Vlaskalin Tatjana, Wong Christine J, Tsilfidis Catherine
Ottawa Health Research Institute, University of Ottawa Eye Institute, 501 Smyth Road, Ottawa, ON K1A 8L6, Canada.
Dev Genes Evol. 2004 Sep;214(9):423-31. doi: 10.1007/s00427-004-0417-1. Epub 2004 Aug 21.
Many of the genes involved in the initial development of the limb in higher vertebrates are also expressed during regeneration of the limb in urodeles such as Notophthalmus viridescens. These similarities have led researchers to conclude that the regeneration process is a recapitulation of development, and that patterning of the regenerate mimics pattern formation in development. However, the developing limb and the regenerating limb do not look similar. In developing urodele forelimbs, digits appear sequentially as outgrowths from the limb palette. In regeneration, all the digits appear at once. In this work, we address the issue of whether regeneration and development are similar by examining growth and apoptosis patterns. In contrast to higher vertebrates, forelimb development in the newt, N. viridescens, does not use interdigital apoptosis as the method of digit separation. During adult forelimb regeneration, apoptosis seems to play an important role in wound healing and again during cartilage to bone turnover in the advanced digits and radius/ulna. However, similar to forelimb development, demarcation of the digits in adult forelimb regeneration does not involve interdigital apoptosis. Outgrowth, rather than regression of the interdigital mesenchyme, leads to the individualization of forelimb digits in both newt development and regeneration.
许多参与高等脊椎动物肢体初始发育的基因，在诸如绿红东美螈等有尾目动物肢体再生过程中也会表达。这些相似性使得研究人员得出结论，即再生过程是发育的重演，并且再生肢体的模式形成模仿了发育过程中的模式形成。然而，发育中的肢体和再生中的肢体看起来并不相似。在发育中的有尾目动物前肢中，指（趾）作为从肢体板长出的结构依次出现。在再生过程中，所有指（趾）同时出现。在这项研究中，我们通过检查生长和凋亡模式来探讨再生与发育是否相似的问题。与高等脊椎动物不同，绿红东美螈前肢发育并不利用指间凋亡作为指（趾）分离的方式。在成年前肢再生过程中，凋亡似乎在伤口愈合中发挥重要作用，并且在晚期指（趾）以及桡骨/尺骨的软骨向骨转换过程中再次发挥作用。然而，与前肢发育类似，成年前肢再生过程中手指（脚趾）的划分并不涉及指间凋亡。在蝾螈发育和再生过程中，指间间充质的生长而非退化导致前肢指（趾）的个体化。
