FOG. 4.

SOX2 expression pattern in human embryonic and fetal tissue (mRNA: A–C, E, F, and I–L; protein: D, G, and H). Transverse (A) and sagittal (B) sections show expression of SOX2 within the developing Rathke’s pouch (Rp) and overlying neural ectoderm at CS16 and CS19, respectively. C and D, Coronal sections of F2 tissue showing SOX2 transcripts and protein continue to be expressed in the cells lining the lumen of the anterior pituitary (AP). Note the absence of expression in the infundibulum (inf) and posterior pituitary (PP). E, Transverse section showing SOX2 expression in the forebrain, including the region of the presumptive hippocampus (arrowhead), and throughout the midbrain and hindbrain in addition to the cerebellum (Ce). F–H, Transverse sections of the forebrain in human fetal tissues at approximately 8-wk development showing expression of SOX2 in the hypothalamus (Hyp). H, Magnified section corresponding to the boxed region in G. I and J, Transverse sections showing expression of SOX2 in the lens (l) vesicle and developing neural retina (nr) at CS16, where expression is restricted to the proximal inner layer, with a boundary of expression in the distal region adjacent to the lens (arrowhead). J, Expression within the lens diminishes by CS20. SOX2 is also expressed in the nasal epithelium (K) and in the tracheoesophageal tract (L), as shown in transverse section. Scale bars: 500 μm (E); 300 μm (B–D, F, G, J, and K); and 100 μm (A, H, I, and L). Di, Diencephalon; Me, mesencephalon; oc, oral cavity; Oe, developing esophagus; phy, presumptive hypothalamus; Rh, rhombencephalon; T, telencephalon; Tr, developing trachea; 3V, third ventricle.