Ablation studies on the developing inner ear reveal a propensity for mirror duplications.
Ablation studies on the developing inner ear reveal a propensity for mirror duplications.
复制标题
对发育中的内耳的消融研究揭示了镜像复制的倾向。
DOI：
10.1002/dvdy.21144
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Collazo,Andres
中科院分区：
文献类型：
--
作者：
Waldman,ErikH;Castillo,Aldo;Collazo,Andres
内耳由简单的外胚层增厚发育而来，称为耳基板。经典的胚胎学操作旋转前瞻性基板组织发现，在确定背腹轴之前确定了前后轴。一小部分这样的旋转也会导致镜像重复耳朵的形成，或对映异体。我们在非洲爪蟾蛙身上展示了一种不同的胚胎学操作：物理移除或消融前半或后半的基板，这导致镜像耳朵的比例更高。切除后半部分导致前镜重复，而切除前半部分导致后镜重复。相反，完全去除会导致更多的可变表型，但不会产生镜像复制。当耳囊肿从表面外胚层分离出来时，完全切除导致没有再生。为了测试剂量反应，切除不同量的耳囊肿或耳基板。切除三分之一的基板导致正常耳，而三分之二的消融导致异常耳，包括镜像重复。最近对斑马鱼的研究表明，hedgehog（Hh）信号通路在耳朵发育的前后模式中起着重要作用。我们使用过表达Hedgehog相互作用蛋白（Hip）来阻断Hh信号传导，并发现这种策略导致了前部结构的镜像复制，与斑马鱼的结果一致。科学进展，2007,26(6):1237 - 1248。©2007 Wiley‐Liss, Inc。
The inner ear develops from a simple ectodermal thickening known as the otic placode. Classic embryological manipulations rotating the prospective placode tissue found that the anteroposterior axis was determined before the dorsoventral axis. A small percentage of such rotations also resulted in the formation of mirror duplicated ears, or enantiomorphs. We demonstrate a different embryological manipulation in the frogXenopus: the physical removal or ablation of either the anterior or posterior half of the placode, which results in an even higher percentage of mirror image ears. Removal of the posterior half results in mirror anterior duplications, whereas removal of the anterior half results in mirror posterior duplications. In contrast, complete extirpation results in more variable phenotypes but never mirror duplications. By the time the otocyst separates from the surface ectoderm, complete extirpation results in no regeneration. To test for a dosage response, differing amounts of the placode or otocyst were ablated. Removal of one third of the placode resulted in normal ears, whereas two‐thirds ablations resulted in abnormal ears, including mirror duplications. Recent studies in zebrafish have demonstrated a role for thehedgehog(Hh) signaling pathway in anteroposterior patterning of the developing ear. We have used overexpression of Hedgehog interacting protein (Hip) to block Hh signaling and find that this strategy resulted in mirror duplications of anterior structures, consistent with the results in zebrafish. Developmental Dynamics 236:1237–1248, 2007. © 2007 Wiley‐Liss, Inc.