Objective To construct a regulatable plasmid containing single chain fusion gene of murine interleukin-12 (mIL-12) which was regulated with mifepristone (RU486) and explore its expression in vitro. Methods The p40 and p35 subunit sequence of mIL-20 were respectively obtained from the plasmid GCp35Ep40PN by polymerase chain reaction (PCR) and they were cloned into pCA14 plasmid after introducing a linker by overlap PCR. The single chain mIL-12 gene was comfirmed by sequencing and subcloned into pRS-17 vector which contains RU486 regulator cassette. The positive clone named pRS-RUmIL-12 was identified by restriction endonuclease digestion and PCR. Lipofectamine 2000 was used to transfect the pRS-RUmIL-12 to HEK293 cells followed by manufacturer’s recommendations. The protein concentration of mIL-12 induced with RU486 in supernatant of the transfected HEK293 cells was measured by ELISA. Results The sequence of single chain mIL-12 what we obtained was the same as the expected result. The results of restriction endonuclease digestion and PCR showed that the RU486-inducible regulatory vector (pRS-RUmIL-12) was successfully constructed. No significant mIL-12 protein concentration in supernatant of HEK293 cells activation was measured without the inducer RU486, whereas higher concentration of the mIL-12 protein was observed in the presence of RU486. The relationship of concentration of the mIL-12 protein and RU486 was positive correlated under definite range. Conclusion A regulatable eukaryotic expression plasmid of mIL-12 single chain fusion gene was constructed, which could be used in the further research of gene regulation and gene therapy.
Objective To construct small interfering RNA（siRNA） eukaryotic expression vector specific for human hnRNP K gene，and to observe its silencing effects on hnRNP K gene in A549 cells.Methods The expression vectors of pSUPER/hnRNP K siRNAa，pSUPER/hnRNP K siRNAc and pSUPER/siRNAn were constructed by gene recombination and then transfected into the A549 lung carcinoma cell line by using Lipofectamine2000（a and c respectively represented A and C fragments in hnRNP K coding sequence contained 19 nts，n represented nonsense fragment as control）.The mRNA and protein were harvested after 24 h and analyzed for the expression of hnRNP K by RT-PCR and Western blotting respectively.Results The siRNA vector targeted to hnRNP K successfully decreased hnRNP K mRNA and protein levels 24 h after transfection in A549 cells.Relative expressed doses of hnRNP K mRNA in lung cancer cells transfected by hnRNP K siRNAa and hnRNP K siRNAc respectively were 0.24±0.53 and 0.28±0.57 after 24 h，which were significantly lower than that in the control group（both Plt;0.01）.The gray scale values of hnRNP K protein were 0.23±0.11 and 0.28±0.09 respectively，which were also significantly lower than those in the control group（both Plt;0.05）.And pSUPER/hnRNP K siRNAa was the most effective one.Conclusion Eukaryotic expression vector of siRNA specific for hnRNP K is successfully constructed，which lays the basis for the function study of hnRNP K gene and its application in the treatment of lung carcinoma.
Abstract: Objective To generate a eukaryotic expression plasmid-pcDNA3.1/human tissue inhibitor of metalloproteinase-1(hTIMP-1)enhanced green fluorescent protein (EGFP), carrying hTIMP-1 and labeled with EGFP, and to examine the expression of hTIMP-1 in vascular smooth muscle cells (SMCs) transferred with hTIMP. Methods The recombinant plasmids of pcDNA3.1/hTIMP-1-EGFP were obtained bypolymerase chain reaction (PCR) amplification, splicing, and insertion of complementary deoxyribonucleic acid (cDNA) fragments of hTIMP-1 and EGFP. The target gene was transferred to the primarily cultured SMCs (pcDNA3.1/hTIMP-1-EGFP transferred group) by using cationic liposome mediated gene transfection technique. EGFP expression was detected by fluorescence microscopy, and the transfection rate was determined by flow cytometry. Reverse transcriptase polymerase chain reaction (RTPCR), Western blotting, and other techniques were used to detect the expression of hTIMP-1 gene. The biological activity of matrix metalloproteinase-2(MMP-2) and matrix metalloproteinase-9(MMP-9) were studied by zymographic analysis of gelatinases. Blank plasmidpcDNA3.1 transferred SMCs (blank plasmid pcDNA3.1 transferred group) and untransferred SMCs (untransferred group) were used as control. Results In cDNA3.1/hTIMP-1-EGFP transferred group,the growth ability of SMCs was profoundly inhibited, bright green fluorescence was observed by fluorescence microscopy 24 hours after transfection in SMCs,the rate of transfection analyzed with flow cytometry was 15%,RT-PCR results showed that the genome of hTIMP-1 transferred SMCs contained a 646 bp specific fragment of hTIMP-1 gene, Western blotting results proved hTIMP-1 protein expression in SMCs transferred by hTIMP-1, zymographic analysis of elatinases showed decreased activity of MMP-2 and MMP-9, compared to those in blank plasmidpcDNA3.1 transferred group and untransferred group, significant differences were observed (Plt;0.05). Conclusion The generation of a eukaryotic expression plasmid carrying TIMP-1 gene and its expression in SMCs provide a sound basis for hTIMP-1 gene therapy.
Objective To construct and screen neurite outgrowth inhibitory 66-samll interfering RNA (nogo66-siRNA) eukaryotic expression vectors of effective interference, so as to lay a foundation for further reconstruction of related viral vector. Methods The nogo66-siRNA fragments were designed and cloned into pGenesil-1.1, 4 plasmids of pGenesil-nogo66-siRNA-1, pGenesil-nogo66-siRNA-2, pGenesil-nogo66-siRNA-hk, and pGenesil-nogo66-siRNA-kb were obtained, sequenced and identified, then were transfected into C6 cell l ine. The transfection efficiency was measured by fluorescence microscope. RT-PCR and Western blot were used to detect the expression of nogo gene and select the plasmid of effective interference. Results DNA sequencing results showed interference sequences were correct. The bands of 800 bp and 4.3 kb were detected when pGenesil-nogo66-siRNAs were digested by Kpn I /Xho I. The expression of green fluorescent protein could be detected under fluorescence microscope, and the transfection efficiency was about 73%. RT-PCR and Western blot results showed that compared to non-transfected cells, the transfection of pGenesil-nogo66-siRNA-1 made the expression of nogo gene decl ine 22% and the expression of nogo protein decl ine 73%; the transfection of pGenesil-nogo66-siRNA-2 made the expression of nogo gene decl ine 28% and the expression of nogo protein decl ine 78%; the differences were significant (P lt; 0.05); and the transfection of pGenesil-nogo66-siRNA-hk and pGenesil-nogo66- siRNA-kb did not make the expressions of nogo gene and nogo protein decrease significantly (P gt; 0.05). Conclusion Nogo66-siRNA eukaryotic expression vector is successfully constructed, it lays an experimental foundation for repair of spinal cord injury.
Objective To clone human bone morphogenetic protein 2 ( BMP-2) gene and construct the gene’s eukaryotic expression vector. Methods The total RNA was extracted from human osteosarcoma cells, the human BMP-2 cDNA was amplified by RT-PCR and inserted into pGEM-T vector. The positive clones were screened out, and the n the recombinant plasmid was confirmed by restriction enzyme digestion, PCR and the analysis of nucleotide sequence. The BMP-2 cDNA in the pGEM-T cloning vec tor was inserted into the pcDNA3.1(+) eukaryotic expression vector. Results The agarose electrophoresis showed that the fragments of BMP-2, pGEMT and pcDNA3.1(+) were 1.2 kbp, 4.0 kbp and 5.0 kbp, respectively. The result of nucleotide sequence confirmed that the cDNA sequence, which was inserted into pGEM-T and pcDNA3.1(+) plasmid was human BMP-2. Conclusion The pcDNA3.1(+)-hBMP-2 eukaryotic vector can be successfully constructed.
Objective To establish a kind of gene therapy method of rheumatoid arthritis, to construct the interleukin-18-PE38 fusion gene expression vectorand to explore the expression of the fusion gene in the chondrocytes and 3T3 cells. Methods Interleukin-18-PE38 fusion gene was cleaved from plasmid PRKL459k-IL-18-PE38 by restriction enzyme digestion,then linked with vectors PsecTag2B and transformed into competence bacteria, positive clones were selected and confimed by restrictive enzyme(EcoRI) digestion assay. The rearrangement plasmid PsecTag2B-IL-18-PE38 was transfected into 3T3 cells and mouse chondrocytes by liposome protocol(experimental group),null vector was used as negative control, and the transient expression was identified by fluorescence immunocytochemical assay. Results Restrictive enzymes digestion analysis revealed thatthe length of theinterleukin-18-PE38 fusion gene was 6 000 bp. Fluorescence immunocytochemical method showed that fluorescence intensity of the experimental group is b,whilefluorescence intensity of the control group is weak. Conclusion the eukaryoticexpression vector PsecTag2B-IL-18-PE38 is established successfully which canbeexpressed in the 3T3 cells and mouse chodrocytes. Our results lay a foundationfor the further investigation for rheumatoid arthritis therapy.
OBJECTIVE: To construct eukaryotic expression vector of rat myogenin gene for further study on its functions in skeletal muscle denervated atrophy and repair. METHODS: The cloning vectors (containing full length of myogenin cDNA and two restriction sites: Hind III and Xho I) were first cut by two restriction endonuclease: Hind III and Xho I, and the same as the eukaryotic expression vector; then, the myogenin cDNA and the digested vector were ligated by T4 DNA ligase, and recombinant eukaryotic expression vector was formed. Its length was certificated by agarose gel electrophoresis analysis, digestion with Hind III and Xho I, PCR; and the rightness of the myogenin cDNA sequence was confirmed by sequencing. RESULTS: The results of agarose gel electrophoresis analysis, digestion, and PCR confirmed the right length of inserted DNA, which was the same as the myogenin cDNA, and the sequencing result of pcDNA3-myogenin was identical with the reported. CONCLUSION: pcDNA3-myogenin a eukaryotic expression vector, is successfully constructed.
OBJECTIVE: To construct eukaryotic expression plasmid of mouse myogenic regulatory factor MyoD gene for further study on MyoD gene function in molecular regulatory mechanism in skeletal muscle repair. METHODS: The plasmids PEMMBC2 beta 5 containing full cDNA length of MyoD inserted in EcoRI restriction site, were first propagated in Escherichia coli DH5a, then extracted and purified with the Wizard Plus Minipreps DNA Purification System (Promega, USA). The coding sequence of MyoD in PEMMBC2 beta 5 was confirmed by agarose gel electrophoresis and DNA sequence analysis. After plasmids PEMMBC2 beta 5 and plasmids pcDNA3-neo were prepared by digestion with EcoRI, the MyoD cDNA fragment was inserted into EcoRI site in pcDNA3-neo eukaryotic expression vector, and pcDNA3/MyoD was formed. The pcDNA3/MyoD, digested with restriction enzymes, was found to contain the MyoD cDNA sequence by agarose gel electrophoresis analysis. RESULTS: The extracted and purified PEMMBC2 beta 5 contained the correct nucleotide sequence for the full length of MyoD cDNA fragment. The MyoD cDNA fragment had been inserted into the eukaryotic expression plasmid pcDNA3-neo, which formed the pcDNA3/MyoD. CONCLUSION: The pcDNA3/MyoD, a eukaryotic expression plasmid, for MyoD is constructed successfully.
Objective To explore the effect of vascular endothelial growth factor-C (VEGF-C) gene transfection on the expression level of VEGF-C in human breast cancer MCF-7 cell. Methods The constructed VEGF-C gene eukaryotic expression vector was transfected into the human breast cancer MCF-7 cell by using lipofectamine transfection reagents， and the positive cell clones were obtained through G418 selection after transfection. The expressions of VEGF-C mRNA and protein were detected by RT-PCR and Western blot respectively. Results Following the transfection of the VEGF-C recombination plasmid, there were significant differences on the expression levels of VEGF-C mRNA and protein between pcDNA3.1-VEGF-C transfection group and pcDNA3.1 transfection group （12.382±2.183 vs 6.039±1.950, P＜0.01; 0.971±0.186 vs 0.594±0.196, P＜0.05). Conclusion With the transfection of pcDNA3.1-VEGF-C vector by using the liposome, the expression levels of VEGF-C mRNA and protein rise up in breast cancer MCF-7 cell.
ObjectiveTo construct eukaryotic expression vector of pEGFP-N3-TFPI-2, and to provide the base of studying the function of TFPI-2 gene. MethodsExtraction of total RNA from placental tissue was extracted at first, and then reverse transcriptase synthesis of cDNA was carried out. The cDNA fragment of TFPI-2 gene which was obtained by real time PCR (RT-PCR) was inserted into eukaryotic expression vector of pEGFP-N3. After double digestion with XhoⅠand KpnⅠ, the recombinant vector of pEGFP-N3-TFPI-2 was identified in 1% agarose gel electrophoresis and was tested by the sequence analysis. Then, the recombinant vector of pEGFP-N3-TFPI-2 (transfection group) and vector of pEGFP-N3 (blank control group) were transfected into Top10 competent cells with LipofectamineTM 2000, but no transfection-related treatment was performed in cells of untransfection group. Western blot method was used to test the expression of TFPI-2 protein in cells of 3 groups. ResultsThe purity of total RNA which were analysis by agarose gel electrophoresis and spectrophotometry were fit for PCR. After coding of TFPI-2 gene fragment and eukaryotic expression vector of pEGFP-N3, the recombinant plasmid of pEGFP-N3-TFPI-2 were got double digestion with XhoⅠand KpnⅠ, and was identified in 1% agarose gel electrophoresis, of which showing that there were 2 specific amplification of strips at 708 bp and 4 700 bp. Result of sequence analysis confirmed that the size of recombinant vector was consistent with the theoretical value. Results of Western blot showed that the expression of TFPI-2 protein in transfection group (0.657 3±0.032 5) was higher than those of blank control group (0.301 7±0.028 7) and untransfection group (0.314 3±0.026 6), P < 0.01. ConclusionsThe eukaryotic expression vector of pEGFP-N3-TFPI-2 has been constructed successfully, which laiding the foundation for the analysis about function of TFPI-2 gene.