File:Mouse pineal E15 to E21 neuroepithelium 01.jpg

The pineal gland develops from neuroepithelial cells that express the transcription factor Pax6 and the intermediate filament vimentin.

Panels display confocal microscopy of immunolabeled sagittal sections of rat pineal gland (PG) from embryonic day (E) 15 to E21. Both male and female rat embryos were used. Panels A1-G1 show expression of Pax6 (green) and vimentin (VIM, red) in pineal precursor cells at low magnification. Panels A2-G2 display the same structures at higher magnification. Panels A3-G3 and A4-G4 show Pax6 and vimentin expression for each stage of development, respectively. Pineal organogenesis begins around E15 as an evagination of the neuroepithelium in the dorsal diencephalon that is densely populated by Pax6-expressing cells (green). The developing PG becomes a tubular extension at E16. The orientation of Pax6/VIM+ cells is radial at these stages. At E17 the pineal neuroepithelium begins to fold and fuses at the midline. After fusion of the neuroepithelium, double immunolabeled rosette-like structures are visible in the E18-E21 developing PG. At E21 the PG has developed into a recognizable globular structure. Inset boxes are shown at higher magnification in Fig 3. (A1-G1) 20x; scale bar: 75 μm. (A2-G4) 60x; scale bar: 25 μm. PC, posterior commissure. SCO, subcommissural organ. 3v, third ventricle.

Fig 1. https://doi.org/10.1371/journal.pone.0167063.g001