Independently specified Atoh1 domains define novel developmental compartments in rhombomere 1.

The rhombic lip gives rise to neuronal populations that contribute to cerebellar, proprioceptive and interoceptive networks. Cell production depends on the expression of the basic helix-loop-helix (bHLH) transcription factor Atoh1. In rhombomere 1, Atoh1-positive cells give rise to both cerebellar neurons and extra-cerebellar nuclei in ventral hindbrain.

Rhombomere-specific analysis reveals the repertoire of genetic cues expressed across the developing hindbrain.

Background: The Hox family of homeodomain transcription factors comprises pivotal regulators of cell specification and identity during animal development. However, despite their well-defined roles in the establishment of anteroposterior pattern and considerable research into their mechanism of action, relatively few target genes have been identified in the downstream regulatory network. We have sought to investigate this issue, focussing on the developing hindbrain and the cranial motor neurons that arise from this region.

Retinoic acid is a potential dorsalising signal in the late embryonic chick hindbrain.

Background: Human retinoic acid teratogenesis results in malformations of dorsally derived hindbrain structures such as the cerebellum, noradrenergic hindbrain neurons and the precerebellar system. These structures originate from the rhombic lip and adjacent dorsal precursor pools that border the fourth ventricle roofplate. While retinoic acid synthesis is known to occur in the meninges that blanket the hindbrain, the particular sensitivity of only dorsal structures to disruptions in retinoid signalling is puzzling.

Temporal identity transition in the avian cerebellar rhombic lip.

The rhombic lip is a discrete strip of neuroepithelium bordering the roofplate of the fourth ventricle, which gives rise to a defined sequence of migratory neuronal derivatives. In rhombomere 1 of the chick, early born cells give rise to post-mitotic hindbrain nuclei, while later derivatives comprise of cerebellar granule cell precursors, a unique proliferative, migratory precursor population that forms the external granule cell layer. We have examined the temporal specification of these two populations using a heterochronic grafting strategy, in ovo.