The retinoid X receptor ligand, 9-cis-retinoic acid, is a potential regulator of early Xenopus development.

Endogenous retinoids are potential regulators of vertebrate embryogenesis that have been implicated in early anterior-posterior patterning and limb-bud development. We have characterized the temporal and spatial distribution of 9-cis-retinoic acid in the Xenopus embryo and compared it to two other retinoids, all-trans-retinoic acid and all-trans-retinoyl-beta-glucuronide. 9-cis-Retinoic acid is first detected after the midblastula transition and by the end of gastrulation is localized primarily within the anterior and posterior dorsal regions of the embryo. Since 9-cis-retinoic acid is a 6-fold more potent dysmorphogen than trans-retinoic acid, we suggest that it is involved in the early specification of the Xenopus anterior-posterior axis. IMAGES: