抗HPV16E7—ribozyme的体外制备与活性鉴定

通过体外转录结合乙醇沉淀，建立了体外大量制备ＨＰＶ１６Ｅ７Ｒｚ的方法，切割实验表明，ｒｉｌｂｏｚｙｍｅ可在体外准确和有效地切割Ｅ７ａｆｃｎＲＮＡ，形成８５ｎｔ和８６ｎｔ大小的切割产物，体外制备的ｒｉｂｏｚｙｍｅ的切割活性、Ｋｍ的ｋｃａｔ值民人工合成的相似。结果说明，体外制备的ｉｉｂｚｙｍｅ具有特殊的催化切割活性。     

抗HPV16E7—ribozyme和靶RNA相互作用的计算机分析

应用计算机分析了抗ＨＰＶ１６Ｅ７－ｒｉｂｏｚｙｍｅ的体外切割反应结果，发现ｒｉｂｏｚｙｍｅ和靶ＲＮＡ的二级结构及其能量变化能影响ｒｉｂｏｚｙｍｅ的切割活性。根据锤头结构ｒｉｂｏｚｙｍｅ的能量变化模型，对抗ＨＰＶ１８Ｅ７－ｒｉｂｏｚｙｍｅ和靶ＲＮＡ在痘苗表达体系及稳定表面体系中的相互作用，进行计算机模拟分析，结果表明，计算机分析ｒｉｂｏｚｙｅ和靶ＲＮＡ在细胞内的相互作用，可以指导ｒｉｂｏｚｙｍｅ的设     

抗HPV16E7－ribozyme和靶RNA相互作用的计算机分析

应用计算机分析了抗ＨＰＶ１６Ｅ７－ｒｉｂｏｚｙｍｅ的体外切割反应结果，发现ｒｉｂｏｚｙｍｅ和靶ＲＮＡ的二级结构及其能量变化能影响ｒｉｂｏｚｙｍｅ的切割活性。根据锤头结构ｒｉｂｏｚｙｍｅ的能量变化模型，对抗ＨＰＶ１６Ｅ７－ｒｉｂｏｚｙｍｅ和靶ＲＮＡ在痘苗表达体系及稳定表达体系中的相互作用，进行计算机模拟分析。结果表明，计算机分析ｒｉｂｏｚｙｍｅ和靶ＲＮＡ在细胞内的相互作用，可以指导ｒｉｂｏｚｙｍｅ的设计和在体内的应用研究。     

原癌基因K-ras mRNA的体外核酶定点切割

目的：确定人工设计的梅核Ｒｘ１９９对原癌基因Ｋ－ｒａｓ ｍＲＮＡ的体外切割活性，为Ｋ－ｒａｓ特异性核酶的体内应用提供依据。方法：利用ＤＮＡ重组技术构建Ｋ－ｒａｓ外显子１及核酶Ｒｚ１９９的体外转录质粒，以Ｔ７ＲＮＡ聚合酶进行转录获得核酶Ｒｚ１９９对其靶ＲＮＡ分子进行切割。结果：Ｋ－ｒａｓ体外转录体为２５４ｎｔ的ＲＮＡ分子，能被核酶Ｒｚ１９９切割成大小分别为９０，１６４ｎｔ的２个片段。结论：梅核Ｒａ１     

抗肿瘤多药抗性核酶转录质粒的构建及其体外切割研究

目的 探讨体外核酶对肿瘤多药抗性相关基因ｍｄｒｌ ｍＲＮＡ的锤头状核酶（ｒｉｂｏｚｙｍｅ），并构建抗ｍｄｒｌ－ｒｉｂｏｚｙｍｅ和靶分子的体外转录质粒，进行体外切割实验。结果 发现抗ｍｄｒ１－ｒｉｂｏｚｙｍｅ能较好地切割ｍｄｒｌ－ｍＲＮＡ。结论 抗肿瘤多药性核酶的体外研究为基体内应用提供了参考，ｒｉｂｏｚｙｍｅ有可能成为逆转肿瘤多药抗性的新药物。     

抗HPV16E6核酶和抗HPV18E6核酶的设计与表达

以核酶的锤头结构为模型，采用计算机软件针对ＨＰＶ１６Ｒ６、ＨＰＶ１６Ｅ６基因，设计了相应的ｒｉｂｏｚｙｍｅ。体外合成ｒｉｂｏｚｙｍｅ基因后，克隆于带自身修剪功能的原核质粒ＰＲＧ５２４中，构建成质粒ｐＲＧ１６ＨＲ、ｐＧＲ１８ＨＲ，为下一步研究抗１６ＨＲ，抗１８ＨＲ的体外活性效应，从而为探索以ｒｉｂｏｚｙｍｅ治疗ＨＰＶ相关性肿瘤的途径打下基础。     

一株IL—11 cDNA转染的成纤维细胞体外促造血活性的鉴定

目的：为了探讨ＩＬ－１１基因修饰成纤维细胞的体外促造血活性及其在造血系统基因治疗中的应用前景。方法：将含ＩＬ－１１ ｃＤＮＡ的逆转录病毒载体转染小鼠成纤维细胞系ＮＩＨ－３Ｔ３细胞，获得了高表达ＩＬ－１１的亚克隆１Ｅ７，通过造血祖细胞集落形成实验及细胞增殖实验对１Ｅ７在体外的促造血活性做了初步的鉴定。     

B7—1基因转当小鼠EL—4淋巴瘤细胞体外诱导免疫小鼠脾细胞产生的白细胞介素

目的 研究Ｂ７－１基因转染小鼠ＥＬ－４淋巴瘤体外诱导免疫小鼠脾细胞产生的白细胞介素－２。方法 以ＣＴＩＬ－２细胞检测ＥＬ－４Ｂ７－１＾＋免疫小鼠的脾细胞与癌细胞共育的ＭＬＴＣ培养上清中的ＩＬ－２活性。结果 ＥＬ－４Ｂ７－１＾＋免疫小鼠的ＳＰＬ经瘤细胞在体外刺激可诱生出明显的ＩＬ－２活性,而ＥＬ－４免疫小鼠的ＳＰＬ则无此作用,两者具有较明显的差异（Ｐ〈０．０１）。结论 Ｂ７－１基因转染小鼠ＥＬ－４淋巴瘤可在体外诱导免疫小鼠脾细胞产生较高水平的白细胞介素－２。     

反义寡脱氧核苷酸抑制丁型肝炎病毒基因链核酶活性的作用

目的探讨反义寡脱氧核苷酸（ａｓＯＤＮ）抑制丁型肝炎病毒（ＨＤV）核酶活性以阻断ＨＤＶ复制的作用，方法在构建含ＨＤＶ基因链和抗基因链核酶ｃＤＮＡ片段的重组质粒ｐＨＤＶｒｚ２７７的基础上，体外转录出１１２聚核苷酸（ｎｔ）的基因链核酶，观察５条ａｓＯＤＮ抑制核酶活性的作用，并对作用最好的一条进行序列优化。结果 互补于６８３－７０３ｎｔ的自裂位点和茎样结构（ｓｔｅｍ）１区的ａｓＯＤＮ可完全抑制该１１２ｎｔ核酶的活性，互补于７５６－７７０ｎｔ（ＳＳｒＢ区）和７２１－７３５ｎｔ（ＳＳｒＡ区）的ａｓＯＤＮ亦有较高活性，抑制率分别为６９．３６％和４８．６４％，而对应于７３６－７５０ｎｔ（ｓｔｅｍｗ区）和７０４－７２０ｎｔ＜ＳＳｒＣ区）者几乎无抑制作用。对互补于６８３－７０３ｎｔ的ａｓＯＤＮ进行序列优化发现，封闭自裂位点在内的１３ｎｔ（６８３－６９５ｎｔ）的ａｓＯＤＮ仍保留很高抑制作用，抑制率大于９０％。结论ｓｔｅｘｎｌ和ＳＳｒＢ在基因链核酶中起重要作用，ａｓＯＤＮ可有效抑制ＨＤＶ基因链核酶活性。     

切割bcl─2RNA核酶的逆转录病毒载体的构建与鉴定

目的：构建逆转录病毒载体介导的切割ｂｃｌ－２ＲＮＡ的核酶（ＲＺ）基因真核细胞表达载体．方法：合成带有和表达载体克隆位点相匹配酶切位点的ＲＺ基因，先克隆于ｐＧＥＭ－３Ｚｆ（－）的ＨｉｎｃⅡ位点，命名为３ＺＲＺ（＋）／（－），用Ｓａｎｇｅｒ双脱氧链终止法进行测序，体外转录，进行体外切割反应．ＲＺ基因酶切回收后，定向克隆于逆转录病毒载体ｐＤＯＲ－ｎｅｏ中．结果：ＲＺ基因序列正确，具有切割活性，经酶切鉴定ＲＺ基因已被克隆于ｐＤＯＲ－ｎｅｏ的ＢａｍＨＩ和ＥｃｏＲＩ位点，重组逆转录病毒载体命名为ｐＤＲＺ－ＲＺ．结论：体外合成ＲＺ基因后，可定向克隆逆转录病毒载体，为细胞内合成ＲＺ提供了手段     

c-myc基因核酶对靶mRNA的切割作用

目的：构建c—myc基因核酶及其靶mRNA的体外转录载体，探讨核酶对靶mRNA的体外切割作用。方法：通过计算机分析c—myc基因mRNA的二级结构，设计核酶基因序列，采用DNA合成仪合成核酶基因，以克隆技术将核酶基因构建入pGEM3Zf( )体外转录载体，将大鼠c—myc基因第2外显子及部分第3外显子的基因片段克隆入pGEM7Zf(-)体外转录载体，分别进行体外转录获得核酶及靶mRNA。在含有Mg^2 的反应体系中，进行核酶对靶mRNA的体外切割反应。结果：经限制性内切酶酶切鉴定，核酶基因准确克隆入pGEM3Zf( )载体，经DNA自动序列分析仪测序分析，大鼠c—myc基因第2外显子及部分第3外显子的基因片段准确克隆入pGEM7Zf(-)载体。核酶对靶mRNA的体外切割活性约为64．5％。结论：该核酶具有切割靶mRNA的活性，可进一步用于细胞内和体内研究。     

Bridge Sequence对M1GS核酶体外切割活性的影响

目的探讨B ridge Sequence(桥序列)对M1GS核酶体外切割活性的影响,从而为人工M1GS核酶的优化设计提供一定的理论依据。方法以含大肠杆菌核酶P催化单位(M1 RNA)基因的pFL117质粒作为模板,通过巧妙设计不同的下游引物,经PCR扩增、扩增产物克隆及克隆基因的体外转录,构建一组具有不同桥序列的人工M1GS核酶。进一步将所构建的上述人工M1GS核酶分别与同位素标记的底物RNA片段进行体外切割试验,并通过同位素扫描成像系统对各M1GS核酶的切割产物加以分析。结果成功构建了针对HCMV UL54mRNA T7靶位的、四种不同桥序列长度的M1GS核酶,其桥序列长度分别为0n、t6nt、20nt和88nt,并依次命名为M1GS-T7(0)、M1GS-T7(6)、M1GS-T7(20)和M1GS-T7(88)。经体外切割试验证实,M1GS-T7(88)的靶向切割活性最强,M1GS-T7(20)的切割活性相对较弱,而M1GS-T7(0)及M1GS-T7(6)则无明显的切割活性。结论人工M1GS核酶中桥序列的长度对于其体外切割活性具有重要影响,提示在人工M1GS核酶的优化设计时,桥序列的长度是不可忽视的因素之一。     

Site-specific cleavage of oncogene Ki-ras mRNA by ribozyme in vitro

Rasisaprotooncogeneencodingguaninenucleotidebindingprotein,ras--p21islocatedinthe.innerplasmamembraneandtransductssignalfromreceptortyrosinekinasetoraff.Ras--pZIproteinparticipatesintheregulationofcellgrowthanddifferentiation[lj.Mutationofras,Ki--rasinparticular,playsanimportantroleincellmalignanttransforming.ThemutantrateofKi--rasinhumanpancreaticadenocarcinomaisashighas95%['].So,blockingrasexpressionshouldbeapotentialmethodforcancertherapy.RibozymeisasmallcatalyticRNAmolecule.Recently,it…     

Effects of anti- HPV16E6- ribozyme on phenotype and gene expression of a cervical cancer cell line

Objective To investigate the effects of anti- HPV16E6- ribozyme (HRz) on phenotype and gene expression of a cervical cancer cell line. Methods HRz was designed by computer programs.HRz’s activity was identified by cleavage experiments in vitro.HRz and empty eukaryotic plasmids were transfected into CaSKi cells with lipofectin, then renamed CaSKi- R and CaSKi- P, respectively. The expression of ribozyme in transfected cells was observed by RNA dot blot.The amounts of E6 mRNA in three kinds of cells lines were detected by Northern blot.Cell growth curves and soft agar forming ability were studied.The ability of each cell line to form tumors was assessed in nude mice.Apoptosis rates and expression of c- myc, bcl- 2, p53 and Fas were detected by flow cytometry (FCM).Antigens of tumor cells, HLA- 1, HLA- 2, B7- 1 and B7- 2 were also detected.NK, LAK, and CD3AK cells were induced.Their cytotoxicities were detected in CaSKi- R, CaSKi- P, and CaSKi cells. Results In vitro cleavage reaction demonstrated that HRz could cleave HPV16E6 mRNA in a site- specific manner.HRz could be expressed stably in transfected CaSKi cells.Northern blot analysis showed that E6 mRNA levels were lower in CaSKi- R than in CaSKi.The growth rate of CaSKi- R was slower than those of CaSKi and CaSKi- P.The soft agar- forming rate of CaSKi- R was lower compared with those of CaSKi and CaSKi- P cells.The ability of CaSKi- R to form tumors in nude mice was also poor.The apoptosis rate of CaSKi- R cells was much higher than those of CaSKi and CaSKi- P.HRz could reduce the expression of E6, c- myc and bcl- 2 proteins, and increase the expression of p53 as well.HRz could increase the expression of HLA- 2, B7- 1 and B7- 2 antigens.The cytotoxicity of NK, LAK and CD3AK cells was much higher in CaSKi- R than in CaSKi- P and CaSKi cells.Conclusion HRz not only reverses the malignant phenotype of CaSKi cells partially, but also induces apoptosis in the cells, and increases sensitivity of CaSKi cells to immune cells.     

10-23 DNA enzyme对乙型肝炎病毒C基因体外转录产物的切割活性

目的:探讨10-23 DNA enzym e对乙型肝炎病毒C基因体外转录产物的特异切割活性。方法:设计并合成3种能针对乙型肝炎病毒C基因开放阅读框A1816UG的特异性脱氧核酶,分别命名为D rzBC-7、D rzBC-8和D rzBC-9。应用体外转录的方法获得相应的底物RNA,观察D rzBC-7、D rzBC-8和D rzBC-9对其的体外切割效应。以D rzBC-9为例,观察不同浓度的M gC l2对体外切割效率的影响,根据L inew eaver Burk作图法,计算相关的酶动力学参数Km、K cat和K cat/Km。结果:通过体外转录获得用于切割反应的底物RNA,其大小为300 nt。在特定的切割条件下,D rzBC-7、D rzBC-8和D rzBC-9均能对相应的底物RNA进行有效的切割,切割产物分别为109 nt和191 n。t以D rzBC-9为例,在切割反应体系中缺乏M gC l2时,未见有切割反应。M gC l2浓度在150 mm o.lL-1时达到最高切割效率,再提高M gC l2的浓度,切割效率未见明显增大。酶动力学参数Km、K cat和K cat/Km分别为1.4×10-9m o.lL-1,1.6 m in-1和1.1×109m o.lL-1.m in-1。结论:针对乙型肝炎病毒C基因的10-23 DNA enzym e在体外对相应的转录产物有特异切割作用。     

Transfection with the ribozyme targeting HPVE6 mRNA results in growth inhibi-tion of E6-expressing cervical carcinoma cells

To acquire a ribozyme against the E6 gene of human papillomaviruses type 16 ( HPV16E6 ) and investigate its effects on the phenotypes and gene expression of cervical cancer cell line. Methods: Anti-HPV16E6 ri-bozyme (HRz) was designed by computer programs and its activity identified by cleavage experiment in vitro before its transfection v/a lipofectin into CaSKi cells with the empty eucaryotic expression plasmid transfection of the cells also performed, the resultant cells designated as CaSKi-R, CaSKi-P respectively. The morphology and the soft agar forming ability were studied in Ca,SKi cells and the transfected cells, and the expression of E6, proliferating cell nuclear antigen (PCNA) and C-erbB-2 genes assayed by flow cytometry. The tumorgenicity of each cell line was evaluated in nude mice receiving inoculations of CaSKi, CaSKi-R and CaSKi-P cells separately, while in one group, both CaSKi and CaS-Ki-R cells were inoculated on different sides of the mice. Results: HRz was able to cleave HPV16E6 mRNA in a site-specific manner and could be expressed stably in transfected CaSKi ceils. Northern blot analysis showed that E6 mRNA was less in CaSKi-R than in CaSKi cells, and no significant difference in the morphology and growth rate was observed between CaSKi and CaSKi-P cells, but the growth rate CaSKi-R was lowered. The colony-forming rate of CaSKi-P insoft agar was similar to that of Ca,SKi cells, while that of CaSKi-R was decreased. Flow cytometry showed that anti-HPV16E6 ribozyme reduced the expression of E6, PCNA and C-erbB-2 genes in CaSKi-R cells, but not in CaSKi-Pcells. The tumorgenicity of CaSKi-R in nude mice was decreased compared with Ca,SKi cells. Conclusion: HRz canpartially reverse the malignant phenotype of Ca,SKi cells, possibly due to decreased E6 gene expression, and the conse-quent decrease of PCNA and C-erbB-2 gene expressions.     

c—myc基因特异核酶的设计及其对靶mRNA的切割

目的：针对ｃ－ｍｙｃ基因第二外显子部分序列设计核酶，探讨生理温度下核酶的切割活性，方法：计算机模拟分析ｃ－ｍｙｃ基因第二外显子部分二级结构，选择核酶切位点，设计核酶，分别构建ｃ－ｍｙｃ基因第二外显子部分序列和核酶体外转录载体并经双脱氧末端终止法测定核酶序列正确无误，体外转录核酶和靶ＲＮＡ分子，生理温度下测定核酶切割活性，结果：所设计的核酶可有效地切割靶ｍＲＮＡ分子。结论：所设计的核酶在生理温度下具     

抗肿瘤多药抗性核酶转录质粒的构建及其体外切割研究

目的 探讨体外核酶对肿瘤多药抗性相关基因mdr1靶RNA分子的切割作用及其影响因素。方法 利用计算机软件设计能特异切割mdr1 mRNA的锤头状核酶（ribozyme）,并构建抗mdr1-ribozyme和靶分子的体外转录质粒,进行体外切割实验。结果 发现抗mdr1-ribozyme能较好地切割mdr1 mRNA。 结论 抗肿瘤多药抗性核酶的体外研究为其体内应用提供了参考,ribozyme有可能成为逆转肿瘤多药抗性的新药物。