Table 1.
Key signaling molecules and TFs implicated in T/PT early development.
| Gene | Relevant Expression Pattern | Relevant Role | Reference (s) |
|---|---|---|---|
| Bmp4 | T presumptive domain; NC-derived mesenchyme, surface ectoderm. | PP patterning; early T/PT development; organs separation and migration; regulation of Foxn1 expression. | [24,58,59,60,61,62,63] |
| Eya1 | PP endoderm; NC-derived mesenchyme; Surface ectoderm. | PP patterning and outgrowth. | [64,65] |
| Fgf8 | PP and pharyngeal endoderm; non-NC-derived mesoderm; Surface ectoderm. | PP formation and patterning, possible role in guiding pouch epithelial outpocketing. | [66,67,68,69] |
| Foxi3 | PP endoderm; surface ectoderm | PA segmentation; T/PT development | [70] |
| Foxn1 | T rudiment. | TEC differentiation. | [25,49,71,72] |
| Gata3 | PP endoderm; organ rudiments | Possible role in PP patterning and survival; PT differentiation and survival | [73,74,75] |
| Gcm2 | PT rudiment. | PT differentiation. | [48,57] |
| Hoxa3 | PP endoderm; NC-derived mesenchyme | PP specification, T/PT primordium formation and survival | [76,77,78] |
| Noggin | PT rudiment; Mesenchyme | PP patterning, opposing Bmp signaling | [24,60] |
| Pax1 | PP endoderm | Early T/PT development, possible regulation of Foxn1 expression | [78,79] |
| Pax3 | NC-derive mesenchyme | Organs boundary formation | [34] |
| Pax9 | PP endoderm | PP development, T/PT primordium formation and separation; possible regulation of Foxn1 expression. | [80,81] |
| RA | Mesenchyme surrounding the pharyngeal endoderm | Posterior PP segmentation and formation | [82,83,84,85] |
| Six1/4 | Surface ectoderm, PP endoderm, NC-derived mesenchyme | Early T/PT formation and survival | [65] |
| Shh | Pharyngeal endoderm, but excluded from PP endoderm | PP patterning and early PT development | [75,86,87,88,89] |
| Tbx1 | Pharyngeal endoderm and presumptive PT domain; non-NC-derived mesenchyme; surface ectoderm. | Pharyngeal region segmentation; PP formation; possible involvement in promoting PT fate/suppressing T fate | [48,90,91] |
| Wnt4 | PP endoderm; mesenchyme | Possible regulation of Foxn1 expression | [92] |
NC—neural crest; PP—pharyngeal pouch; PT—Parathyroid glands; T—thymus; TEC—thymic epithelial cell.