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

摘要: Previous analysis of the muscle creatine kinase (MCK) gene indicated that control elements required for transcription in adult mouse differed from those cell culture, suggesting distinct modes regulation occur vivo. To examine this further, we measured activity MCK transgenes containing E-box and promoter deletions a variety striated muscles. Simultaneous mutation three E boxes 1,256-bp 5' region, which abolished cultures, had strikingly different effects mice. The mutations transgene expression cardiac tongue caused reduction soleus (a with many slow fibers) but did not affect predominantly fast muscles: quadriceps, abdominals, extensor digitorum longus. Other regulatory sequences muscle-type-specific activities were found within 358-bp 5'-flanking region. This proximal region conferred relatively strong limb abdominal skeletal muscles was inactive However, when 206-bp enhancer ligated to high levels tissue-specific restored all types. These results indicate are differentially maximal overall also imply muscles, steady-state possibly other genes depends on transcriptional mechanisms differ between fibers as well anatomical physiological attributes each specific muscle.