MAPPING AND CHARACTERIZING THE NEUROPIL-ASSOCIATED GLIAL CELLS IN DROSOPHILA LARVAE

picture of Si Woo Lee presenting his/her poster: MAPPING AND CHARACTERIZING THE NEUROPIL-ASSOCIATED GLIAL CELLS IN DROSOPHILA LARVAE

Si Woo Lee , Lynne Oland, Sarah MacNamee

MAPPING AND CHARACTERIZING THE NEUROPIL-ASSOCIATED GLIAL CELLS IN DROSOPHILA LARVAE

In the Drosophila central nervous system, astrocyte-like glial cells participate in many functions, including immune defense, energy metabolism, neurotransmission, and adult neurogenesis.  Astrocyte-like glial cells are one of the two subtypes of glia (the other being ensheathing glia) that closely associate with the synaptic region neuropil in the ventral nerve cord.  This study aims to map the distribution of these glial cells and characterize their morphology in order to have a better understanding of their potential contribution to neuronal circuit function. The first phase of the study involves identifying the number of glial cells and their positions in two specific segments of the ventral nerve cord of 3rd instar Drosophila larvae. We have employed a genetically encoded fluorescent protein, GFP, targeted specifically to the astrocyte-like glial cells and in the same preparations, use immunocytochemistry to label a reproducible Fasciclin II landmark system to be used as a fiduciary system against which to chart the location of glial cells. We also are currently using the Flybow technique to induce expression of different fluorescent proteins in individual astrocyte-like glial cell in the same preparation.  This allows us to categorize individual astrocyte-like glial cells by their branching pattern (highly branched or tufted morphology) and by the neuropil territory they occupy, all with respect to the landmark system.  Our data suggest that subsets of these glial cells occupy stereotyped positions in the neuropil, that these glia are typically highly branched and that their arbor is generally restricted to particular regions of the neuropil.  In two preparations with adjacent glial cells labeled, there was little overlap between their processes.  This method will further reveal whether each glial cell occupies its own territory or overlaps with other glial cells. The second phase of this project involves electron microscopy to allow us to determine the average distance from glial processes to neuronal synapses.  The data from these studies will guide our electrophysiology studies on neuron-glia interactions in this neuropil and expand our understanding of the communication mechanisms by which glial cells modulate the neuronal activity.

 

Funded by a Microscopy Society of America grant to SWL.

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