Roof plate in cerebellar neurogenesis

Abstract

The roof plate is a distinct group of cells located at the dorsal midline of the developing central nervous system extending along its entire anterior-posterior axis. In the developing hindbrain, the roof plate comprises a simple epithelial layer covering the dorsal opening of the 4th ventricle. As development proceeds, the 4th ventricle roof plate differentiates into choroid plexus epithelium, which produces cerebrospinal fluid and serves as a blood-cerebrospinal fluid barrier. A growing amount of evidence indicates that both the 4th ventricle roof plate and its later derivative, the hindbrain choroid plexus, produce various secreted molecules, which critically regulate development of the adjacent cerebellum. Bone morphogenetic proteins secreted from the roof plate are crucial to the induction of the cerebellar rhombic lip. Signals from the early roof plate and later secretion of Sonic hedgehog from the choroid plexus promote proliferation of progenitors in the cerebellar ventricular zone. This chapter discusses recent studies that established the roles of the 4th ventricle roof plate and the hindbrain choroid plexus in cerebellar neurogenesis and the molecular mechanisms of their action.