(2017) Asymmetric morphogenesis of the parapineal organ in the embryonic zebrafish brain.


Introduction: The establishment of asymmetry in the embryoniczebrafish brain begins with the left-sided asymmetric positioning ofthe parapineal organ (PpO), an event that is required for furtherdevelopment of asymmetries in neighbouring diencephalic nuclei.Previous studies have shown that PpO asymmetric morphogenesisrequires Nodal and Fgf8 dependent signalling but the cellularbehaviours that are controlled by these signalling pathways are stillunclear. Here we investigated these behaviours.Material and Methods: We developed and applied mathematicalcomputational image processing tools for in vivo 3D microscopy datasets,which were combined with indirect immunofluorescence to unravel thetransformations of neuroepithelial cell morphology and organisationunderlying PpO formation in Tg(flh::EGFP) zebrafish embryos.Results: We found that precursor cells of the PpO display early left-right differences in cell behaviour during the process of nucleogenesis.Left-sided precursors contract their axis of elongation while right-sidedprecursors move across the midline to assemble with left-sidedprecursors and form a left-sided compact cluster organised in a 3dimensional rosette. This process precedes the detachment of the PpOfrom de pineal complex.Discussion: Establishment of asymmetry in the PpO involves theconcerted organisation of precursor cells into a rosette-like structure onthe left-side, which is the seed for further transformation of PpOprecursors into an asymmetric nucleus. These results will be contrastedwith conditions devoid of Nodal and Fgf8 signallin

Lemus C, Palma K, Jara J, Härtel S, Concha M

Mechanisms Of Development (Mech Dev.)

junio 06, 2017

DOI: 10.1016/j.mod.2017.04.112

Investigador BNI: Steffen Härtel , Miguel Concha