E-box sites and a proximal regulatory region of the muscle creatine kinase gene differentially regulate expression in diverse skeletal muscles and cardiac muscle of transgenic mice.
E-box sites and a proximal regulatory region of the muscle creatine kinase gene differentially regulate expression in diverse skeletal muscles and cardiac muscle of transgenic mice.
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肌肉肌酸激酶基因的E-box位点和近端调节区差异调节转基因小鼠不同骨骼肌和心肌中的表达。
DOI：
10.1128/mcb.16.9.5058
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发表时间：
1996
影响因子：
5.3
通讯作者：
Hauschka,SD
中科院分区：
文献类型：
--
作者：
Shield,MA;Haugen,HS;Clegg,CH;Hauschka,SD
以前的肌肉肌酸激酶（MCK）基因的分析表明，在成年小鼠肌肉转录所需的控制元件不同于细胞培养所需的，这表明不同的肌肉基因调控模式发生在体内。为了进一步研究这一点，我们测量了MCK转基因的活性含有E-box和启动子缺失在各种横纹肌。在1，256-bp MCK 5′区同时突变三个E盒，在肌肉培养物中消除转录，在小鼠中产生显著不同的效果。这些突变消除了心肌和舌肌中的转基因表达，并导致比目鱼肌（一种具有许多慢纤维的肌肉）中的表达减少，但不影响主要是快肌的表达：四头肌，腹肌和趾长伸肌。在358 bp的5′侧翼区发现了其他具有肌肉类型特异性活性的调控序列。该近端区域在肢体和腹部骨骼肌中表达相对较强，但在心肌和舌肌中不活跃。然而，当206-bp的5′端增强子连接到358-bp区域时，在所有肌肉类型中恢复了高水平的组织特异性表达。这些结果表明，E盒和近端调控区的差异需要最大的MCK转基因表达在不同的横纹肌。总体结果还意味着，在骨骼肌内，MCK基因和可能的其他肌肉基因的稳态表达取决于转录机制，该机制在快纤维和慢纤维之间以及在每个特定肌肉的解剖和生理属性之间存在差异。
Previous analysis of the muscle creatine kinase (MCK) gene indicated that control elements required for transcription in adult mouse muscle differed from those required in cell culture, suggesting that distinct modes of muscle gene regulation occur in vivo. To examine this further, we measured the activity of MCK transgenes containing E-box and promoter deletions in a variety of striated muscles. Simultaneous mutation of three E boxes in the 1,256-bp MCK 5′ region, which abolished transcription in muscle cultures, had strikingly different effects in mice. The mutations abolished transgene expression in cardiac and tongue muscle and caused a reduction in expression in the soleus muscle (a muscle with many slow fibers) but did not affect expression in predominantly fast muscles: quadriceps, abdominals, and extensor digitorum longus. Other regulatory sequences with muscle-type-specific activities were found within the 358-bp 5′-flanking region. This proximal region conferred relatively strong expression in limb and abdominal skeletal muscles but was inactive in cardiac and tongue muscles. However, when the 206-bp 5′ enhancer was ligated to the 358-bp region, high levels of tissue-specific expression were restored in all muscle types. These results indicate that E boxes and a proximal regulatory region are differentially required for maximal MCK transgene expression in different striated muscles. The overall results also imply that within skeletal muscles, the steady-state expression of the MCK gene and possibly other muscle genes depends on transcriptional mechanisms that differ between fast and slow fibers as well as between the anatomical and physiological attributes of each specific muscle.