MECHANISMS OF SALIVARY GLAND DEVELOPMENT

啮齿动物颌下腺(SMG)是研究颌下腺的良好系统。 几种分泌细胞类型对分泌上皮发育的影响 沿着共同的导管生长，腺体要到3：00才成熟 4个月大。此外，改变比例的可能性 这些导管分泌细胞的一部分在整个成年期都保留着。通过 利用特定的细胞类型标记，对各种细胞类型进行分化 可以通过开发恢复到原来的位置。未出现腺泡细胞(AC) 直到出生后3天，粘蛋白的免疫定量研究，一种AC 标记，表明在出生前的动物体内存在粘蛋白。 交流的外观。粘蛋白的积累模式是一个双相的。 自然，表明AC在之前经历了原分化阶段 到细胞分化。敏感的蛋白质合成分析将是 用来验证粘蛋白合成是否发生在这一阶段。 表皮生长因子的免疫定量和蛋白质合成研究 (EGF)将同样决定颗粒曲管细胞(GCT) 通思进入了原始分化阶段。产前和成体的克隆 将执行SMG以确定GCT和AC是否共用一个主干 细胞在发育过程中，并用于成人的细胞替换。这一链接 分化和细胞替代之间的关系将进一步通过 通过细胞分选和检测分离纯GCT和纯AC群体 看看每种分化的细胞类型是否保留了原分化的细胞 另一方的能力。 最近的研究表明，粘蛋白存在于颗粒中。 成年女性腺体的间质导管细胞(GID)。也许这些细胞 是交流更换过程中的中间人。通过利用成果 从分泌单位的三维重建和DNA标记，以及 应说明是否有条纹分泌物 小管细胞(SST)和GID分别是GCT和AC的中间产物， 在更换过程中。这些观察也可能提供证据 用于成人体内的多能性干细胞，或者相反，用于个体 每种分泌细胞类型的祖细胞系。 最终，我们将确定分泌细胞处于什么阶段 颌下腺和颌下腺的发育顺序不同 以确定负责的基因控制水平。

The rodent submandibular gland (SMG) poses an excellent system to study the development of secretory epithelium because several secretory cell types arise along a common duct and the gland does not reach maturity until 3 to 4 months of age. Furthermore, the potential for changing the proportions of these ductal secretory cells is retained throughout adulthood. By utilizing specific cell type marker, differentiation of various cell types can be racked back through development. Acinar cells (AC) do not appear until 3 days after birth, yet immunoquantitation studies of mucin, an AC marker, indicate that mucin is present in prenatal animals, prior to the appearance of AC. The pattern of accumulation for mucin is a biphasic nature, indication that AC pass through a protodifferentiated stage prior to cytodifferentiation. Sensitive protein synthesis assays will be performed to verify that mucin synthesis occurs during this stage. Immunoquantitation and protein synthesis studies on epidermal growth factor (EGF) will determine if granular convoluted tubule cells (GCT) likewise pass thought a protodifferentiated stage. Cloning of prenatal and adult SMG will be performed determine whether GCT and AC share a common stem cell during development and for cell replacement in adults. The link between differentiation and cell replacement will be pursued further by isolating pure GCT and pure Ac populations by cell sorting and then testing to see if each differentiated cell type retains the protodifferentiated capability for the other. Recent studies have shown that mucin is present in the granular intercalated duct cell (GID) from adult female glands. Perhaps these cells are an intermediate in the AC replacement process. By utilizing results from 3-D reconstructions and DNA labelling of secretory units, an indication should be provided as to whether or not striated secretory tubule cells (SST) and GID are intermediates of GCT and AC, respectively, in the replacement process. These observations may also provide evidence for a pleuripotent stem cell in adults or conversely, for individual progenitor cell lines for each secretory cell type. Ultimately, we are tying to determine at what stage secretory cell divergence occurs in the sequence of development of submandibular gland and to identify the level of gene control that is responsible.