MYOSIN HEAVY-CHAIN EXPRESSION WITHIN THE TAPERED ENDS OF SKELETAL-MUSCLE FIBERS
MYOSIN HEAVY-CHAIN EXPRESSION WITHIN THE TAPERED ENDS OF SKELETAL-MUSCLE FIBERS
复制标题
DOI：
10.1002/ar.1092420404
复制
发表时间：
1995-08-01
影响因子：
--
通讯作者：
BANDMAN, E
中科院分区：
文献类型：
--
作者：
ROSSER, BWC;WALDBILLIG, DM;BANDMAN, E
背景资料：鸡的胸肌含有快速收缩糖酵解纤维，其在发育期间经历其肌球蛋白重链（MyHC）含量从胚胎到新生儿到成年同种型的转化（Bandman等人，1990年）。然而，我们对这些或其他肌纤维末端的MyHC表达知之甚少，在这里我们检验了这样一个假设，即成熟骨骼肌纤维的锥形末端含有比通常在其整个长度中发现的较不成熟的MyHC同种型。方法：我们应用氨性银组织学染色和抗新生和成年鸡胸肌MyHCs的单克隆抗体，来自五只成熟鸡的胸肌。结果：大部分（约81.8%）的小直径（20 μ m）纤维含有新生的MyHC，通过连续切片观察这些小纤维，我们发现它们是大纤维的锥形末端。新生儿MyHC仅限于锥形纤维末端，而成人MyHC存在于所有纤维的整个长度，我们还证明了乙酰胆碱酯酶（AChE）活性在这些纤维末端的一些。我们推测，成人肌肉中肌原纤维的纵向生长的特征是与快速生长的肌肉中观察到的类似的MyHC亚型的顺序表达，并且神经递质的存在在锥形纤维末端的AChE水解酶可能与新生儿MyHC的保留有关。(C)1995年Wiley-Liss，Inc.
Background: The pectoralis muscle of the chicken contains fast-twitch glycolytic fibers, which during development undergo a transformation in their myosin heavy chain (MyHC) content from embryonic to a neonatal to an adult isoform (Bandman et al., 1990). Little, however, is known of MyHC expression within the ends of these or other muscle fibers, Here we test the hypothesis that the tapered ends of mature skeletal muscle fibers contain a less mature MyHC isoform than that typically found throughout their lengths.Methods: We apply an ammoniacal silver histological stain for endomysium and monoclonal antibodies against neonatal and adult MyHCs of chicken pectoralis to transverse serial sections of pectoralis from five mature chickens. The ''lesser fiber diameters'' of populations of fibers from each bird are also measured.Results: Most (similar to 81.8%) of the small (20 pm) diameter fibers contain the neonatal MyHC, Following these smaller fibers through serial sections, we show that they are the tapered ends of the larger fibers. Whereas neonatal MyHC is restricted to the tapered fiber ends, adult MyHC is present throughout the entire lengths of all fibers, We also demonstrate acetylcholinesterase (AChE) activity at some of these fiber ends.Conclusions: We postulate that longitudinal growth of myofibrils in adult muscle is characterized by the sequential expression of MyHC isoforms similar to that observed in rapidly growing muscle and that the presence of the neurotransmitter hydrolase AChE at the tapered fiber ends may be related to the retention of neonatal MyHC. (C) 1995 Wiley-Liss, Inc.