Chen, Wenjun et al. (2019) International Worm Meeting "Germline RNA helicases drive the phase separation and perinuclear anchoring of germ granules to promote piRNA-mediated genome surveillance."

Zhang, Donglei, Lee, Heng-Chi, Tu, Shikui, Weng, Zhiping, Chen, Wenjun, Munro, Ed, Lang, Charles, Bennett, Karen, Brown, Jordan

[International Worm Meeting, 2019]

piRNAs function as a guardian of the genome through the silencing of foreign or selfish nucleic acids. However, it remains unknown how piRNAs effectively identify foreign/selfish RNAs among many endogenous mRNAs. Intriguingly, many piRNA pathway factors are enriched in germ granules, the major sites of RNA export in germ cells, implying their localization may facilitate the detection and silencing of foreign nucleic acids. Here we showed that two germline helicases, GLH-1 and GLH-4, play a redundant role in germ granule formation. In glh-1;glh-4 double mutants, many germ factors, including PGL-1 and PRG-1, become completely dispersed into the cytoplasm. To investigate the roles of germline helicases in controlling germ granule formation, we created gene-edited worms that express various mutated GLH-1 helicases. We found that GLH-1 controls the formation and disassembly of germ granules through their binding and release of RNAs, respectively, which are coupled to distinct steps of its ATP hydrolysis cycle. Microscopic and proteomic analyses support a model that RNA binding by GLH-1 allows for the assembly of germ granule factors on RNAs, which promote the phase separation of germ granules. In addition, the FG repeats of GLH-1 is required for the anchoring of germ granules to perinuclear foci. Importantly, piRNA reporter analyses and small RNA cloning data suggest that normal germ granule dynamics and proper nuclear membrane association are both critical for the production of secondary small RNAs and gene silencing. Furthermore, we showed that these glh-1 mutants with abnormal germ granules also exhibit defects in transgenerational gene silencing. Together, our research suggests that the localization and dynamics of germ granules are both controlled by germline helicases and their RNA-bound complexes drive the phase separation of germ granules. In addition, our data support a model that germ granules function as a checkpoint, where small RNAs survey mRNA transcripts as they exit nuclei to identify RNA targets for gene silencing.

Po MD et al. (2012) Neuron "Releasing the inner inhibition for axon regeneration."

Po MD, Calarco JA, Zhen M

[Neuron, 2012]

The adult mammalian central nervous system exhibits restricted regenerative potential. Chen etal. (2011) and El Bejjani and Hammarlund (2012) used Caenorhabditis elegans to uncover intrinsic factors that inhibit regeneration of axotomized mature neurons, opening avenues for potential therapeutics.

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.

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.

Akin O et al. (2014) Cell "The shape of things to come."

Akin O, Zipursky SL

[Cell, 2014]

Surface receptors can link binding of ligands to changes in the actin-based cell cytoskeleton. Chia etal. and Chen etal. provide evidence for direct binding between the cytoplasmic tails ofreceptorsand the WAVE complex, a regulator of the actin nucleator Arp2/3 complex, which mighthelp to explain how environmental signals are translated into changes in morphology andmotility.

Chen X et al. (2015) Mol Neurodegener "Erratum to: Ethosuximide ameliorates neurodegenerative disease phenotypes by modulating DAF-16/FOXO target gene expression."

McCue HV, Chen X, Morgan A, Kashyap SS, Barclay JW, Kraemer BC, Burgoyne RD, Wong SQ

[Mol Neurodegener, 2015]

The original version of this article [1] unfortunately contained a mistake. The author list contained a spelling error for the author Hannah V. McCue. The original article has been corrected for this error. The corrected author list is given below:Xi Chen, Hannah V. McCue, Shi Quan Wong, Sudhanva S. Kashyap, Brian C. Kraemer, Jeff W. Barclay, Robert D. Burgoyne and Alan Morgan

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.

Frederick J Tan et al. (2004) West Coast Worm Meeting "Functions of the Outer Mitochondrial Membrane Protein CED-9"

R Blake Hill, Andrew Z Fire, Frederick J Tan

[West Coast Worm Meeting, 2004]

CED-9 (CEll Death abnormal) negatively regulates the programmed cell death pathway in C. elegans . This membrane associated pro-survival protein prevents the activation of the CED-3 caspase. Loss of function ced-9 animals arrest at early embryogenesis, presumably dying from ectopic cell deaths. Conversely, gain of function animals appear healthy, albeit with extra cells (Hengartner, Ellis and Horvitz, 1992). These effects have been ascribed to the ability of CED-9 to sequester the CED-4/CED-3 caspase complex at the mitochondria (Chen, et al. , 2000). We hope to understand the structural features of CED-9 that participate in its function. To this end, we are assaying the activity of various CED-9 mutants and derivatives for ability to prevent cell death and respond to appropriate modulating signals. A question that we consider to be central is whether the C-terminal transmembrane domain of CED-9 serves only as a targeting sequence to the mitochondrion, or plays a more active role. We have demonstrated that this domain is essential for mitochondrial localization and plays some role in the function of CED-9. Distinction between localization and other structural and functional roles is in progress. Hengartner MO, Ellis RE and HR Horvitz. 1992. Caenorhabditis elegans gene ced-9 protects cells from programmed cell death. Nature 356 , 494-499. Chen F, Hersh BM, Conradt B, Zhou Z, Riemer D, Gruenbaum Y, and HR Horvitz. 2000. Translocation of C. elegans CED-4 to Nuclear Membranes During Programmed Cell Death. Science 287 , 1485-1489.