Pineal progenitors originate from a non-neural territory limited by FGF signalling.

The embryonic development of the pineal organ, a neuroendocrine gland on top of the diencephalon, remains enigmatic. Classic fate-mapping studies suggested that pineal progenitors originate from the lateral border of the anterior neural plate. We show here, using gene expression and fate mapping/lineage tracing in zebrafish, that pineal progenitors originate, at least in part, from the non-neural ectoderm.

Zebrafish atlastin controls motility and spinal motor axon architecture via inhibition of the BMP pathway.

To better understand hereditary spastic paraplegia (HSP), we characterized the function of atlastin, a protein that is frequently involved in juvenile forms of HSP, by analyzing loss- and gain-of-function phenotypes in the developing zebrafish. We found that knockdown of the gene for atlastin (atl1) caused a severe decrease in larval mobility that was preceded by abnormal architecture of spinal motor axons and was associated with a substantial upregulation of the bone morphogenetic protein (BMP) signaling pathway. Overexpression analyses confirmed that atlastin inhibits BMP signaling.

The homeodomain transcription factor drg11 is expressed in primary sensory neurons and their putative CNS targets during embryonic development of the zebrafish.

The drg11 gene is a member of the vertebrate aristaless-related gene family and encodes a paired homeodomain transcription factor. Its expression is largely restricted to PNS neurons subserving somatosensory functions and their CNS targets in rodents. The phenotype of drg11 null mice suggests that it is crucial for the proper development in the embryo of nociceptive circuits.

Molecular evidence from Ciona intestinalis for the evolutionary origin of vertebrate sensory placodes.

Cranial sensory placodes are focused areas of the head ectoderm of vertebrates that contribute to the development of the cranial sense organs and their associated ganglia. Placodes have long been considered a key character of vertebrates, and their evolution is proposed to have been essential for the evolution of an active predatory lifestyle by early vertebrates. Despite their importance for understanding vertebrate origins, the evolutionary origin of placodes has remained obscure.

Pax gene expression in the developing central nervous system of Ciona intestinalis.

We compare the expression patterns in Ciona intestinalis of three members of the Pax gene family, CiPax3/7, CiPax6 and Cipax2/5/8. All three genes are expressed in restricted patterns in the developing central nervous system. At the tailbud stage, CiPax3/7 is present in three patches in the brain and along the posterior neural tube, CiPax6 throughout the anterior brain and along the posterior neural tube and CiPax2/5/8 in a restricted region of the posterior brain.