Targeted deletion of the zebrafish obscurin A RhoGEF domain affects heart, skeletal muscle and brain development.
Targeted deletion of the zebrafish obscurin A RhoGEF domain affects heart, skeletal muscle and brain development.
复制标题
斑马鱼 obscurin A RhoGEF 结构域的靶向删除会影响心脏、骨骼肌和大脑发育。
DOI：
10.1016/j.ydbio.2009.11.018
复制
发表时间：
2010
影响因子：
2.7
通讯作者：
Russell,MarkW
中科院分区：
文献类型：
--
作者：
Raeker,MaideO;Bieniek,AshleyN;Ryan,AlisonS;Tsai,Huai-Jen;Zahn,KatelinM;Russell,MarkW
暗蛋白是一种巨大的结构和信号蛋白，参与横纹肌原纤维的组装和结构完整性。以前的工作已经研究了obscurin和其他细胞骨架元素之间的物理相互作用，但其在细胞信号转导中的体内作用，包括其RhoGTF交换因子（RhoGEF）结构域的功能尚未得到表征。在这项研究中，morpholino反义寡核苷酸被用来创建一个框内删除的obscurin A RhoGEF结构域的活性位点，以检查其在斑马鱼发育中的功能。在morphant胚胎心肌细胞缺乏闰盘，目前在控制72，在更严重的影响胚胎，收缩丝没有组织成成熟的肌节。神经异常包括视网膜分层延迟或缺失。通过共注射微小隐球蛋白A表达构建体来挽救表型证明，所观察到的效应是由于隐球蛋白A导致的小GT3活化的丧失。在morphant胚胎中观察到的心肌细胞和视网膜成神经细胞的未成熟表型表明，obscurin A介导的小GT3信号传导促进组织特异性细胞分化。这是第一次证明obscurin A介导的RhoGEF信号在脊椎动物器官发生中的重要性，并突出了obscurin A在横纹肌和神经发育中的核心作用。
Obscurin is a giant structural and signaling protein that participates in the assembly and structural integrity of striated myofibrils. Previous work has examined the physical interactions between obscurin and other cytoskeletal elements but its in vivo role in cell signaling, including the functions of its RhoGTPase Exchange Factor (RhoGEF) domain have not been characterized. In this study, morpholino antisense oligonucleotides were used to create an in-frame deletion of the active site of the obscurin A RhoGEF domain in order to examine its functions in zebrafish development. Cardiac myocytes in the morphant embryos lacked the intercalated disks that were present in controls by 72 and, in the more severely affected embryos, the contractile filaments were not organized into mature sarcomeres. Neural abnormalities included delay or loss of retinal lamination. Rescue of the phenotype with co-injection of mini-obscurin A expression constructs demonstrated that the observed effects were due to the loss of small GTPase activation by obscurin A. The immature phenotype of the cardiac myocytes and the retinal neuroblasts observed in the morphant embryos suggests that obscurin A-mediated small GTPase signaling promotes tissue-specific cellular differentiation. This is the first demonstration of the importance of the obscurin A-mediated RhoGEF signaling in vertebrate organogenesis and highlights the central role of obscurin A in striated muscle and neural development.