional endosomes to lysosomes including CCZ-1 and RAB-7. A CCZ-1/SAND-1 complex acts as a guanine nucleotide exchange factor (GEF) to activate RAB-7 and promote early endosome to late endosome maturation and RAB-5 to RAB-7 conversion. There are also factors with intestinal cell restricted expression such as GLO-3 and the Rab GTPase GLO-1 that are essential for gut granule biogenesis. Our recent studies suggest that CCZ-1, but not SAND-1, functions with GLO-3 as a GEF for GLO-1. We investigated this model by analyzing and comparing gut granule protein trafficking of three integral gut granule proteins and find that ccz-1(-) displays phenotypes distinct from glo-1(-) and glo-3(-). However, glo-1(-); sand-1(-) and glo-3(-); sand-1(-) mutants resemble ccz-1(-), consistent with distinct trafficking phenotypes in ccz-1(-) resulting from its function in endosome maturation and gut granule biogenesis. If CCZ-1/GLO-3 functions as a GEF for GLO-1 then it should promote the GTP-bound and membrane associated form of GLO-1. We find that glo-3(-) and ccz-1(-), but not sand-1(-), mutants lead to increased cytoplasmic levels of GFP::GLO-1. Weak alleles of glo-3(-) display reduced numbers of enlarged autofluorescent and birefringent compartments in embryos. We find that these organelles have hybrid late endosome/gut granule characteristics, whereby they contain some gut granule proteins (PGP-2 and CDF-2::GFP) but lack others (LMP-1) and they are often marked by RAB-7, which does not normally associate with gut granules. These results suggest that GLO-3 prevents the accumulation of RAB-7, possibly via Rab conversion, and point to these organelles being intermediates in the LRO biogenesis pathway. We screened our collection of gut granule biogenesis mutants for cytoplasmic accumulation of GLO-1::GFP and identified a phenotype similar to ccz-1(-) and glo-3(-) in wht-2(-) mutants. WHT-2 is an ABCG family membrane transporter, which we find is localized to the gut granule membrane. wht-2(-) mutants display only subtle defects in the formation of gut granules. However, the activity of GLO-1 spontaneous nucleotide exchange mutants, which can bypass the requirement of both GLO-3 and CCZ-1 in gut granule biogenesis, requires WHT-2 function, suggesting a novel role for an ABC transporter in Rab GTPase recruitment/activation.

Foster, K.J. et al. (2019) International Worm Meeting "Olfactory neuron protein promotes intestinal immune homeostasis to ensure evolutionary fitness."

Liu, P., Pukkila-Worley, R., Cheesman, H.K., Foster, K.J., Peterson, N.D.

[International Worm Meeting, 2019]

Innate immune homeostasis is critically important for the health of metazoans, including C. elegans. Here, we demonstrate that control of innate immune activation via a signaling axis between sensory neurons and the intestine is required for reproductive fitness. We show that an olfactory neuron protein functions in the cell non-autonomous suppression of the canonical p38 MAP kinase PMK-1 immune pathway in the intestine. Immune de-repression in loss-of-function mutants causes constitutive activation of the p38 MAP PMK-1, hyperinduction of immune effector transcription and resistance to bacterial infection. Importantly, we demonstrate that regulation of the p38 MAPK PMK-1 pathway is required for healthy nematode development and reproduction. These data demonstrate that olfactory neurons regulate the p38 MAPK PMK-1 immune pathway in the intestine and indicate that maintenance of immune homeostasis is an evolutionarily ancient requirement for growth and reproduction of free-living organisms.

Ahn, Soungyub et al. (2015) International Worm Meeting "Novel regulators of RUNX transcription factor in Caenorhabditis elegans."

Chun, Jongsik, Swoboda, Peter, Ahn, Soungyub, Lee, Junho, Oh, Hyun-Seok

[International Worm Meeting, 2015]

RUNX transcription factors play pivotal roles in mammalian development and carcinogenesis. Proper expression and regulation of RUNX foster proper organismal development and prevent cancer development. We previously reported that RNT-1, the C. elegans sole RUNX homolog protein, is degraded by ubiquitin-proteasome system (UPS) and is stabilized upon acute oxidative stress response by repressing UPS. Nevertheless, other mechanisms of RNT-1 degradation remain elusive. To solve this question, we tried to find the novel regulator of RNT-1 stability and understand its mechanism. We isolated novel regulator genes involved in RNT-1 stabilization by random mutagenesis. Now we are characterizing RNT-1-stabilized mutants, and investigating the effect of the mutation on RNT-1 stability. Our study will contribute to further understanding of RUNX-involved development and carcinogenesis.

Page K E et al. (2010) Aging, Metabolism, Stress, Pathogenesis, and Small RNAs, Madison, WI "Genes Affecting Aluminium Toxicity in Caenorhabditis elegans"

McCrohan C R, Page K E, White K N, Lithgow G J

[Aging, Metabolism, Stress, Pathogenesis, and Small RNAs, Madison, WI, 2010]

Aluminium (Al) is a highly abundant crustal metal with known toxic effects in multiple biological systems. Using the nematode C. elegans we have found a set of genetic modulators of Al toxicity. C. elegans is widely used for toxicity and aging studies due to its small size, large progeny numbers, short lifespan, and simple methods of genetic manipulation. This makes C. elegans a good model to study the toxicity mechanism of Al in animals. The exposures were carried out on agar plates, with Al in the form of Al(NO3)3, mixed with a concentrated Escherichia coli food source. Here we show that a selection of genes involved in the mechanisms of Al toxicity and/or metabolism have potential relevance in the metallostasis (metal homeostasis) of other metals, or are key regulators of known stress resistance pathways. Al negatively affects C. elegans developmental progression from 3 microM Al, fertility at 30 microM Al, and body size from 1.9 mM Al. The developmental delay phenotype caused by Al exposure can be passed on to the un-exposed next generation. At 4.8mM exposures Al affects the levels of Al and other elements in C. elegans; shown using ICP-OES. We are also investigating the effect of Al exposure to the course of normal aging in C. elegans.

Gumienny, T.L. et al. (2017) International Worm Meeting "TWU Active Engagement Academy: Improving active engagement in academic courses."

Gumienny, T.L., Westmoreland , S.

[International Worm Meeting, 2017]

High enrollment classes (>50 students) have historically been associated with lower student engagement and higher failure rates than lower enrollment classes. Active learning has been demonstrated to increase student engagement and, indirectly, student persistence. In addition, faculty who use high engagement in their classrooms become pedagogical role models for the future teachers who are enrolled in their courses. By initiating an Active Engagement Academy at Texas Woman's University, faculty who teach large lecture classes have been recruited and trained to use active learning and teaching methods to foster student engagement, academic success, and retention. The Active Engagement Academy model will be self-perpetuating as participating faculty will become role models within their academic departments for other faculty and for the teacher candidates enrolled in their courses. This presentation will provide a model and framework for other instructors who wish to promote active engagement in their institution's classrooms, including the rationale, recruiting information, workshop plans, and designs for active engagement implementations and measurements for intervention success.

Shelli N Williams et al. (2002) Mid-west Worm Meeting "Cytoskeletal defects associated with NUD-1 knockdown in early embryogenesis of C. elegans"

Shelli N Williams, Kim A Caldwell, Guy A Caldwell

[Mid-west Worm Meeting, 2002]

Dawe et al. Dev Genes Evol. (2001) 211:434-441.

Page, Kathryn E. et al. (2009) International Worm Meeting "Exploring Aluminium Toxicity in C. elegans."

Page, Kathryn E., McCrohan, Catherine R., White, Keith N., Lithgow, Gordon J.

[International Worm Meeting, 2009]

Aluminium (Al) is a highly abundant crustal metal with known toxic effects in multiple biological systems. Caenorhabditis elegans (C. elegans) is widely used for toxicity and aging studies due to its small size, large progeny numbers, short lifespan, and simple methods of genetic manipulation. C. elegans is a good model to study the toxic mechanism of Al in animals, and has been widely used for the study of environmental metal toxicology. Here we show Al effects fertility, and development progression, and that these phenotypes are transferable to the progeny of exposed worms. The exposures were carried out on agar plates with the Al mixed with concentrated OP50 which was then fed to the worms. Al negatively affects C. elegans developmental progression at 0.1 to 300 mM Al food concentration, and fertility at 1 mM Al food concentration. The developmental delay phenotype caused by Al exposure can be passed on to the next generation. It is possible that the mechanism of Al toxicity is similar to that of other toxic metals.

Richard S Allan et al. (2005) International Worm Meeting "High-resolution, digitally-encoded phenotypic analysis of gonadogenesis in C. elegans"

E Jane Albert Hubbard, Richard S Allan, Philip MacMenamin, Kristin C Gunsalus, Fabio Piano, Krishna Vijayendran

[International Worm Meeting, 2005]

A fundamental premise of genetic analysis is that genes with similar loss-of-function phenotypes likely act in similar developmental processes. Extending this concept to RNAi-based genome-scale functional characterization, Piano et al. (2002) defined 47 embryonic phenotypic characters in C. elegans and generated a digital phenotypic signature for each RNAi experiment. Genes conferring similar signatures were clustered (phenoclusters), placing previously uncharacterized genes in clusters with genes of known function. The primary data (high-magnification time-lapse movies), scoring criteria and results are publicly available and can be analyzed and queried using additional tools (e.g. Phenoblast) (Gunsalus et al., 2004; http://www.RNAi.org).We have applied this approach to gonadogenesis and germline development in C. elegans. In previous large-scale RNAi screens, over 800 genes are reported to confer a sterile (Ste) or sterile progeny (Stp) phenotype, based on low-magnification screening (Gonczy et al., 2000; Fraser et al. 2001; Piano et al., 2001; Maeda et al., 2001; Hanazawa et al. 2001; Piano et al., 2002; Kamath et al., 2003; Simmer et al., 2003). A subset of these have been examined under high magnification (Maeda et al., 2001; Hanazawa et al., 2001; Colaiacovo et al., 2002), but these data are not available in a systematic digital format amenable to analyses such as phenoclustering or Phenoblast, nor to phenotypic search criteria.We developed and are implementing a web-based digital scoring system (currently 262 characters) for high-magnification phenotypes in adult hermaphrodites. Characters include both quantitative and qualitative features of the gonad, germ line and gametes as well as several gonad-related characters. We generate a series of digital Z-plane images at high magnification from each RNAi experiment. All data will be made publicly available on the RNAi.org website. Our test set is 147 Stp genes and 260 Ste genes conferring a wide range of RNAi-induced defects.

Page, Kathryn E. et al. (2011) International Worm Meeting "Aluminium Toxicity and Elemental Composition Changes in Caenorhabditis elegans."

Killilea, David W., Lithgow, Gordon J., McCrohan, Catherine R., White, Keith N., Page, Kathryn E.

[International Worm Meeting, 2011]

Environmental metal contamination events such as the alumina sludge spill in Hungary last year highlight the importance of understanding metal toxicity and predicting detrimental effects. Aluminium (Al) is highly abundant in our environment, but can elicit a variety of toxic responses. Here we present the first characterization of the effects of Al exposure in the nematode worm Caenorhabditis elegans by identifying phenotypic abnormalities and disruption in whole body metal homeostasis (metallostasis) following Al exposure. Lifespan was decreased in worms exposed to low levels of Al, but was unexpectedly increased when the Al concentration reached higher levels. Interestingly, this bi-phasic phenotype was only observed when Al exposure occurred during development, as adult worm lifespan was unaffected by Al at similar exposures. Al negatively affected C. elegans developmental progression and self-fertility when exposed to as little as 30mM Al, and reduced body size when exposed to 1.9 mM Al. Significant developmental delay was observed even when Al exposure was restricted to embryogenesis. Widespread changes to the elemental content of adult nematodes was observed when chronically exposed to Al from L1. Specifically we saw increased Ba, Cr, Cu, and Fe content, and a reduction in Ca levels. Similar changes have been noted in human Al toxicity, suggesting that C. elegans may be exploited to understand the mechanisms of Al toxicity in human tissue. Elemental homeostasis is obviously highly regulated, and here we see that changing the levels of only one element can alter the whole elemental profile. This raises the question of how genes affect these elemental profiles. Here we determine how gene knockdown can alter metallostasis and elemental profiles in C. elegans. It is notable that these genetic modulators of elemental profiles are not only important for metallostasis, but are key regulators of known stress response mechanisms. Knock-down of these gene products alters the elemental profile of the worm, which suggests novel mechanisms of action for these genes in metal toxicity and general stress response.

Saleel Raut et al. (2008) C.elegans Neuronal Development Meeting "HLH-3, a C. elegans Achaete/Scute protein, has a role in the axonal pathfinding of hermaphrodite-specific motor neuron (HSN) that is independent of UNC-40."

Aixa Alfonso, Saleel Raut

[C.elegans Neuronal Development Meeting, 2008]

The basic helix loop helix protein, HLH-3, is a member of the achaete/scute family in C. elegans hlh-3 mutants have an egg-laying defective (Egl) phenotype. We have shown (Doonan et al., 2008 submitted) that the mutant phenotype results from abnormal axonal pathfinding in hermaphrodite-specific motor neurons (HSNs) that fail to innervate the vulval muscles. The NETRIN/UNC-6 receptor UNC-40/DCC is necessary for the guidance of the HSN axons (Garriga et al.,1993; Chan et al., 1996; Gitai et al., 2003; Adler et al., 2006). We hypothesized that mutant animals are not uncoordinated (Unc). Currently we are looking at SYG-1, a receptor on HSN''s that binds with the guidepost signal SYG-2 for proper synapse formation (Shen et al., 2004), as a possible target of HLH-3.