人肝再生增强因子表达载体的构建及其在酵母中的表达

肝再生增强因子是一种多肽调节因子,具有重要的生物学功能,与高等生物线粒体的生成、细胞分裂周期调节及肝脏,睾丸等重要脏器发育有关,最主要是能特异的刺激肝源细胞的增殖。对于肝再生增强因子（augmenter of liverregeneration,ALR）的产生、分泌、体内转运的过程都存有诸多疑间。因此为了进一步研究该蛋白质的功能,我们在酵母细胞中表达了ALR。     

重组人肝再生增强因子原核表达载体的构建及其在大肠杆菌中的表达

目的 用聚合酶链反应法（ＰＣＲ）和基因重组技术构建重组人肝再生增强因子原核表达载体并在大肠杆菌中进行表达。方法 利用ＰＣＲ方法从我们构建的ＰＵＣ１９－ｈＡＬＲ质粒中扩增出带ＮｄｅⅠ和ＢａｍＨⅠ酶切位点的ｈＡＬＲ编码区ＤＮＡ。ＰＣＲ产物和质粒ｐＥＴ１１ａ分别被相应内切酶消化,然后被Ｔ４ ＤＮＡ连接酶连接以获取重组表达质粒。重组表达质粒ｐＥＴ１１ａ－ｈＡＬＲ经电转化入大肠杆菌ＢＬ２１（ＤＥ３）中,在Ｉ     

重组人肝再生增强因子抑制实验性肝纤维化明胶酶A基因表达

目的　了解重组人肝再生增强因子 (hALR)对实验性肝纤维化明胶酶A(MMP2 )基因表达的影响。方法　建立CCl4中毒性及人血白蛋白免疫损伤性两种大鼠肝纤维化模型 ,在造模的同时给予不同剂量 (10 ,5 0 μg·kg-1·d-1)的hALR。在不同的时间点留取大鼠肝组织标本 ,提取总RNA ,用逆转录定量聚合酶链反应 (RT PCR)测定MMP2 的基因表达水平。结果　在两种模型中两个剂量hALR预防组大鼠肝组织MMP2 的基因表达水平在模型形成的不同阶段均明显低于模型组 ;高剂量hALR组大鼠肝组织MMP2 的基因表达水平均明显低于低剂量组。结论　重组人肝再生增强因子可能有抑制大鼠实验性肝纤维化MMP2 基因表达的作用     

重组人肝再生增强因子可促进实验性肝纤维化基质分解素-1的基因表达

目的：了解重组人肝再生增强因子（hALR)对实验性肝纤维化基质分解素－1（MMP3）基因表达的影响。方法：建立四氯化碳（CCl4)中毒性及人血白蛋白免疫损伤性两种大鼠肝纤维化模型,在造模的同时给予不同剂量的重组hALR。在不同的时间点留取大鼠肝组织标本,提取总RNA,用RT－PCR测定MMP3的基因表达水平。结果：在两种模型中,hALR治疗组大鼠肝组织MMP3的基因表达水平在模型形成的不同阶段均明显高于模型组;高剂量hALR组大鼠肝组织MMP3的基因表达水平均明显高于低剂量组。结论：重组hALR可能有促进大鼠实验性肝纤维化MMP3基因表达的作用。     

重组肝再生增强因子对大鼠肝纤维化的保护作用

目的　观察重组肝再生增强因子 (rALR)对大鼠肝纤维化的保护作用。方法　构建表达ALR的质粒 ,将得到的rALR用于CCl4 致肝纤维化的大鼠 ,观察rALR对肝纤维化动物模型肝功能、血清细胞外基质水平及肝组织纤维化程度的影响。结果　rALR可显著改善CCl4 肝纤维化模型大鼠肝功能 ,降低血清细胞外基质水平和肝组织纤维化程度。结论　rALR对实验大鼠肝功能具有显著的改善作用 ,对抗肝纤维化亦有一定的作用。     

大鼠肝再生增强因子在酵母菌中的表达及生物活性研究

目的构建大鼠肝再生增强因子(rALR)酵母重组表达质粒,在毕赤酵母菌GS115中进行表达.表达产物经超滤方法纯化后在体外进行生物活性研究. 方法以重组质粒pcDNA3.1-rALR为模板,聚合酶链反应(PCR)扩增rALR编码区的DNA,构建重组质粒pPIC9K-rALR,然后电转化至毕赤酵母菌GS115中,在甲醇诱导下进行表达.表达产物经1.5% SDS-PAGE电泳和western blot鉴定后进行超滤纯化.用3H-TdR掺入法检测重组大鼠ALR(rrALR)体外刺激QGY和HepG2人肝癌细胞株和原代大鼠肝细胞的增殖情况. 结果重组质粒经酶切及PCR证实rALR编码区DNA正确插入质粒载体中.重组大鼠ALR被GS115菌以外分泌方式表达,其DNA分子量约为1.5×104,与理论预期值相符,western bolt鉴定发现rrALR能与抗人ALR多克隆抗体发生特异性反应,说明人和大鼠ALR抗原性上存在部分交叉.超滤纯化获得大量高纯度的rrALR.在所测定的剂量范围内,rrALR在体外以剂量依赖方式刺激QGY和HepG2肝癌细胞株增殖,但对原代大鼠肝细胞无刺激增殖作用. 结论 rrALR在毕赤酵母菌GS115中获得分泌性高效表达,rrALR在体外以剂量依赖方式刺激QGY和HepG2肝癌细胞株增殖,但对原代大鼠肝细胞无刺激增殖作用,表明肝癌细胞和正常肝细胞表达的ALR受体不同.人和大鼠ALR在生物学活性和抗原性上存在交叉.     

肝再生增强因子在肝癌细胞中的表达及意义

目的研究肝再生增强因子(ALR)对肝癌细胞和原代大鼠肝细胞增殖作用的影响及在肝细胞癌(HCC)中的表达。方法将不同种属的ALR分别与原代大鼠肝细胞和人肝癌细胞株QGY和HepG2共同培养后，用^3H-胸腺嘧啶核苷掺入法测定这些细胞的增殖情况。并应用免疫组织化学法对9例正常肝组织和21例HCC组织中ALR的表达进行了研究。结果不同种属的ALR在体外均能刺激人肝癌细胞株QGY和HepG2增殖，并呈剂量依赖关系，但对原代大鼠肝细胞均无刺激增殖作用。在正常肝组织中ALR不表达，但在HCC肝组织中ALR均表达，且ALR的表达程度与HCC分化程度和大小均无关。结论ALR可能在HCC的发生发展中起着重要作用。     

肝细胞生长因子与肝再生增强因子重组表达质粒对大鼠肝纤维化的影响

目的 研究肝细胞生长因子(HGF)与肝再生增强因子(ALR)重组表达质粒对大鼠实验性肝纤维化的治疗作用.方法 建立二甲基亚硝胺肝纤维化模型后的90只S-D大鼠分为空白组、pcDNA3.1治疗组、pcDNA3.1-HGF治疗组、pcDNA3.1-ALR治疗组、pcDNA3.1-HGF与pcDNA3.1-ALR共治疗组、pcDNA3.1-HGF-ALR治疗组,每组15只.各治疗组大鼠每24小时经尾静脉注射1次相应质粒0.1 μmol,连续3次,空白组不接受任何治疗,另取同批次S-D大鼠10只作为对照组.治疗结束后4 d处死大鼠,留取肝组织采用HE染色观察肝脏的病理形态,采用免疫组织化学染色检测增殖细胞核抗原(PCNA)和c-jun的表达.计量资料采用单因素方差分析,两两比较采用SNK检验,计数资料采用Fisher确切概率法分析.结果 空白组和pcDNA3.1治疗组大鼠肝组织有明显的条索状纤维间隔形成,可见假小叶,两组肝纤维化程度差异无统计学意义(x2=0.317,P=1. 000);其他治疗组肝纤维化均有不同程度改善,以pcDNA3.1-HGF-ALR治疗组改善最明显.对照组肝组织PCNA和c-jun表达均较低,其吸光度值分别为8.6±1.9和3.2±1.2;空白组与pcDNA3.1治疗组肝组织PCNA和c-jun表达均增加,其吸光度值分别为24.1±3.0.24.5±4.3与23.8±3.1、24.9±4.2,与对照组比较,差异有统计学意义(均P＜0.01);其他治疗组的PCNA表达显著增加,c-jun表达显著降低,均以pcDNA3.1-HGF-ALR治疗组的变化最明显.结论 重组表达质粒pcDNA3.1-HGF-ALR能较好地改善大鼠实验性肝纤维化,并可能通过促进肝细胞增殖和抑制原癌基因c-jun的表达来发挥其抗肝纤维化作用.     

Expression, purification and bioactivity of human augmenter of liver regeneration

AIM: To construct the expression vectors for prokaryotic and eukaryotic human augmenter of liver regeneration (hALR) and to study their biological activity. METHODS: hALRcDNA clone was obtained from plasmid pGEM-T-hALR, and cDNA was subcloned into the prokatyotic expression vector pGEX-4T-2. The recombinant vector and pGEX-4T-2hALR were identified by enzyme digestion and DNA sequencing and transformed into E coli JM109. The positively selected clone was induced by the expression of GST-hALR fusion protein with IPTG, then the fusion protein was purified by glutathine s-transferase (GST) sepharose 4B affinity chromatography, cleaved by thrombin and the hALR monomer was obtained and detected by measuring H thymidine incorporation. RESULTS: The product of PCR from plasmid pGEM-T-hALR was examined by 1.5% sepharose electrophoresis. The specific strap was coincident with the theoretical one. The sequence was accurate and pGEX-4T-hALP digested by enzymes was coincident with the theoretical one. The sequence was accurate and the fragment was inserted in the positive direction. The recombinant vector was transformed into E coli JM109. SDS-PAGE proved that the induced expressive fusion protein showed a single band with a molecular weight of 41 kDa. The product was purified and cleaved. The molecular weights of GST and hALR were 26 kDa, 15 kDa respectively. The recombinant fusion protein accounted for 31% of the total soluble protein of bacterial lysate. HALR added to the culture medium of adult rat hepatocytes in primary culture and HepG2 cell line could significantly enhance the rate of DNA synthesis compared to the relevant control groups (P < 0.01). CONCLUSION: Purified hALR has the ability to stimulate DNA synthesis of adult rat hepatocytes in primary culture and HepG2 cells in vitro, and can provide evidence for its clinical application.     

大鼠肝细胞生长因子与肝再生增强因子融合基因真核表达质粒的构建及鉴定

目的 构建大鼠肝细胞生长因子(rHGF)与大鼠肝再生增强因子(rALR)融合基因的真核表达质粒并进行鉴定,为新的肝纤维化治疗方法奠定实验基础.方法 分别以重组质粒pUC18-rHGF和pUC18-rALR为模板,进行PCR扩增,获得rHGF和rALR的基因片段;利用重叠延伸PCR方法将获得的基因片段通过一个连接序列(linker)进行连接,构建融合基因rHGF-linker-rALR,将融合基因定向插入pcDNA3.1真核表达质粒的Kpn Ⅰ和Xba Ⅰ酶切位点之间,构建重组真核表达质粒pcDNA3.1-rHGF-linker-rALR,并进行双酶切及测序鉴定.结果 rHGF和rALR的PCR扩增产物电泳后分别观察到2200 bp和400 bp的条带,与理论值相符.重叠延伸PCR获得的融合基因产物电泳后观察到2600 bp的条带,与预期值一致.重组真核表达质粒pcDNA3.1-rHGF-linker-rALR经双酶切,电泳后观察到2600 bp和5400 bp的两条DNA条带,与预期值相符,测序鉴定结果表明序列正确.结论 成功构建了rHGF与rALR融合基因的真核表达质粒,为肝纤维化的基因治疗奠定了实验基础.     

鼠人肝再生增强因子的cDNA克隆及序列分析

目的克隆大鼠及人肝再生增强因子的ｃＤＮＡ．方法按文献报道大鼠及人肝再生增强因子核苷酸序列设计合成引物．利用ｍＲＮＡ抽提试剂盒分别从乳鼠及人胎肝组织中提取ｍＲＮＡ，再逆转录聚合酶链反应扩增出需要的ｃＤＮＡ片段，经克隆入ｐＧＥＭＴ质粒后以Ｔ７ＤＮＡ聚合酶序列分析试剂盒测定ｃＤＮＡ的序列．结果经ＲＴＰＣＲ反应顺利扩增到４７０ｂｐ的鼠肝再生增加因子ｃＤＮＡ及３８４ｂｐ的人肝再生增强因子．结论所得到的ｃＤＮＡ序列与文献报道一致     

大鼠肝细胞生长因子与肝再生增强因子融合基因真核表达质粒的构建及鉴定

Objective To construct and identify an eukaryotic expression plasmid containing rat hepatocyte growth factor(rHGF)gene and rat augmenter of liver regeneration(rALR)gene,so that to provide experimental basis for developing new treatments of hepatic fibrosis.Methods The gene fragments of rHGF and rALR were amplified from recombinant prokaryotic plasmid pUC18-rHGF and pUC18-rALR by polymerase chain reaction(PCR),respectively,then were spliced by overlap extension PCR with a linker,and the fusion gene rHGF-linker-rALR was constructed.The fusion gene was directionally inserted into the eukaryotic expression plasmid pcDNA3.1 between restriction sites of Kpn Ⅰ and Xba Ⅰ to construct the recombinant eukaryotic expression plasmid pcDNA3.1-rHGF-linker-rALR,and the new constructed recombinant plasmid was identified by double restriction digestion and DNA sequencing.Results DNA fragments of 2200 bp and 400 bp were observed after the electrophoresis of products amplified from recombinant prokaryotic plasmid pUC18-rHGF and pUC18-rALR,respectively,which was consistent with the theoretical value.The electrophoresis of fusion gene rHGF-linker-rALR obtained by overlap extension PCR technique showed only a 2 600 bp DNA fragment,which was in accordance with the expected value.Electrophoresis of products of pcDNA3.1-rHGF-linker-rALR digested with Kpn Ⅰ and Xba Ⅰ showed two DNA fragments with 2600 bp and 5400 bp,which were both consistent with the expected value.The sequences were confirmed correctly by DNA sequencing.Conclusion The recombinant eukaryotic expression plasmid pcDNA3.1-rHGF-linker-rALR is successfully constructed,which provides experimental basis for developing gene therapy of hepatic fibrosis.     

大鼠肝细胞生长因子与肝再生增强因子融合基因真核表达质粒的构建及鉴定

Objective To construct and identify an eukaryotic expression plasmid containing rat hepatocyte growth factor(rHGF)gene and rat augmenter of liver regeneration(rALR)gene,so that to provide experimental basis for developing new treatments of hepatic fibrosis.Methods The gene fragments of rHGF and rALR were amplified from recombinant prokaryotic plasmid pUC18-rHGF and pUC18-rALR by polymerase chain reaction(PCR),respectively,then were spliced by overlap extension PCR with a linker,and the fusion gene rHGF-linker-rALR was constructed.The fusion gene was directionally inserted into the eukaryotic expression plasmid pcDNA3.1 between restriction sites of Kpn Ⅰ and Xba Ⅰ to construct the recombinant eukaryotic expression plasmid pcDNA3.1-rHGF-linker-rALR,and the new constructed recombinant plasmid was identified by double restriction digestion and DNA sequencing.Results DNA fragments of 2200 bp and 400 bp were observed after the electrophoresis of products amplified from recombinant prokaryotic plasmid pUC18-rHGF and pUC18-rALR,respectively,which was consistent with the theoretical value.The electrophoresis of fusion gene rHGF-linker-rALR obtained by overlap extension PCR technique showed only a 2 600 bp DNA fragment,which was in accordance with the expected value.Electrophoresis of products of pcDNA3.1-rHGF-linker-rALR digested with Kpn Ⅰ and Xba Ⅰ showed two DNA fragments with 2600 bp and 5400 bp,which were both consistent with the expected value.The sequences were confirmed correctly by DNA sequencing.Conclusion The recombinant eukaryotic expression plasmid pcDNA3.1-rHGF-linker-rALR is successfully constructed,which provides experimental basis for developing gene therapy of hepatic fibrosis.