Development of the serotonergic cells in murine raphe nuclei and their relations with rhombomeric domains.

The raphe nuclei represent the origin of central serotonergic projections. The literature distinguishes seven nuclei grouped into rostral and caudal clusters relative to the pons. The boundaries of these nuclei have not been defined precisely enough, particularly with regard to developmental units, notably hindbrain rhombomeres.

Megalin mediates the influence of sonic hedgehog on oligodendrocyte precursor cell migration and proliferation during development.

Oligodendrocyte precursor cells (OPCs) of the optic nerve are generated in the preoptic area, from where they migrate to colonize it entirely. Sonic hedgehog (Shh) induces the proliferation of these cells as well as influencing their migration, acting through its canonical receptor (Ptc-1). However, the multiligand receptor megalin (or LRP-2) is also involved in Shh-induced OPC proliferation and migration, and thus, we have evaluated the relevance of this interaction.

Comparison of Pretectal Genoarchitectonic Pattern between Quail and Chicken Embryos.

Regionalization of the central nervous system is controlled by local networks of transcription factors that establish and maintain the identities of neuroepithelial progenitor areas and their neuronal derivatives. The conserved cerebral Bauplan of vertebrates must result essentially from conserved patterns of developmentally expressed transcription factors. We have previously produced detailed molecular maps for the alar plate of prosomere 1 (the pretectal region) in chicken (Ferran et al.

Topography of Somatostatin Gene Expression Relative to Molecular Progenitor Domains during Ontogeny of the Mouse Hypothalamus.

The hypothalamus comprises alar, basal, and floor plate developmental compartments. Recent molecular data support a rostrocaudal subdivision into rostral (terminal) and caudal (peduncular) halves. In this context, the distribution of neuronal populations expressing somatostatin (Sst) mRNA was analyzed in the developing mouse hypothalamus, comparing with the expression pattern of the genes Orthopedia (Otp), Distal-less 5 (Dlx5), Sonic Hedgehog (Shh), and Nk2 homeobox 1 (Nkx2.

The HUDSEN Atlas: a three-dimensional (3D) spatial framework for studying gene expression in the developing human brain.

We are developing a three-dimensional (3D) atlas of the human embryonic brain using anatomical landmarks and gene expression data to define major subdivisions through 12 stages of development [Carnegie Stages (CS) 12-23; approximately 26-56 days post conception (dpc)]. Virtual 3D anatomical models are generated from intact specimens using optical projection tomography (OPT). Using MAPAINT software, selected gene expression data, gathered using standard methods of in situ hybridization and immunohistochemistry, are mapped to a representative 3D model for each chosen Carnegie stage.

Sonic hedgehog promotes the migration and proliferation of optic nerve oligodendrocyte precursors.

Optic nerve (ON) oligodendrocyte precursors (OPCs) are generated under the influence of the Sonic hedgehog (Shh) in the preoptic area from where they migrate to colonise the entire nerve. The molecular events that control this migration are still poorly understood. Recent studies suggested that Shh is often used by the same cell population to control different processes, including cell proliferation and migration, raising the possibility that Shh could contribute to these aspects of OPC development.