Hofmann ER et al. (2000) Cold Spring Harb Symp Quant Biol "DNA-damage-induced checkpoint pathways in the nematode Caenorhabditis elegans."

Milstein S, Hengartner MO, Hofmann ER

[Cold Spring Harb Symp Quant Biol, 2000]

Genomic instability is believed to be an enabling characteristic of cancer (Hanahan and Weinberg 2000). Therefore, it is not surprising that sophisticated mechanisms exist to maintain the integrity of the genome. Damage to DNA triggers checkpoint controls that result in cell cycle arrest and repair of the lesion (Nurse, 1997, 2000; Weinert 1998). In multicellular organisms, when DNA damage is extensive, these potentially harmful cells are eliminated by apoptosis (Enoch and Norbury 1995; Evan and Littlewood 1998)...

emb-13

Caenorhabditis elegans

Acts upstream of or within embryonic morphogenesis.

Teshiba E et al. (2016) Biosci Biotechnol Biochem "Glucose-induced abnormal egg-laying rate in Caenorhabditis elegans."

Teshiba E, Miyahara K, Takeya H

[Biosci Biotechnol Biochem, 2016]

High glucose reduced the egg-laying rate of the nematode Caenorhabditis elegans and was dependent on serotonergic signaling. Antidiabetic drugs of the biguanide and thiazolidine classes ameliorated the detrimental effect of glucose on egg-laying rate, suggesting the possibility that this quick and easy assay system may be applicable to whole-animal screening for novel antidiabetic drugs, at least, of these classes.

Saito R et al. (2018) Genes Cells "Intestinal F-box protein regulates quick avoidance behavior of Caenorhabditis elegans to the pathogenic bacterium Pseudomonas aeruginosa."

Doi M, Saito R, Shinkai Y

[Genes Cells, 2018]

In most animals, avoiding pathogenic bacteria is crucial for better health and a long-life span. For this purpose, animals should be able to quickly sense the presence or uptake of pathogens. The intestine could be a candidate organ to induce escape behaviors, however, the intestinal signaling mechanism for acute regulation of neuronal activity is not well understood. Here we show that adult Caenorhabditis elegans can respond to the pathogenic bacterium Pseudomonas aeruginosa within 30 min of exposure. This behavior was much faster than previously observed avoidance behaviors in response to P. aeruginosa. By genetic screening, we isolated a mutant defective in this quick avoidance behavior and found that the novel F-box protein FBXC-58 is involved. FBXC-58 is expressed in several tissues, but defective avoidance was rescued by expression of the protein in the intestine. Interestingly, we also found that some but not all mutants in the p38-MAPK and insulin-like signaling pathways, which function in the immune response to pathogens in the intestine, were defective in the quick avoidance behavior to P. aeruginosa. These results suggest that a novel signaling pathway in the intestine exists to regulate neuronal activity for a quick behavioral response. This article is protected by copyright. All rights reserved.

qtc

Drosophila melanogaster

quick-to-court (qtc) encodes an alpha-helical coiled-coiled protein whose mutants exhibit altered male courtship behavior.

Saito, R. et al. (2017) International Worm Meeting "The molecular mechanism regulating quick avoidance behavior to pathogenic bacteria P. aeruginosa."

Saito, R., Shinkai, Y., Doi, M.

[International Worm Meeting, 2017]

Avoidance from unfavorable environments is one of important survival strategies in many animals. As for Caenorhabditis elegans, avoidance from pathogenic bacteria is required to select its better living environment. Worms show this avoidance behavior to Pseudomonas aeruginosa which is a common Gram-negative pathogenic bacterium and is known to affect health condition in many animals including humans. For this reason, C. elegans which fed P. aeruginosa shows an associative learning behavior between odors (secondary metabolites from the bacteria) and several uncomfort in the body. The components of secondary metabolites, which are perceived by single class of sensory neuron, have been identified. However, it is not clear what kind of uncomfort signals is detected in the body, and how those signals are integrated into the nervous system to regulate learning behavior. Therefore, in this study, we are trying to elucidate the molecular and cellular mechanism which acts to detect an uncomfort signal from P. aeruginosa in the body. To identify the genes involved in the detection of bacteria as an unfavorable signal, we searched mutants which show altered response to P. aeruginosa (PA14). The immune response systems in C. elegans is known to be activated from 4 hours after worms fed PA14. We found that spending more than 6 hours on the PA14 lawn was required to retain an associative learning in the bacteria choice assay. We also examined how quickly worms respond to PA14, and found that more than 80% of wild-type animals showed avoidance behavior to PA14 within 1 hour. Therefore, we screened mutants which did not show quick avoidance behavior to PA14 in this period. We successfully isolated a candidate mutant allele (ta218) which show a significantly lower quick avoidance behavior to PA14 (only 20% avoidance in 1 hour). We mapped the ta218 mutation at the central region of the 4th chromosome. Simultaneously, we focused on the immune response pathway in C. elegans whether some genes are responsible for quick avoidance behavior or not. Using avoidance assay, we found that some mutants such as age-1 and sek-1, both are known to function for the worm immune response, did not show quick avoidance behavior to PA14, suggesting that not all but some genes may be acting to detect pathogenic bacteria for quick avoidance. We are now trying to identify the corresponding gene for the ta218 mutant by using both SNP mapping and next-generation sequence analysis. We hope that our analyses will identify the molecular mechanism for the pathogenic bacteria detection, separated from existing immune response pathway in C. elegans.

Waddell, Brandon et al. (2021) International Worm Meeting "The C. elegans Shugoshin (SGO-1) is a cilia resident protein that interacts with TAC-1/TACC"

Li, Chunmei, Giesbrecht, Lesa, Timbers, Tiffany A., Park, Kwangjin, Waddell, Brandon, Quick, Evan, Egydio de Carvalho, Carlos, Leroux, Michel R.

[International Worm Meeting, 2021]

In organisms with monocentric chromosomes, the Shugoshin family of cell cycle regulators have conserved functions in spindle attachment and sister chromatid cohesion during mitosis and meiosis. In worms, the sole Shugoshin homolog (sgo-1) has early roles in meiosis but is otherwise dispensable for gamete and embryo viability. We have identified a novel function of SGO-1 in sensory neurons. sgo-1 is expressed in a series of adult amphid and phasmid neurons where the protein localizes to the base of cilia. sgo-1 mutants display behavioural and dauer entry defects consistent with dysfunctional cilia. These phenotypes are in turn rescued by a sgo-1(+) construct specifically expressed in cilia-producing neurons. In a screen for SGO-1-interacting proteins, we identified TAC-1, a regulator of spindle microtubule dynamics. TAC-1 co-localizes with SGO-1 in the base of cilia and a tac-1 mutation suppresses sgo-1 sensory and dauer entry defects. We are exploring the hypothesis that SGO-1 influences microtubule maintenance in the ciliary axoneme through the recruitment of TAC-1 to the basal body. These results add to a growing body of evidence suggesting that kinetochore and centrosomal proteins are transiently targeted to cilia and represent the first description of a non-nuclear role of Shugoshin in a post-differentiated cell type.

Hashmi S et al. (1995) Biotechniques "Genetic transformation of nematodes using arrays of micromechanical piercing structures."

Gaugler R, Hashmi S, Reed M, Ling P, Trimmer W, Hashmi G

[Biotechniques, 1995]

Foreign genes were expressed in the nematode Heterorhabditis bacteriophora using a new micro-mechanical device to inject DNA-coated microprobe through the nematode cuticle. After introduction of a plasmid in which a Caenorhabditis elegans 16-kDa heat shock promoter was fused to Escherichia coli, a beta-galactosidase gene was expressed in the progeny of the injected worms. The tip of the microprobe penetrated through the nematode cuticle without causing injury to the nematode, and about 8% of the total progeny tested expressed the foreign gene. We describe and validate a new and efficient genetic transformation system for nematodes. The method is quick and easy to use.

Candido EPM et al. (1996) Trends Biotechnol "Transgenic Caenorhabditis elegans strains as biosensors."

Candido EPM, Jones D

[Trends Biotechnol, 1996]

Toxicity bioassays rely largely on lethality measurements. Such assays are generally lengthy and expensive, and provide little information on mechanisms of toxicity. A desire to understand the mechanisms by which cells respond to physical and chemical stresses has led to interest in measuring stress proteins as toxicological endpoints. Transgenic strains of the nematode Caenorhabditis elegans that carry a reporter enzyme under control of a stress-inducible promoter have been created. The reporter is easily quantified in intact nematodes, and it responds to a wide range of chemical stressors. Therefore, transgenic C. elegans can provide the basis for a wide range of quick, simple and informative bioassays.

Loxterkamp, Elizabeth et al. (2021) MicroPubl Biol

Cha, Jaaram, Sullivan, Janessa, Holbrook, Olivia, Srun, Lena, Ghaith, Hazar, Wu, Katharine, Loxterkamp, Elizabeth, Bauer, Deborah E.

[MicroPubl Biol, 2021]

C. elegans are microscopic nematodes used extensively as a model organism due to their simplicity, allowing researchers to study basic molecular processes in biology. Most C. elegans are hermaphrodites, possessing two X chromosomes and the ability to reproduce asexually, but approximately 0.1% are males, arising due to a spontaneous loss of an X chromosome. In order to evaluate the behavioral sex differences in C. elegans, we expanded upon existing literature and compared spontaneous movement, sensitivity to mechanosensation, and sensitivity to chemosensation between males and hermaphrodites. In our paradigms, we found that males and hermaphrodites exhibit similar spontaneous movement as well as similar slow and sustained behaviors such as chemotaxis, but differ in quick-response to mechanical and chemosensory stimuli.