BACKGROUND The tetracycline-responsive system (Tet-ON/OFF) has proven to be a valuable tool for manipulating gene expression in an inducible, temporal, and tissue-specific manner. The purpose of this study was to create and characterize a new transgenic mouse strain utilizing the human skeletal muscle α-actin (HSA) promoter to drive skeletal muscle-specific expression of the reverse tetracycline transactivator (rtTA) gene which we have designated as the HSA-rtTA mouse. METHODS To confirm the HSA-rtTA mouse was capable of driving skeletal muscle-specific expression, we crossed the HSA-rtTA mouse with the tetracycline-responsive histone H2B-green fluorescent protein (H2B-GFP) transgenic mouse in order to label myonuclei. RESULTS Reverse transcription-PCR confirmed skeletal muscle-specific expression of rtTA mRNA, while single-fiber analysis showed highly effective GFP labeling of myonuclei in both fast- and slow-twitch skeletal muscles. Pax7 immunohistochemistry of skeletal muscle cross-sections revealed no appreciable GFP expression in satellite cells. CONCLUSIONS The HSA-rtTA transgenic mouse allows for robust, specific, and inducible gene expression across muscles of different fiber types. The HSA-rtTA mouse provides a powerful tool to manipulate gene expression in skeletal muscle.

中文翻译：

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一种用于骨骼肌特异性基因表达的新型四环素反应性转基因小鼠品系。

背景技术四环素响应系统（Tet-ON/OFF）已被证明是一种有价值的工具，用于以可诱导的、时间的和组织特异性的方式操纵基因表达。本研究的目的是创建和表征一种新的转基因小鼠品系，利用人类骨骼肌 α-肌动蛋白 (HSA) 启动子来驱动我们指定为 HSA 的反向四环素反式激活因子 (rtTA) 基因的骨骼肌特异性表达-rtTA 鼠标。方法 为了证实 HSA-rtTA 小鼠能够驱动骨骼肌特异性表达，我们将 HSA-rtTA 小鼠与四环素反应性组蛋白 H2B-绿色荧光蛋白 (H2B-GFP) 转基因小鼠杂交以标记肌核。结果 逆转录-PCR 证实了 rtTA mRNA 的骨骼肌特异性表达，而单纤维分析显示在快肌和慢肌骨骼肌中肌核的高效 GFP 标记。骨骼肌横截面的 Pax7 免疫组织化学显示卫星细胞中没有明显的 GFP 表达。结论 HSA-rtTA 转基因小鼠允许在不同纤维类型的肌肉中进行稳健、特异性和可诱导的基因表达。HSA-rtTA 鼠标提供了一个强大的工具来操纵骨骼肌中的基因表达。