利用RNA干涉文库进行大规模高通量的功能基因扫描,已成为发现新功能基因的重要方式和手段.为了寻找在细胞增殖和分化过程中的新功能基因,根据斯坦福大学公布的与人类胚胎干细胞和造血干细胞增殖和分化过程中有关基因的基因芯片的分析结...利用RNA干涉文库进行大规模高通量的功能基因扫描,已成为发现新功能基因的重要方式和手段.为了寻找在细胞增殖和分化过程中的新功能基因,根据斯坦福大学公布的与人类胚胎干细胞和造血干细胞增殖和分化过程中有关基因的基因芯片的分析结果,组建了与细胞增殖和分化有关的RNA限制性干涉文库.该文库包括靶向各类基因的载体,如包括转录因子、各类蛋白激酶、细胞周期调控蛋白以及一些未知功能基因在内的225个基因.利用这个限制性RNA干涉文库对控制HeLa细胞增殖的基因进行筛选.并通过WST-1高通量检测,发现了2个同HeLa细胞增殖相关的基因:CNKSR3(Homo sapiens CNKSR family member 3)和Fosl2(Homo sapiens FOS-like antigen 2),并初步证实:沉默CNKSR3会促进HeLa细胞的增殖,而沉默Fosl2则抑制HeLa细胞的增殖功能.展开更多
Small interfering RNA (siRNA) and microRNA (miRNA) are small RNAs of 18-25 nucleotides (nt) in length that play important roles in regulating gene expression. They are incorporated into an RNA-induced silencing comple...Small interfering RNA (siRNA) and microRNA (miRNA) are small RNAs of 18-25 nucleotides (nt) in length that play important roles in regulating gene expression. They are incorporated into an RNA-induced silencing complex (RISC) and serve as guides for silencing their corresponding target mRNAs based on complementary base-pairing. The promise of gene silencing has led many researchers to consider siRNA as an anti-viral tool. However, in long-term settings, many viruses appear to escape from this therapeutical strategy. An example of this may be seen in the case of human immunodeficiency virus type-1 (HIV-1) which is able to evade RNA silencing by either mutating the siRNA- targeted sequence or by encoding for a partial suppressor of RNAi (RNA interference). On the other hand, because miRNA targeting does not require absolute complementarity of base-pairing, mutational escape by viruses from miRNA- specified silencing may be more difficult to achieve. In this review, we discuss stratagems used by various viruses to avoid the cells’ antiviral si/mi-RNA defenses and notions of how viruses might control and regulate host cell genes by encoding viral miRNAs (vmiRNAs).展开更多
OBJECTIVE To construct a eukaryotic expression vector for RNA interference of the human cyclinD1 gene, and to detect its interference effect in human ovarian cancer cells （HO-8910）. METHODS Four target gene segments...OBJECTIVE To construct a eukaryotic expression vector for RNA interference of the human cyclinD1 gene, and to detect its interference effect in human ovarian cancer cells （HO-8910）. METHODS Four target gene segments were synthesized and cloned into the pSUPER vector respectively to construct four recombinant eukaryotic expression vectors, pSUPER-C1-4. The four recombinant vectors were identified by enzyme digestion analysis and DNA sequencing. Then HO-8910 cells were transfected with the pSUPER-C1-4 vectors and subjected to G418 selection. In G418-resistant cells, the interference effect was detected by RT-PCR. RESULTS Enzyme digestion analysis and DNA sequencing showed that the target segments were cloned into the pSUPER vector. The four recombinant vectors inhibited transcription of the cyclinD1 gene. The pSUPER-C2 vector had a better interference effect. CONCLUSION The sequence-specific siRNA effectively interfered with expression of the cyclinD1 gene that was selected. The transcription and expression of the cyclinD1 gene were inhibited effectively by the constructed RNAi eukaryotic expression vectors in the ovarian cancer cells. These results indicate that it is possible to search for a new tumor gene therapy method,展开更多
Purpose: The transforming growth factor beta1 (TGFB1) pathway has been linked to fibrosis in several tissues including skin, liver, kidney and the cornea. In this study, a RNA interference-based approach using siRNAs ...Purpose: The transforming growth factor beta1 (TGFB1) pathway has been linked to fibrosis in several tissues including skin, liver, kidney and the cornea. In this study, a RNA interference-based approach using siRNAs targeting three critical scarring genes, TGFB1, TGFB receptor 2 (TGFBR2) and connective tissue growth factor (CTGF), was tested for effects on reducing alpha smooth muscle actin (SMA) and corneal scarring (haze) in excimer laser ablated rabbit corneas. Methods: Levels of TGFB1 and CTGF mRNAs were measured using qRT-PCR in the epithelial and endothelial cell layers of normal and excimer ablated rabbit corneas at 30 minutes, 1 day and 2 days after ablation. Two different scarring models were utilized to assess the effects of the triple siRNA combination on corneal scarring. In the first model, rabbit corneas were unevenly ablated creating a mesh pattern then treated immediately with the triple siRNA combination. After 1 day the ablated areas of corneas were collected and levels of mRNAs for TGFB1, TGFBR2 and CTGF were measured. After 14 days, levels of mRNA for SMA were measured and SMA protein immunolocalized in frozen sections. In the second model, rabbit corneas were uniformly ablated to a depth of 155 microns followed by three daily doses of the triple combination of siRNA. After 14 days, corneas were photographed and images were analyzed using Image J software to assess corneal scarring. Corneas were also analyzed for levels of SMA mRNA. Results: In both unwounded and wounded corneas, levels of TGFB1 and CTGF mRNA were always significantly higher in endothelial cells than in epithelial cells (10 to 30 fold). Thirty minutes after injury, levels of both TGFB1 and CTGF mRNAs increased approximately 20-fold in both epithelial and endothelial cells, and further increased approximately 60-fold in 2 days. In the first therapeutic experiment with a single siRNA dose, two of three rabbits showed substantial reductions of all three target genes after 1 day with a maximum knock down of 80% of TGFb 1, 50% reduction of TGFBR2 and 40% reduction of CTGF mRNA levels and reduced SMA mRNA at day 14. In the second therapeutic experiment with multiple doses of siRNA treatment, both rabbits showed a ~22% reduction in scar formation at day 14 as calculated by image analysis. There was also a corresponding 70% and 60% reduction of SMA RNA expression. Conclusion: These results demonstrate that both TGFB1 and CTGF dramatically increase in rabbit corneal epithelial and endothelial cells after injury. Treatment of excimer ablated rabbit corneas with a triple combination of siRNAs effectively reduced levels of the target genes and SMA, leading to reduced corneal scarring at 14 days, suggesting that this triple siRNA combination may be an effective new approach to reducing scarring in cornea and other tissues.展开更多
文摘利用RNA干涉文库进行大规模高通量的功能基因扫描,已成为发现新功能基因的重要方式和手段.为了寻找在细胞增殖和分化过程中的新功能基因,根据斯坦福大学公布的与人类胚胎干细胞和造血干细胞增殖和分化过程中有关基因的基因芯片的分析结果,组建了与细胞增殖和分化有关的RNA限制性干涉文库.该文库包括靶向各类基因的载体,如包括转录因子、各类蛋白激酶、细胞周期调控蛋白以及一些未知功能基因在内的225个基因.利用这个限制性RNA干涉文库对控制HeLa细胞增殖的基因进行筛选.并通过WST-1高通量检测,发现了2个同HeLa细胞增殖相关的基因:CNKSR3(Homo sapiens CNKSR family member 3)和Fosl2(Homo sapiens FOS-like antigen 2),并初步证实:沉默CNKSR3会促进HeLa细胞的增殖,而沉默Fosl2则抑制HeLa细胞的增殖功能.
文摘Small interfering RNA (siRNA) and microRNA (miRNA) are small RNAs of 18-25 nucleotides (nt) in length that play important roles in regulating gene expression. They are incorporated into an RNA-induced silencing complex (RISC) and serve as guides for silencing their corresponding target mRNAs based on complementary base-pairing. The promise of gene silencing has led many researchers to consider siRNA as an anti-viral tool. However, in long-term settings, many viruses appear to escape from this therapeutical strategy. An example of this may be seen in the case of human immunodeficiency virus type-1 (HIV-1) which is able to evade RNA silencing by either mutating the siRNA- targeted sequence or by encoding for a partial suppressor of RNAi (RNA interference). On the other hand, because miRNA targeting does not require absolute complementarity of base-pairing, mutational escape by viruses from miRNA- specified silencing may be more difficult to achieve. In this review, we discuss stratagems used by various viruses to avoid the cells’ antiviral si/mi-RNA defenses and notions of how viruses might control and regulate host cell genes by encoding viral miRNAs (vmiRNAs).
文摘OBJECTIVE To construct a eukaryotic expression vector for RNA interference of the human cyclinD1 gene, and to detect its interference effect in human ovarian cancer cells （HO-8910）. METHODS Four target gene segments were synthesized and cloned into the pSUPER vector respectively to construct four recombinant eukaryotic expression vectors, pSUPER-C1-4. The four recombinant vectors were identified by enzyme digestion analysis and DNA sequencing. Then HO-8910 cells were transfected with the pSUPER-C1-4 vectors and subjected to G418 selection. In G418-resistant cells, the interference effect was detected by RT-PCR. RESULTS Enzyme digestion analysis and DNA sequencing showed that the target segments were cloned into the pSUPER vector. The four recombinant vectors inhibited transcription of the cyclinD1 gene. The pSUPER-C2 vector had a better interference effect. CONCLUSION The sequence-specific siRNA effectively interfered with expression of the cyclinD1 gene that was selected. The transcription and expression of the cyclinD1 gene were inhibited effectively by the constructed RNAi eukaryotic expression vectors in the ovarian cancer cells. These results indicate that it is possible to search for a new tumor gene therapy method,
文摘Purpose: The transforming growth factor beta1 (TGFB1) pathway has been linked to fibrosis in several tissues including skin, liver, kidney and the cornea. In this study, a RNA interference-based approach using siRNAs targeting three critical scarring genes, TGFB1, TGFB receptor 2 (TGFBR2) and connective tissue growth factor (CTGF), was tested for effects on reducing alpha smooth muscle actin (SMA) and corneal scarring (haze) in excimer laser ablated rabbit corneas. Methods: Levels of TGFB1 and CTGF mRNAs were measured using qRT-PCR in the epithelial and endothelial cell layers of normal and excimer ablated rabbit corneas at 30 minutes, 1 day and 2 days after ablation. Two different scarring models were utilized to assess the effects of the triple siRNA combination on corneal scarring. In the first model, rabbit corneas were unevenly ablated creating a mesh pattern then treated immediately with the triple siRNA combination. After 1 day the ablated areas of corneas were collected and levels of mRNAs for TGFB1, TGFBR2 and CTGF were measured. After 14 days, levels of mRNA for SMA were measured and SMA protein immunolocalized in frozen sections. In the second model, rabbit corneas were uniformly ablated to a depth of 155 microns followed by three daily doses of the triple combination of siRNA. After 14 days, corneas were photographed and images were analyzed using Image J software to assess corneal scarring. Corneas were also analyzed for levels of SMA mRNA. Results: In both unwounded and wounded corneas, levels of TGFB1 and CTGF mRNA were always significantly higher in endothelial cells than in epithelial cells (10 to 30 fold). Thirty minutes after injury, levels of both TGFB1 and CTGF mRNAs increased approximately 20-fold in both epithelial and endothelial cells, and further increased approximately 60-fold in 2 days. In the first therapeutic experiment with a single siRNA dose, two of three rabbits showed substantial reductions of all three target genes after 1 day with a maximum knock down of 80% of TGFb 1, 50% reduction of TGFBR2 and 40% reduction of CTGF mRNA levels and reduced SMA mRNA at day 14. In the second therapeutic experiment with multiple doses of siRNA treatment, both rabbits showed a ~22% reduction in scar formation at day 14 as calculated by image analysis. There was also a corresponding 70% and 60% reduction of SMA RNA expression. Conclusion: These results demonstrate that both TGFB1 and CTGF dramatically increase in rabbit corneal epithelial and endothelial cells after injury. Treatment of excimer ablated rabbit corneas with a triple combination of siRNAs effectively reduced levels of the target genes and SMA, leading to reduced corneal scarring at 14 days, suggesting that this triple siRNA combination may be an effective new approach to reducing scarring in cornea and other tissues.
