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. Author manuscript; available in PMC: 2008 Aug 15.
Published in final edited form as: Dev Biol. 2007 May 31;308(2):343–354. doi: 10.1016/j.ydbio.2007.05.030

Figure 2.

Figure 2

The posterior forelimb continues to respond to Shh signaling at late stages. Shh, Ptc1, and Ptc2 are all expressed in the posterior limb at stage 21 (A,B,C) and stage 24 (E,F,G). Gli1, though expressed in the very posterior limb at stage 21 (D), is downregulated in the posterior at stage 24 (H). This tissue is still sensitive to Shh signaling at late stages as shown by the downregulation of Ptc1 and Ptc2 12 hours after cyclopamine treatment (J,K). Gli1 is also downregulated (L). Shh continues to be expressed (I) as does the AER domain of Ptc2 expression (K), showing that the effect is not nonspecific. Extended exposure to a Shh bead downregulates Gli1 (M).