Chen YA et al. (2015) Curr Mol Biol Rep "Non-Coding RNAs in Transcriptional Regulation: The review for Current Molecular Biology Reports."

Chen YA, Aravin AA

[Curr Mol Biol Rep, 2015]

Transcriptional gene silencing guided by small RNAs is a process conserved from protozoa to mammals. Small RNAs loaded into Argonaute family proteins direct repressive histone modifications or DNA cytosine methylation to homologous regions of the genome. Small RNA-mediated transcriptional silencing is required for many biological processes, including repression of transposable elements, maintaining the genome stability/integrity, and epigenetic inheritance of gene expression. Here we will summarize the current knowledge about small RNA biogenesis and mechanisms of transcriptional regulation in plants, Drosophila, C. elegans and mice. Furthermore, a rapidly growing number long non-coding RNAs (lncRNAs) have been implicated as important players in transcription regulation. We will discuss current models for long non-coding RNA-mediated gene regulation.

Silverstein NJ et al. (2017) Immunity "Interleukin-17: Why the Worms Squirm."

Huh JR, Silverstein NJ

[Immunity, 2017]

IL-17 is a cytokine known primarily for its role in inflammation. In a recent issue of Nature, Chen etal. (2017) demonstrate that IL-17 plays a neuromodulatory role in Caenorhabditis elegans by acting directly on neurons to amplify neuronal responses to stimuli and produce changes in animal behavior.

Nishino A et al. (2015) Comp Biochem Physiol A Mol Integr Physiol "Extension of the established period of diacetyl adaptation by oxygen intermediates in the nematode Caenorhabditis elegans."

Matsuura T, Sato F, Ito K, Nishino A

[Comp Biochem Physiol A Mol Integr Physiol, 2015]

After pre-exposure to the odorant diacetyl, the nematode Caenorhabditis elegans showed a decline in chemotactic responses to diacetyl, a phenomenon known as diacetyl adaptation. In the present study, we found that the established period of diacetyl adaptation in nematodes increased with the breeding temperature. When wild-type (N2) nematodes were bred at 15C, adaptation was observed from the young adult (YA) to the 3-day-old adult that is reached 3 days after the YA stage. On breeding nematodes at 20C and 25C, adaptation was observed between the YA and 5-day-old adult and between the YA and the 7-day-old adult, respectively. Breeding temperature has been shown to correlate with the rate of aging in nematodes, which is related to the level of oxygen consumption. Accordingly, long-lived isp-1 and clk-1 mutants that demonstrate decreased levels of oxygen consumption showed a shorter established period of adaptation than N2 nematodes, whereas short-lived gas-1 and mev-1 mutants that have a hypersensitive response to oxygen showed a longer period of adaptation than the N2. Moreover, the established period of diacetyl adaptation in N2 nematodes was shortened by the antioxidant -lipoic acid. These results suggest that oxygen intermediates, which are produced by oxygen consumption, play a significant role in diacetyl adaptation. Although this is only one of many factors that regulate diacetyl adaptation, such as the release of neurotransmitters and changes in intracellular conditions, the acquisition of this adaptation requires an increase in the intensity of moderate oxygen signals.

Artan M et al. (2016) Dev Cell "Heat FLiPs a Hormonal Switch for Longevity."

Lee SV, An SW, Artan M

[Dev Cell, 2016]

Temperature-sensing neurons in C.elegans reduce the life-shortening effects of high temperatures via steroid signaling. In this issue of Developmental Cell, Chen etal. (2016) elucidate the underlying mechanisms by which the transcription factor CREB induces the neuropeptide FLP-6 in the temperature-sensing neurons to counteract the life-shortening effects of high temperature.

Matsuura T et al. (2015) Biosci Biotechnol Biochem "Chronic nicotine exposure augments gustatory plasticity in Caenorhabditis elegans: involvement of dopamine signaling."

Matsuura T, Urushihata T

[Biosci Biotechnol Biochem, 2015]

The chemotaxis of wild-type NaCl-conditioned nematodes exposed to 100 mM NaCl, maintained on a growth medium containing 0.3 mM nicotine from first larva to young adult (YA) hermaphrodite, was significantly weaker than the chemotaxis of those maintained on a medium without nicotine. The result indicates that chronic nicotine exposure augments gustatory plasticity. The gustatory plasticity was also augmented when tph-1 mutants, with a defect in serotonin biosynthesis, were maintained on a medium containing nicotine until the YA stage. Chronic nicotine exposure did not augment gustatory plasticity in bas-1 mutants, which had defects in both serotonin and dopamine biosynthesis, and in cat-2 mutants, which had a defect in dopamine biosynthesis. However, augmentation of gustatory plasticity was observed when bas-1 and cat-2 mutants were maintained on a growth medium containing nicotine along with dopamine, suggesting that dopamine signaling is involved in the augmentation of gustatory plasticity due to chronic nicotine exposure.

Palikaras K et al. (2016) Bio Protoc "Measuring Oxygen Consumption Rate in Caenorhabditis elegans."

Palikaras K, Tavernarakis N

[Bio Protoc, 2016]

The rate of oxygen consumption is a vital marker indicating cellular function during lifetime under normal or metabolically challenged conditions. It is used broadly to study mitochondrial function (Artal-Sanz and Tavernarakis, 2009; Palikaras et al., 2015; Ryu et al., 2016) or investigate factors mediating the switch from oxidative phosphorylation to aerobic glycolysis (Chen et al., 2015; Vander Heiden et al., 2009). In this protocol, we describe a method for the determination of oxygen consumption rates in the nematode Caenorhabditis elegans.

Chen CH et al. (2021) STAR Protoc "Live-cell imaging of PVD dendritic growth cone in post-embryonic C.elegans."

Chen CH, Pan CL

[STAR Protoc, 2021]

Live-cell imaging analysis provides tremendous information for the study of cellular events such as growth cone migration in neuronal development. Here, we describe a protocol for live-cell imaging of migrating PVD dendritic growth cones in the nematode <i>C.elegans</i> by spinning-disk confocal microscopy. Fluorescently labeled growth cones and cytoskeletal proteins could be continuously observed for 4-6h in mid-stage larvae. This protocol is suitable for revealing the dynamic molecular and cellular events in dendrite and axon development of <i>C.elegans</i>. For complete details on the use and execution of this protocol, please refer to Chen etal. (2019).

Memar, Nadin et al. (2022) MicroPubl Biol

Memar, Nadin, Lambie, Eric J, Sethi, Aditya, Luehr, Sebastian, Conradt, Barbara

[MicroPubl Biol, 2022]

Visualization of genomic loci with open chromatin state has been reported in mammalian tissue culture cells using a CRISPR/Cas9-based system that utilizes an EGFP-tagged endonuclease-deficient Cas9 protein (dCas9::EGFP) (Chen et al. 2013). Here, we adapted this approach for use in Caenorhabditis elegans . We generated a C. elegans strain that expresses the dCas9 protein fused to two nuclear-localized EGFP molecules (dCas9::NLS::2xEGFP::NLS) in an inducible manner. Using this strain, we report the visualization in live C. elegans embryos of two endogenous repetitive loci, rrn-4 and rrn-1 , from which 5S and 18S ribosomal RNAs are constitutively generated.

Matsuura T et al. (2007) Comp Biochem Physiol A Mol Integr Physiol "Developmental changes in chemotactic response and choice of two attractants, sodium acetate and diacetyl, in the nematode Caenorhabditis elegans."

Ichinose M, Endo S, Matsuura T, Takahashi H, Iwamoto R

[Comp Biochem Physiol A Mol Integr Physiol, 2007]

The chemotactic behavior of the nematode Caenorhabditis elegans to chemical attractants, water-soluble sodium acetate and odorant diacetyl, was investigated using nematodes at various developmental stages to examine the effects of postembryonic development on chemotactic response and spontaneous locomotion. The chemotactic responses to attractants increased as development progressed, and the largest responses to either 1.0 M sodium acetate or 0.1% diacetyl were seen at the young adult (YA) or day adult (A1) stage, respectively. Responses to the chemicals declined thereafter in-line with increasing age. The chemotaxis indices for attractants correlated with activity of spontaneous locomotion (p&lt;0.01), suggesting that a change in spontaneous locomotion is one of the factors involved with the change in chemotactic responses during development. We also investigated the effect of aging on attractant choice by the simultaneous presentation of 0.6 M sodium acetate and 0.1% diacetyl. In the presence of both attractants, the fraction of larval animals at the sodium acetate location was greater than that at the diacetyl location (p&lt;0.05). The fractions of YA animals that gathered at either location were almost identical, whereas the fraction of adult animals at the diacetyl location was greater than that at the sodium acetate location (p&lt;0.05). The patterns of attractant choice of the long-lived daf-2 mutants and short lifespan mev-1 mutants showed the same tendency as those of wild type nematodes in the presence of both attractants. These results suggest that a change in the neuronal mechanisms controlling attractant choice and preference occurs during developmental progression.

Wu N et al. (2022) Biochem Biophys Res Commun "The EGL-30 pathway regulates experience-dependent aversive behavior of Caenorhabditis elegans to the pathogenic bacterium Pseudomonas aeruginosa."

Zou CG, Ma YC, Wu N, Chen YA, Wu QY, Gu KZ, Zhu Q, Son CH

[Biochem Biophys Res Commun, 2022]

Avoidance of harmful substances is survival strategy used cross invertebrates and vertebrates. For example, the nematode Caenorhabditis elegans evolves a sufficient avoidance response to pathogenic bacteria. Despite G protein has been found to exert neural plasticity for avoidance behaviours in C.&#xa0;elegans, the function of Gi/o and Gq subunit signalling in experience-dependent aversive behaviour remains unclear. In this study, we show that EGL-30/Gq coupled with EGL-8/UNC-13 regulates aversive behaviour of C.&#xa0;elegans to pathogenic bacterium Pseudomonas aeruginosa PA01 via acetylcholine and its receptor nAChR. Pyocyanin, a toxin secreted from P.&#xa0;aeruginosa, acts as a signal molecule to trigger aversive behaviour. ODR-3 and ODR-7 in AWA and AWC neurons function as upstream of EGL-30 to induce experience-dependent aversive behaviour to P.&#xa0;aeruginosa, respectively. These results suggested that a novel signalling pathway to regulate a behavioural response.