Megan Guziewicz et al. (2001) International C. elegans Meeting "Vesicle Transport and"

Rebecca Eustance Kohn, Bethany Simmons, Toni Vitullo, Megan Guziewicz

[International C. elegans Meeting, 2001]

We developed a laboratory exercise to illustrate how defects in the nervous system affect movement. The experiment engages students in a study which combines organismal and cell biology. It allows students to gain hands on laboratory experience exploring animal movement, neuron function, and vesicle transport. Students gain experience using a fluorescent microscope to visualize GFP in cells. The exercise has been used successfully with both first year and second year undergraduate students in classes ranging from 12 to 24 people. Students characterize the movement of C. elegans and then determine the nature of nervous system defects. Using a dissecting microscope, students distinguish between healthy worms and partially paralyzed worms. The partially paralyzed strains are either unc-104 mutants, which have a defect in vesicle transport, or unc-13 mutants, which have a defect in vesicle fusion. The synaptic vesicles in these strains are labeled with GFP. Students next observe the strains under a fluorescent microscope to distinguish between worms with vesicle transport or vesicle fusion defects. The nervous system of the healthy worms and the unc-13 worms appear the same, because the vesicles are transported to the synapses. In unc-104 mutants, most vesicles are trapped in the neuron cell bodies and few reach the synapses. Based on their observations of movement and vesicle localization, students determine which worms have defects in vesicle transport and which worms have defects in vesicle fusion.

Bethany Simmons et al. (2001) International C. elegans Meeting "Regulation of unc-13 and Subcellular Localization of its Protein Products"

Alan Cohen, Bethany Simmons, Amy Garber, Rebecca Eustance Kohn, Toni Vitullo, Lynn Schwarting, Megan Guziewicz, Kelly Howell

[International C. elegans Meeting, 2001]

We are examining regulation of synaptic neurotransmission. We are studying the unc-13 gene, which is part of a signal transduction pathway affecting neurotransmitter release. At least one product of this gene is involved in the step between synaptic vesicle docking and fusion. While most studies of UNC-13 have examined the 200 kDa form of the protein, multiple forms of UNC-13 proteins are expressed. At least three types of proteins are made from the gene, and these proteins may have different functions in cells. We are interested in understanding the roles of the different forms of UNC-13 in C. elegans . In particular, we are asking where the protein products localize and how protein expression is regulated. To approach these questions, we are developing antibodies to identify the subcellular localization patterns of the different UNC-13 proteins. Antibodies were made previously to recognize the 200 kDa form of the protein, but these antibodies cannot label all forms of UNC-13. We are interested in determining whether all forms of the proteins are found in neurons and whether they localize in synapses. We are also examining the possibility that an internal promoter is involved in gene regulation. We are constructing GFP fusions to determine whether an internal region of the unc-13 gene is capable of driving transcription of a subset of unc-13 mRNA.