Roxani Gatsi et al. (2005) International Worm Meeting "Suppressor screens for the dissection of the IP3 signalling pathway in the pharynx"

Roxani Gatsi, Howard Baylis

[International Worm Meeting, 2005]

IP3 mediated calcium signalling in C. elegans determines specificity of cellular responses to extracellular stimuli. Specialized IP3 receptors (IP3Rs), which are located on the endoplasmic reticulum membrane, regulate cytoplasmic calcium concentrations that determine various cellular functions. One of these functions is the up-regulation of pharyngeal pumping in response to food (Walker et al, 2002a). Relatively little is known about the IP3-mediated regulation of the rhythmic pumping of the pharynx. Walter et al (2002b) has shown that interaction between IP3Rs and myosin are required for regulation of pharynx pumping but not for other physiological rythmic functions in C. elegans, indicating the importance of protein interactions for determining specificity. In order to identify additional components of the IP3 signalling pathway in the pharynx we performed genetic suppressor screens using an IP3R mutant (sa73), which shows reduced pharyngeal pumping. We have isolated various mutants that suppress various defects of the sa73 phenotype. The results from the characterization of these mutants, as well as the approach to map the mutations will be presented. Walker DS., et al. (2002a) Mol Biol Cell 13, 1329-1337. Walker DS., et al. (2002b) Curr Biol 12, 951-956

K Kawamura et al. (1999) International C. elegans Meeting "Structure of Neural Network of C. elegans Observed by a Random Walker"

Y Osana, K Kawamura, K Oka, K Oshio, Y Funabashi, S Morita

[International C. elegans Meeting, 1999]

A database of synaptic connectivity of 302 neurons of the C. elegans has been constructed[1] from the observations of Albertson and Thomson[2] and White et al.[3] by some of the present authors. A network formed by 302 neurons of the C. elegans is represented on a computer by a network which consists of 302 dots combined by (arrowed) bonds. To analyse the structure of the neural network, behavior of a random walker on it is studied. The walker is displaced among dots which represent neurons over bonds which model synaptic connection. In terms of walking distance defined by minimum time steps which is necessary for the random walker to be displaced between neurons, distances among all neurons, whose synaptic connectivity are described by the above authors, have been determined. Almost all neurons are located within the walking distance of three time steps but walking distance among phalingeal neurons and somatic neurons are more than four time steps. The network is extended in a (more than) nine dimensional space around three nanohedra which are mutually combined by manifolds of less dimension. Each nanohedron consists of nine dots representing interneurons mutually connected by synapses and these nanohedra are located near the center of the network. The lattice is biased by the rectification of the chemical synapse in the sence that a random walker prefers to be displaced from sensory neurons to motor neurons. [1] K. Oshio, S. Morita, Y. Osana and K. Oka: C. elegans connectivity data, Technical report of CCEP, Keio Future No.1 (1998) [2] D. G. Albertson and J. N. Thomson: Phil. Trans R. Soc. Lond. B. 275 (1976) 299 [3] J. G. White, E. Southgate, J. N. Thomson and S. Brenner: Phil. Trans. R. Soc. Lond. B 314 (1986) 1.

Birgitta Olofsson (2009) European Worm Neurobiology Meeting "Optimal foraging in C.elegans"

Birgitta Olofsson

[European Worm Neurobiology Meeting, 2009]

Variation in food quality and abundance requires animals to choose whether to stay on poor food patch or wander off in search of better food. Although optimal foraging choice is central to evolutionary survival, the molecular and neuronal mechanisms underlying it are poorly understood. I will present my work on this problem in C.elegans.

Hunter C (2010) Aging, Metabolism, Stress, Pathogenesis, and Small RNAs, Madison, WI "Stressing about the function of the RNA channel SID-1"

Hunter C

[Aging, Metabolism, Stress, Pathogenesis, and Small RNAs, Madison, WI, 2010]

My group investigates how RNA signals are transported between tissues and cells in C.elegans. When Fire and Mello reported their discovery of RNAi in C. elegans they also reported that silencing signals spread throughout the animal. These observations suggested the existence of an efficient RNA transport pathway. My lab subsequently identified components of the RNA transport machinery, including a double-strand RNA (dsRNA) channel protein called SID-1and a likely endocytosis RNA receptor called SID-2. SID-1 is highly conserved in nematodes and our analysis indicates that its transport function is highly selective for dsRNA. These observations suggest that SID-1 is under strong selection to specifically transport dsRNA. I will present progress in our efforts to identify and characterize exogenous and endogenous transported RNAs as well as our effort to determine their physiological and/or developmental roles in the worm.

Sangari, Sadaf et al. (2021) International Worm Meeting "Understanding the Role of Scaffold Protein Activated C Kinase 1 (RACK-1) in Germ Line Stem Cells of Caenorhabditis elegans"

Sangari, Sadaf, Vanden Broek, Kara, Hansen, Dave, Wang , Chris

[International Worm Meeting, 2021]

Stem cells are unspecialized cells that are able to proliferate to produce more stem cells (mitosis) or differentiate to produce specialized cells. The balance between proliferation and differentiation is controlled by highly regulated signaling pathway(s). The C. elegans germ line is a powerful model that allows genes and pathways that play a crucial role in establishing and maintaining this balance to be identified. The C. elegans gonad contains two gonad arms, where proliferating germline stem cells are located at the distal ends of each arm, while differentiating cells such as sperm and oocyte are located more proximally. The balance between proliferation and differentiation allows this spatial patterning to be maintained in the germline. Recently, our lab has identified the influence of the scaffold protein RACK-1, which is conserved between humans and C. elegans, on the proliferation vs. differentiation pathway. My research is investigating the role of this scaffold protein on maintaining the balance between proliferation and differentiation. A mutation that eliminates rack-1 results in lowering and mis-localization of the translational repressor protein GLD-1 (Germ Line Defective-1) in the differentiation pathway. Furthermore, loss of rack-1 results in lower brood size and sterility at higher temperatures. My research seeks to identify the mechanism (either direct or indirect) by which RACK-1 is impacting GLD-1 and furthermore, the differentiation and proliferation decision. My research will provide insight into how stem cell behaviour is regulated in the C. elegans germline.

Kirby, Cait S. et al. (2017) International Worm Meeting "Mitochondrial DNA copy number in C. elegans is regulated by a functional output."

Patel, Maulik R., Kirby, Cait S.

[International Worm Meeting, 2017]

Besides the nuclear genome, eukaryotic cells also contain a circular mitochondrial DNA (mtDNA). mtDNA encodes essential components of the mitochondrial electron transport chain, which produces most of the cellular ATP. Cells typically contain hundreds to thousands of copies of mtDNA. While it is known that the number of mtDNA copies per cell is tightly regulated, the cellular and molecular mechanisms underlying this mtDNA copy number control remain poorly understood. A major difficulty in studying mtDNA copy number control arises from the lack of genetically tractable systems with evidence of robust mtDNA regulation, as well as lack of quantitative methods to accurately determine mtDNA copies. To overcome these challenges, I have developed protocols to accurately and precisely measure mtDNA copy number from single C. elegans individuals at all stages of development. My analyses reveal that the adult C. elegans germline, which harbors most of the mtDNA content, employs active homeostatic mechanisms to regulate mtDNA copy number. In addition, I have discovered that mtDNA encodes a functional feature, which is sensed by the cell to "count" mtDNA copy number. Consistent with this hypothesis, my mutational analysis shows that mutations in mtDNA that disrupt this functional output fail to get counted, resulting in an overabundance of mtDNA copies. Taken together, my results provide fundamental insights into mechanisms of mtDNA copy number control. I am now poised to determine the molecular machinery that counts mtDNA copies, and determine how it is mechanistically coupled with mtDNA replication.

Abby F Dernburg et al. (2001) International C. elegans Meeting "Chromosome remodeling during meiosis"

Abby F Dernburg, Bobby Hogg, Carol Anderson

[International C. elegans Meeting, 2001]

This abstract is being submitted as a placeholder for a revised abstract to be entered during the week of April 20. This delay is necessary because we would like to include data from different lab personnel, and my rotation students (currently comprising the entire lab) will be making their final lab decisions that week. We are working on several questions regarding chromosome and chromatin remodeling. In particular, we are interested in how chromatin is remodeled during meiosis to accomplish chromosome pairing, crossing-over, and segregation.

Judith Kimble (2006) Development & Evolution Meeting "Regulation of Germline Stem Cells in Caenorhabditis elegans"

Judith Kimble

[Development & Evolution Meeting, 2006]

The adult C. elegans germ line is organized with stem cells at one end and maturing gametes at the other. A single somatic cell, called the distal tip cell (DTC), provides an essential microenvironment or "niche" for the germ line. Our current knowledge of the DTC niche and its control over germline stem cells is the product of many years of work by an ever-increasing and wonderfully active community of scientists. In my talk, I will highlight key advances over the years, our current thinking and major questions for the future.

Phedra Amayed et al. (2003) International Worm Meeting "Functional analysis of the Caenorhabditis elegans AIR-1 kinase and identification of its cellular partners."

Phedra Amayed, Jill M Schumacher

[International Worm Meeting, 2003]

Genome instability and supernumerary centrosomes are characteristic of many tumor cells. To investigate these abnormalities, I am using C. elegans as a model system to study the regulation of microtubule dynamics and centrosome function. My project is focused on AIR-1, a member of the growing Aurora/Ipl1 kinase family. This kinase is associated with mitotic centrosomes, and plays an important role in the formation of bipolar mitotic spindles that can direct accurate chromosome segregation. AIR-1 plays an essential role in centrosome maturation and accumulation of -tubulin. During my postdoctoral training, I would like to identify the cellular partners of this kinase and the regulatory pathway(s) leading to its activation. Two methods will be used to identify these proteins: 1) yeast two-hybrid and 2) solid-phase phosphorylation screenings. These two methods will identify candidates that potentially interact upstream or downstream of AIR-1. The in vivo function of each candidate will be tested by RNA mediated interference (RNAi). The elucidation of AIR-1 regulatory pathway(s) will contribute to our understanding of microtubule dynamics and chromosome segregation in other organisms and may explain the oncogenic power of the mammalian Aurora A kinases.

Tim H Lindblom (2003) International Worm Meeting "Student directed C. elegans research in the physiology laboratory"

Tim H Lindblom

[International Worm Meeting, 2003]

Faced with the task of designing a semester of physiology laboratory exercises in my first semester as an assistant professor, I turned to my research and found what I had always suspected: worms are as wonderful in the teaching laboratory as they are in the research laboratory. As a supplement to several traditional physiology laboratory exercises, for the past two Spring semesters I have required my comparative physiology students to design and implement physiology research projects involving C. elegans. Although I tend to guide the student's projects as little as possible, the level of instructor involvement can be quite variable. By requiring students to write a research proposal prior to initiating their experiments, they can be directed towards realistic projects likely to succeed. The only stipulations were that 1. the research investigate some area of physiology and 2. they not reproduce published data or experiments. At the first laboratory meeting, I introduce C. elegans as a research organism and ask them to consider their favorite area of physiology. From this interest, I guided them towards the relevant C. elegans literature and ultimately to a research plan. Prior to spring break, the students had solidified a research plan that included a hypothesis, a detailed experimental design, and identification of the relevant controls. This way, during the break, I am able to gather the required reagents, strains, and supplies. As the groups begin their experimentation, it is important to regularly check their progress in the event that experimental design troubleshooting is required. Ultimately, the students are responsible for initiating the experiments, limited troubleshooting, data collection, and assembly of the data into a research paper. I required that the research papers adhere to a specific journal format, typically one that is readily available for examples such as Current Biology. In this way, they experience the many steps in the process of converting great research ideas into meaningful publications. In the future, I plan to incorporate peer review into the process by having their papers reviewed by their student peers and other biology faculty prior to completion of the project. At the end of the semester, I also require the students to present their hypothesis, experimental design, data, and conclusions to their colleagues in order to gain experience in oral research presentations and expose all the students to the various research projects. At the meeting, I will present the data collected by four of my undergraduate research teams who investigated many areas of physiology including chemosensory adaptation, learning, and Pseudomonas pathogenecity.