Gupta M P, Wiesner R J, Mouly V, Zak R, Lemonnier M
Department of Medicine, University of Chicago, IL 60637.
J Muscle Res Cell Motil. 1993 Aug;14(4):377-84. doi: 10.1007/BF00121288.
The expression of the alpha fast (alpha f) and beta tropomyosin (TM) genes has been analysed with muscle-specific and common cDNA probes after unilateral nerve section of the pectoralis major muscle (PM) in 4-week-old chickens. The following were observed in denervated muscles. (1) The beta TM mRNA, which was repressed during development, reaccumulates in a biphasic curve with the increase in the beta TM protein lagging behind the changes in its mRNA. Accordingly, no beta TM is seen in products translated in vitro from total and polyA+ RNA obtained 1 week after denervation. No such translation block is seen with RNA obtained from control or muscles denervated for 6 weeks. (2) No changes in the alpha fTM mRNA and corresponding protein are observed. (3) RNA processing of the two genes is not changed. (4) In the contralateral muscles, transitory increases in alpha f and beta TM mRNAs are observed while the corresponding proteins remain unchanged. Our data suggest that muscle fibres display early and long-term responses to the loss of neural input which might result from a combination of changes produced by regenerative processes and reprogramming of existing fibres. Moreover, in contrast to normal development, no reciprocal changes of alpha f and beta TM expression are seen in denervated muscles.
在4周龄鸡的胸大肌（PM）单侧神经切断后，使用肌肉特异性和通用cDNA探针分析了α快肌动蛋白（αf）和β原肌球蛋白（TM）基因的表达。在去神经支配的肌肉中观察到以下情况。（1）在发育过程中受到抑制的βTM mRNA，随着βTM蛋白的增加以双相曲线重新积累，其蛋白变化滞后于mRNA的变化。因此，在去神经支配1周后从总RNA和聚腺苷酸加尾RNA（polyA+ RNA）体外翻译的产物中未检测到βTM。从对照或去神经支配6周的肌肉中获得的RNA未观察到这种翻译阻滞现象。（2）未观察到αfTM mRNA和相应蛋白的变化。（3）两个基因的RNA加工未发生改变。（4）在对侧肌肉中，观察到αf和βTM mRNA短暂增加，而相应蛋白保持不变。我们的数据表明，肌纤维对神经输入丧失表现出早期和长期反应，这可能是由再生过程产生的变化和现有纤维的重新编程共同导致的。此外，与正常发育相反，在去神经支配的肌肉中未观察到αf和βTM表达的相互变化。
