Scadding S R, Maden M
Department of Zoology, University of Guelph, Ontario, Canada.
Dev Biol. 1994 Apr;162(2):608-17. doi: 10.1006/dbio.1994.1114.
Retinoids have been implicated in pattern formation processes in both developing chick limbs and in the regenerating limbs of urodele amphibians as well as in other aspects of embryonic development. Since chick wing buds have been shown to have a higher concentration of all-trans-retinoic acid (RA) in the posterior region than in the anterior region, we set out to look for a gradient of RA in the regenerating limb of the axolotl, Ambystoma mexicanum. We used high-performance liquid chromatography to separate, identify, and measure the concentration of retinoids present in the tissues. Our results show that the concentration of RA is about five times higher in posterior quarters of the limb regeneration blastema compared to anterior quarters. In addition, levels of RA are about two and a half times higher in blastemas from the radius-ulna level of the limb compared to those from the humerus level. By contrast, the limb regenerates of the African clawed frog, Xenopus laevis (which produce a regenerative outgrowth which is pattern-deficient), do not exhibit an anteroposterior gradient of any of the retinoids investigated. This paper also reports on the levels of retinoids in a number of other tissues as well. This anteroposterior gradient of RA in the axolotl limb regeneration blastema has significant implications for pattern formation during limb development and regeneration.
维甲酸已被证明与发育中的鸡肢体、有尾两栖动物再生肢体的模式形成过程以及胚胎发育的其他方面有关。由于已发现鸡翼芽后区的全反式维甲酸（RA）浓度高于前区，我们着手在墨西哥钝口螈的再生肢体中寻找RA梯度。我们使用高效液相色谱法分离、鉴定并测量组织中维甲酸的浓度。我们的结果表明，肢体再生芽基后四分之一处的RA浓度比前四分之一处高约五倍。此外，与肱骨水平的芽基相比，肢体桡尺骨水平芽基中的RA水平高约两倍半。相比之下，非洲爪蟾（其再生的芽体缺乏模式）的肢体再生没有表现出所研究的任何一种维甲酸的前后梯度。本文还报告了许多其他组织中的维甲酸水平。墨西哥钝口螈肢体再生芽基中RA的这种前后梯度对肢体发育和再生过程中的模式形成具有重要意义。
