Non-overlapping expression of CRBP I and CRABP I during pattern formation of limbs and craniofacial structures in the early mouse embryo.
Retinoic acid (RA), a physiological metabolite of retinol (vitamin A), is thought to be of importance for pattern formation in the developing embryo. However, the mechanism by which RA is generated, as well as the site of its formation in the developing embryo, is still unknown. In this paper, we show that radiolabelled retinol, administered to pregnant mice, is accumulated in specific locations in the embryos. As revealed by immunohistochemistry using antibodies to cellular retinol-binding protein I (CRBP I), retinol accumulates in regions of the embryo expressing CRBP I. In limbs and craniofacial structures, CRBP I expression and retinol accumulation was seen in endoderm and surface ectoderm. Most mesenchymal cells of the limbs and craniofacial structures did not express detectable levels of CRBP I but instead expressed cellular retinoic acid-binding protein I (CRABP I). Previous results have demonstrated that CRABP I is involved in accumulation of RA in the embryo. Thus, the spatially closely related but non-overlapping domains of expression of CRBP I and CRABP I suggests a role of a retinol/RA pathway in epithelial-mesenchymal interactions during pattern formation of limbs and of craniofacial structures.
Department of Toxicology, Uppsala University, Sweden.
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Gustafson
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Dencker
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Eriksson
D000818:Animals; D001345:Autoradiography; D002352:Carrier Proteins / Q000235:genetics*; D004848:Epithelium / Q000196:embryology; D005121:Extremities / Q000196:embryology*; D015870:Gene Expression / Q000235:genetics*; D006257:Head / Q000196:embryology*; D007150:Immunohistochemistry; D008648:Mesoderm / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D009024:Morphogenesis / Q000235:genetics; D018168:Receptors, Retinoic Acid; D012177:Retinol-Binding Proteins / Q000235:genetics*; D054840:Retinol-Binding Proteins, Cellular; D014212:Tretinoin / Q000494:pharmacology*; D014801:Vitamin A / Q000494:pharmacology
D002352:Carrier Proteins; D018168:Receptors, Retinoic Acid; D012177:Retinol-Binding Proteins; D054840:Retinol-Binding Proteins, Cellular; D014801:Vitamin A; D014212:Tretinoin