841C Poster - 13. Neural development and physiology
Saturday April 09, 1:30 PM - 3:30 PM

Authors:
Katherine Clayworth; Vanessa Auld

Affiliation: Life Sciences Institute, University of British Columbia, Vancouver, BC

Keywords:
k. glia; s. extracellular matrix

Peripheral nervous system (PNS) health is largely dependent on proper glial cell functioning during development. Myelinating and non-myelinating Schwann cells (MSCs and NMSCs, respectively) are glial cells in the PNS that ensheathe and protect axons. Communication between Schwann cells and the extracellular matrix (ECM) is essential for PNS development. The ECM protein laminin, and its receptor dystroglycan [Dg; part of the dystrophin-glycoprotein complex (DGC)], are important for MSC development, however very little is known about the mechanisms underlying the role of laminins, Dg, and the DGC in NMSC development. We use developing Drosophila wrapping glia (WG), which ensheathe axons similarly to NMSCs, as a model to study the role of laminin/Dg in NMSC development. We found strong expression of LanA (one of two laminin alpha subunits in Drosophila), around WG. Wing blister, the other laminin alpha subunit, is not strongly expressed the peripheral nerve, indicating that the LanA-containing isoform is the primary laminin isoform expressed. Knockdown of LanA in WG eliminated LanA expression around WG and caused WG swellings, suggesting that LanA is expressed by WG. Preliminary data suggests that LanA is most often found at the adaxonal WG membrane (between WG and axons), rather than the abaxonal WG membrane (between WG and its adjacent glial layer, subperineurial glia). These results potentially indicate a form of WG polarization, a feature that has not been well understood in WG thus far. We found the laminin receptor Dg is also expressed on WG membranes, however there are three isoforms of Dg and their individual expression patterns in the PNS are unknown. Therefore, we are in the process of tagging alternatively spliced exons of Dg, which will allow us to follow their localization in vivo. Knockdown of Dg and dystrophin (a component of the DGC), leads to WG ensheathment failure, indicating that Dg and dystrophin are important for WG development. We are investigating other DGC components (e.g., dystrobrevin, syntrophins) to determine the composition of the DGC in WG. Due to the highly conserved nature of laminins and DGC proteins, our results have implications for NMSC development—thus improving our understanding of the factors underlying PNS development in all animals.