Pax6 Is a Human Neuroectoderm Cell Fate Determinant

SummaryThe transcriptional regulation of neuroectoderm (NE) specification is unknown. Here we show that Pax6 is uniformly expressed in early NE cells of human fetuses and those differentiated from human embryonic stem cells (hESCs). This is in contrast to the later expression of Pax6 in restricted mouse brain regions. Knockdown of Pax6 blocks NE specification from hESCs. Overexpression of either Pax6a or Pax6b, but not Pax6▵PD, triggers hESC differentiation. However, only Pax6a converts hESCs to NE. In contrast, neither loss nor gain of function of Pax6 affects mouse NE specification. Both Pax6a and Pax6b bind to pluripotent gene promoters but only Pax6a binds to NE genes during human NE specification. These findings indicate that Pax6 is a transcriptional determinant of the human NE and suggest that Pax6a and Pax6b coordinate with each other in determining the transition from pluripotency to the NE fate in human by differentially targeting pluripotent and NE genes.

Graphical AbstractFigure optionsDownload high-quality image (151 K)Download as PowerPoint slideHighlights
► Pax6 is ubiquitously expressed in the human neural plate
► Pax6 is necessary and sufficient for human neuroectoderm (NE) specification
► Pax6 represses pluripotent genes and activates neural genes
► Mouse NE specification does not require Pax6