Ben Kemp et al. (2006) Development & Evolution Meeting "Forward and Reverse Genetic Analysis of gem-1"

Ben Kemp, BARBARA CONRADT, Laura Sternick, Eric Lambie, Diane Church, Justine Modica, Josh Cornman-Homonoff, Pamela Tieu

[Development & Evolution Meeting, 2006]

gon-2 encodes a TRPM channel that is required for the initiation of postembryonic divisions by the gonadal precursor cells. We have performed an extensive forward genetic screen for revertants of the hypomorphic allele, gon-2(q388). The majority of the suppressor mutations correspond to gain-of-function alleles of a single locus, gem-1. gem-1 encodes a member of the SLC superfamily of solute transporter proteins. We have generated a functional GEM-1::GFP reporter and find that the fusion protein localizes to the plasma membrane of Z1 and Z4. Since gem-1(gf) can suppress a candidate null allele of gon-2 it appears that a high level of gem-1 activity is able to bypass the requirement for gon-2 in the initiation of gonadogenesis. Furthermore, a candidate null allele of gem-1 acts as an enhancer of gon-2(388), indicating that the wild type gem-1 gene product ordinarily functions in parallel to gon-2. To facilitate the construction of transgenes that carry gem-1(gf) alleles, we have established conditions for efficient in vivo recombination between co-injected DNA fragments.

Valenzuela MRL et al. (1991) International C. elegans Meeting "STRUCTURES AND FUNCTIONS OF THE REPEATING MOTIFS IN TWITCHIN."

Valenzuela MRL, Benian GM

[International C. elegans Meeting, 1991]

Twitchin, the 753,570 Da polypeptide encoded by the unc-22 gene, was the first member of a growing family of intracellular and mostly muscle proteins, found in diverse animals, composed of multiple copies of motif I (fibronectin type III domain-like) and motif II ( immunoglobulin C2 domain-like). To date, this family includes, smooth muscle and non-muscle myosin light chain kinases, titin, C-protein, 86 kDa protein, skelemin and probably insect projectin. The similarities to motifs found in extracellular and cell surface proteins engaged in recognition or adhesion suggests that motifs I and II of muscle proteins are also involved in binding--probably to myosin, other thick filament components, and also binding of these proteins to themselves and other family members. We hope to be able to demonstrate binding of small numbers of these motifs to thick filament components both in vitro and in vivo. Crystallographic structure determination will be done in collaboration with Pamela Bjorkman (Cal Tech). Using the pGEX- 2T vector, we have been able to express and purify large quantities of motif I, motif II and the predominant triplet I,I,II as glutathione-S- transferase (GST) fusion proteins in E. coli. We have succeeded with the thrombin cleavage of the motifs from GST and are trying ELISA-type binding assays with nematode and rabbit myosin. For in vivo 'binding' studies, we have cloned motif I, motif II, the trio I,I,II and the C- terminal 5 motif IIs into Andy Fire's pPD30.38 vector which directs body wall muscle expression. These constructs will be microinjected into unc-22 nulls and transgenics examined by immunofluorescence for co-localization to myosin.

Ruiz, Manuel (2021) International Worm Meeting "Glucose impacts HSN morphology and induces an egg-laying defective phenotype dependent of the serotonin-signaling pathway"

Ruiz, Manuel

[International Worm Meeting, 2021]

Glucose impacts HSN morphology and induces an egg-laying defective phenotype dependent of the serotonin-signaling pathway Manuel Axel Ruiz and Pamela Padilla Peripheral neuropathy is a common and often painful complication that results from a chronic state of hyperglycemia. In recent years, research has shown that in humans altered levels of serotonin is highly associated to a chronic state of hyperglycemia. Additionally, altered levels of serotonin are associated with various neurological disorders. However, the mechanism by which hyperglycemia impacts serotonin processes is not understood. Here we are using the genetic model system Caenorhabditis elegans as a hyperglycemia model to further understand the impact of a glucose-supplemented diet on the animal's egg-laying behavior. C. elegans possess a nervous system that is composed of 302 neurons. In C. elegans the Hermaphrodite-Specific serotonergic motor Neurons (HSN) play an essential role in regulating egg-laying. Using this model organism, we conducted genetic and cell biological analysis to examine the role a glucose-supplemented diet has on the serotonergic HSN motor neurons. Our preliminary data shows that a glucose-supplemented diet impacts egg-laying and HSN morphology. A significant proportion of animals raised in a glucose-supplemented diet have a higher incidence of intra-uterine egg-hatching, HSN axonal degeneration, and abnormal HSN morphology. We used genetic mutants to dissect out the role the serotonin pathway has on the response to a glucose diet. Furthermore, through RNA-sequencing, we examined how a glucose-supplemented diet alters the expression of genes responsible of serotonergic functions. This work will lead to the further understanding of the molecular mechanisms that are involved on altered serotonergic neuronal functions as a result of a chronic hyperglycemic state.