Cardiac myofibrillogenesis inside intact embryonic hearts
Cardiac myofibrillogenesis inside intact embryonic hearts
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DOI：
10.1016/j.ydbio.2008.03.011
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发表时间：
2008-06-15
影响因子：
2.7
通讯作者：
Sanger, Joseph W.
中科院分区：
文献类型：
--
作者：
Du, Aiping;Sanger, Jean M.;Sanger, Joseph W.
蛋白质如何组装成肌节阵列以形成肌原纤维是有争议的。对来自 10 天禽胚胎的心肌细胞培养物进行免疫染色和转染，我们提出组装分三个阶段进行，首先是前肌原纤维的形成，然后是新生肌原纤维，最后形成成熟的肌原纤维。然而，在形成的禽类心脏中原位检查的早期心肌细胞中尚未检测到前肌原纤维和新生肌原纤维阵列，这表明肌原纤维发生的机制在培养和未培养的细胞中是不同的。为了解决原位肌原纤维生成的问题，我们应用非酶程序和反卷积成像技术在 2 至 13 体节阶段（搏动从 9 体节阶段开始）原位检查早期心脏形成区域，时间跨度约为 23 小时。这些方法使我们能够检测发育中心脏的三个肌原纤维阶段，支持心肌细胞中肌原纤维发生的三步模型，无论它们存在于原位、器官培养物还是组织培养物中。我们还发现，在肌动蛋白组织之前，第一根肌肉肌球蛋白丝的长度约为成熟 A 带中存在的 1.6 μm 丝的长度的一半。这支持了肌联蛋白可能在肌球蛋白丝的长度测定中发挥作用的提议。 (C) 2008 Elsevier Inc. 保留所有权利。
How proteins assemble into sarcomeric arrays to form myofibrils is controversial. Immunostaining and transfections of cultures of cardiomyocytes from 10-day avian embryos led us to propose that assembly proceeded in three stages beginning with the formation of premyofibrils followed by nascent myrofibrils and culminating in mature myofibrils. However, premyofibril and nascent myofibril arrays have not been detected in early cardiomyocytes examined in situ in the forming avian heart suggesting that the mechanism for myofibrillogenesis differs in cultured and uncultured cells. To address this question of in situ myofibrillogenesis, we applied non-enzymatic procedures and deconvolution imaging techniques to examine early heart forming regions in situ at 2- to 13-somite stages (beating begins at the 9-somite stage), a time span of about 23 h. These approaches enabled us to detect the three myofibril stages in developing hearts supporting a three-step model of myofibrillogenesis in cardiomyocytes, whether they are present in situ, in organ cultures or in tissue culture. We have also discovered that before titin is organized the first muscle myosin filaments are about half the length of the 1.6 mu m filaments present in mature A-bands. This supports the proposal that titin may play a role in length determination of myosin filaments. (C) 2008 Elsevier Inc. All rights reserved.