Het1基因在肌肉再生中的作用

发布时间：2018-11-19 08:20

【摘要】：HET1是Dbl蛋白结构域家族的一类鸟苷酸交换因子,它能够调节Rho家族的G蛋白与GDP或GTP的结合状态。当G蛋白与GTP连接,其GTPase活性激活,其下游效应蛋白被激活,传递细胞信号；当G蛋白与GDP结合时,其GTPase失活,则不发挥作用。HET1对Rac1、 Cdc42和RhoA结合GTP状态和GDP结合状态之间的转换,具有重要调控作用。HET1在脑、心脏、肌肉等兴奋组织中广泛并高表达,它能通过对小G蛋白的激活调控,进而影响细胞形状、分裂、迁移,细胞极性和细胞粘连。以往的研究表明,肌肉损伤后HET1表达上调,并且利用腺病毒外源性过表达HETl能加快肌肉损伤的修复,并且Racl,Cdc42和RhoA GTPase激活。在体外C2C12细胞系中,HET1能促使C2C12向肌细胞分化,并抑制其向脂肪细胞分化。尽管如此,由于体内基因敲除小鼠模型的缺乏,Het1在体内肌肉再生和分化中的功能仍不清楚,我们首次建立了Hetlf1/fl小鼠,使之与EII-Cre转基因小鼠杂交,得到HET1全敲小鼠,PCR与Southern的结果都显示,HET1全敲小鼠中基因片段的剔除。但是全敲小鼠与野生型小鼠的生活状况无明显差异,而且心、肌肉、胃和肠的组织切片对比,观察发现两者无明显区别。我们利用注射心脏毒素(CTX)成功诱导了一个肌肉损伤和修复的模型。我们向小鼠骨骼肌注射50μ1的10μg/ml的心脏毒,通过检测c-myc、MyoD和myogenin因子发现,在注射CTX5天后,肌肉卫星细胞增殖和向肌细胞分化达到顶峰。而且我们通过对全敲小鼠和野生型小鼠分别注射心脏毒素5天,10天后,取肌肉损伤部位进行组织切片对比,观察发现HET1全基因敲除鼠,肌肉损伤恢复状况较野生型小鼠明显延迟。我们的结果首次在体内证明,HET1在调节肌肉损伤修复中的重要作用。
[Abstract]:HET1 is a kind of guanosine exchange factor of Dbl domain family. It can regulate the binding of G protein of Rho family to GDP or GTP. When G protein is connected with GTP, its GTPase activity is activated, and its downstream effector protein is activated, transmitting cell signal. When G protein binds to GDP, its GTPase inactivation does not play a role. HET1 plays an important role in regulating the transition between Rac1, Cdc42 and RhoA binding GTP states and GDP binding states. HET1 is widely and overexpressed in brain, heart, muscle and other excitatory tissues. It can affect cell shape, division, migration, cell polarity and cell adhesion by regulating the activation of small G protein. Previous studies have shown that the expression of HET1 is up-regulated after muscle injury, and that exogenous overexpression of HETl by adenovirus can accelerate the repair of muscle injury and the activation of Racl,Cdc42 and RhoA GTPase. In vitro C2C12 cell line, HET1 could induce C2C12 to differentiate into myocytes and inhibit its differentiation into adipocytes. However, due to the lack of gene knockout mice in vivo, the function of Het1 in muscle regeneration and differentiation in vivo is still unclear. We established Hetlf1/fl mice for the first time and hybridized them with EII-Cre transgenic mice to obtain HET1 knockout mice. The results of PCR and Southern showed that the gene fragments of HET1 knockout mice were eliminated. However, there was no significant difference in the living conditions between the total knockout mice and the wild type mice, and there was no obvious difference between the two groups by comparing the tissue sections of heart, muscle, stomach and intestine. We successfully induced a model of muscle damage and repair by injection of cardiac toxin (CTX). We injected 50 渭 1 10 渭 g/ml cardiac toxin into the skeletal muscle of mice. By detecting c-mycine MyoD and myogenin factors, we found that the proliferation and differentiation of muscle satellite cells reached its peak after CTX5 injection. After 5 days and 10 days of cardiotoxin injection into the whole knockout mice and the wild type mice, the muscle injury sites were taken and compared with each other. We observed and found that the whole gene knockout mice of HET1 were removed. The recovery of muscle injury was significantly delayed than that of wild-type mice. Our results demonstrate for the first time in vivo that HET1 plays an important role in regulating the repair of muscle injury.
【学位授予单位】：湖南师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R394

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