Brunschwig K et al. (1995) International C. elegans Meeting "A DELETION DERIVATIVE OF CEH-13"

Wittmann C, Tobler H, Brunschwig K, Plasterk RHA, Mueller F

[International C. elegans Meeting, 1995]

The C. elegans HOM-Cluster is located on the third chromosome and consists of at least four Antennapedia-class homeobox genes: lin-39, ceh-13, mab-5 and egl-5. Mutants of lin-39, mab-5 and egl-5 show defects in the specification of positional cell fate along the anterior-posterior axis[1].

Kohler R et al. (1997) International C. elegans Meeting "MAPPING THE CEH-13 ENHANCER"

Kohler R, Tobler H, Brunschwig K, Fleischmann M, Mueller F

[International C. elegans Meeting, 1997]

Metazoan development is in part regulated by a group of homeobox containing genes arrayed in an evolutionarily conserved cluster. ceh-13, a member of the C. elegans HOM-C cluster, is the orthologue of the Drosophila labial gene. Antibody staining and reporter gene expression experiments have revealed that CEH-13 has a highly complex and dynamic expression pattern (see also posters by Fleischmann M. and Brunschwig K.). Additionally, these studies identified an 8 kb upstream enhancer/promoter region that was sufficient to confer essentially wild type expression to GFP reporter gene constructs. Different biochemical and genetic aspects of the regulation of Hox/HOM-C expression have been described in various species. Nevertheless a complete picture of Hox/HOM-C transcriptional control awaits to be put forward. Furthermore, recent studies indicated that the control of these genes in C. elegans may be significantly different from what is known from other species. For those reasons, we initiated a detailed in vivo analysis of the ceh-13 enhancer region by means of expression monitoring of various GFP reporter gene constructs in transgenic animals. So far these studies have shown that different, dissectable enhancer elements are present in the ceh-13 regulatory region. These elements appear to independently direct different aspects of CEH-13 expression. A preliminary analysis of different enhancer elements and their significance in the context of C. elegans development will be presented.

Xin Li et al. (2007) International Worm Meeting "The functions of HOM-C genes in P11/P12 development."

Xin Li, Russell Hill, Helen Chamberlin

[International Worm Meeting, 2007]

During postembryonic C.elegans development, ventral ectoblasts called P cells divide to produce ventral cord neurons and hypodermal cells. While each of the 12 P cells undergoes a similar cell lineage, P cells in different anterior/posterior positions undergo different variations of this lineage in response to the action of homeotic complex (HOM-C) genes. The two most posterior P cells initially have similar potential to undergo two patterns of development known as the P11 and P12 cell fates. In normal development, the Abdominal-B (Abd-B) homolog egl-5 is necessary and sufficient for P12 development. Because the expression pattern of egl-5 is important for P12 development, we are studying the mechanisms that control egl-5 expression. EGL-5 is expressed during early and late steps of P12 development. We have mapped a 365bp cis regulatory region (present within a previously mapped 1.3kb hindgut enhancer called pLG7, Teng et. al. 2004 Dev.Biol. 276:476) of the egl-5 gene that is sufficient for the late expression of EGL-5 in P12.pa. This region contains a potential HOM-C/PBC binding site that is conserved in closely related nematode species. Site-directed mutagenesis of this element eliminates the enhancer activity, confirming that this site is necessary for late expression in the P12 lineage. Furthermore, we have shown that the expression from this region can be activated by induced expression of EGL-5, indicating that it is a functional HOM-C response element. This element does not promote early expression in P12, suggesting that a separate cis regulatory region that we call the "initiation element" is necessary for the early expression of EGL-5. The mapping of the initiation element is ongoing. While egl-5 is required for P12 specification in normal development, this requirement for egl-5 is influenced by other HOM-C genes. If egl-5 is removed in combination with the adjacent HOM-C gene mab-5/Abdominal-A, then P12 development can occur (Kenyon C. 1986 Cell 46:477 and personal observation). This suggests that other genes can specify the P12 fate, but that MAB-5 normally prevents these genes from being active in P12. We hypothesize that one or both of two other Abd-B homologs (php-3 and nob-1) may be responsible for P12 fate in the double mutant. We have shown that induced NOB-1 expression is sufficient to rescue P12 development in egl-5(n945) mutants, indicating that Abd-B homologs retain some common functions. We are testing whether induced PHP-3 expression can likewise rescue P12 development.

Martin Gutternigg et al. (2006) European Worm Meeting "Glycosidases of Caenorhabditis elegans involved in N-glycan processing"

Martin Gutternigg, Matthias Hackl, Ute Stemmer, Iain B. H. Wilson, Petra Geier, Gunter Lochnit, Ramona Ranftl, Katharina Paschinger, Verena Jantsch, Dorothea Lubich

[European Worm Meeting, 2006]

Martin Gutternigg, Dorothea Lubich, Matthias Hackl, Katharina Paschinger, Ute Stemmer, Verena Jantsch1, Gnter Lochnit2, Ramona Ranftl, Petra Geier and Iain B. H. Wilson. Recent data indicates that in addition to the Golgi ?-mannosidases, the model nematode Caenorhabditis elegans also possesses, like insects, an N-acetylhexosaminidase activity putatively involved in N-glycan processing in the Golgi. The presence of such an activity is invoked, not just on the basis of the detected enzyme activity, but also to explain the absence of terminal N-acetylglucosamine residues on structures which require the prior action of N-acetylglucosaminyltransferase I during their biosynthesis. In order to understand the genetic basis for these activities, we have cloned cDNAs encoding members of both glycohydrolase families 20 and 38 from the worm. The encoded glycosidases were expressed in the yeast Pichia pastoris as soluble forms lacking putative cytoplasmic and transmembrane domains. Four glycohydrolase family 20 members were shown to cleave p-nitrophenyl-?-N-acetylglucosaminide and/or p-nitrophenyl-?-N-acetylgalactosaminide, but showed contrasting specificities with regard to N-glycan substrates. On the other hand, one glycohydrolase family 38 member was shown to be active using p-nitrophenyl-?-mannoside as a substrate and, in addition, had mannosidase II activity. Analysis of the glycans of the relevant mutant showed large-scale changes in the N-glycosylation spectrum. These, therefore, are the first data on the activity of Caenorhabditis glycosidases towards N-glycan substrates and should aid the further elucidation of N-glycan processing in this organism.

ZHANG, Gaotian et al. (2015) International Worm Meeting "Characterization of nematode-infecting microsporidia and natural variation in sensitivity of Caenorhabditis nematodes to microsporidia."

Zhang, Gaotian, Felix, Marie-Anne

[International Worm Meeting, 2015]

The microsporidian Nematocida parisii is the first characterized intracellular pathogen of Caenorhabditis elegans; and a second Nematocida species, called N. sp. 1, was also reported from an Indian C. briggsae isolate (Troemel et al. 2008). In our lab we further established a collection of wild rhabditid nematodes suspected with microsporidian infection. Here, we characterize molecularly these wild microsporidia and study their specificity of infection.First, the potentially infected rhabditid isolates were characterized using newly designed PCR primers specific for 18S and beta-tubulin genes of microsporidia. In addition to C. elegans, we found wild C. briggsae and Oscheius tipulae as natural hosts for N. parisii; in addition to C. briggsae, we found C. elegans and C. remanei as natural hosts of N. sp. 1. We further found three new microsporidian species. Two of them are close to the Nematocida species in microsporidian clade II and preliminarily named N.-like sp. 2 and N.-like sp. 3. The third species (or group of species), infecting Oscheius, is very distant, and found in microsporidian clade IV, that includes most human pathogens. They are closest to Orthosomella operophterae (with 18S), and thus preliminarily named Orthosomella-like spp.. Phylogenetic analyses with the 18S and beta-tubulin genes provide the same relationships of Nematocida spp. and the three putative new microsporidia species. Co-infections of two microsporidian species occurr in two wild O. tipulae strains, of which one infected with N. parisii and O.-like spp., the other infected with N. sp. 1 and O.-like spp. (confirmed by specific FISH probes).Secondly, two transgenic C. elegans strains ERT54 jyIs8[C17H1.6p::gfp; myo-2p::mCherry] and ERT72 jyIs15[F26F2.1p::gfp; myo-2::mCherry], which express a constitutive fluorescent Cherry marker and will induce GFP upon infection with N. parisii (Bakowski et al. 2014), were used in infection tests. Our results show that N. parisii, N. sp. 1, N.-like sp. 2 and N.-like sp. 3 can infect ERT54 and ERT72, forming meronts and spores; N. sp. 1 does not induce the GFP reporter (or only rarely), while the other three induce it consistently, suggesting that C. elegans has a different transcriptional response to the infection of N. sp. 1 than to other Nematocida spp. (see also abstract of Luallen et al.). The results also showed that O.-like spp. could not infect the two transgenic C. elegans strains (nor induce the GFP signals).

Jeon, JiHae et al. (2021) International Worm Meeting "N. parisii compensates for genomic loss of dihydroceramide desaturase through reliance on C. elegans sphingolipid biosynthesis"

Jeon, JiHae, Burton, Nick, Reinke, Aaron, Zhao, Winnie

[International Worm Meeting, 2021]

Microsporidia are obligate intracellular parasites that have lost many metabolic enzymes, resulting in the smallest known eukaryotic genomes. Microsporidia are highly dependant upon host nutrients, but it is poorly understood the effect that these parasites have on host metabolism. Using N. parisii, a natural microsporidian parasite of C. elegans, we describe how infection alters host lipid metabolism. We show that the C. elegans lipase ATGL-1 is upregulated in response to N. parisii infection and that host fat stores are depleted. Metabolic profiling of infected animals reveals large changes in lipid composition including changes consistent with nutrient starvation. Additionally, we identify novel ceramides only generated in animals infected with N. parisii. Genomic analysis reveled that N. parisii has lost the enzymes necessary for the de novo synthesis of these sphingolipids. Mutations in C. elegans dihydroceramide desaturases F33D4.4 and ttm-5 or acid ceramidase asah-2, reduce N. parisii growth. Supplementation with sphingosine, a substrate for ceramide synthesis, enhances N. parisii proliferation. Together, our data demonstrate that N. parisii exploits sphingolipid biosynthesis in C. elegans and reveals an evolutionary strategy used by microsporidian parasites to cope with extreme genomic reduction.

di Luccio, Eric et al. (2021) International Worm Meeting "N-NOSE is an innovative, non-invasive and highly sensitive cancer screening method based on the chemotaxis of C. elegans"

di Luccio, Eric, Hirotsu, Takaaki

[International Worm Meeting, 2021]

A simple, affordable, non-invasive, and highly sensitive cancer detection method is the Holy Grail in health screening. Especially early diagnosis of cancer is critical to increase the likelihood of recovery. N-NOSE (Nematode-NOSE) is a pioneering cancer screening method based on the chemotaxis of C. elegans which shows evasive behavior from the urine of healthy individuals while being attracted to the urine of cancer patients. N-NOSE has an average cancer-detection sensitivity of 86.3% in a clinical setting and detect the presence of cancer for 15 types at all stages: stomach, colorectal, lung, breast, uterine, liver, prostate, esophageal, ovarian, bile duct, gallbladder, bladder, kidney, pharyngeal, and pancreatic cancer. N-NOSE relies on a single drop of urine, is non-invasive and cheap, and is notably more sensitive than the blood tumor markers CEA, CA19-9 and CA15-3. In this presentation, we detail the C. elegans olfaction and chemotaxis method behind N-NOSE. Next, we review and summarize our recently published clinical studies on N-NOSE performed in several hospitals in Japan and compare N-NOSE performance to other cancer screening methods. Then, we briefly comment on the next generation of N-NOSE methods currently under development. Lastly, we outline our "World Consortium" R&D grant initiative to anyone in the world with the goal of contributing to the development of next generations of N-NOSE cancer-specific using nematodes. N-NOSE by Hirotsu Bio Science has been launched commercially in 2020 in Japan and is quickly seeking to expand overseas.

Pierce-Shimomura JT et al. (2000) West Coast Worm Meeting "Mutation in the LIM homeobox gene lim-6 disrupts asymmetric function of the ASE chemosensory neurons"

Gaston MR, Lockery SR, Pierce-Shimomura JT, Pearson BJ

[West Coast Worm Meeting, 2000]

C. elegans detects chemicals with 11 pairs of bilaterally symmetric sensory neurons. All of the right-left members of these pairs share similarity in lineage, morphology, and synaptic connectivity. However, one of these pairs (ASE) expresses genes asymmetrically1. ASEL expresses two putative chemoreceptor guanylyl cyclases gcy-6&7 and the homeobox gene lim-6, while ASER expresses a different guanylyl cyclase gcy-5. The ASE neurons are important for chemotaxis to soluble attractants including salts3. We tested whether the asymmetry in expression pattern correlated with an asymmetry in function by ablating ASER, ASEL, or both neurons in individual worms and tracked each animal during chemotaxis in gradients of ammonium chloride, sodium acetate, potassium acetate, and ammonium acetate. To measure chance performance, we tracked worms (n=74) in the absence of a gradient, but analyzed them as if they were in a gradient. Most ASER- (n=29) and ASE- (n=27) worms failed to reach the peak of the NH4Cl gradient, while most ASEL- worms (n=22) reached the peak similar to sham worms (anaesthetized and recovered but not ablated; n=35). Likewise, most ASER- (n=17) and ASE- (n=15) worms failed to reach the peak of the K-acetate gradient, while most ASEL- worms (n=20) reached the peak similar to sham worms. Surprisingly, most ASEL- (n=26) and ASE- (n=12) worms failed to reach the peak of the Na-acetate gradient, while most ASER- worms (n=25) reached the peak similar to sham worms. Worms did not perform better than chance in the ammonium-acetate gradient (n=37). Thus, ASER controls chemotaxis to Cl- and K+, while ASEL controls chemotaxis to Na+. In lim-6 deletion mutants gcy-5 is ectopically expressed in ASEL, while gcy-6&7 expression is correctly restricted to ASEL2. To examine if LIM-6 specifies asymmetry in ASE function, we tested whether ASE neurons retain their asymmetric function in lim-6 mutants. In contrast to wildtype worms, many ASER- lim-6 worms (n=28) were able to reach the peak of the ammonium chloride gradient. Thus, a homeobox gene is involved in breaking symmetry in neuronal function. 1. Yu et al (1997) PNAS 95:3384-7 2. Hobert et al (1999) Dev 126:1547-62 3. Bargmann & Horvitz (1991) Neuron 7:729-42

Caldwell GA et al. (1998) East Coast Worm Meeting "MEC-14 May Modulate Mechanosensory Channels"

Chen L, Tu Y, Hom N, Chalfie M, Caldwell GA, Gangadharan S, Huang MX

[East Coast Worm Meeting, 1998]

The product of the C. elegans mec-14 gene is required for the function of the six touch receptor neurons. Mutant animals are touch insensitive, yet have differentiated touch receptor neurons. Genetic interactions between mec genes have suggested that mec-14 encodes a protein that may modulate the proposed mechanosensory apparatus. The mec-14 gene had been previously mapped to a region on Chr. III. We have cloned the mec-14 gene using a combination of transposon-tagging and cosmid/plasmid rescue and find that MEC-14 is a protein of 453 amino acids that exhibits some similarity to aldo-keto reductases and the b-subunit of Shaker-type potassium channels. Although this homology is weak, it is suggestive of a regulatory role for the MEC-14 protein in mechanotransduction. Sequence analysis of all 9 existing alleles of mec-14 indicates that these mutations lie within this predicted open-reading frame. Furthermore, northern blot analysis shows a transcript of approximately 1.5 Kb that disappears in mec-3 mutants and is truncated in a partial deletion of the mec-14 locus. We have generated both GFP and lacZ fusions to the C-terminal codon of mec-14 that restore touch sensitivity in mutants with the mec-14 (u82) deletion allele. Transformed animals from several stable lines with either of these constructs exhibit a distinctive expression pattern that is restricted to the six touch cells. Specifically, animals display a bright and punctate staining/ fluorescence in both the cell body (excluding the nucleus) and along the length of the axons of the touch neurons. This pattern of expression may represent the distribution of mechanosensory channels and their associated proteins in the touch cells. Experiments to further analyze this expression pattern in various mutant animals are in progress, as are yeast two-hybrid studies to determine putative interaction partners with MEC-14 in touch cells.

Driscoll MA et al. (1987) International C. elegans Meeting "progress in cloning mec genes."

Way JC, Hom N, Driscoll MA, Ferguson EL, Savage C, Chalfie M

[International C. elegans Meeting, 1987]