Absence of an external germinal layer in zebrafish and shark reveals a distinct, anamniote ground plan of cerebellum development.

ABSTRACT: The granule cell layer of the cerebellum comprises the largest population of neurons in the vertebrate CNS. In amniotes, its precursors undergo a unique phase of transit amplification, regulated by Sonic hedgehog. They do so within a prominent but transient secondary proliferative epithelium, the external germinal layer, which is formed by tangential migration of precursor cells from the rhombic lip. This behavior is a hallmark of bird and mammal cerebellum development. Despite its significance for both development and disease, it is unclear whether an external germinal layer is a requirement for granule cell production or an expedient of transit amplification. Evidence for its existence in more basal vertebrates is contradictory. We therefore examined cerebellum development in the zebrafi

SUBMITTER: Chaplin N 

PROVIDER: S-EPMC2883741 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature