Nariya, Hardik et al. (2017) International Worm Meeting "An investigation of the effects of artificial light at night on C. elegans offspring production and lifespan."

Buchanan, Bryant, Wise, Sharon, Zhushma, Rosa, Nariya, Hardik, Shinn-Thomas, Jessica

[International Worm Meeting, 2017]

Artificial light at night (ALAN) has many broad-scale and global implications for ecosystems and wildlife that have evolved under a 24-h circadian cycle. With increased urbanization, artificial light at night has directly altered natural photoperiods and nocturnal light intensity. Artificial light at night can disrupt behavioral patterns such as foraging activity and mating in animals. Disturbances in natural light and dark cycles also affect melatonin-regulated circadian and seasonal rhythms in Drosophila. We investigated the impact of ecologically relevant levels of light pollution on an important invertebrate model, Caenorhabditis elegans, as the impact of night lighting at these light levels is currently unknown. In this study, we exposed worms to artificial light at four intensities: 10-4 lx (control, comparable to natural nocturnal darkness), 10-2 lx (comparable to full-moon lighting and a low level of light pollution), 1 lx (comparable to dawn/dusk or intense light pollution), and 100 lx (dim daylight level comparable to extreme light pollution) on a 12L:12D photoperiod (100 lx treatments experienced constant light). We measured the impact of these light treatments on offspring production in hermaphroditic C. elegans. We grew worms for 2 generations in each light treatment, and then recorded the lifespan and counted the number of hatched offspring produced in the F3 generation. Our data show no significant differences among light levels for lifespan or offspring production suggesting that at least for these life history traits, ALAN does not affect these soil nematodes. Future directions include measuring additional life history traits and circadian gene expression for worms exposed to ALAN.

Skop AR et al. (1995) International C. elegans Meeting "Cloning of the Drosophila Discs Large Homolog in C. elegans"

Hardin JD, Skop AR

[International C. elegans Meeting, 1995]

Our laboratory is interested in how cell-cell interactions mediate the fate and proliferation of epithelial cells. It is known in Drosophila that the discs large (dlg) gene product is required for septate junction formation, apical basal polarity, and cell interactions that control proliferation. This suggests that cell signalling events at the apical junctions are important for cell fate and proliferation.1 By studying discs large in C. elegans, we hope to further the understanding of how signalling events occuring between epithelial cells dictate differentiation in the developing embryo. Using PCR primers, created from the expressed sequence tag (EST), CEMSH84, (W.R. McCombie et al, 1992. Nature Genetics, 1:124-131), we have set out to clone and characterize the C. elegans homolog of the Drosophila dlg tumor suppressor gene. By using a fragment created via PCR, we probed a mixed stage cDNA library to recover clones that are homologous to the dlg gene family. These clones have been partially characterized and are homologous to the Drosophila dlg tumor suppressor gene family. Preliminary data suggest that the C-terminal guanylate kinase domain of both the worm and humans ESTs match the Drosophila sequence.2 We plan to create knockout lines via Tc1 insertions to investigate epithelial structure, cell-cell communication, differentiation, and cell proliferation control in the developing C. elegans embryo. 1. Woods, D. F., and Bryant, P. J. (1993). Journal of Cell Science, Supplement 17:171-181. 2. McCombie et al, (1992). Nature Genetics, 1: 124-131.

Daphne B. Pontier et al. (2006) European Worm Meeting "Sreen for Synthetic Lethality with Tumor Suppressors and the Development of a DSB Repair Assay"

Ronald H.A. Plasterk, Marcel Tijsterman, Daphne B. Pontier

[European Worm Meeting, 2006]

Synthetic lethality is the phenomenon that a mutation in gene X or gene Y is viable, whereas inactivation of both X and Y simultaneously is lethal. Recently, the breast cancer susceptibility gene BRCA-2 was found to be synthetic lethal with PARP-1 in human cell cultures and in mice, possibly making PARP a potent and specific drug target for breast cancer in humans (Bryant et al, 2005; Farmer et al, 2005). Using C. elegans, we aim to identify additional synthetic lethal interactions with several tumor suppressor genes, such as dog-1 (BACH1/FANCJ), Y41E3.9 (FANCD2), pme-1 (PARP-1), pme-2 (PARP-2), cep-1 (p53) and atm-1 (ATM). At least two alleles will be used for each gene to prevent nonspecific interactions due to background mutations. These alleles are used in a genome-wide liquid RNAi screen for synthetic lethality, by comparing the presence of offspring in mutant alleles to N2. Positive hits will be further validated and checked for homology in humans.. For this screen, we will isolate new mutant alleles from our EMS library. We use LIMSTILL software (available at http://limstill.niob.knaw.nl) for amplicon selection, primer design, sequence analysis and mutation annotation, facilitating high-throughput sequencing. Up to 3072 sequences can be processed and aligned simultaneously and can therefore be easily screened for mutations. In addition, we are optimizing a reporter assay for double strand break (DSB) repair. We have developed transgenic animals that carry a reporter LacZ sequence interrupted by the restriction site of the yeast rare-cutting endonuclease I-SceI. Animals also carry a hsp::I-SceI array that allows the introduction of a localized DSB in the LacZ reporter sequence by heatshock treatment. Inadequate repair of the DSB can be detected by LacZ expression or by PCR of the sequence flanking the DSB. This assay can be used to study localized DSB repair and may also be used for genome-wide screens for additional DSB-repair and signaling genes.