Walker RJ et al. (2000) Acta Biol Hung "Physiological and pharmacological studies on nematodes."

Holden-Dye L, Franks CJ, Pemberton DJ, Rogers C, Walker RJ

[Acta Biol Hung, 2000]

Classical transmitters and neuroactive peptides act as transmitters or modulators within the central and peripheral nervous systems of nematodes, for example Ascaris suum and Caenorhabditis elegans. Acetylcholine (ACh) and gamma-aminobutyric acid (GABA) are respectively the excitatory and inhibitory transmitters onto somatic body wall muscle while 5-hydroxytrypamine (5-HT) is the excitatory transmitter onto pharyngeal muscle. 5-HT also reduces ACh-induced contractions of somatic muscle and this action of 5-HT is mediated through activation of adenylate cyclase while that on pharyngeal muscle is mediated through inositol phosphate activation. Glutamate, dopamine and octopamine also have transmitter roles in nematodes. Neuroactive peptides of the RFamide family can excite somatic muscle, for example, AF-1 (KNEFIRFamide), AF-2 (KHEYLRFamide), AF-3 (AVPGVLRFamide) and AF-4 (GDVPGVLRFamide) or inhibit and relax this muscle, for example, PF-1 (SDPNFLRFamide), PF-2 (SADPNFLRFamide) and PF-4 (KPNlRFamide). In addition PF-3 (AF-8) (KSAYMRFamide) has a biphasic action on pharyngeal muscle, excitation followed by inhibition while AF-1 only inhibits this muscle. The peptide effects can be either pre- or postsynaptic or both and are likely to be mediated through second messenger systems. In addition these peptides modulate the action of classical transmitters, particularly ACh.

Hung T-J et al. (1996) East Coast Worm Meeting "CHASING DOWN THE par-6 GENE"

Hung T-J, Kemphues KJ

[East Coast Worm Meeting, 1996]

The six par genes, which show a strict maternal effect, play an important role in the generation of polarity in the one-cell embryo. As part of the effort to characterize the par genes at the molecular level, we are cloning par-6. The phenotype of par-6 mutant embryos is typical of par mutants in general. But in particular, par-6 embryos closely resemble par-3 mutants in several aspects-improper localization of P granules, disruption of the asymmetric accumulation of SKN-1 protein, and improper localization of PAR-1 and PAR-2 proteins. Since PAR-3 protein is absent from the cortex of par-6 mutant embryos, it is thought that par-6 acts by localizing or stabilizing the PAR-3 protein (Watts et al., submitted). We mapped par-6 to the right arm of LG-I about 0.5 m.u. to the right of unc-101. Deletion mapping put the par-6 gene within the region bordered by the two cosmids W05A3 and C10D1 (thanks to Dr. Ann Rose for providing the deletion stains). Preliminary results suggest that the cosmic T07D10 can weakly rescue the par-6 maternal effect lethal phenotype. We are currently injecting the cosmids overlapping T07D10 to find out if we can get stronger rescue. We are also trying to find allele-specific polymorphisms using T07D10 and overlapping cosmids as probes.

Wesley L Hung et al. (2003) International Worm Meeting "Dissecting the role of sad-1 pathway in synaptogenesis"

Wesley L Hung, Mei ZHEN

[International Worm Meeting, 2003]

Formation of synapses is essential for establishing neural circuits during the development of a nervous system. Signaling mechanisms that control the initiation and maintenance of synapses, however, remain largely unknown. SAD-1 family serine/threonine kinase was first identified in C. elegans in genetic screens designed to isolate mutations affecting synaptogenesis. Loss of sad-1 functions results in a variable and wide range of synaptic development defects including diffuse distribution of synaptic vesicles at some synapses, failure to develop synapses in certain axonal regions, and axons passing their targets. These observations strongly suggest that SAD-1 kinase activity is a key factor to promote the formation of synapses (Crump et al., Neuron. 2001 1:115-29). The presence of fly, mouse and human homologues as revealed by BLAST search suggests that SAD-1 function is evolutionarily conserved. Further elucidating the SAD-1 signaling pathways would thus provide insights on mechanisms regulating synaptogenesis. In a yeast two-hybrid screen, we have identified several potential interacting proteins of SAD-1. Out of the screen, we identified a homologue of mammalian neurabin gene, nab-1. Like the mammalian homologue, NAB-1 is expressed in the nervous system. Preliminary results suggest that NAB-1 interacts with SAD-1 through its PDZ domain. In addition, two novel genes were identified to interact with SAD-1. sai-1, SAD-1 interacting protein, encodes a novel zinc finger containing protein that expresses solely in the nervous system and shows co-localization with SAD-1. Many proteins involved in synapse function, such as Picolo and Rim1/unc-10, have been shown to interact with other proteins through their zinc finger domains. sai-2 encodes a novel protein with homology to S. cerevisiae Vps36, which is involved in vacuolar protein sorting. Expression studies of sai-2 revealed that it is expressed in the nervous system as well as the muscle dense bodies. Further studies will be presented to elucidate the roles of these genes in synaptogenesis.

Hung WL et al. (2013) EMBO J "Attenuation of insulin signalling contributes to FSN-1-mediated regulation of synapse development."

Hung WL, Stigloher C, Hwang C, Liao EH, Gao S, Bessereau JL, Zhen M, Wang Y, Li H, Chitturi J

[EMBO J, 2013]

A neuronal F-box protein FSN-1 regulates Caenorhabditis elegans neuromuscular junction development by negatively regulating DLK-mediated MAPK signalling. In the present study, we show that attenuation of insulin/IGF signalling also contributes to FSN-1-dependent synaptic development and function. The aberrant synapse morphology and synaptic transmission in fsn-1 mutants are partially and specifically rescued by reducing insulin/IGF-signalling activity in postsynaptic muscles, as well as by reducing the activity of EGL-3, a prohormone convertase that processes agonistic insulin/IGF ligands INS-4 and INS-6, in neurons. FSN-1 interacts with, and potentiates the ubiquitination of EGL-3 in vitro, and reduces the EGL-3 level in vivo. We propose that FSN-1 may negatively regulate insulin/IGF signalling, in part, through EGL-3-dependent insulin-like ligand processing.

Wendy WK Hung et al. (2004) West Coast Worm Meeting "Conservation and architecture of the mesendoderm gene network."

Gina Broitman-Maduro, Wendy WK Hung, Morris F Maduro, Tan-Hui Lin

[West Coast Worm Meeting, 2004]

At the four-cell stage of C. elegans development, the ventralmost cell, EMS, expresses the GATA-type transcription factors MED-1/2, which specify the fates of the EMS daughter cells MS and E. MS will produce mesodermal cell types, including body muscles and cells of the pharynx. In the E cell, MED-1/2 directly activate the genes end-1 ,3 (for en doderm- d etermining) to specify an endoderm fate. The genome of the related nematode C. briggsa e, estimated to be diverged from C. elegans by ~100 MYr, encodes putative END and MED homologs. We are interested in the conservation of mechanisms of MED-1 gene activation and in identifying new MED-1 target genes. Previous work has shown that recombinant MED-1 can bind the end-1 and end-3 promoters in vitro (G. Broitman-Maduro, M. Maduro and J. Rothman, unpublished) and in vivo (Maduro et al ., 2002). To study this interaction in C. briggsae , Cb -MED-1 is being expressed in E. coli , with a view towards performing gel shift assays using fragments of the Cb-end-1 gene. Identification of the binding sites using DNaseI footprinting will allow us to ask how this cell specification pathway has changed over evolutionary time. In a related project, we are using UV-crosslinked chromatin immunoprecipitation (UV-X-ChIP) to identify new MED-1 targets in C. elegans . Early blastomeres from worms expressing GFP: :MED -1 are being isolated, and protein-bound chromatin UV-crosslinked and sheared using sonication. MED-1-bound chromatin will be immunoprecipitated, cloned using linker DNA fragments, and sequenced. Progress with these experiments will be reported.

Shih, Hung-jen et al. (2021) International Worm Meeting "Collagen gene variants, endoplasmic reticulum homeostasis, and aging"

Flibotte, Stephane, Shih, Hung-Jen, Hu, Patrick, Allen, Matthew, Cha, Jeeyeon, Bastarache, Lisa

[International Worm Meeting, 2021]

One third of all proteins are cotranslationally translocated into the endoplasmic reticulum (ER) during their biogenesis. A conserved homeostatic mechanism known as the ER unfolded protein response (UPR) has evolved to ensure protein folding homeostasis (proteostasis) in the ER lumen by tuning ER chaperone and protein degradative capacity to accommodate changes in unfolded protein load. Failure of the ER UPR can lead to protein misfolding and aggregation, a condition known as "ER stress" which is associated with common human diseases associated with aging such as Alzheimer's disease, Parkinson's disease, and diabetes. Therefore, insights into the molecular underpinnings of the ER UPR will likely lead to improved strategies to promote healthy aging through the maintenance of ER homeostasis. In previous studies we discovered that trap-1 null mutants exhibit constitutive expression of the hsp-4::GFP ER UPR reporter. To gain insight into how TRAP-1 contributes to ER homeostasis, we performed a genetic screen for modifiers of the trap-1 mutant phenotype. We mutagenized trap-1;hsp-4::GFP worms and screened for F2 progeny with either increased or decreased GFP expression. One strain with increased GFP expression harbored a causal missense mutation in the col-75 collagen gene (dp691). A col-75 nonsense allele does not induce hsp-4::GFP expression, indicating that hsp-4::GFP induction is not due to loss of col-75 activity. Surprisingly, while col-75 is expressed primarily in the excretory cell, socket glia, and pharyngeal neurons, it induces hsp-4::GFP expression non-autonomously and specifically in intestine and spermatheca. Intriguingly, although germline missense mutations in human collagen genes that induce chronic ER stress typically cause disease, col-75(dp691) animals are healthy and retain wild-type levels of resistance to the ER stress inducer tunicamycin. A phenome-wide association study (PheWAS) of all common human COL missense alleles in the BioVU de-identified electronic health record-linked DNA biobank captured on the Illumina Exome BeadChip array revealed the association of several COL gene variants with protection from diagnoses of aging-related diseases such as heart failure, cancer, kidney disease, spinal stenosis, and inflammatory bowel disease. We hypothesize that collagen gene missense mutations that cause constitutive ER UPR induction have context-dependent effects on cellular and organismal fitness and may contribute to human health through constitutive ER UPR induction.

Tak Hung et al. (2002) West Coast Worm Meeting "cep-1/p53-Independent Activation of Apoptosis in the C. elegans Germline"

Tak Hung, Mike Costa, Dianne Parry, Garth McGrath, Mark Lackner, Carol O'Brien, Lisa Moore, Kevin Keegan, Mark Maxwell

[West Coast Worm Meeting, 2002]

We have isolated a deletion mutant in the C. elegans p53 gene ortholog, cep-1. In agreement with the phenotypic analysis of cep-1 RNAi (Derry et al., 2001; Schumacher et. al., 2001) and a dominant negative cep-1 mutant (Derry et al., 2001), we find that the cep-1 deletion blocks radiation-induced apoptosis in the meiotic germline, but does not alter physiological germ cell death. In addition, the cep-1 deletion mutant displays hypersensitivity to radiation-induced germline proliferation defects, although this phenotype is less penetrant than that of the checkpoint mutants hus-1 and rad-5. Some experiments suggest that the cep-1 deletion may also partially block cell cycle arrest of the mitotic germline in response to DNA damage. We are carrying out an RNAi screen for increased germline apoptosis in the cep-1 deletion mutant, with the goal of identifying candidate drug targets for inducing apoptosis of p53 mutant tumor cells. Inactivation of cpl-1, an ortholog of the protease cathepsin L, was found to induce germline apoptosis in a manner independent of cep-1 gene activity, but dependent on ced-3/caspase and ced-4/Apaf-1 activities. We will discuss models by which the function of a lysosomal protease might normally prevent apoptosis.

Hung YC et al. (2010) J Exp Biol "Effects of static magnetic fields on the development and aging of Caenorhabditis elegans."

Lee JH, Hung YC, Huang GS, Chen HM

[J Exp Biol, 2010]

The current study investigated the possible effects of static magnetic fields (SMFs) on the developmental and aging processes of Caenorhabditis elegans. Nematodes were grown in the presence of SMFs of strengths varying from 0 to 200 mT. The rate of development and the lifespan were recorded. Treatment with a 200 mT SMF reduced the development time from the L2 to the L3 stage by 20%, from L3 to L4 by 23%, and from L4 to young adult by 31%. After SMF treatment, the average lifespan was reduced from 31 days to 24 days for wild-type nematodes. The up-regulation of clk-1, lim-7, daf-2, unc-3 and age-1 after SMF treatment was verified by quantitative real-time RT-PCR. Apparently, induction of gene expression is selective and dose dependent. The total developmental time was significantly reduced for the lin-4, lin-14, lin-41 and lim-7 mutants, but not for the let-7, clk-1, unc-3 and age-1 mutants. Lifespan analyses revealed that the let-7, unc-3 and age-1 mutants were not affected by SMF treatment. Here we show that SMFs accelerate nematode development and shorten nematode lifespan through pathways associated with let-7, clk-1, unc-3 and age-1.

Hung M-S et al. (1995) Worm Breeder's Gazette "vab-8 May Encode a Protein with Kex2 Cleavage Sites."

Hung M-S, Way JC

[Worm Breeder's Gazette, 1995]

vab-8 may encode a protein with Kex2 cleavage sites Ming-shiu Hung and Jeff Way. Dept. of Biology, Nelson Labs, Rutgers University, Piscataway NJ 08855. We have identified and sequenced a ~5kb DNA fragment that rescues the withered tail phenotype of vab-8(e1017), and isolated some corresponding, incomplete cDNAs. vab-8 is adjacent to myo-3 and these two genes are transcribed towards each other. Our current interpretation of the sequence suggests that the vab-8 protein is 571 amino acids and contains 20 sites where two or three arginine and/or lysine residues are adjacent. Such pairs of basic amino acids are the target for the Kex2 protease, which is located in the Golgi and which cleaves secreted proteins. In addition, there may be a 18 aa hydrophobic stretch at the N-terminus, followed by a His-Lys sequence that also might be a cleavage site. The C terminal 300 amino acids are confirmed by our cDNAs, but the putative N-terminus has been identified only by sequence-gazing and still needs to be confirmed. vab-8 mutants show a withered tail phenotype as a result of a failure of the posterior migration of the CAN neuron. In addition, some alleles cause an anterior over-migration of the HSN cell (Manser and Wood, Devel. Genetics 11: 49-64). At a low frequency, extra mec-3-expressing PLM cells are observed (Way et al., Dev. Dynamics 194: 289-302), which could be due to a failure in sensing the anterior-posterior direction leading to an asymmetric cell division defect. Bruce Wightman and Gian Garriga (personal communication) have also shown that vab-8 is allelic to unc-107, which has an axon guidance defect, and that the extension of many axons is defective vab-8(-). Only events in the anterior-posterior direction are affected in this mutant. Thus, vab-8 may be part of a directional information system that would be complementary to the unc-5/unc-6 system for the dorsal-ventral direction.

Hung, Wesley et al. (2015) International Worm Meeting "The C. elegans RID neuron is a neurosecretory cell that modulates locomotion."

Lu, Yangning, Holmyard, Douglas, McWhirter, Rebecca, Samuel, Aravinthan, Laskova, Valeriya, Zhen, Mei, Ji, Ni, Miller, David M., Chitturi, Jyothsna, Hung, Wesley, Ho, Chi-Yip, Calarco, John, Lim, Maria A

[International Worm Meeting, 2015]

* contributed equallyComplex behaviors are modulated by endocrine neurons, which secrete neuropeptides and hormones. Homeostasis of these neuromodulators is critical, and its disruption has been associated with disease. Despite the ancient and significant role that neuromodulators play in complex behaviors across organisms, a comprehensive understanding of neuroendocrine cell function and their regulation is limited. The C. elegans nervous system provides an excellent genetic platform to investigate neural network functions and behavior. However, despite a fully annotated nervous system, a neuron with dedicated neurosecretory properties has not been identified. Using serial transmission electron microscopy, we identified RID as a potential endocrine cell. RID is the only neuron that extends an axon along the full length of the dorsal nerve cord and almost exclusively contains dense core vesicles, which package and secrete neuromodulators. Using a combination of laser ablation, genetics, and imaging techniques, we provide several lines of evidence that the RID neuron is a neuroendocrine cell that modulates motor behaviors. Using transcriptome profiling of a subpopulation of neurons isolated from both wild-type and unc-39 mutant worms, wherein the RID neuron is absent, we found that the RID neuron is enriched with neuropeptides, including flp-14. We confirm that flp-14 is expressed in the RID neuron and that flp-14 mutants possess locomotor defects similar to RID mutants. Our results demonstrate a neuromodulatory role for the RID neuron in regulating locomotion. We propose that the C. elegans RID neuron may be a useful genetic model to probe for conserved molecular mechanisms underlying neuroendocrine cell development and function. .