Figure 3. Retinoic acid signaling during development of the anterior segment.
(A) Simplified overview of retinoic acid production and function in intracrine or paracrine signaling. Note: addition factors involved in functions such as transport have been omitted for simplicity. (B) Summary of tissues producing retinoic acid (blue) at e11.5 based on expression of RALDH1 and/or RALDH3. (C) Summary of tissues responding to retinoic acid signaling at e11.5 based on expression pattern of RARE-lacZ reporter transgene. Key: C, cornea; ADH, alcohol dehydrogenase; RAR, retinoic acid receptor; RALDH1-3, retinaldehyde dehydrogenase 1-3; RDH10, retinol dehydrogenase 10; M, mesenchyme; OS, optic stalk; R, retina; PRE, retinal pigmented epithelium; RXR, retinoid X receptor.