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Retinoic acid (simplified nomenclature for all-trans-retinoic acid) is a metabolite of vitamin A 1 (all-trans-retinol) that is required for embryonic development, male fertility, regulation of bone growth and immune function. [2] All-trans-retinoic acid is required for chordate animal development, which includes all higher animals from fish to ...
Establishment of the forelimb field (but not hindlimb field) requires retinoic acid signaling in the developing trunk of the embryo from which the limb buds emerge. [ 2 ] [ 3 ] Also, although excess retinoic acid can alter limb patterning by ectopically activating Shh or Meis1/Meis2 expression, genetic studies in mouse that eliminate retinoic ...
Retinoic acid via the retinoic acid receptor influences the process of cell differentiation and, hence, the growth and development of embryos. During development, there is a concentration gradient of retinoic acid along the anterior-posterior (head-tail) axis. Cells in the embryo respond to retinoic acid differently depending on the amount present.
This endoplasmic reticulum protein acts on retinoids, including all-trans-retinoic acid (RA), with both 4-hydroxylation and 18-hydroxylation activities. This enzyme regulates the cellular level of retinoic acid which is involved in regulation of gene expression in both embryonic and adult tissues.
During development, retinoic acid, a metabolite of vitamin A, is used to stimulate the growth of the posterior end of the organism. [12] Retinoic acid binds to retinoic acid receptors that acts as transcription factors to regulate the expression of Hox genes. Exposure of embryos to exogenous retinoids especially in the first trimester results ...
The head of the embryo forms at the point of highest concentration of bicoid and the anterior pattern depends upon the concentration of bicoid. Bicoid works as a transcriptional activator of the gap genes hunchback (hb), buttonhead (btd), empty spiracles (ems), and orthodentical (otd) while also acting to repress translation of caudal.
Although endogenous retinoic acid is required in higher vertebrates to limit the caudal Fgf8 domain needed for somitogenesis in the trunk (but not tail), some studies also point to a possible role of retinoic acid in ending somitogenesis in vertebrates that lack a tail (human) or have a short tail (chick). [16]
Products that contain retinoic acid (alternatively retinol or vitamin A) have the potential to cause severe birth defects when used during pregnancy. [9] Induction of Stra8 by retinoic acid can result in premature cell differentiation in the embryo. Products that contain retinoic acid should be avoided during pregnancy.