da Silva AF et al. (2022) Neurotoxicology "JM-20 affects GABA neurotransmission in Caenorhabditis elegans."

Arantes LP, Soares MV, Nunez-Figueredo Y, Cordeiro LM, da Silveira TL, Soares FAA, Baptista FBO, Machado ML, Zamberlan DC, da Silva AF, Rodriguez EO

[Neurotoxicology, 2022]

Along with the discovery of new candidate molecules for pharmaceuticals, several studies have emerged showing different mechanisms of action and toxicological aspects. 3-ethoxycarbonyl-2-methyl-4- (2-nitrophenyl)4,11-dihydro-1H-pyrido [2,3-b] [1,5] benzodiazepine (JM-20) is a hybrid molecule. It is derived from 1,5-benzodiazepines and structurally differentiated by the addition of 1,4-dihydropyridine bonded to the benzodiazepine ring. This gives this molecule potential neuroprotective, antioxidant, and anxiolytic activity. As this is a promising multi-target molecule, further studies are necessary to improve the knowledge about its mechanism of action. In our study, we used Caenorhabditis elegans (C. elegans) to investigate the effects of chronic treatment with JM-20. Nematodes from the wild-type strain (N2) were treated chronically at different concentrations of JM-20. Our results show that JM-20 does not cause mortality, but higher concentrations can delay the development of worms after 48h exposure. We assessed basic behaviors in the worm, and our data demonstrate decreased defecation cycle. Our results suggest that JM-20 acts on the C. elegans GABAergic system because GABA neurotransmission is associated with the worm intestine. We also observed increased locomotor activity and decreased egg-laying after JM-20 treatment. When both behaviors were evaluated in mutants with have reduced levels of GABA (unc-25), this effect is no observed, suggesting the GABAergic modulation. Still, the JM-20 exert similar effect of Diazepam in basic behaviors observed. To reinforce neuromodulatory action, computational analysis was performed, and results showed a JM-20 binding on allosteric sites of nematodes GABA receptors. Overall, this work provided a better understanding of the effects of JM-20 in C. elegans as well as showed the effects of this new molecule on the GABAergic system in this animal model.

Killeen M et al. (2002) Dev Biol "UNC-5 function requires phosphorylation of cytoplasmic tyrosine 482, but its UNC-40-independent functions also require a region between the ZU-5 and death domains."

Culotti J, Pawson T, Tong J, Steven R, Killeen M, Krizus A, Scott I

[Dev Biol, 2002]

Members of the UNC-5 protein family are transmembrane receptors for UNC-6/netrin guidance cues. To analyze the functional roles of different UNC-5 domains, we sequenced mutations in seven severe and three weak alleles of unc-5 in Caenorhabditis elegans. Four severe alleles contain nonsense mutations. Two weak alleles are truncations of the cytodomain, but one is a missense mutation in an extracellular immunoglobulin domain. To survey the function of different regions of UNC-5, wild-type and mutant unc-5::HA transgenes were tested for their ability to rescue the unc-5(e53) null mutant. Our data reveal partial functional requirements for the extracellular domains and identify a portion of the cytoplasmic juxtamembrane (JM) region as essential for rescue of migrations. When nine cytodomain tyrosines, including seven in the JM region, are mutated to phenylalanine, UNC-5 function and tyrosine phosphorylation are largely compromised. When F482 in the JM region of the mutant protein is reverted to tyrosine, UNC-5 tyrosine phosphorylation and in vivo function are largely recovered, suggesting that Y482 phosphorylation is critical to UNC-5 function in vivo. Our data also show that part of the ZU-5 motif is required for UNC-40-independent signaling of UNC-5.

Maartens A (2019) Development "An interview with Judith Kimble."

Maartens A

[Development, 2019]

Judith Kimble is Vilas Professor of Biochemistry at the University of Wisconsin-Madison and a Howard Hughes Medical Institute Investigator (since 1994). Her lab is interested broadly in the molecular regulation of animal development, with a focus on stem cell self-renewal, fate specification and reprogramming in <i>Caenorhabditis elegans</i> We caught up with Judith after she delivered her Keynote Lecture at the 2019 Santa Cruz Developmental Biology Meeting, and heard about her circuitous route to basic research, her passion for black boxes in science and why London is her cabin the woods.

Hill RJ et al. (1992) Nature "The gene lin-3 encodes an inductive signal for vulval development in C. elegans."

Hill RJ, Sternberg PW

[Nature, 1992]

The lin-3 gene is necessary for induction of the Caenorhabditis elegans vulva by the anchor cell. It encodes a molecule similar to epidermal growth factor and to transforming growth factor-alpha and acts through the epidermal growth factor receptor homologue let-23. Expression of lin-3 in the anchor cell stimulates vulval induction; lin-3 may encode the vulval inducing signal.AD - Howard Hughes Medical Institute, California Institute of Technology, Pasadena 91125.FAU - Hill, R JAU - Hill RJFAU - Sternberg, P WAU - Sternberg PWLA - engPT - Journal ArticleCY - ENGLANDTA - NatureJID - 0410462RN - 0 (Helminth Proteins)RN - 0 (Recombinant Fusion Proteins)RN - 148412-70-8 (Lin 3 protein)RN - 62229-50-9 (Epidermal Growth Factor)SB - IM

Aroian RV et al. (1990) Nature "The let-23 gene necessary for Caenorhabditis elegans vulval induction encodes a tyrosine kinase of the EGF receptor subfamily."

Mendel JE, Ohshima YM, Sternberg PW, Koga M, Aroian RV

[Nature, 1990]

The let-23 gene is required for induction of the Caenorhabditis elegans vulva. It is shown that let-23 encodes a putative tyrosine kinase of the epidermal growth factor receptor subfamily. Thus, let-23 might encode the receptor for the inductive signal required for vulval development. Because let-23 acts upstream of let-60 ras in the vulval determination pathway, the identification of the let-23 product provides support for a link in vivo between tyrosine kinase growth factor receptors and ras proteins in a pathway of cell-type determination.AD - Howard Hughes Medical Institute, Division of Biology, California Institute of Technology, Pasadena 91125.FAU - Aroian, R VAU - Aroian RVFAU - Koga, MAU - Koga MFAU - Mendel, J EAU - Mendel JEFAU - Ohshima, YAU - Ohshima YFAU - Sternberg, P WAU - Sternberg PWLA - engPT - Journal ArticleCY - ENGLANDTA - NatureJID - 0410462RN - 0 (RNA, Messenger)RN - 9007-49-2 (DNA)RN - EC 2.7.1.112 (Protein-Tyrosine Kinase)RN - EC 2.7.11.- (Receptor, Epidermal Growth Factor)SB - IM

Coohill T et al. (1988) Mutat Res "Ultraviolet mutagenesis of radiation-sensitive (rad) mutants of the nematode Caenorhabditis elegans."

Coohill T, Schubert WW, Marshall TM, Nelson GA

[Mutat Res, 1988]

A mutational tester strain (JP10) of the nematode C. elegans was used to capture recessive lethal mutations in a balanced 300 essential gene autosomal region. The probability of converting a radiation interaction into a lethal mutation was measured in young gravid adults after exposure to fluences of 254-nm ultraviolet radiation (UV) ranging from 0 to 300 Jm-2. Mutation frequencies as high as 5% were observed. In addition, three different radiation-hypersensitive mutations, rad-1, rad-3 and rad-7 were incorporated into the JP10 background genotype, which allowed us to measure mutation frequencies in radiation-sensitive animals. The strain homozygous for rad-3 was hypermutable to UV while strains homozygous for rad-1 and rad-7 were hypomutable. Data showing the effects of UV on larval development and fertility for the rad mutants is also shown and compared for wild-type and JP10 backgrounds.

Garofalo A et al. (2003) J Biol Chem "The FAR protein family of the nematode Caenorhabditis elegans. Differential lipid binding properties, structural characteristics, and developmental regulation."

Price NC, Kennedy MW, Bradley JE, Hughes JM, Cooper A, Watson DG, Garofalo A, Kelly SM, Rowlinson MC, Amambua NA

[J Biol Chem, 2003]

Parasitic nematodes of humans and plants secrete a structurally novel type of fatty acid- and retinol-binding protein, FAR, into the tissues they occupy. These proteins may interfere with intercellular lipid signaling to manipulate the defense reactions of the host or acquire essential lipids for the parasites. The genome of the nematode Caenorhabditis elegans encodes eight FAR-like proteins (Ce-FAR-1 to -8). These fall into three discrete groups as indicated by phylogenetic sequence comparisons and intron positions, the proteins from parasitic nematodes falling into group A. Recombinant Ce-FAR-1 to -7 were produced in Escherichia coli and tested for lipid binding in fluorescence-based assays. Ce-FAR-1 to -6 bound DAUDA (11-((5-dimethylaminonaphthalene-1-sulfonyl)amino)undecanoi c acid), cis-parinaric acid, and retinol with dissociation constants in the micromolar range, whereas Ce-FAR-7 bound the latter two lipids relatively poorly. Each protein produced a characteristic shift in peak fluorescence emission of DAUDA, and one (Ce-FAR-5) produced a shift greater than has been observed previously for any lipid-binding protein. Selected Ce-FAR proteins were analyzed by circular dichroism (CD) and differential scanning calorimetry, were, found to be helix-rich, and exhibited high thermal stability (transition midpoint, 82.7 degreesC). CD and secondary structure predictions, however, both indicated that Ce-FAR-7 possesses substantially less helix than the other FAR proteins. The genes encoding the Ce-FAR proteins were found to be transcribed differentially through the life cycle of C. elegans, such that Ce-far-4 was transcribed at highest levels in the fourth larval stage, and Ce-far-3 and -7 predominated in males.

Beitel GJ et al. (1990) Nature "Caenorhabditis elegans ras gene let-60 acts as a switch in the pathway of vulval induction."

Beitel GJ, Horvitz HR, Clark SG

[Nature, 1990]

The let-60 gene, an essential ras gene of the nematode Caenorhabditis elegans, acts as a switch in the inductive signalling pathway that initiates vulva formation. Recessive let-60 mutations that cause a vulvaless phenotype prevent let-60 function in response to the inductive signal. These mutations are clustered and define regions necessary either for the activation or for the action of the let-60 ras protein. Dominant let-60 mutations that cause a multivulva phenotype alter codon 13 and activate let-60 in vivo, rendering it independent of the inductive signal. The let-60 gene acts within an extensively defined genetic pathway, and other genes within this pathway seem likely to encode molecules that regulate let-60 function as well as molecules that are targets of let-60 action.AD - Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.FAU - Beitel, G JAU - Beitel GJFAU - Clark, S GAU - Clark SGFAU - Horvitz, H RAU - Horvitz HRLA - engPT - Journal ArticleCY - ENGLANDTA - NatureJID - 0410462RN - 0 (Codon)RN - EC 3.6.1.- (GTP-Binding Proteins)RN - EC 3.6.1.- (Proto-Oncogene Protein p21(ras))SB - IM

McIntire SL et al. (1993) Nature "The GABAergic nervous system of Caenorhabditis elegans."

Horvitz HR, Kaplan JM, McIntire SL, Jorgensen EM

[Nature, 1993]

gamma-Aminobutyric acid (GABA) is the most abundant inhibitory neurotransmitter in vertebrates and invertebrates. GABA receptors are the target of anxiolytic, antiepileptic and antispasmodic drugs, as well as of commonly used insecticides. How does a specific neurotransmitter such as GABA control animal behaviour? To answer this question, we identified all neurons that react with antisera raised against the neurotransmitter GABA in the nervous system of the nematode Caenorhabditis elegans. We determined the in vivo functions of 25 of the 26 GABAergic neurons by killing these cells with a laser microbeam in living animals and by characterizing a mutant defective in GABA expression. On the basis of the ultrastructurally defined connectivity of the C. elegans nervous system, we deduced how these GABAergic neurons act to control the body and enteric muscles necessary for different behaviours. Our findings provide evidence that GABA functions as an excitatory as well as an inhibitory neurotransmitter.AD - Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, 02139.FAU - McIntire, S LAU - McIntire SLFAU - Jorgensen, EAU - Jorgensen EFAU - Kaplan, JAU - Kaplan JFAU - Horvitz, H RAU - Horvitz HRLA - engPT - Journal ArticleCY - ENGLANDTA - NatureJID - 0410462RN - 56-12-2 (gamma-Aminobutyric Acid)SB - IM

De Bono M et al. (1998) Cell "Natural variation in a neuropeptide Y receptor homolog modifies social behavior and food response in C. elegans."

Bargmann CI, De Bono M

[Cell, 1998]

Natural isolates of C. elegans exhibit either solitary or social feeding behavior. Solitary foragers move slowly on a bacterial lawn and disperse across it, while social foragers move rapidly on bacteria and aggregate together. A loss-of-function mutation in the npr-1 gene, which encodes a predicted G protein-coupled receptor similar to neuropeptide Y receptors, causes a solitary strain to take on social behavior. Two isoforms of NPR-1 that differ at a single residue occur in the wild. One isoform, NPR-1 215F, is found exclusively in social strains, while the other isoform, NPR-1 215V, is found exclusively in solitary strains. An NPR-1 215V transgene can induce solitary feeding behavior in a wild social strain. Thus, isoforms of a putative neuropeptide receptor generate natural variation in C. elegans feeding behavior.AD - Howard Hughes Medical Institute, Department of Anatomy, The University of California, San Francisco 94143-0452, USA.FAU - de Bono, MAU - de Bono MFAU - Bargmann, C IAU - Bargmann CILA - engSI - GENBANK/U49944PT - Journal ArticleCY - UNITED STATESTA - CellJID - 0413066RN - 0 (Helminth Proteins)RN - 0 (Receptors, Neuropeptide Y)RN - EC 3.6.1.- (GTP-Binding Proteins)SB - IM