Molecular mechnisms of cell fusion during myogenic differentiation

成肌分化过程中细胞融合的分子机制

• 批准号: 08680755
• 负责人: ENDO Takeshi
• 金额: $ 1.6万
• 依托单位: Chiba University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08680755/
• 关键词: muscle cell differentiation; cell fusion; fusion peptide; membrane protein; ADAM family; small GTPase; actin cytoskeleton; Rho; Ras; アクチン線維再構成

The cell fusion during skeletal muscle cell differentiation is considered to be induced by certain protein (s) with the fusion peptide. Intracellular signal transduction generated by this protein might regulate the cell fusion or some cellular events following the cell fusion. To elucidate the signal transduction pathway for cell fusion, we addressed the following three studies. (1) We examined the localization of the novel membrane protein ermelin, which contains a sequence homologous to the fusion peptide. Immunofluorescence microscopy in combination with epitope tagging and with an antibody to ermelin exhibited that the protein is present in the endoplasmic reticulum (ER). Immunoelectron microscopy located ermelin on the ER membrane. We are studying whether ermelin is involved in fusion of the ER membrane. (2) Meltrin alpha, which is reported to be participating in muscle cell fusion, contains in its cytoplasmic domain the consensus sequences for binding to the SH3 domain. The bindi … More nig experiments with bacterially expressed recombinant proteins and bovine brain extracts showed that the SH3 domains of Src, Yes, and Grb2 bound to the meltrin alpha cytoplasmic domain. Consequently, meltrin alpha is likely to be involved in some signal transduction for myogenic differentiation through the interaction with these proteins. (3) The novel small GTPases M-Ras and RhoD were cloned during investigation of the signal transduction for muscle cell fusion. We examined the cellularfunctions of M-Ras and RhoD by transfection of the cDNAs and microinjection of the recombinant proteins. M- Ras caused reorganization of the actin cytoskeleton including the microspike fromation and loss of the stress fibers. It induced dendritic cell morphology in fibroblasts and neurite outgrowth in PC12 cells. RhoD induced loss of the stress fibers and inhibited cell motility. It generated multinucleated cells by preventing cytokinesis. We are examining whether these GTPases are implicated in the signal transduction for cell fusion. Less

骨骼肌细胞分化过程中的细胞融合被认为是由某一种蛋白质(S)与融合多肽共同诱导的。该蛋白产生的细胞内信号转导可能调节细胞融合或细胞融合后的某些细胞事件。为了阐明细胞融合的信号转导途径，我们进行了以下三项研究。(1)我们检测了新的膜蛋白Ermelin的定位，该蛋白含有一个与融合肽同源的序列。免疫荧光显微镜结合表位标记和Ermelin抗体显示该蛋白存在于内质网(ER)中。免疫电子显微镜显示Ermelin位于内质网细胞膜上。我们正在研究Ermelin是否参与了ER膜的融合。(2)据报道参与肌肉细胞融合的Meltrinα在其胞浆结构域中包含与SH3结构域结合的共同序列。The Bindi…用细菌表达的重组蛋白和牛脑提取物进行的更多NIG实验表明，Src、Yes和Grb2的SH3结构域与Meltrinα细胞质结构域结合。因此，Meltrinα很可能通过与这些蛋白的相互作用而参与肌源性分化的一些信号转导。(3)在研究肌细胞融合的信号转导过程中，克隆了新的小分子GTP酶M-Ras和Rhod。通过基因转染法和显微注射法检测M-RAS和Rhod的细胞功能。M-RAS引起肌动蛋白细胞骨架的重组，包括微刺的形成和应力纤维的丢失。诱导成纤维细胞中的树突状细胞形态和PC12细胞中的突起生长。Rhod诱导应激纤维丢失，抑制细胞运动。它通过阻止胞质分裂产生多核细胞。我们正在研究这些GTP酶是否与细胞融合的信号转导有关。较少

项目成果

T.Endo: "Temporal and spatial expression of distinct troponin T genes in embryonic/larval tail striated muscle and adult body wall smooth muscle of ascidian." Cell Struct.Funct.22(in press). (1997)

T.Endo：“海鞘胚胎/幼虫尾部横纹肌和成体体壁平滑肌中不同肌钙蛋白 T 基因的时间和空间表达。”

Okuyama, Y., Sowa, Y., Fujita, T., Mizuno, T., Nomura, H., Nikaido, T., Endo, T., and Sakai, T.: "ATF site of human RB gene promoter is a responsive element of myogenic differentiation." FEBS Lett.397 (2/3). 219-224 (1996)

Okuyama, Y.、Sowa, Y.、Fujita, T.、Mizuno, T.、Nomura, H.、Nikaido, T.、Endo, T. 和 Sakai, T.：“人 RB 基因启动子的 ATF 位点是

Y.Okuyama: "ATF site of human RB gene promoter is a responsive element of myogenic differentiation." FEBS Lett.397. 219-224 (1996)

Y.Okuyama：“人类 RB 基因启动子的 ATF 位点是生肌分化的响应元件。”

K.Fukami: "Identification of aphosphatidylinositol 4,5-bisphosphate-binding site in chicken skeletal muscle α-actinin." J.Biol.Chem.271(5). 2646-2650 (1996)

K.Fukami：“鸡骨骼肌 α-肌动蛋白中磷脂酰肌醇 4,5-二磷酸结合位点的鉴定。J.Biol.Chem.271(5) (1996)。

Y.Okuyama: "ATF site of human RB gene promoter is a responsive element of myogenic differentiation." FEBS Lett.397(2/3). 219-224 (1996)

Y.Okuyama：“人类 RB 基因启动子的 ATF 位点是生肌分化的响应元件。”