Atsuta F, Sato K, Maruyama K, Shimada Y
Department of Anatomy and Cell Biology, School of Medicine, Chiba University, Japan.
J Muscle Res Cell Motil. 1993 Oct;14(5):511-7. doi: 10.1007/BF00297213.
The distribution of connectin (titin), nebulin and alpha-actinin in the areas of myotendinous junctions of chicken pectoralis muscles was examined by immunocytochemical methods. Staining with antibodies against connectin (4C9, SM1 and P1200) and nebulin formed 'doublets' flanking nonterminal Z-bands; near the end of muscle fibres 'singlets' were seen within the terminal sarcomere on the side adjacent to the terminal Z-bands. The apical regions of muscle processes, where no myosin filaments are present although actin filaments exist, were reactive with anti-nebulin but not with anti-connectin. Antibodies against pectoralis (skeletal muscle type) alpha-actinin stained non terminal Z-bands and that against gizzard (smooth muscle type) the sarcolemma. Terminal Z-bands were unreactive with both of these antibodies. These findings indicate that, although terminal and nonterminal Z-bands differ in their molecular composition, connectin and nebulin filaments appear to link myosin and actin filaments, respectively, to both Z-band types.
采用免疫细胞化学方法检测了连接蛋白（肌联蛋白）、伴肌动蛋白和α-辅肌动蛋白在鸡胸大肌肌腱连接区域的分布情况。用抗连接蛋白（4C9、SM1和P1200）和伴肌动蛋白的抗体染色，在非终末Z线两侧形成“双条带”；在肌纤维末端附近，在与终末Z线相邻一侧的终末肌节内可见“单条带”。肌突的顶端区域，虽然存在肌动蛋白丝但不存在肌球蛋白丝，与抗伴肌动蛋白抗体反应，但不与抗连接蛋白抗体反应。抗胸大肌（骨骼肌型）α-辅肌动蛋白抗体染色非终末Z线，抗砂囊（平滑肌型）α-辅肌动蛋白抗体染色肌膜。终末Z线与这两种抗体均无反应。这些发现表明，尽管终末和非终末Z线的分子组成不同，但连接蛋白丝和伴肌动蛋白丝似乎分别将肌球蛋白丝和肌动蛋白丝与两种类型的Z线相连。
