SALIVARY MUCIN SYNTHESIS, PROCESSING, AND SECRETION

该提案的一个关键目的是在体内标准化和描述 小鼠颌下腺粘蛋白的刺激-分泌-合成周期。 该系统旨在提供对控制和合成的深入了解 负责外分泌昼夜补充的过程 唾液腺中的蛋白质 据推测，通过澄清 正常的事件流程，将有可能开始了解一些 唾液腺功能障碍的形式。 描述了用于获得 在不同温度下，粘蛋白核心蛋白的合成和降解速率 循环的阶段。 粘蛋白寡糖组装的速率和顺序 也将得到确认。 一项战略，确定 激活的合成阶段进行了描述和可能的协调 将测试翻译和糖基化过程之间的关系。 最终 项目这一部分的第一阶段将审查 不同的刺激。 我们将把我们最近对年轻到中年的衰老小鼠的研究扩展到衰老小鼠。 表明粘蛋白寡糖组成稳定的小鼠 慢性异丙肾上腺素治疗。 本阶段研究的目的是 是为了确定粘蛋白的碳水化合物组成是否在老年人中变化更大， 如果异丙肾上腺素治疗可以减少这种情况， 变化量 慢性毛果芸香碱治疗的效果将在 相同的年龄组。 不同促分泌素与粘蛋白关系的研究 唾液中的浓度将在小鼠中重复和延长 种群中固有的变异已大大减少。 已采取步骤提供这一人口和其他办法 正在接受调查 在之前的研究中， 刺激后观察唾液中粘蛋白浓度的范围 相同剂量的毛果芸香碱在不同动物的分泌中的作用 常规实验室人群。 我们计划比较不同的 剂量，但不能预测成功，除非固有的变化减少。 最后，我们提出的证据表明，粘蛋白经历了一个 分泌时的寡糖加工步骤。 两个协议将对此进行测试 可能性 如果处理得到确认，我们将确定哪一类 寡糖受到影响，这如何影响细胞内唾液酸 以及相关的机制。

A key purpose of this proposal is to standardize and describe in vivo the stimulus-secretion-synthesis cycle of a mouse submandibular gland mucin. This system is intended to provide insight into the control and synthesis processes which are responsible for the diurnal replenishment of exocrine proteins in the salivary glands. It is postulated that by clarifying the normal flow of events, it will be possible to begin to understand some forms of salivary gland dysfunction. Protocols are described for obtaining rates of synthesis and degradation of the mucin core protein at different stages of the cycle. Rates and sequence of mucin oligosaccharide assembly will also be ascertained. A strategy for identifying the mechanism for activation of the synthesis phase is described and possible coordination between translation and glycosylation processes will be tested. The final phase of this part of the project will be to examine the effects of different stimuli on the cycle. We will extend to senescent mice our recent study with young to mid-adult mice which indicated that mucin oligosaccharide composition was stabilized by chronic isoproterenol treatment. The intent of this phase of the study is to determine if the carbohydrate composition of mucin varies more in old mice than in young and if isoproterenol treatment can reduce this variation. The effects of chronic pilocarpine treatment will be tested in the same age groups. A study of the relationship of different secretagogues to mucin concentrations in saliva will be repeated and extended in a mouse population in which inherent variation has been reduced substantially. Steps have been taken to provide this population and additional approaches are under investigation. In the previous study, a greater than 60-fold range of mucin concentrations in saliva was observed following stimulation of secretion with the same dosage of pilocarpine in different animals of a regular laboratory population. We plan to compare effects of different dosages but do not predict success unless the inherent variation is reduced. Finally, we present evidence suggesting that mucin undergoes an oligosaccharide processing step at secretion. Two protocols will test this possibility. If processing is confirmed, we will determine which class of oligosaccharides is affected, how this impacts intracellular sialic acid and the mechanisms involved.