Saenz-Narciso, Beatriz et al. (2011) International Worm Meeting "Characterizing the adrenomedullin homologue in C. elegans."

Martinez, Alfredo, Cabello, Juan, Gomez-Orte, Eva, Saenz-Narciso, Beatriz

[International Worm Meeting, 2011]

Adrenomedullin (AM) is a peptide hormone that shows multiple physiological functions in vertebrates, such as bronchodilation, neurotransmission, hormone regulation, antimicrobial activity or growth regulation. Deregulation of AM has been shown in different human pathologies such as diabetes, cancer, hypertension, heart failure, and sepsis. Research on molecules capable of modulating AM and its effects may lead to the discovery of new pharmacological agents to treat these important human diseases. Highly interesting is the role of AM in cancer. It has been proven that AM acts as an autocrine/paracrine tumor cell survival factor and its elevated expression in cancer cells can promote angiogenesis leading to tumor progression. While AM has been well characterized in other research models, little is known about this molecule in C. elegans. We have found and characterized a mutant in the AM homologue of C.elegans, here called wam-1. 4D microscopy analysis of wam-1 mutants shows defects in the migration of the hermaphrodite gonad. There are also several defects in embryonic development. Some embryos have cells that are excluded out of the worm during development while fate specification, as well as proliferation is normal. This suggests a function of wam-1 in cell adhesion. To localize the expression of the worm AM homologue protein, we performed inmunostaining using mouse anti-AM antibodies. The AM protein was localized in the hypodermis. In contrast, we also generated transgenic lines expressing GFP under the control of the wam-1 promoter. GFP expression was detected in the mouth of the worm, although due to its homology with secreted hormones, the protein could play a role far away from the secretory cells. At the moment, we are performing a detailed molecular and genetic characterization, in order to understand the function of this molecule.

Cristina Nieto et al. (2008) European Worm Meeting "Analysis of the adrenomedullin homologue in C.elegans."

Cristina Nieto, Alfredo Martinez, Sergio Moreno, Juan Cabello

[European Worm Meeting, 2008]

In vertebrates, adrenomedullin (AM) is a peptide hormone that shows. multiple physiological functions, such as bronchodilation,. neurotransmission, hormone regulation, antimicrobial activity or growth. regulation. Deregulation of AM has been shown in different human. pathologies such as diabetes, cancer, hypertension, heart failure, and. sepsis.. Research on molecules capable of modulating AM and its effects may lead to. the discovery of new pharmacological agents to treat these important human. diseases. Thus, the injection of a monoclonal antibody against AM produces. an antidiabetic effect, by reducting the glycemic level in diabetic. experimental animals, since AM has been shown to reduce insulin secretion.. Highly interesting is the role of AM in cancer. It has been proven that AM. acts as an autocrine/paracrine tumor cell survival factor and its elevated. expression in cancer cells can promote angiogenesis leading to tumor. progression.. While AM has been well characterized in other research models, little is. known about this molecule in C. elegans. We have found and characterized a. mutant in the AM homologue of C.elegans, here called wam-1. 4D microscopy. analysis of wam-1 mutants shows defects in the migration of the. hermaphrodite gonad. There are also several defects in embryonic. development. Some embryos have cells that are excluded out of the worm. during development while fate specification, as well as proliferation are. normal. This suggests a function of wam-1 in cell adhesion.. To localize the expression of the worm AM homologue protein, we generated. transgenic lines expressing GFP under the control of the wam-1 promoter.. GFP expression is detected in the mouth of the worm although due to its. homology with secreted hormones, the protein could play a role far away. from the secretory cells.. At present, we are performing a detailed molecular and genetic. characterization, in order to understand the function of this molecule.

Wightman BC et al. (1995) International C. elegans Meeting "GENES REQUIRED FOR AXON OUTGROWTH AND ORGANIZATION OF THE VENTRAL NERVE CORD"

Garriga G, Wightman BC, Taskar AM

[International C. elegans Meeting, 1995]

The left bundle of the ventral nerve cord (VNC) provides a simple system with a limited number of axons to study the mechanism of axon bundling (fasciculation). Four axons extend most of the length of the adult left VNC bundle: PVPR, PVQL, AVKR, and HSNL. The HSNL growth cone requires the presence of PVPR and PVQL axons, but not the AVKR axon, to fasciculate and extend along the left VNC bundle. In the absence of these two axons the HSNL growth cone extends inappropriately along the right VNC bundle. In order to identify the molecules that function in interactions between the HSN growth cone and the PVPR and PVQL axons, we have screened through more than 100 existing and new mutants using anti-serotonin antiserum in immunofluorescence experiments to identify mutations that cause the HSNL axon to extend inappropriately along the right VNC bundle. We have also examined the anatomy of the AVKR axon and additional axons using anti-FMRFamide antiserum in selected mutants. Mutations in the following genes cause defects in HSNL and AVKR pathfinding in the left VNC bundle: unc-3, unc-30, unc-42, unc-115, fax-1(defective fasciculation of axons), and enu-1 (enhancer of unc-107). Some of these genes may function in the recognition of PVPR and/or PVQL axons by the HSNL and AVKR growth cones. We are currently cloning unc-42 (see abstract by Baran and Garriga) and fax-1. In addition, two genes are required for longitudinal extension of VNC axons: unc-20 and unc-71. Four genes are required for the longitudinal extension of axons both in the VNC and lateral axon bundles: unc-34, unc-53, unc-69, and unc-76. A larger group of genes are required for extension of axons in multiple directions and in several bundles (e.g. unc-73).

Waring DA (1996) West Coast Worm Meeting "A C. ELEGANS HOMOLOG OF NEUROD"

Waring DA

[West Coast Worm Meeting, 1996]

The neuroD gene was identified in our lab as a bHLH transcription factor controlling neuronal differentiation in mouse and Xenopus. Extopic expression in Xenopus embryos leads to production of ectopic neurons within the epidermis. It is proposed that neuroD acts downstream of the proneural genes and negative regulators of the Notch/Delta pathway. I am characterizing a C. elegans homolog of neuroD cnd-1. In order understand the function of the gene I am in the process of knocking the gene out. I have identified an insertion of a transposable element within an intron of the gene. This has no phenotype and is apparently spliced out without effecting the gene. I am presently screening for imprecise excision of the transposable element that will knock out cnd-1. In addition I am characterizing larger deficiencies and lethal mutation in the region. I have generated antibodies to cnd-1 and I am beginning to characterize the expression pattern. Neurogenesis in C. elegans is still poorly characterized. Several bHLH proteins related to the Achaete/Scute family, have been found in C. elegans, but as yet there is functional data for only one of these, lin-32 which was identified by mutations lacking a subset of neuroblasts, suggesting that as in other species bHLH proteins may regulate neurogenesis. If cnd-1 functions in C. elegans as its homologs do in vertebrates, the single cell resolution that C. elegans affords should be very useful in understanding its role in neurogenesis, and its relationship to the proneural genes.

Carson CC et al. (1995) International C. elegans Meeting "BIOCHEMICAL AND GENETIC ANALYSIS OF A C. ELEGANS ELAV-LIKE PROTEIN IMPLICATED IN GROWTH AND DIFFERENTATION"

Carson CC, Keene JD

[International C. elegans Meeting, 1995]

ELAV is a Drosophila protein that has been linked genetically to the differentiation of neuroblasts to neurons and is also responsible for the maintenance of terminally differentiated neurons. It has been shown that ELAV like proteins bind to the 3' UTR of selected transcription factors and cytokines. It is hypothesized that the expression of the ELAV family of proteins help take proliferating cells out of the cell cycle and enhance differentiation. I am using both biochemical approaches and genetic analysis to study the mechanism and function of the ELAV family of proteins in C. elegans. Using antibodies to an ELAV like protein, I have detected a protein in C. elegans mixed-stage extracts that migrates at 45 kDa on an SDS-PAGE gel. By screening of lambda zap libraries, I have obtained clones of Cel-1(C. elegans ELAV Like protein 1) that correspond to a putative ORF found by the genomic sequencing project, and appears to correspond to the 45kDa protein detected by immunoblotting. Given the striking homology among the vertebrate and invertebrate forms of the ELAV family within the RRM regions, it is clear that these are important cellular RNA-binding proteins that likely target homologous, key mRNAs regulated in growth and differentiation from worms to humans. I am in the process of expressing the Cel-1 clone in E. coli to determine if the protein is cross reactive to the Hel-N1 antibodies, to perform in vitro RNA binding experiments, make rabbit polyclonal sera, and to utilize random RNA selection. I am also attempting to determine if the Cel-1 protein is developmentally regulated, if there are pre existing mutants, where the protein is localized, and am collaborating with Dr. Plasterk, to isolate Tc1 insertions in the Cel -1 gene for genetic analysis.

Wolf FW et al. (1995) International C. elegans Meeting "Genetic and molecular separation of the cell migration and axon outgrowth defects of vab-8"

Taskar AM, Wightman BC, Hung M-S, Way JC, Garriga G, Wolf FW

[International C. elegans Meeting, 1995]

Mutations in the vab-8 gene cause defects in the posterior-directed migrations of cells and axon growth cones. vab-8 alleles fall into three classes, based on behavioral and morphological phenotypes: Strong mutants are highly penetrant for the uncoordinated (Unc) and withered tail (Wit) phenotypes, Weak mutations are less penetrant for both phenotypes, and the Unc mutations are fully penetrant for the Unc phenotype but are never Wit. The Strong mutations genetically act as severe loss-of-function alleles, as do the Unc mutations, whereas the Weak mutations act as hypomorphs. This shows that vab-8 encodes at least two functions and suggests that the Unc mutants are defective either in regulation, or in the splicing or activity of a specific domain. At the cellular level, both cell and axon migrations are defective in Strong and Weak class mutants. In contrast, only axon growth cone migrations are defective in Unc mutants, and so the separation of vab-8 function is reflected at the cellular level. In collaboration with Jeff Way's lab we have shown that a 6.4 kb region of the vab-8 locus is sufficient to rescue the Wit but not the Unc phenotypes of a Strong vab-8 mutant, and an overlapping 13.5 kb region is sufficient to fully rescue both phenotypes. Genomic probes from the smaller, Wit-rescuing region recognize three transcripts, whereas a probe unique to the region required for full rescue recognize only the largest transcript. This data allows us to propose a model in which the product of one or both of the smaller vab-8 transcripts is required for posterior-directed cell migrations and the largest vab-8 transcript is required for posterior directed axon guidance.

Heon S Kim (2004) East Coast Worm Meeting "Roles of PAR-3 and PKC-3 in establishment and maintenance of epithelial cell polarity in C. elegans"

Heon S Kim

[East Coast Worm Meeting, 2004]

Cell polarity is required at many different stages of development, including early embryogenesis and organogenesis. Intercellular junctions are believed to be required to polarize epithelial cells. PAR-3/PKC-3/PAR-6 complex, which serves as one of the earlist polarity cues during the early embryogenesis in C. elegans , has been found to be localized at apical junctions of gut epithelium in C. elegans , Drosophila , and mammals. However, the function of PAR-3/PKC-3/PAR-6 in establishment and maintenance of epithelial cell polarity in C. elegans has not been studied, mainly because the loss of function of this protein complex perturbs early embryogenesis. I am trying to overcome this barrier in two different ways. Heat shock-induced par-3 RNAi, right after early embryogenesis will deplete par-3 mRNA and hopefully will result in par-3 knock-out phenotypes in late embryos or L1~L2 larvae. Alternatively, I am examining the effect of a mutation in pkc-3 on epitheial polarity. I have a pkc-3 mutant, which is newly generated by Vancouver Gene Knockout Lab. This mutant carries a 1.5kb deletion ( ok544 ) that removes kinase domain. Homozygotes undergo normal embryogenesis due to maternal contribution, but they are arrested as L2 larvae. Currently I am trying to optimize the heat shock conditions for par-3 RNAi, and to identify the phenotypes of arrested pkc-3 mutants.

Wightman BC et al. (1995) International C. elegans Meeting "THE VAB-8 GENE GUIDES POSTERIOR-DIRECTED AXON OUTGROWTH AND CELL MIGRATION"

Forrester WC, Wightman BC, Garriga G, Taskar AM, Clark SG, Wolf FW, Bargmann CI

[International C. elegans Meeting, 1995]

The existence of cues in C. elegans and vertebrates that guide migrations of cells and axon growth cones along the dorsal-ventral axis raises the possibility that global cues may also guide migrations along the anterior-posterior axis. The vab-8 gene appears to encode a component of such a global anterior-posterior signaling system. Mutations in vab-8 disrupt 14 of 17 different posterior-directed cell and growth cone migrations. In contrast, vab-8 mutations disrupt only 2 of 17 different anterior-, dorsal-, or ventral-directed cell and growth cone migrations. Furthermore, for neurons that extend axons both anteriorly and posteriorly, vab-8 mutations disrupt only the migrations of the posterior-directed growth cone. A specific class of vab-8 mutations disrupt growth cone migrations but do not disrupt most cell migrations. In addition, a portion of the vab-8 gene defined by germ-line transformation rescue experiments can rescue cell migrations but not growth cone migrations. These results indicate that vab-8 is a complex gene that encodes at least two activities, one of which may be specifically required for growth cone migrations (see abstract by Wolf et al). So far, sequencing indicates that the vab-8 gene encodes novel protein(s) (see abstract by Hung et al). We propose that the vab-8 product(s) function in the production or interpretation of a longitudinal guidance cue, conceptually analogous to the unc-6-mediated circumferential guidance cue.

Anne B Allison et al. (2007) International Worm Meeting "A Meiotic Nuclear Envelope Bridge Complex in C. elegans."

Anne B Allison, Abby F Dernburg

[International Worm Meeting, 2007]

Events in meiotic cell division, such as homologous chromosome pairing, synapsis, and recombination, are required for proper chromosome segregation. I am investigating how Pairing Centers, cis-acting sites required for homologous chromosome pairing during meiosis in C. elegans, attach to the nuclear envelope via a Nuclear Envelope Bridge Complex (NEBC). Recently, the Dernburg Lab identified a family of related zinc-finger proteins required for Pairing Center function. These proteins form patches at the nuclear periphery with nuclear envelope proteins, such as ZYG-12 and SUN-1. These two factors a part of the NEBC that bridges the inner and outer nuclear membranes thereby connecting chromosomes with microtubules external to the nucleus. I am identifying additional components of the NEBC through suppressor screens of mutations in zyg-12 and sun-1. This work will address fundamental mechanisms of interaction between chromosomes, the nuclear envelope, and the cytoskeleton to better understand their contribution to normal cell division.

Nicola Tremain et al. (2002) European Worm Meeting "Suppressors of social feeding behaviour"

Mario De Bono, Nicola Tremain

[European Worm Meeting, 2002]

npr-1 encodes a putative G-protein coupled receptor similar to neuropeptide Y receptors. Social or solitary feeding behaviour in wild isolates of C. elegans is associated with a single residue change in this receptor1. Null mutants of npr-1 exhibit strong social feeding behaviour, suggesting that this gene acts to suppress social feeding. I am characterizing and mapping mutations that disrupt social feeding to delineate molecular pathways and neuronal networks that regulate this behaviour.