Pax6 organizes the anterior eye segment by guiding two distinct neural crest waves

by Masanari Takamiya, Johannes Stegmaier, Andrei Yu Kobitski, Benjamin Schott, Benjamin D. Weger, Dimitra Margariti, Angel R. Cereceda Delgado, Victor Gourain, Tim Scherr, Lixin Yang, Sebastian Sorge, Jens C. Otte, Volker Hartmann, Jos van Wezel, Rainer Stotzka, Thomas Reinhard, Günther Schlunck, Thomas Dickmeis, Sepand Rastegar, Ralf Mikut, Gerd Ulrich Nienhaus, Uwe Strähle

Cranial neural crest (NC) contributes to the developing vertebrate eye. By multidimensional, quantitative imaging, we traced the origin of the ocular NC cells to two distinct NC populations that differ in the maintenance of sox10 expression, Wnt signalling, origin, route, mode and destination of migration. The first NC population migrates to the proximal and the second NC cell group populates the distal (anterior) part of the eye. By analysing zebrafish pax6a/b compound mutants presenting anterior segment dysgenesis, we demonstrate that Pax6a/b guide the two NC populations to distinct proximodistal locations. We further provide evidence that the lens whose formation is pax6a/b-dependent and lens-derived TGFβ signals contribute to the building of the anterior segment. Taken together, our results reveal multiple roles of Pax6a/b in the control of NC cells during development of the anterior segment.