Jones AK et al. (2011) J Biol Chem "A Cys-loop mutation in the Caenorhabditis elegans nicotinic receptor subunit UNC-63 impairs but does not abolish channel function."

Jones R, Bouzat CB, Maynard TP, Buckingham SD, Jones AK, Hernando G, Sattelle DB, Rayes D, Al-Diwani A

[J Biol Chem, 2011]

The nematode Caenorhabditis elegans is an established model organism for studying neurobiology. UNC-63 is a C. elegans nicotinic acetylcholine receptor (nAChR) -subunit. It is an essential component of the levamisole-sensitive muscle nAChR (L-nAChR) and therefore plays an important role in cholinergic transmission at the nematode neuromuscular junction. Here, we show that worms with the unc-63(x26) allele, with its C151Y mutation disrupting the Cys-loop, have deficient muscle function reflected by impaired swimming (thrashing). Single-channel recordings from cultured muscle cells from the mutant strain showed a 100-fold reduced frequency of opening events and shorter channel openings of L-nAChRs compared with those of wild-type worms. Anti-UNC-63 antibody staining in both cultured adult muscle and embryonic cells showed that L-nAChRs were expressed at similar levels in the mutant and wild-type cells, suggesting that the functional changes in the receptor, rather than changes in expression, are the predominant effect of the mutation. The kinetic changes mimic those reported in patients with fast-channel congenital myasthenic syndromes. We show that pyridostigmine bromide and 3,4-diaminopyridine, which are drugs used to treat fast-channel congenital myasthenic syndromes, partially rescued the motility defect seen in unc-63(x26). The C. elegans unc-63(x26) mutant may therefore offer a useful model to assist in the development of therapies for syndromes produced by altered function of human nAChRs.

Vo, An A. et al. (2021) MicroPubl Biol

Vo, An A., Levenson, Max T., Ragle, James Matthew, Ward, Jordan D.

[MicroPubl Biol, 2021]

The AID system has emerged as a powerful tool to conditionally deplete proteins in a wide-range of organisms and cell types (Nishimura et al. 2009; Holland et al. 2012; Zhang et al. 2015; Natsume et al. 2016; Trost et al. 2016; Brown et al. 2017; Daniel et al. 2018; Chen et al. 2018; Camlin and Evans 2019). The system is comprised of two components. A plant F-box protein Transport Inhibitor Response 1 (TIR1) is expressed and forms a complex with endogenous Skp1 and Cul1 proteins to form a functional SCF ubiquitin ligase (Nishimura et al. 2009; Natsume and Kanemaki 2017). TIR1 can either be expressed constitutively or in a tissue-specific manner depending on promoter choice. A degron sequence from the IAA17 protein is fused to the protein of interest (Nishimura et al. 2009; Natsume and Kanemaki 2017). Commonly used auxin-inducible degrons include 44 amino acid (AID*) and 68 amino acid (mAID) fragments of IAA17 (Morawska and Ulrich 2013; Li et al. 2019). Addition of the plant hormone auxin bridges an interaction between TIR1 and the degron and the SCF ligase ubiquitylates the degron-fused protein leading to proteasomal degradation.

Driesschaert, Brecht et al. (2022) MicroPubl Biol

Temmerman, Liesbet, Driesschaert, Brecht

[MicroPubl Biol, 2022]

The Q system is a genetic tool developed to deliver spatiotemporal control over gene expression (Giles et al. 1991; Potter et al. 2010; Wei et al. 2012). Although it has already been adapted for use in C. elegans by Wei et al. in 2012, to date, the Q system has not been applied extensively in this nematode. In the relatively few available reports, it is mainly used to constitutively restrict gene expression in a spatial manner (e.g. Schild et al. 2014; Schild and Glauser 2015; Jee et al. 2016; Tolstenkov et al. 2018; Chiyoda et al. 2021), while but a handful of studies also explore the temporal aspect of the system (Matus et al. 2015; Yuan et al. 2016; Cottee et al. 2017; Hoang and Miller 2017). We aimed to apply this tool in the C. elegans nervous system to gain both spatial and temporal control over expression of a gene encoding a reporter protein that is targeted to the secretory pathway. Despite our efforts, we here report that in our hands, the Q system is not suitable for application in the neurons due to a lack of dynamic range.

Halic M et al. (2009) Mol Cell "22G-RNAs in transposon silencing and centromere function."

Halic M, Moazed D

[Mol Cell, 2009]

Three recent papers (Gu et al., 2009; Claycomb et al., 2009; van Wolfswinkel et al., 2009) provide evidence that links a new class of small RNAs and Argonaute-associated complexes to centromere function and genome surveillance.

Kazatskaya, Anna et al. (2020) MicroPubl Biol

Philbrook, Alison, Sengupta, Piali, Amin-Wetzel, Niko, Kazatskaya, Anna, de Bono, Mario, Yuan, Lisa

[MicroPubl Biol, 2020]

A subset of sensory neurons in C. elegans contains compartmentalized sensory structures termed cilia at their distal dendritic ends (Ward et al. 1975; Perkins et al. 1986; Doroquez et al. 2014). Cilia present on different sensory neuron types are specialized both in morphology and function, and are generated and maintained via shared and cell-specific molecules and mechanisms (Perkins et al. 1986; Evans et al. 2006; Mukhopadhyay et al. 2007; Mukhopadhyay et al. 2008; Morsci and Barr 2011; Doroquez et al. 2014; Silva et al. 2017). The bilaterally symmetric pair of URX oxygen-sensing neurons in the C. elegans head (Figure 1A) is thought to be non-ciliated (Ward et al. 1975; Doroquez et al. 2014) but nevertheless exhibits intriguing morphological similarities with ciliated sensory neurons. URX dendrites extend to the nose where they terminate in large bulb-like complex structures (Ward et al. 1975; Doroquez et al. 2014; Cebul et al. 2020) (Figure 1A). These structures concentrate oxygen-sensing signaling molecules (Gross et al. 2014; Mclachlan et al. 2018) suggesting that similar to cilia, these structures are specialized for sensory functions. Microtubule growth events similar to those observed in ciliated sensory neurons were also reported at the distal dendritic regions of URX, implying the presence of a microtubule organizer such as a remodeled basal body (Harterink et al. 2018). Moreover, a subset of ciliary genes is expressed in URX (Kunitomo et al. 2005; Harterink et al. 2018; Mclachlan et al. 2018). We tested the hypothesis that URX dendrites contain cilia at their distal ends.

Huang, George et al. (2021) MicroPubl Biol

Meng, Carrie, Rhodes, Anita, Doonan, Ryan, Sylvester, Melynda, Huang, George, de Jesus, Bailey, Blanco, Sara, Ren, Cassie, Dickinson, Daniel J, Koh, Alex, Rettmann, Aubrie, Alicea, Persephone, DeMott, Ella, Flynn, Abbey, Waterland, Skye

[MicroPubl Biol, 2021]

The self-excising cassette (SEC) knock-in approach uses hygromycin selection and a visible roller phenotype to identify knock-ins, followed by a heat-shock induced excision of these visible markers to yield a seamless insertion of a fluorescent protein into the genome (Dickinson et al. 2015). Compared to protocols that utilize Cas9 protein and linear DNA repair templates (Paix et al. 2015; Dokshin et al. 2018; Ghanta and Mello 2020), the plasmid-based SEC approach employs a simpler screening strategy but requires more worms to be injected (Dickinson and Goldstein 2016).

Wolf, Trevor et al. (2020) MicroPubl Biol

Harris, Gareth, Perez, Ariana, Wolf, Trevor

[MicroPubl Biol, 2020]

Sensation of environmental cues and decisions made as a result of processing of specific sensory cues underlies a myriad of behavioral responses that control every-day life decisions and ultimately survival in many organisms. Despite the appreciation that organisms can sense, process, and translate sensory cues into a behavioral response, the neural mechanisms and molecules that mediate these behaviors are still unclear. Neurotransmitters, such as glutamate, have been implicated in a variety of sensory-dependent behavioral responses, including olfaction, nociception, mechanosensation, and gustation (Mugnaini et al., 1984, Wendy et al., 2013, Daghfous et al., 2018). Despite understanding the importance of glutamate signaling in sensation and translation of contextual cues on behavior, the molecular mechanisms underlying how glutamatergic transmission influences sensory behavior is not fully understood. The nematode, C. elegans, is able to sense a variety of sensory cues. These types of sensory-dependent behavioral responses are mediated through olfactory, gustatory, mechanosensory and aerotactic circuits of the worm (Lans and Jansen, 2004, Milward et al., 2011, Bretscher et al., 2011, Kodama-Namba et al., 2013, Ghosh et al., 2017). Odor guided behavior toward attractants, such as, food cues requires neurotransmitters, that include, glutamate (Chalasani et al., 2007, Chalasani et al., 2010). More specifically, once on a food source, wild type N2 hermaphrodites will generally be retained on a food source (Shtonda and Avery, 2006, Milward et al., 2011, Harris et al., 2019). The types, quality, pathogenicity, and perception of food can modulate food recognition, food leaving rates, and overall navigational strategies towards food (Zhang et al., 2005, Shtonda and Avery, 2006; Ollofsson et al., 2014). These types of behaviors are based on detection of environmental cues, including oxygen, metabolites, pheromones, and odors. Food leaving behaviors have been shown to be influenced by a number of neuronal signals (Shtonda and Avery, 2006, Bendesky et al., 2011, Ollofsson et al., 2014, Meisel et al., 2014, Hao et al., 2018).

Chamoli, Manish et al. (2020) MicroPubl Biol

Lithgow, Gordon J, Chamoli, Manish, Andersen, Julie K, Chinta, Shankar J

[MicroPubl Biol, 2020]

Kavain belongs to a group of lactone-based compounds collectively known as kavalactones, present in the pepper plant kava (P. methysticum). Kavalactones have been shown to possess diverse biological activities including sedation and anxiolysis (Ooi et al., 2018). Kavain in particular has been demonstrated to show potent anti-inflammatory properties in various in vitro and animal models (Guo et al., 2018; Singh et al., 2018; Tang and Amar, 2016; Yuan et al., 2011). A study in C. elegans reported that kavain increases lifespan by inhibiting advance glycation end-products (AGEs), which are known to suppress lifespan (Chaudhuri et al., 2016; Upadhyay et al., 2014). Another study reported that kavain increases acetylcholine (ACh) transmission at the neuromuscular junction (Kautu et al., 2017). Since loss in ACh transmission and increased formation of AGEs are closely linked to A-pathology, we hypothesized that kavain may protect against A-induced toxicity (Kar et al., 2004; Li et al., 2013). We tested kavain in the C. elegans GMC101 strain that over-expresses human Ain body wall muscle cells (McColl et al., 2012). Kavain at a concentration of 40 and 80 M was shown to increase lifespan, thus we decided to use a dose between these ranges (Upadhyay et al., 2014). We observed GMC101 animals fed 50 M kavain showed significantly less paralysis when shifted to the higher permissive temperature (25o C). The result shows that kavain suppresses A-induced proteotoxicity.

Page KE et al. (2012) Metallomics "Aluminium exposure disrupts elemental homeostasis in Caenorhabditis elegans."

McCrohan CR, Page KE, White KN, Killilea DW, Lithgow GJ

[Metallomics, 2012]

Aluminium (Al) is highly abundant in the environment and can elicit a variety of toxic responses in biological systems. Here we characterize the effects of Al on Caenorhabditis elegans by identifying phenotypic abnormalities and disruption in whole-body metal homeostasis (metallostasis) following Al exposure in food. Widespread changes to the elemental content of adult nematodes were observed when chronically exposed to Al from the first larval stage (L1). Specifically, we saw increased barium, chromium, copper and iron content, and a reduction in calcium levels. Lifespan was decreased in worms exposed to low levels of Al, but unexpectedly increased when the Al concentration reached higher levels (4.8 mM). This bi-phasic phenotype was only observed when Al exposure occurred during development, as lifespan was unaffected by Al exposure during adulthood. Lower levels of Al slowed C. elegans developmental progression, and reduced hermaphrodite self-fertility and adult body size. Significant developmental delay was observed even when Al exposure was restricted to embryogenesis. Similar changes in Al have been noted in association with Al toxicity in humans and other mammals, suggesting that C. elegans may be of use as a model for understanding the mechanisms of Al toxicity in mammalian systems.

Wang W et al. (2009) Biochem Biophys Res Commun "Ced-9 inhibits Al-induced programmed cell death and promotes Al tolerance in tobacco."

Pan J, Bian H, Wang W, Shao H, Wang J, Chen H, Zheng K, Zhu M, Guo Y, Han N

[Biochem Biophys Res Commun, 2009]

Our previous data showed that apoptotic suppressors inhibit aluminum (Al)-induced programmed cell death (PCD) and promote Al tolerance in yeast cells, however, very little is known about the underlying mechanisms, especially in plants. Here, we show that the Caenorhabditis elegans apoptotic suppressor Ced-9, a Bcl-2 homologue, inhibited both the Al-induced PCD and Al-induced activity of caspase-like vacuolar processing enzyme (VPE), a crucial executioner of PCD, in tobacco. Furthermore, we show that Ced-9 significantly alleviated Al inhibition of root elongation, decreased Al accumulation in the root tip and greatly inhibited Al-induced gene expression in early response to Al, leading to enhancing the tolerance of tobacco plants to Al toxicity. Our data suggest that Ced-9 promotes Al tolerance in plants via inhibition of Al-induced PCD, indicating that conserved negative regulators of PCD are involved in integrated regulation of cell survival and Al-induced PCD by an unidentified mechanism.