TY - JOUR TI - Pioneer neurog1 expressing cells ingress into the otic epithelium and instruct neuronal specification AU - Hoijman, Esteban AU - Fargas, L AU - Blader, Patrick AU - Alsina, Berta A2 - Bronner, Marianne VL - 6 PY - 2017 DA - 2017/05/24 SP - e25543 C1 - eLife 2017;6:e25543 DO - 10.7554/eLife.25543 UR - https://doi.org/10.7554/eLife.25543 AB - Neural patterning involves regionalised cell specification. Recent studies indicate that cell dynamics play instrumental roles in neural pattern refinement and progression, but the impact of cell behaviour and morphogenesis on neural specification is not understood. Here we combine 4D analysis of cell behaviours with dynamic quantification of proneural expression to uncover the construction of the zebrafish otic neurogenic domain. We identify pioneer cells expressing neurog1 outside the otic epithelium that migrate and ingress into the epithelialising placode to become the first otic neuronal progenitors. Subsequently, neighbouring cells express neurog1 inside the placode, and apical symmetric divisions amplify the specified pool. Interestingly, pioneer cells delaminate shortly after ingression. Ablation experiments reveal that pioneer cells promote neurog1 expression in other otic cells. Finally, ingression relies on the epithelialisation timing controlled by FGF activity. We propose a novel view for otic neurogenesis integrating cell dynamics whereby ingression of pioneer cells instructs neuronal specification. KW - neuronal specification KW - cell dynamics KW - neurog1 KW - morphogenesis KW - FGF JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -