title: BMP signaling orchestrates photoreceptor specification in the zebrafish pineal gland in collaboration with Notch.
abstract: A variety of signaling pathways have been shown to regulate specification of neuronal subtype identity. However, the mechanisms by which future neurons simultaneously process information from multiple pathways to establish their identity remain poorly understood. The zebrafish pineal gland offers a simple system with which to address questions concerning the integration of signaling pathways during neural specification as it contains only two types of neurons - photoreceptors and projection neurons. We have previously shown that Notch signaling inhibits the projection neuron fate. Here, we show that BMP signaling is both necessary and sufficient to promote the photoreceptor fate. We also demonstrate that crosstalk between BMP and Notch signaling is required for the inhibition of a projection neuron fate in future photoreceptors. In this case, BMP signaling is required as a competence factor for the efficient activation of Notch targets. Our results indicate that both the induction of a photoreceptor fate and the interaction with Notch relies on a canonical BMP/Smad5 pathway. However, the activation of Notch-dependent transcription does not require a canonical Smad5-DNA interaction. Our results provide new insights into how multiple signaling influences are integrated during cell fate specification in the vertebrate CNS.
authors.affiliation: Université de Toulouse, UPS, Centre de Biologie du Développement (CBD), CNRS, Toulouse, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Quillien
authors.forename: Bernardo
authors.initials: B
authors.lastname: Blanco-Sanchez
authors.forename: Caroline
authors.initials: C
authors.lastname: Halluin
authors.forename: John C
authors.initials: JC
authors.lastname: Moore
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Lawson
authors.forename: Patrick
authors.initials: P
authors.lastname: Blader
authors.forename: Elise
authors.initials: E
authors.lastname: Cau
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics / Q000378:metabolism*; D052004:Bone Morphogenetic Protein Receptors / Q000378:metabolism; D002454:Cell Differentiation; D018507:Gene Expression Regulation, Developmental; D005818:Genetic Engineering; D017403:In Situ Hybridization; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D020419:Photoreceptor Cells, Vertebrate / Q000166:cytology*; D010870:Pineal Gland / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction; D051902:Smad5 Protein / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D055396:Bone Morphogenetic Protein 2; D051880:Receptors, Notch; D051902:Smad5 Protein; D029961:Zebrafish Proteins; C497801:smad5 protein, zebrafish; D052004:Bone Morphogenetic Protein Receptors