Retinoid signaling is required for the establishment of a ZPA and for the expression of Hoxb-8, a mediator of ZPA formation.
We show that retinoid receptor antagonists applied to the presumptive wing region block the formation of a zone of polarizing activity (ZPA). This suggests a direct relationship between retinoid signaling and the establishment of the ZPA. We provide evidence that the Hox gene, Hoxb-8, is a direct target of retinoid signaling since exogenously applied RA rapidly induces this gene in the absence of protein synthesis and, moreover, retinoid receptor antagonists down-regulate Hoxb-8 expression. In addition, we find that, in the lateral plate mesoderm, the domains of Hoxb-8 expression and of polarizing activity are coextensive. Taken together, these findings support the hypothesis that retinoids are required for the establishment of a ZPA, and that retinoids act, at least in part, through Hoxb-8, a gene associated with ZPA formation (Charité et al., 1994).
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Developmental Biology Program, and V. and M. McLean Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77030, USA.
Revelli
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JP
Goering
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Thaller
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Eichele
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D000595:Amino Acid Sequence; D000818:Animals; D001565:Benzoates / Q000494:pharmacology; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens; D002839:Chromans / Q000494:pharmacology; D004527:Egg Proteins / Q000096:biosynthesis*; D004627:Embryonic Induction; D015870:Gene Expression; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000737:chemistry; D018878:Limb Buds / Q000637:transplantation; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D008648:Mesoderm / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D011956:Receptors, Cell Surface / Q000096:biosynthesis; D018168:Receptors, Retinoic Acid / Q000037:antagonists & inhibitors / Q000502:physiology*; D047488:Retinoid X Receptors; D012176:Retinoids / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000187:drug effects*; D013764:Tetrahydronaphthalenes / Q000494:pharmacology; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000502:physiology*; D014212:Tretinoin / Q000494:pharmacology*; D014921:Wings, Animal / Q000196:embryology; D000072216:Zona Pellucida Glycoproteins
D001565:Benzoates; D002839:Chromans; D004527:Egg Proteins; D018398:Homeodomain Proteins; C095822:Hoxb8 protein, mouse; C101596:LG 100754; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D018168:Receptors, Retinoic Acid; D047488:Retinoid X Receptors; D012176:Retinoids; D013764:Tetrahydronaphthalenes; D014157:Transcription Factors; D000072216:Zona Pellucida Glycoproteins; C084904:Ro 41-5253; D014212:Tretinoin