Temporal distribution, localization and metabolism of all-trans-retinol, didehydroretinol and all-trans-retinal during Xenopus development

1994 ◽  
Vol 301 (1) ◽  
pp. 111-119 ◽  
Author(s):  
J Creech Kraft ◽  
T Schuh ◽  
M R Juchau ◽  
D Kimelman
Keyword(s):  
Spatial Distribution ◽  
Retinoic Acid ◽  
Distribution Patterns ◽  
Retinoid Receptor ◽  
Temporal And Spatial Distribution ◽  
Spatial Distribution Patterns ◽  
Xenopus Embryos ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Temporal And Spatial

Recently, the temporal and spatial distribution patterns of the retinoid receptor ligands 9-cis-retinoic acid and all-trans-retinoic acid were described in Xenopus embryos during early development [Creech Kraft, Schuh, Juchau and Kimelman (1994) Proc. Natl. Acad. Sci. U.S.A., in the press]. The present study demonstrates the presence and distribution of their likely precursors, all-trans-retinol, didehydroretinol, didehydroretinal and all-trans-retinal, as well as the occurrence of 4-oxo metabolites, in Xenopus embryos. The temporal and spatial distribution patterns of all-trans-retinol, didehydroretinol and all-trans-retinal did not coincide with that observed for 9-cis-retinoic acid but, in certain regards, were similar to the patterns delineated for all-trans-retinoic acid and all-trans-retinoyl beta-glucuronide. Evidence is presented that 9-cis-retinoic acid can be synthesized from both all-trans-retinoic acid and all-trans-retinol in Xenopus embryos, suggesting that the difference between the distributions of 9-cis-retinoic acid and the other retinoids may be caused by selective synthesis and/or protein binding of the 9-cis isomer.

scholarly journals Studies on the mechanism of retinoid-induced pattern duplications in the early chick limb bud: temporal and spatial aspects.

1985 ◽  
Vol 101 (5) ◽  
pp. 1913-1920 ◽  
Author(s):  
G Eichele ◽  
C Tickle ◽  
B M Alberts
Keyword(s):  
Spatial Distribution ◽  
Retinoic Acid ◽  
Limb Bud ◽  
Lag Phase ◽  
Temporal And Spatial Distribution ◽  
Metabolic Pattern ◽  
Continuous Release ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Temporal And Spatial

All-trans-retinoic acid causes striking digit pattern changes when it is continuously released from a bead implanted in the anterior margin of an early chick wing bud. In addition to the normal set of digits (234), extra digits form in a mirror-symmetrical arrangement, creating digit patterns such as a 432234. These retinoic acid-induced pattern duplications closely mimic those found after grafts of polarizing region cells to the same positions with regard to dose-response, timing, and positional effects. To elucidate the mechanism by which retinoic acid induces these pattern duplications, we have studied the temporal and spatial distribution of all-trans-retinoic acid and its potent analogue TTNPB in these limb buds. We find that the induction process is biphasic: there is an 8-h lag phase followed by a 6-h duplication phase, during which additional digits are irreversibly specified in the sequence digit 2, digit 3, digit 4. On average, formation of each digit seems to require between 1 and 2 h. The tissue concentrations, metabolic pattern, and spatial distribution of all-trans-retinoic acid and TTNPB in the limb rapidly reach a steady state, in which the continuous release of the retinoid is balanced by loss from metabolism and blood circulation. Pulse-chase experiments reveal that the half-time of clearance from the bud is 20 min for all-trans-retinoic acid and 80 min for TTNPB. Manipulations that change the experimentally induced steep concentration gradient of TTNPB suggest that a graded distribution of retinoid concentrations across the limb is required during the duplication phase to induce changes in the digit pattern. The extensive similarities between results obtained with retinoids and with polarizing region grafts raise the possibility that retinoic acid serves as a natural "morphogen" in the limb.

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