HORMONAL CONTROL OF UTERINE MUSCLE K-CHANNEL MRNA

描述：(改编自《调查者摘要》) 拟议研究的长期目标是了解分子 子宫肌电活动的调控机制 以确定可能在管理中有用的分子靶点 不正常的分娩。雌激素对子宫肌层mRNA的明显诱导作用 导致电压依赖性钾的表达非常缓慢的物种 非洲爪哇卵母细胞中的电流已被证实。这是一种mRNA 物种在足月和动情前期可检测到，但在妊娠中期或 发情期。据推测，这种信使核糖核酸编码一种平滑的 在发情周期中表达水平变化的肌肉K+通道 以及怀孕取决于雌激素水平。增加的效果 慢激活K+电流的表达可能是通过增强细胞膜 通过将膜电位带入最佳范围来提高兴奋性 发电所必需的电压相关电流的运行 自发活动。建议的主要问题是 研究的内容是：变化的作用是什么，在表达中缓慢 激活钾电流在调节肌层兴奋性中的作用 用雌激素？首先，编码慢K通道的序列将是 下定决心。慢K+通道的全长cDNA克隆将是 从子宫cDNA库中分离并在非洲爪哇卵母细胞中表达。 其次，将研究这一基因物种的生理调节。 组织特异性和激素调节的mRNA物种表达 编码慢速K+通道将使用核酸来表征 杂交法。第三，信使核糖核酸调控对细胞周期的影响 将检测子宫肌层细胞中K+通道的数量。单人 钾通道将在急性分离的子宫平滑肌中进行研究 肌肉细胞使用贴片技术。最后，打压的效果 钾通道基因在电信号转导中的翻译 雌激素的特性将使用杂交抑制技术在 雌激素作用于体外培养的子宫肌层细胞。

DESCRIPTION: (Adapted from the Investigator's Abstract) The overall long-term objective of the proposed studies is to understand the molecular mechanisms which control electrical activity in uterine smooth muscle and to identify molecular targets which might be useful in the management of abnormal labor. The apparent induction by estrogen of a myometrial mRNA species which causes expression of a very slow voltage-dependent potassium current in Xenopus oocytes has previously been demonstrated. This mRNA species is detectable at term and proestrus but not at midgestation or metestrus. It was hypothesized that this mRNA species encodes a smooth muscle K+ channel whose level of expression varies during the estrous cycle and pregnancy depending upon estrogen levels. The effect of increasing expression of the slowly activating K+ current may be to enhance membrane excitability by bringing the membrane potential into an optimum range for the operation of voltage-dependent currents necessary for generating spontaneous activity. The main question to be addressed by the proposed studies is: What is the role of changes in the expression of the slowly activating potassium current in the regulation of myometrial excitability by estrogen? First, the sequence encoding the slow K channel will be determined. Full-length cDNA clones for the slow K+ channel will be isolated from a uterine cDNA library and expressed in xenopus oocytes. Second, the physiological regulation of this mRNA species will be studied. The tissue-specific and hormone-regulated expression of the mRNA species encoding the slow K+ channel will be characterized using nucleic acid hybridization methods. Third, the effect of the mRNA regulation on the numbers of K+ channels in the myometrial cells will be examined. Single potassium channels will be studied in acutely dissociated uterine smooth muscle cells using patch techniques. Finally, the effect of suppressing translation of the K channel mRNA on the transformation of electrical properties by estrogen will be examined using hybrid-arrest techniques in myometrial cells treated with estrogen in vitro.