SONIC HEDGEHOG AND TOOTH DEVELOPMENT

描述：这个新的RO 3应用程序建议测试假设， 声刺猬（Shh）是一种重要形态发生蛋白，在牙齿发育中起着重要作用 发展，并可能作为一个早期信号分子和调节器， 细胞分化事件。 嘘是果蝇的脊椎动物同源物 片段极性基因hedgehog及其在早期模式形成和 鸡和小鼠发育过程中的形态发生事件， 广泛研究。 该实验室和其他实验室最近的报告显示， 描述了Shh在牙形成过程中的出现。 Shh mRNA出现 早期在牙板的起始部位，然后持续在 活跃形态发生期间釉质结的区域。 在 细胞分化阶段，Shh基因表达仍然局限于年轻 牙尖部有分泌性成釉细胞。 初步数据显示， 实验室还显示，当第12.5天 胚胎下颌骨用抗N-末端的抗体处理， 嘘目标1将描述时间和空间模式并将其联系起来 使用基因特异性探针在mRNA和蛋白质水平上检测Shh表达 和针对N-和C-末端的同种型特异性多克隆抗体 Shh的片段将在首席研究员的 实验室 Aim 2将使用这些抗体制剂来阻断Shh 在下颌骨外植体和磨牙器官培养物中的活性，以确定 这种分子是牙齿发育所必需的。 目标3将决定 Shh的异位表达是否影响体外牙齿发育。 是 预测，这两个实验操作的Shh表达， 牙齿器官培养会导致异常的牙齿发生。 结果 这些调查应提供及时和重要的信息， 这种有效的信号蛋白在牙齿发育中的作用。

DESCRIPTION: This new RO3 application proposes to test the hypothesis that sonic hedgehog (Shh), an important morphogen, plays a key role in tooth development and may act as an early signaling molecule and a regulator of cytodifferentiation events. Shh is the vertebrate homolog of the Drosophila segment polarity gene, hedgehog, and its roles in early patterning and morphogenesis events during chick and mouse development have been extensively studied. Recent reports from this and other laboratories have described the appearance of Shh during odontogenesis. Shh mRNA appears early at the sites of initiation of dental lamina and then persists in the area of the enamel knot during active morphogenesis. At the cytodifferentiation stage, Shh gene expression remains restricted to young secretory ameloblasts at the cusp tip. Preliminary data from this laboratory also show an inhibition of tooth morphogenesis when day 12.5 embryonic mandibles are treated with antibodies against the N-terminal of Shh. Aim 1 will characterize and correlate the temporal and spatial patterns of Shh expression at both mRNA and protein levels using gene-specific probes and isoform-specific polyclonal antibodies to the N- and C-terminal fragments of Shh that will be generated in the principal investigator's laboratory. Aim 2 will use these antibody preparations to block Shh activity in mandibular explant and molar organ cultures to establish that the molecule is required for tooth development. Aim 3 will determine whether ectopic expression of Shh affects tooth development in vitro. It is predicted that both these experimental manipulations of Shh expression in tooth organ cultures should result in abnormal odontogenesis. Results of these investigations should provide timely and significant information on the role of this potent signaling protein in tooth development.