Yusuke Hokii et al. (2006) East Asia C. elegans Meeting "Spatio temporal distribution patterns of C.elegans small ncRNAs"

Yusuke Hokii, Yuko Endo, Yuko Mizuki, Chisato Ushida, Yuki Sugawara, Fumitoshi Harada, Hyouta Himeno, Takayuki Konno, Akira Muto

[East Asia C. elegans Meeting, 2006]

CeR 3, 4, 6, 7, 8, 9, 19 RNAs that were encoded in the regions corresponding to the introns of protein coding genes were isolated from Caenorhabditis elegans. These seven RNAs showed typical snoRNA secondary structures. CeR 19 RNA is included in C/D snoRNA and the other RNAs were classified in H/ACA snoRNAs. Four of the seven isolated snoRNAs (CeR 6, 7, 9, 19) could form base pairings with parts of rRNAs, suggesting that they have a potential to guide pseudouridylation and methylation of rRNAs. CeR 6 RNA may guide modification of U1254 of 18S rRNA. The predicted targets of CeR 7 RNAs are U778 and U827 of 18S rRNA, U866, U1058, U2400 and U2546 of 26S rRNA and U89 of 5.8S rRNA. CeR 9 RNA guides probably pseudouridylation of U513 of 18S rRNA. CeR 19 RNA has two base paring sites that ribose 2 O methylation of U308 of 26S rRNA and C642 of 18S rRNA. In the recent study of Schmitz et al. the targets of CeR 3, 4 and 8 RNA were predicted. These RNAs perhaps guide modification U3035 (CeR 3), U2558 (CeR 4), U2098 and U3035 (CeR 8) of rRNAs, respectively. Here we examined whole mount in situ hybridization to know the localization of these RNAs in cells and their spatiotemporal distribution patterns in worms. As expected, all these RNAs are localized in the nucleolus of most cells of the worm. Their expressions were observed from early embryonic stage to adult. Chemical modification experiments of rRNAs indicated that a predicted target of CeR 9 RNA, U513 of 18S rRNA, was pseudouridine. Further analysis will reveal the whole positions of C.elegans rRNA pseudouridine and demonstrate whether the potential target sites of CeR RNAs are indeed modified or not.

P Polk et al. (1999) International C. elegans Meeting "In Search of Phenotypes for ptl-1"

P Polk, E Aamodt, S Aamodt

[International C. elegans Meeting, 1999]

In mammals, the microtubule-associated protein tau is located in the axons of neuronal cells and is believed to stabilize the microtubule cytoskeleton and function in neurite outgrowth. A C. elegans homologue of tau, ptl-1 (protein with tau-like repeats), was identified by the C. elegans Genome Sequencing Consortium and characterized by us (McDermott et al, 1996, Biochemistry 35: 9415-9423) and Goedert et al. (1996, J. Cell Sci. 109:2661-2672). We obtained a C. elegans strain with a deletion of the repeat region from the NemaPharm Group at Axys Pharmaceuticals. The ptl-1 deletion strain has no apparent phenotype and we have not detected differences between N2 and the ptl-1 deletion strain in sensitivity to colchicine, benomyl or cytochalasin D. Work done by N. Hirokawa and colleagues has shown that in mice, tau functions redundantly with microtubule-associated protein MAP1B. Mice homozygous for a null allele of tau (Harada et al., 1994, Nature 369: 488-491) or MAP-1B (Takei et al., 1997, J. Cell Biol. 137: 1615-1626) have mild phenotypes, but double mutants have severe defects in brain development as a result of defects in neurite outgrowth (Takei et al., 1998, Mol. Biol. of the Cell 9:394a). Because of this precedent for redundancy in the function of tau and MAP-1B, we searched for C. elegans genome for a MAP1B homologue but no candidate was found. To attempt to identify proteins that act cooperatively or are redundant to ptl-1 , we have begun a screen for synthetic mutations. We crossed the ptl-1 deletion into a strain (obtained from David Baillie) that has cosmid F42G9 (containing ptl-1 ) and rol-6 as an extrachromosomal array. We will mutagenize the ptl-1 deletion strain containing the F42G9 array to screen for genes that are synthetic to ptl-1 .

Alcantara, Alfredo Jr. et al. (2021) International Worm Meeting "Simulated Microgravity Impairs C. elegans Gut Immunity"

Higashibata, Akira, Higashitani, Atsushi, Lee, Jin Il, Alcantara, Alfredo Jr., Hashizume, Toko

[International Worm Meeting, 2021]

Humanity had been fascinated with space exploration and habitation. However, weak gravity force in outer space, termed as microgravity, has been known to alter normal human biology and induce health risks, such as muscle atrophy and compromised immunity. The underlying processes on how gravity is sensed by the body and how it affects immunity are still unclear. The nematode Caenorhabditis elegans, is a well-known model organism in the field of innate immunity and space research. Similar to humans, worm immune response signaling is regulating by MAPK and TGFbeta pathways. Previous microgravity experiments in C. elegans have shown an increase in p38 MAPK pmk-1 expression in simulated microgravity (Li, Wang, & Wang, 2018) and decreased expression of TGFbeta ligand dbl-1 in space (Harada et al., 2016). In this study, we have utilized Enterobacter cloacae carrying tdTomato fluorescence reporter to observe gut colonization in C. elegans under simulated microgravity using a 3D clinostat. E. cloacae is a known commensal in C. elegans' gut but is invasive in immunocompromised dbl-1 mutant worms (Berg et al., 2019). Our preliminary results have shown that simulated microgravity can induce E. cloacae gut colonization in wild type C. elegans and aggravated colonization in pmk-1 mutants, while there is no difference observed in dbl-1 mutants which have robust colonization in both normal earth gravity and simulated microgravity, which demonstrates potential involvement of these pathways. Our study aims to discover the underlying mechanism of gravity sensing and how it affects the immune signaling pathways. In addition, spaceflights are already scheduled to send C. elegans aboard the International Space Station (ISS) for actual space gravity experiments.

Eki, Toshihiko et al. (2009) International Worm Meeting "A lifespan-based assay to assess the long-term toxicity of prolonged exposure to ecotoxic agents using C. elegans."

Harada, Hiroaki, Eki, Toshihiko, Morise, Hisashi, Kurauchi, Masaru

[International Worm Meeting, 2009]

Nematodes are highly abundant organisms found in soil or sedimentary habitats and the free-living nematode Caenorhabditis elegans (C. elegans) has been used as an excellent model for monitoring ecotoxicity in soil. The acute toxicities of toxic agents have been well examined with respect to several endpoints, such as mortality, for application to toxicity tests for environmental assessments. However, chronic influences of these agents on multicellular organisms still need to be determined. Here we studied long-term effects on the lifespan of a free-living nematode C. elegans resulting from prolonged exposure to heavy metals metals (CuSO4 and CdCl2), detergents (sodium dodecyl sulfate and a commercially available household detergent), a perfluoro organic compound (pentadecafluorooctanoic acid) and an organophosphate insecticide (dichlorvos) as well as short-term inhibitory effects on egg production and growth. These agents except for dichlorvos inhibited growth of hatched larvae and reproductive capacity in a concentration-dependent manner. They also effectively shortened the lifespan of the adult nematode over the same concentration range. Since toxic effects on both the growth and the lifespan were observed over similar concentration ranges, where acute toxicities in various endpoints are detected, the shortening of the lifespan can be used as a new endpoint for the assessment of various ecotoxic agents. We have also used a daf-16(mu86) mutant CF1038 strain, which has a deficient transcription factor DAF-16 regulating a variety of the genes involved in longevity and stress response, for ecotoxicity assays, however, both strains unexpectedly exhibited comparable reductions in these endpoints including lifespan by exposure to these ecotoxicants, indicating that DAF-16 does not largely contribute to tolerance to these agents. By virtue of a shorter assay period, the lifespan-based assay using the daf-16 mutant can be useful for assessing the ecotoxicity of ecotoxic chemicals. Ref. Harada et al., Ecotoxicol. Environ. Saf., 66, 378-383 (2007).

Ali MY et al. (1998) Midwest Worm Meeting "DPY-20 a LIN-39 like transcription factor, defines a novel class of motor neuron specific regulatory protein in Caenorhabditis elegans"

Siddiqui OS, Siddiqui ZK, Siddiqui SS, Matsuo T, Janke DL, Ali MY, Hori F, Azham S, Baillie DL, Umehara M

[Midwest Worm Meeting, 1998]

A number of heriditary neural diseases such as Lou Gehrig syndrome (Amyotyrophic Lateral Sclerosis) are typified by a late onset of motor neuron degeneration and loss of function. In C. elegans mutations in dpy-20 gene have been described previously (Hosono et al., 1982; Clark et al., 1995) that range from a small size, hypodermal defects, abnormal head morphology and lethality. Here we report that dpy-20 encodes a novel inhibitor of transcription in motor neurons (Fukushige and Siddiqui, 1995), that is selectively expressed during post-embryonic development. A dpy-20::lacZ reporter gene was constructed and shown to express in the ventral cord motor neurons and hypodermal cells (Ali et al., WBG 15, 51-53, 1998). Temporal expression pattern of the reporter gene is consistent with the temperature shift experiments using a dpy-20(e1282)ts allele (Clark et al., 1995), that suggests that the gene is transcribed increasingly in larval development from the late L1 stage to L3 larval stage, and is not expressed in adults. In situ RNA hybridization data on early embryos and germ line cells suggests that the dpy-20 gene is not transcribed during embryogenesis or during germ line development, suggesting its expression limited to the post-embryonic larval development. Since severe alleles of dpy-20 display defective locomotion, we have tested expression of the dpy-20::lacZ gene in a variety of mutant backgrounds that show abnormal locomotion. We have also examined expression of reporter genes that are known to express in the ventral cord motor neurons in dpy-20 mutant background. Our results suggest that there is a strong genetic interaction between dpy-20 and a variety of genes that express in motor neurons and hypodermal cells. Finally, the amino acid sequence deduced from the cloned dpy-20 gene does not show a significant homology to any protein in data bases; however, we find that the DPY-20 harbors several motifs that are conserved in transcription factors and regulatory proteins. Although DPY-20 has no homeobox sequence, it has 41% simailrity with LIN-39 transcription factor(Kenyon,1994) of C. elegans.We thank J.Miwa, Y. Kohara, R. Holmgren, A. Otsuka, R. Hosono, K. Harada, and K.Nishikawa for help in this work.