title: Reiterative AP2a activity controls sequential steps in the neural crest gene regulatory network.
abstract: The neural crest (NC) emerges from combinatorial inductive events occurring within its progenitor domain, the neural border (NB). Several transcription factors act early at the NB, but the initiating molecular events remain elusive. Recent data from basal vertebrates suggest that ap2 might have been critical for NC emergence; however, the role of AP2 factors at the NB remains unclear. We show here that AP2a initiates NB patterning and is sufficient to elicit a NB-like pattern in neuralized ectoderm. In contrast, the other early regulators do not participate in ap2a initiation at the NB, but cooperate to further establish a robust NB pattern. The NC regulatory network uses a multistep cascade of secreted inducers and transcription factors, first at the NB and then within the NC progenitors. Here we report that AP2a acts at two distinct steps of this cascade. As the earliest known NB specifier, AP2a mediates Wnt signals to initiate the NB and activate pax3; as a NC specifier, AP2a regulates further NC development independent of and downstream of NB patterning. Our findings reconcile conflicting observations from various vertebrate organisms. AP2a provides a paradigm for the reiterated use of multifunctional molecules, thereby facilitating emergence of the NC in vertebrates.
authors.affiliation: Institut Curie, Institut National de la Santé et de la Recherche Médicale U1021, Centre National de la Recherche Scientifique Unité Mixte de Recherche 3347, F-91405 Orsay, France.
authors.forename: Noémie
authors.initials: N
authors.lastname: de Crozé
authors.forename: Frédérique
authors.initials: F
authors.lastname: Maczkowiak
authors.forename: Anne H
authors.initials: AH
authors.lastname: Monsoro-Burq
mesh_terms: D000818:Animals; D024202:Electrophoretic Mobility Shift Assay; D004843:Epistasis, Genetic; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D055785:Gene Knockdown Techniques; D053263:Gene Regulatory Networks / Q000235:genetics*; D006801:Humans; D008954:Models, Biological; D009432:Neural Crest / Q000196:embryology / Q000378:metabolism*; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050656:Transcription Factor AP-2 / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D029867:Xenopus Proteins / Q000235:genetics* / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology*
chemical_list: D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; C489411:Pax3 protein, Xenopus; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D029867:Xenopus Proteins; C116546:Zic1 protein, Xenopus; C493675:tfap2a protein, Xenopus