Abstract: Felix BABATZ

Analysis of the Drosophila blood brain barrier

---

Felix Babatz , Christian Klämbt

Institute for Neurobiology, University of Münster, Münster Germany

---

The correct function of a complex nervous system depends on an intact blood brain barrier (BBB). To maintain correct ion concentrations and protect the brain from xenobiotic substances and pathogens, intercellular diffusion has to be prevented by occluding junctions. For this purpose, vertebrates developed tight junctions, which are formed by the vascular endothelium. In invertebrates like Drosophila, this insulation is performed by subperineurial glial cells, which cover the whole nervous system and are tightly connected by septate junctions. They are similar to the septate-like junctions formed by Schwann cells at the so-called paranodal junctions while establishing the tight electrical insulation of the axon. Drosophila septate junctions and mammalian septate-like junctions both contain a set of evolutionary conserved transmembrane proteins (e.g. NeurexinIV / Caspr, Neuroglian / Neurofascin, dContactin / Contactin). The formation of septate junctions requires a tight temporal and spatial organisation of the junctional components. In a genetic approach we already identified several genes, which are necessary for the correct formation of the septate junctions and the integrity of the BBB. All of them encode small Ly-6 / CD59 like proteins attached to the membrane via a GPI anchor. Analysis towards an understanding of the role of these proteins during BBB formation will be presented.