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1、人胰島素樣生長因子I和II基因的克隆與表達(dá)摘要胰島素樣生長因子(insulin-likegrowthfactors,IGFs)是體內(nèi)重要的生長因子,其由兩種相關(guān)多肚組成:IGF-I和IGF-II。大量研究表明,它們對組織細(xì)胞的增殖、分化、凋亡,機體的生長發(fā)育及腫瘤的發(fā)生發(fā)展起重要的調(diào)節(jié)作用。為了獲得大量純度高的、具有生物學(xué)活性的人IGFs以滿足基礎(chǔ)研究與臨床應(yīng)用的需要,本文將hlGFs基因與pET系列原核表達(dá)載體進(jìn)行了重組,在大腸桿菌BL21中初步進(jìn)行了表達(dá)方面的實驗研究。I,以人胎盤組織為實驗材料,采用RT-PCR方法,獲得了包含CDS的hIGF-I和hIGF-II基因片段,分別連入克
2、隆載體pMD18-T中,測序結(jié)果分析表明擴增的片段均為目的基因。2各另外設(shè)計一對特異性PCR引物,導(dǎo)入適當(dāng)限制性內(nèi)切酶切點,以上述連有目的基因的克隆載體為模板,采用PCR方法擴增基因片段,獲得長度約230bp的IGF-I和219bp的IGF-II成熟膚基因序列。3.將hIGF-I與hIGF-II成熟膚基因進(jìn)行雙酶切后,分別連入原核表達(dá)載體pET-32a(+)和pET-30a(+)中,構(gòu)建原核表達(dá)重組質(zhì)粒pET-32a(+)-IGF-I和pET-30嶺卜IGF-II。測序驗證表達(dá)載體構(gòu)建正確后,以BL21CDE3)作為宿主菌,進(jìn)行融合表達(dá)研究。4.SDS-PAGE分析表明,重組質(zhì)粒pET-
3、32a(+)-IGF-I在IPTG誘導(dǎo)下表達(dá)分子量約30kDa的融合蛋白,但其表達(dá)量不高,約為菌體總蛋白的10%左右;重組質(zhì)粒pET-30a(+)-IGF-II在IPTG誘導(dǎo)下表達(dá)分子量約14kDa的重組蛋白,融合蛋白表達(dá)量約占菌體蛋白總量的35%05菌體采用溶菌酶裂解,融合蛋白以包涵體形式存在;對hIGF-I融合蛋白進(jìn)行了westernblot分析,確認(rèn)所表達(dá)蛋白為目的蛋白。關(guān)鍵詞:人胰島素樣生長因子I;人胰島素樣生長因子I;基因克隆;基因表達(dá)CloningandExpressingofInsulin-likeGrowthFactorIandIIAbstractInsulin-like
4、growthfactors(IGFs)areconsistedoftwokinds叮peptide,oneisinsulin-likegrowthfactorI(IGF-I)andanotherisinsulin-likegrowthfactorll(IGF-II).ManystudiesshowedthatIGFsplayveryimportantregulatedrolesinthecellproliferationandapoptosis,pathogenesisofhumancancerandtissuedifferentiation.Inorderto洲sufficientqu
5、antitiesofpurebiological珍activehIGFstomeettheneedofbasicresearchandclinicaluse,weclonedthegeneofIGFsintopETplasmids,aseriesofprokaryoticexpressionvector,andexpressedtherecombinantplasmidsintheE.coliofBL211.GenesofIGFs,whichincludeCDS,wereclonedbywayofRT-PCRfromthetissueofhumanplacenta,thenligated
6、thegenesofIGFstothevectorofpMD18一thesequencesofIGFsarecorrectbysequencing.2.GenescodingmaturepeptideofIGFswereachievedbyPCRusinganotherpairofoligo-nucleotideprimerstoinducetothesuitablerestrictionenzymesite,andtheIGF-IproductofPCRcontains230basepairs,IGF-11contains2份basepairs.3.ThegenesofhIGF·工an
7、dhlGF-IIwereligatedintotheexpressionvectorpET-32a(+)andpET-30a(+)respectivelyaftercutbytherestrictionenzymes.weintroducedtherecombinantvectorpET-32a(+)-IGF-IandpET-30a(+)-IGF-I1intotheE.cotiofBL21(DE3)afterencodingfrag