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. Author manuscript; available in PMC: 2011 Sep 22.
Published in final edited form as: Dev Biol. 2008 Apr 25;319(2):248–257. doi: 10.1016/j.ydbio.2008.04.019

Figure 6.

Figure 6

Delta-Notch Signaling acts during a critical 2-hour time-period to specify pituitary placodal cell fates. Adenohypophysis placode cells express delta and notch homologs between 15h –48h. delta and notch expression begins around 14h in the immature placode. Delta-Notch expression is downregulated by 48h when the three subdomains APD, PPD, and PI are composed of terminally differentiated pituitary cell types. Long-range signals are thought to regionalize the placode into three subdomains, whereas short-range delta notch signals specify the cell-types within each subdomain. The black and grey stripes above the timeline indicate delta and notch expression between 15h–48h post fertilization. The sketch below the timeline indicates the position of the immature pituitary placode (left, green) around 19h. The magnification of the placode indicates the regionalized placode (middle) and the regionalized adenohypophysis with specified cell types (right).