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Full Abstracts – NEURAL DEVELOPMENT
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Ly6 related proteins in Drosophila Blood Brain Barrier.
Mubarak Hussain Syed
1
, Alice Krudewig
2
, Daniel Engelen
1
, Tobias Stork
3
, Christian Klambt
1
.
1) Institute for neurobiology, University of Muenster, Muenster, NRW, Germany; 2) Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056
Basel, Switzerland; 3) University of Massachusetts Medical School, Department of Neurobiology, 362 Plantation Street, LRB 740, Worcester, MA 01605.
The Blood Brain Barrier (BBB) is a highly specialised structure, which ensures the constant ionic microenvironment needed for reliable neuronal
functions. The Drosophila BBB is formed by a thin layer of subperinurial glial cells, which cover the entire nervous system and posses laterally localised
homotypic septate junctions. Disruption of these septate junctions leads to a defective BBB and fluorescent probes can easily penetrate into the CNS. In
order to find new components of BBB, we performed dextran uptake screen and identified mutants in coiled and leaky having severe BBB defects. coiled
encodes a GPI linked cell surface homophilic adhesion molecule, which is a member of the Ly6 super family, and is predicted to form three-finger folds.
Coiled and Leaky are expressed in all septate junction forming cells, particularly in the BBB forming subperinurial glial cells. The kinetics of Dextran
uptake in coiled mutants is similar to nrx IV mutants showing a severely affected BBB. Likewise leaky mutants result in a severely compromised BBB. In
coiled and leaky mutants septate junction molecules like Neurexin IV, Discs large and Coracle are mislocalized basally. EM analysis of coiled mutants
revealed the lack of septate junctions in the subperineurial glia. We could rescue septate junction assembly and dye penetration phenotype in a cell specific
manner implying that Coiled functions cell autonomously in subperineurial glial cells. Clonal studies show that symmetric distribution of Coiled is required
in both the cells participating in septate junction. Further analysis of coiled and leaky will be presented.