GENE EXPRESSION IN OLD AND/OR DENERVATED MUSCLE

本项目旨在验证我们的假设，即EF的姐妹基因S1- 1 α，作为一个候选的“维持基因”，以维持 肌管的长寿命和终末分化状态 肌肉. 在肌肉发育过程中，S1表达被激活， 伴随EF-1 α蛋白水平下降，而不是信息水平下降， 提示转录后抑制EF的调节， 1 α丰度，并导致EF-1 α比率从高 到低 低EF-1 α/S1比值在成人肌肉中持续存在， 马卡因引起的损伤，长期去神经支配，或 极端高龄 我们还发现，S1稳定转染S1- 阴性小鼠成纤维细胞诱导内源性EF-抑制 1阿尔法。 计划中的实验是为了验证我们的工作假设， 在肌管中，S1可能起着“调光开关”的作用，抑制EF。 1 α活性通过翻译降低其蛋白丰度 抑制和/或快速蛋白质周转。 这种抑制作用 可能使EF-1 α不仅在其传统功能方面受到限制， 蛋白质翻译，但也有其他已知的功能，如参与 在信号传导中，切断微管，或捆绑肌动蛋白 所有这些都可以导致建立均匀的档位范围 有利于成熟肌肉的长期非凋亡状态。 的 制定的具体目标是：1.为了测试转录后是否 抑制成年肌肉中EF-1 α蛋白水平， 发育和S1基因表达依赖性; 2.以确定 转录后抑制EF的调节模式- 1 α蛋白水平; 3.为了研究S1基因的表达是如何影响 与EF-1 α蛋白丰度的抑制有关， 鉴定负责推定顺式元件和反式因子; 4. 在培养物中测试肌纤维萎缩是由于 肌管凋亡与卫星细胞复制性衰老 人口; 5. 来检验从低到高的变化 EF-1 α/S1比值参与了细胞死亡的激活。 肌管;和6. 调查监管机制 控制EF-1 α/S1比值从低到高的变化， 损伤、长期去神经支配和衰老。 研究机制 调节EF-1 α/S1比值将最终允许设计 控制或减缓肌肉退化的分子操作， 大多数老年人都有这种情况。

This project aims to test our hypothesis that S1, a sister gene of EF- 1alpha, functions as a candidate "maintenance gene" to maintain the long-lived and terminally differentiated state for myotubes in mature muscle. During development in muscle, S1 expression is activated with a concomitant decline in EF-1alpha protein, but not message, level, suggesting a posttranscriptional suppression of the regulation of EF- 1alpha abundance, and resulting a shift in EF-1alpha ratio from high to low. The low EF-1alpha/S1 ratio persists in adult muscle except in the cases of marcaine-induced injury, long-term denervation, or extreme old age. We also found that stable transfection of S1 into S1- negative mouse fibroblasts induces suppression of endogenous EF- 1alpha. Experiments planned are to test our working hypothesis that in myotubes, S1 may function as a "dimmer switch", dampening EF- 1alpha activity by reducing its protein abundance via translational suppression and/or rapid protein turnover. This dampening action may leave EF-1alpha restrained in not only its traditional function in protein translation, but also other known functions such as involvement in signal transduction, severing microtubles, or bundling actin filaments, all of which may result in establishing an even gear range favorable to the long-term nonapoptotic state in mature muscle. The specific aims formulated are: 1. To test whether posttranscriptional suppression of EF-1alpha protein level in adult muscle is developmentally-and S1 gene expression-dependent; 2. To determine the regulatory mode for the posttranscriptional suppression of EF- 1alpha protein level; 3. To investigate how S1 gene expression is related to this suppression of EF-1alpha protein abundance, and to identify responsible putative cis-element(s) and trans-factor(s); 4. Testing, in cultures, the hypothesis that muscle fibers' atrophy is due to myotube apoptosis and replicative senescence of the satellite cell population; 5. to test the hypothesis that a change from low to high EF-1alpha/S1 ratio is involved in the activation of death in cultured myotubes; and 6. To investigate the regulatory mechanism(s) governing the shift of EF-1alpha/S1 ratio from low to high during injury, long-term denervation, and aging. Studying the mechanism(s) regulating the EF-1alpha/S1 ratio will ultimately allow the design of molecular manipulation to control or slow down muscle degeneration, a condition plaguing most of the elderly.