Development of heterodont dentition in house shrew (Suncus murinus).
Development of heterodont dentition in house shrew (Suncus murinus).
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DOI：
10.1111/j.1600-0722.2007.00499.x
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发表时间：
2007-12
影响因子：
1.9
通讯作者：
A. Yamanaka;K. Yasui;T. Sonomura;M. Uemura
中科院分区：
文献类型：
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作者：
A. Yamanaka;K. Yasui;T. Sonomura;M. Uemura
哺乳动物的异齿牙齿包括门齿、犬齿、前磨牙和磨牙。虽然已经有深入的研究，这些特定的牙齿类型的模式尚未阐明。为了将基因表达数据与牙齿类型的确定联系起来，首先需要精确地确定下颌原基中的门牙区、犬牙区、前磨牙区和磨牙区。为了实现这一目标，我们研究了保留了所有牙齿类型的家鼩（Suncus murinus）的牙齿发育，使用了来自连续组织学切片和Sonic hedgehog （Shh）表达模式的三维重建。在牙齿形成的形态学迹象出现之前，Shh表达定位于假定的牙齿形成区域，其中近端和远端表达域分别对应于门牙和前磨牙形成区域。发现上切牙区域延伸跨越额鼻突和上颌突之间的边界。犬齿形成区后来出现在上颌突和下颌突的中间部分。磨牙形成区域后来通过远端二次延伸出现在最初划定的牙齿形成区域的远端。家鼩下颚原基Shh表达模式的划分可能代表了哺乳动物异齿动物牙齿的基本发育模式。
Mammalian heterodont dentition comprises incisors, canines, premolars, and molars. Although there has been intensive research, the patterning of these specific tooth types has not yet been elucidated. In order for the gene expression data to be linked with tooth type determination, it is first necessary to determine precisely the incisor-, canine-, premolar-, and molar-forming regions in the jaw primordia. To accomplish this, we studied dentition development in the house shrew (Suncus murinus), which has retained all the tooth types, using three-dimensional reconstructions from serial histological sections and the Sonic hedgehog (Shh) expression patterns. Before the appearance of morphological signs of odontogenesis, Shh expression localized to the presumptive tooth-forming regions, in which the mesial and distal expression domains corresponded to the incisor- and premolar-forming regions, respectively. The upper incisor region was found to extend across the boundary between the frontonasal and the maxillary processes. The canine-forming regions later appeared in the intermediate portions of the maxillary and the mandibular processes. The molar-forming regions later appeared distal to the initially demarcated tooth-forming regions by secondary extension of the distal ends. The demarcation visualized by the Shh expression pattern in the jaw primordia of the house shrew probably represents the basic developmental pattern of mammalian heterodont dentition.