【摘要】：HET1是Dbl蛋白結(jié)構(gòu)域家族的一類鳥苷酸交換因子,它能夠調(diào)節(jié)Rho家族的G蛋白與GDP或GTP的結(jié)合狀態(tài)。當(dāng)G蛋白與GTP連接,其GTPase活性激活,其下游效應(yīng)蛋白被激活,傳遞細(xì)胞信號；當(dāng)G蛋白與GDP結(jié)合時,其GTPase失活,則不發(fā)揮作用。HET1對Rac1、 Cdc42和RhoA結(jié)合GTP狀態(tài)和GDP結(jié)合狀態(tài)之間的轉(zhuǎn)換,具有重要調(diào)控作用。HET1在腦、心臟、肌肉等興奮組織中廣泛并高表達(dá),它能通過對小G蛋白的激活調(diào)控,進而影響細(xì)胞形狀、分裂、遷移,細(xì)胞極性和細(xì)胞粘連。以往的研究表明,肌肉損傷后HET1表達(dá)上調(diào),并且利用腺病毒外源性過表達(dá)HETl能加快肌肉損傷的修復(fù),并且Racl,Cdc42和RhoA GTPase激活。在體外C2C12細(xì)胞系中,HET1能促使C2C12向肌細(xì)胞分化,并抑制其向脂肪細(xì)胞分化。盡管如此,由于體內(nèi)基因敲除小鼠模型的缺乏,Het1在體內(nèi)肌肉再生和分化中的功能仍不清楚,我們首次建立了Hetlf1/fl小鼠,使之與EII-Cre轉(zhuǎn)基因小鼠雜交,得到HET1全敲小鼠,PCR與Southern的結(jié)果都顯示,HET1全敲小鼠中基因片段的剔除。但是全敲小鼠與野生型小鼠的生活狀況無明顯差異,而且心、肌肉、胃和腸的組織切片對比,觀察發(fā)現(xiàn)兩者無明顯區(qū)別。我們利用注射心臟毒素(CTX)成功誘導(dǎo)了一個肌肉損傷和修復(fù)的模型。我們向小鼠骨骼肌注射50μ1的10μg/ml的心臟毒,通過檢測c-myc、MyoD和myogenin因子發(fā)現(xiàn),在注射CTX5天后,肌肉衛(wèi)星細(xì)胞增殖和向肌細(xì)胞分化達(dá)到頂峰。而且我們通過對全敲小鼠和野生型小鼠分別注射心臟毒素5天,10天后,取肌肉損傷部位進行組織切片對比,觀察發(fā)現(xiàn)HET1全基因敲除鼠,肌肉損傷恢復(fù)狀況較野生型小鼠明顯延遲。我們的結(jié)果首次在體內(nèi)證明,HET1在調(diào)節(jié)肌肉損傷修復(fù)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.
【學(xué)位授予單位】：湖南師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：R394

【共引文獻】

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