Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Japan.
J Exp Zool B Mol Dev Evol. 2010 Nov 15;314(7):539-51. doi: 10.1002/jez.b.21359.
The vertebrate hand plate is flattened and paddle shaped; that is, it is wide along the anteroposterior (AP) axis (thumb to little finger) and thin along the dorsoventral axis (back of hand to palm). To learn how the hand plate develops its three-dimensional architecture, we observed morphological changes in the distal limb bud of the chick embryo at stages 23-27 and the gecko embryo 11-13 days after oviposition. Cell population of the posterior distal limb bud expanded more than that of the anterior one in the chick embryo. Taken together with the observation that these two cell populations did not show significant differences in their expansion along the proximodistal axis, we propose that the cell population in the posterior limb bud contributes more to the morphogenetic increase along the AP axis, which widens the limb bud for the formation of the hand plate. Our observation that more mitoses were oriented anteroposteriorly than dorsoventrally in the chick embryo at around stage 25 suggests that the oriented cell division contributes to the morphogenetic increase along the AP axis.
脊椎动物手板是扁平的桨状的；也就是说，它在前后轴（从拇指到小指）方向较宽，而在背腹轴（手背面到手掌）方向较薄。为了了解手板如何发育出其三维结构，我们观察了鸡胚阶段 23-27 和壁虎胚胎产卵后 11-13 天的远端肢芽的形态变化。鸡胚的后远端肢芽的细胞群体比前远端肢芽的细胞群体扩张得更多。结合这两个细胞群体在沿近-远轴的扩张方面没有表现出显著差异的观察结果，我们提出后肢芽的细胞群体对沿 AP 轴的形态发生增加贡献更多，这增加了肢芽的宽度以形成手板。我们观察到，在大约 25 阶段的鸡胚中，有更多的有丝分裂沿前后方向而不是背腹方向定向，这表明定向细胞分裂有助于沿 AP 轴的形态发生增加。
