Neuronal migration defects cause severe neurological diseases like Lissencephaly and Heterotopia, which are associated with mental retardation and epileptic seizures. Because the cerebellum is evolutionary highly conserved, its development is well suited to be studied in the transparent zebrafish embryo. As polarity is crucial for directed migration and final maturation, we investigated the role of the polarity proteins aPKCi and MPP5 in these processes within granule cells (GC). This work demonstrates the importance of aPKCi and MPP5 in cerebellar development. It is shown that aPKCi is necessary for GC differentiation. In vivo time-lapse recordings reveal proper motility of GCs in apkci mutants. However, GCs migrate aimlessly and to ectopic positions even across the cerebellar border into the hindbrain. Further, aPKCi is essential to maintain cerebellar tissue integrity, which in turn is necessary for directed GC migration.     «

Neuronal migration defects cause severe neurological diseases like Lissencephaly and Heterotopia, which are associated with mental retardation and epileptic seizures. Because the cerebellum is evolutionary highly conserved, its development is well suited to be studied in the transparent zebrafish embryo. As polarity is crucial for directed migration and final maturation, we investigated the role of the polarity proteins aPKCi and MPP5 in these processes within granule cells (GC). This work demon...     »