Castillo-Quan JI et al. (2016) Cell "Metformin: Restraining Nucleocytoplasmic Shuttling to Fight Cancer and Aging."

Castillo-Quan JI, Blackwell TK

[Cell, 2016]

In this issue of Cell, Wu etal. employed C.elegans and human cell experiments to identify a pathway through which metformin increases lifespan and inhibits growth. A key transcriptional target, ACAD10, is activated when metformin induces nuclear exclusion of the GTPase RagC, thereby inhibiting mTORC1 through an unexpected mechanism.

Ji Wu et al. (2002) East Coast Worm Meeting "Regulation of Touch Cell Functional Genes"

Ji Wu, Martin Chalfie

[East Coast Worm Meeting, 2002]

We have previously shown that egl-44 and egl-46 are two transcription regulators involved in the development of several types of neurons in C. elegans, with significant homology in other organisms, and that they repress the expression of touch cell-specific features in FLP neurons (Wu et al., 2001,Genes. Dev., 15: 789).

Brissette B et al. (2019) Neuron "Insulin-like Peptides as Agents of Social Change."

Ringstad N, Brissette B

[Neuron, 2019]

Many behaviors promote reproduction or food finding. These critical functions of behavior can conflict; successful reproductive strategies can grow populations to the point where food is depleted. In this issue of Neuron, Wu etal. (2019) show how the nematode C.elegans detects crowding to change feeding behavior by coupling pheromone sensing to signaling via insulin-like peptides.

Li T et al. (2022) STAR Protoc "Live imaging of postembryonic developmental processes in C.elegans."

Wang X, Zou Y, Li T, Feng Z

[STAR Protoc, 2022]

Live imaging is an important tool to track dynamic processes such as neuronal patterning events. Here, we describe a protocol for time-lapse microscopy analysis using neuronal migration and dendritic growth as examples. This protocol can provide detailed information for understanding cellular dynamics during postembryonic development in Caenorhabditis elegans (C. elegans). For complete details on the use and execution of this protocol, please refer to Feng etal. (2020), Li etal. (2021), and Wang etal. (2021).

Juan Wang et al. (2004) West Coast Worm Meeting "Characterization of a mutant affecting ADPKD Homologue Gene Expression and Male Mating"

Juan Wang, Maureen M Barr

[West Coast Worm Meeting, 2004]

lov-1 and pkd-2 are the homologues of the human autosomal dominant polycystic kidney disease (ADPKD) genes PKD1 and PKD2. lov-1 and pkd-2 are required for male mating behavior and function as male sensory genes. These two genes are exclusively expressed in male specific neurons: four head CEMs, ray RnBs rarely (in R2B and R6B) and hook HOB from late L4 through adulthood. How lov-1 and pkd-2 are temporally and spatially regulated is largely unknown. egl-46 is required for pkd-2 expression in the HOB neuron, but not the CEMs or RnBs (Yu et al. 2003). daf-19 , an RFX transcription factor, is required for expression of several cilium structure genes (Swoboda et al. 2000) as well as pkd-2 (Yu et al. 2003). We are interested in understanding the mechanisms underlying lov-1 and pkd-2 transcriptional regulation, male sensory neuronal development, and male mating behavior. n4132 was obtained in a screen for ceh-30 suppressors (See 2004 East Coast Worm Meeting abstract 248 Varner et al. ) and found to prevent pkd-2 expression. Our further characterization shows that the n4132 mutant lacks expression of both lov-1 and pkd-2 but not cilia structure genes such as osm-5 and osm-6 . In contrast to daf-19 mutants, we propose that n4132 disrupts transcriptional regulation of certain male sensory genes but not general cilia structure genes. I will describe the mapping, cloning, and molecular characterization of this new gene. References Swoboda P. et al. (2000). Molecular Cell 5: 411-421. Yu, H. et al. (2003). Development 130(21): 5217-5227.

Jia-Yun Chen et al. (2003) International Worm Meeting "A new gene in the C. elegans programmed cell death pathway"

Yi-Chun Wu, Pei-Ju Ru, Yu-Feng Wu, Jia-Yun Chen, Ruey-Hwa Chen

[International Worm Meeting, 2003]

Programmed cell death in C. elegans is controlled by the central pathway consisting of at least three major pro-apoptotic genes, egl-1, ced-3 and ced-4 (1, 2 and 3). Strong mutations in any of these genes block most of programmed cell deaths. The gene ced-8 appears to affect the timing of programmed cell death as strong mutations in ced-8 delay programmed cell death (4). We have identified a new gene, tentatively termed ced-x in this abstract, which may be a positive regulator in the programmed cell death pathway. Both ced-x (null) and ced-x (RNAi) mutants displayed decreased numbers of cell corpses throughout embryogenesis as compared to wild type. Such a phenotype was enhanced by the weak ced-4 (n2273) but not strong ced-8 (n1891) mutations. Therefore, ced-x may act with ced-4 in a ced-8-independent manner during programmed cell death. Consistent with the phenotype of decreased cell corpses, ced-x (null) embryos also showed less TUNEL signals than wild type. Although ced-x (RNAi) mutants had very few extra surviving cells in the anterior region of the pharynx, weak mutations in ced-3 significantly increased the extra cell number in ced-x (RNAi) mutants. These results altogether suggest that ced-x may act as a positive regulator during programmed cell death. To position ced-x in the central programmed cell death pathway, we performed transcriptional overexpression experiments. We found that ced-x (null) mutation significantly suppressed the killing activity induced by overexpression of egl-1 or ced-4 but not ced-3. This result suggests that ced-x may act downstream of (or parallel to) egl-1 and ced-4 but upstream of (or parallel to) ced-3 in a genetic pathway that leads to programmed cell death in C. elegans. We generate a ced-x::gfp translational fusion construct to explore the expression pattern of ced-x. The CED-X::GFP fusion protein exhibited a filamentous pattern predominantly in the cytosol of many cells during embryogenesis. We are currently doing more experiments and hope to understand the mechanism by which ced-x functions during programmed cell death. As we found that the human ced-x homologue can functionally substitute the C. elegans ced-x gene, the function of ced-x is likely evolutionarily conserved. References 1. Yuan, J. Y., Horvitz, H. R. (1990) Dev. Biol. 138, 33-41. 2. Yuan, J., Horvitz, H. R. (1992) Development 116, 309-320. 3. Conradt, B., Horvitz, H. R. (1998) Cell 93, 519-529. 4. Stanfield, GM., Horvitz, H. R. (2000) Mol. Cell 5, 423-433

Oh, Jun Young et al. (2019) MicroPubl Biol

Wang, Han, Sternberg, Paul W, Gharib, Shahla, Liu, Jonathan, Oh, Jun Young

[MicroPubl Biol, 2019]

cGAL, a recently developed temperature-robust bipartite GAL4-UAS system in C. elegans, consists of two components: a cGAL driver that expresses the cGAL protein in specific cells using a promoter (i.e. neuron-specific or tissue-specific), and an effector that carries a gene of interest downstream of UAS (Wang et al., 2017). Crossing or combining a driver with an effector leads to the expression of the gene of interest in a cell-specific or tissue-specific manner.Here we report a new cGAL driver for the DVC interneuron. The ceh-63 promoter was chosen due to its restricted expression in the DVC neuron (Feng et al. 2012). The DVC interneuron driver construct containing the ceh-63 promoter (646 bp upstream of ATG translation start site) was injected into N2 and an integrated DVC driver line was generated. When crossed with the UAS-GFP effector strain (PS6843), the ceh-63 cGAL driver dictated GFP expression in the single DVC neuron (Figure 1), in addition to GFP in the coelomocyte from Punc-122::gfp co-injection marker. We did not observe GFP expression in uterus as reported by Feng et al., 2012.

Rauthan, M. et al. (2017) International Worm Meeting "MicroRNA regulation of nicotine-dependent behavior in C. elegans."

Rauthan, M., Ronan, E.A., Gong, J., Xu, X.Z.S., Liu, J., Wescott, S.

[International Worm Meeting, 2017]

Tobacco smoking is the leading cause of preventable death in developed nations. Nicotine is the principle addictive substance in cigarettes. Chronic exposure to nicotine up-regulates nAChRs and is thought to play a critical role in the primary steps of nicotine dependence, but the underlying mechanisms are not well understood. We have previously developed a C. elegans model of nicotine dependent behavior, and shown that the nAChR gene acr-15 is required for acute response to nicotine (Feng et al., 2006). Here we identify a key role for microRNA in regulating nicotine-dependent behavior by modulating nAChR expression in C. elegans. Specifically, we show that chronic nicotine treatment down-regulates microRNA machinery, leading to up-regulation of another nAChR gene that is specifically required for nicotine withdrawal behavior. This effect is mediated by a microRNA that recognizes the 3'UTR of nAChR transcripts. These observations uncover an interesting phenomenon that different nAChRs mediate distinct aspects of nicotine dependence in C. elegans. Our results reveal a functional link between nicotine, microRNA, nAChRs, and nicotine-dependent behavior. Reference(s): 1. Feng, Z., Li, W., Ward, A., Piggott, B.J., Larkspur, E., Sternberg, P.W., and Xu, X.Z.S. (2006). A C. elegans model of nicotine-dependent behavior: regulation by TRP family channels. Cell 127, 621-633.

Wu D et al. (1997) Science "Interaction and regulation of subcellular localization of CED-4 by CED-9."

Wallen HD, Nunez G, Wu D

[Science, 1997]

The Caenorhabditis elegans survival gene ced-9 regulates ced-4 activity and inhibits cell death, but the mechanism by which this occurs is unknown. Through a genetic screen for CED-4-binding proteins, CED-9 was identified as an interacting partner of CED-4. CED-9, but not loss-of-function mutants, associated specifically with CED-4 in yeast or mammalian cells. The CED-9 protein localized primarily to intracellular membranes and the perinuclear region, whereas CED-4 was distributed in the cytosol. Expression of CED-9, but not a mutant lacking the carboxy-terminal hydrophobic domain, targeted CED-4 from the cytosol to intracellular membranes in mammalian cells. Thus, the actions of CED-4 and CED-9 are directly linked, which could provide the basis for the regulation of programmed cell death in C. elegans.AD - Department of Pathology and Comprehensive Cancer Center, The University of Michigan Medical School, Ann Arbor, MI 48109, USA.FAU - Wu, DAU - Wu DFAU - Wallen, H DAU - Wallen HDFAU - Nunez, GAU - Nunez GLA - engID - CA-64556/CA/NCIID - T32A107413-03/PHSPT - Journal ArticleCY - UNITED STATESTA - ScienceJID - 0404511RN - 0 (Calcium-Binding Proteins)RN - 0 (Ced-4 protein)RN - 0 (Ced-9 protein)RN - 0 (Helminth Proteins)RN - 0 (Proto-Oncogene Proteins)RN - 0 (bcl-x protein)SB - IM

Wu Y et al. (2010) Neurobiol Aging "Heat shock treatment reduces beta amyloid toxicity in vivo by diminishing oligomers."

Cao Z, Klein WL, Luo Y, Wu Y

[Neurobiol Aging, 2010]

Heat shock response, mediated by heat shock proteins, is a highly conserved physiological process in multicellular organisms for reestablishment of cellular homeostasis. Expression of heat shock factors and subsequent heat shock protein plays a role in protection against proteotoxicity in invertebrate and vertebrate models. Proteotoxicity due to beta-amyloid peptide (Abeta) oligomerization has been linked to the pathogenesis of Alzheimer's disease. Previously, we demonstrated that progressive paralysis induced by expression of human Abeta(1-42) in transgenic Caenorhabditis elegans was alleviated by Abeta oligomer inhibitors Ginkgo biloba extract and its constituents [Wu, Y., Wu, Z., Butko, P., Christen, Y., Lambert, M.P., Klein, W.L., Link, C.D., Luo, Y., 2006. Amyloid-beta-induced pathological behaviors are suppressed by Ginkgo biloba extract EGb 761 and ginkgolides in transgenic Caenorhabditis elegans. J. Neurosci. 26(50): 13102-13113]. In this study, we apply a protective heat shock to the transgenic C. elegans and demonstrate: (1) a delay in paralysis, (2) increased expression of small heat shock protein HSP16.2, and (3) significant reduction of Abeta oligomers in a heat shock time-dependent manner. These results suggest that transient heat shock lessens Abeta toxicity by diminishing Abeta oligomerization, which provides a link between up regulation of endogenous chaperone proteins and protection against Abeta proteotoxicity in vivo.