Expression and function of a limb-patterning gene Distal-less in the soldier-specific morphogenesis in the nasute termite Nasutitermes takasagoensis.
Expression and function of a limb-patterning gene Distal-less in the soldier-specific morphogenesis in the nasute termite Nasutitermes takasagoensis.
复制标题
鼻白蚁 Nasutitermes takasagoensis 肢体模式基因 Distal-less 在士兵特异性形态发生中的表达和功能。
DOI：
10.1111/j.1525-142x.2012.00545.x
复制
发表时间：
2012
影响因子：
2.9
通讯作者：
K. Maekawa
中科院分区：
文献类型：
--
作者：
K. Toga;M. Hojo;T. Miura;K. Maekawa
进化发育生物学的主要焦点之一是了解获得形态新颖性的发育机制。白蚁士兵，高度专业化的防御种姓，表现出夸张的物种特异性形态，主要是扩大的下颚。然而，白蚁亚科（白蚁科）的士兵在头部拥有一种新颖的防御结构，即角状的额突（鼻），防御化学物质从鼻中排出。在工蜂蜕皮前（兵蚁蜕皮前），在工蜂头部角质层下观察到鼻盘或鼻原基。为了了解这种进化上新颖的结构的发育基础，本研究使用鼻白蚁Nasutitermes takasagoensis研究了同源盒基因Distal ‐less（Dll）在鼻发育过程中的作用。组织学观察表明，复杂的发育过程，包括表皮外翻和内陷，通过细胞形状的变化和细胞增殖形成的突起和腺体。免疫组化显示Dll定位于发育中的鼻盘，但不在额腺原基中。与这一发现一致，DllRNA干扰仅抑制鼻生长，而不是额腺形成。总之，Dllis的共同选择建议有助于在白蚁谱系中获得一种新的防御结构，再加上获得适应性防御行为。
One of the major foci in evolutionary developmental biology is to understand developmental mechanisms that underlie the acquisition of morphological novelties. Termite soldiers, the highly specialized defensive caste, show exaggerated species‐specific morphologies, mostly enlarged mandibles. Soldiers of the subfamily Nasutitermitinae (Termitidae), however, possess a novel structure for defense in their heads, that is a horn‐like frontal projection (nasus) from which defensive chemicals are discharged. Just prior to the molt into presoldiers (the preceding stage to soldiers) from workers, a nasus disc, or a nasus primordium, is observed under the worker head cuticle. In order to understand the developmental underpinnings of this evolutionarily novel structure, the role of a homeobox geneDistal‐less(Dll) during nasus development was examined in this study, using a nasute termiteNasutitermes takasagoensis. Histological observations showed that complex developmental processes comprising epidermal evagination and invagination through changes in cell shape and cell proliferation formed the projection and the gland. Immunohistochemistry showed that Dll was localized in the developing nasus disc, but not in the frontal‐gland primordium. Consistent with this finding,DllRNA interference only repressed nasus growth not the frontal‐gland formation. Taken together, the co‐option ofDllis suggested to contribute to the acquisition of a novel defensive structure in a termite lineage, coupled with the acquisition of adaptive defensive behaviors.