Characterization of Semaphorin 4C and Semaphorin 4G as candidate ligands of Plexin-B2.

Semaphorins and Plexins are cognate ligand-receptor families that regulate a wide range of biological processes. So far relatively little is known about the in vivo function of Plexin-Bs and their respective ligands. It was therefore the goal of my thesis work to identify candidate ligands for Plexin-B2, which is critically involved in neural tube closure and cerebellar granule cell development, and to examine the in vivo function of these molecules in neural development. It was shown by expression and binding assays, phenotypic analyses and genetic interactions studies that two members of the Semaphorin 4 family, Sema4C and Sema4G, are functional ligands of Plexin-B2. All these results indicate that Sema4C and Sema4G control cerebellar development through regulation of the migratory properties of granule cell precursors by binding to the Plexin-B2 receptor