Awani, Awani et al. (2011) International Worm Meeting "Genome wide RNAi screen to study uv1 cell necrosis."

Awani, Awani, Hanna-Rose, Wendy, Crook, Matt

[International Worm Meeting, 2011]

Necrosis is more than a phenomenon of uncontrolled cell death. There is increasing evidence to suggest that necrosis is genetically programmed. We are exploiting a new model to investigate necrotic cell death. In worms that lack pnc-1 nicotinamidase, the four uv1 cells die by necrosis (1). We want to investigate why uv1 cells die in pnc-1 mutants and to identify genes that promote or inhibit uv1 cell necrosis. In pnc-1 mutant animals with a uv1 cell specific GFP transgene, we can screen for rescue of uv1 cell necrosis by screening for animals that retain the uv1 GFP signal. We aim to screen using the genome-wide RNAi library and expect to gain insight into how and why uv1 cells die in pnc-1 mutants. We are using a split GFP system to engineer animals with uv1 cell specific GFP expression for this screen (2), and we will discuss progress in engineering the strain and preparing for the screen. Reference: 1. EGF signaling overcomes a uterine cell death associated with temporal mis-coordination of organogenesis within the C. elegans egg-laying apparatus. Li Huang , Hanna-Rose Wendy 2. Antiparallel Leucine Zipper-Directed Protein Reassembly: Application to the Green Fluorescent Protein. Indraneel Ghosh , Andrew D. Hamilton , Lynne Regan.

Birgit Gerisch et al. (2007) International Worm Meeting "RNAi screen for genes that regulate stress resistance and life span."

Adam Antebi, Birgit Gerisch, Hans Lehrach

[International Worm Meeting, 2007]

Management of stress appears to be intimately related to the regulation of animal life span. Notably, most known long-lived mutants tested so far are resistant to various forms of environmental stress. In particular, long-lived mutants of the daf-2/insulin-like receptor (insulin/IGF-1 signaling) show increased resistance to heat and oxidative stress. We are using the correlation between longevity and stress resistance to identify genes that are involved in the process of life span regulation. We screened over 900 RNAis corresponding to phosphatases and kinases, as well as some kinase associated or regulated genes with wild type for enhanced survival under stress. We obtained 40 RNAis that result in strong resistance to oxidative stress, 37 with resistance to heat stress, and 6 with resistance to both. Some of the identified genes were previously shown to play a role in stress resistance and longevity, such as the guanylyl cyclase gcy-23 (Inada et al., 2006 and Hamilton et al., 2006). Selected candidate RNAis are currently being tested in aging experiments. In a similar approach we also screened the kinase RNAis for suppression of daf-2. Using a long-lived and stress resistant daf-2 mutant, we screened for reduced survival under heat and/or oxidative stress. Twelve candidates were identified and analyzed in aging experiments. Further characterization and assignment of the identified genes to pathways should yield insights into cellular processes involved in stress resistance and longevity.

Bell, Taylor et al. (2011) International Worm Meeting "A writing intensive Caenorhabditis elegans laboratory exercise for undergraduates examining oxidative stress and antioxidants."

Ryan, Rabiul, King, Lauren, Slaunwhite, Erin, Murley, Kathleen, March, Amanda, Bell, Taylor, Kohn, Rebecca E., Murphy, Katherine, Betzu, Justine, Pall, Matthew, Hartl, Amy, Frymoyer, Christopher, Brown, Loreal, Fontana, Marissa, Hamilton, Christina, McLarnon, Caitlyn, Meeley, Lauren

[International Worm Meeting, 2011]

An open-ended laboratory exercise was developed for an undergraduate Molecular Neurobiology course. The goal of the exercise was for students to design and carry out an experiment to examine how oxidative stress affects Caenorhabditis elegans strains with mutations affecting nervous system function and whether an antioxidant could protect the worms from damage. A writing intensive component of the laboratory was included for students to submit their findings to a peer-reviewed journal. This exercise would be accessible for a variety of upper level courses, including neuroscience and cell biology. Students successfully designed their experiments based on information in the Materials and Methods sections in related scientific journal articles. Students chose conditions for inducing oxidative stress and for incorporating an antioxidant in the experiment. The professor teaching the course and a student teaching assistant experienced with C. elegans research guided students in experimental design, trouble shooting difficulties, and analyzing findings. Students' results showed that strains with defects in neurotransmitter release had a higher percentage of lethality than a strain with a wild type nervous system. The antioxidant they chose to work with, L-ascorbic acid, decreased the percentage of lethality for some strains. Students worked in groups of four during scheduled laboratory times as well as during additional times to maintain their strains and perform experimental trials. During laboratory meeting times, students spent part of their time discussing effective approaches for writing scientific papers. Drafts of student manuscripts went through student peer-review and review by their instructor to prepare for submission to a journal. Three student groups chose to submit their manuscripts to the journal, IMPULSE, An Undergraduate Journal for Neuroscience, and one group chose to submit to The Journal of Young Investigators. Both journals are designed for undergraduate authors.

Christina Dittrich et al. (2006) European Worm Meeting "Identifying Novel Genes Involved in DNA Damage Response Pathways in C. elegans"

Michael O. Hengartner, Christina Dittrich

[European Worm Meeting, 2006]

Christina Dittrich and Michael O. Hengartner1. Upon DNA damage, a cell responds by arresting its cell cycle, changing its transcription patterns, recruiting the repair machinery or, most severely, by executing its own death by apoptosis. Malfunction of any of these pathways allows cells to replicate in spite of DNA lesions, and thus their genomes accumulate mutations and becomes unstable, a hallmark of tumor cells. Therefore, it is not only of paramount biological, but also of high medical interest, to understand the molecular pathways underlying DNA damage responses. Genotoxic stress induces in the germ line of Caenorhabditis elegans a spectrum of DNA damage responses similar to that observed in humans. Because important genes are often conserved throughout evolution, studies in C. elegans might improve our understanding of the molecular programmes safeguarding the genome of human cells. Wild-type C. elegans animals carry out proper DNA damage responses following exposure to ionizing radiation (IR), thus most of their progeny survive. In contrast, radiation-sensitive (Rad) mutants, which are defective in these pathways, show high levels of embryonic lethality upon IR. Taking advantage of this phenotype, we performed a forward genetic screen and identified 17 mutants whose embryos show reduced viability following IR treatment. Two of those mutants, op442 and op444, display a strong Rad phenotype. We are currently mapping the affected genes taking advantage of molecular polymorphisms between the Bristol and the Hawaii isolate of C. elegans. Additionally, we are characterising those two mutants further in order to learn more about the molecular nature underlying the observed defects.