BACKGROUND: Hypermethylation of the promoter region is one of the major mechanisms of tumor suppressor gene inactivation. DNA methyltransferase 3b (DNMT3b), an enzyme that participates in the establishment of de novo ...BACKGROUND: Hypermethylation of the promoter region is one of the major mechanisms of tumor suppressor gene inactivation. DNA methyltransferase 3b (DNMT3b), an enzyme that participates in the establishment of de novo methylation patterns, is highly expressed in many tumor cells and tissues, and it is closely associated with hypermethylation of the promoter of tumor suppressor genes. The aim of this study was to explore the effect of transfection with antisense DNMT3b gene eukaryotic expression plasmid on the expression of the DNMT3b gene in human biliary tract carcinoma cell. METHODS: The constructed antisense DNMT3b gene eukaryotic expression plasmid was transfected into the human biliary tract carcinoma cell line QBC-939 with lipofectamine transfection reagent, and positive cell clones were formed using G418 selection after transfection. The constructed recombinant plasmid was transfected into QBC-939 cells successfully and was confirmed by amplification of the exogenous neo^R gene with the polymerase chain reaction method. The expression of DNMT3b gene mRNA and protein was detected by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and flow cytometry respectively. RESULTS: Following transfection, the mRNA level of the DNMT3b gene decreased from 0.956±0.053 to 0.209±0.023, and the protein level of the DNMT3b gene also decreased from (75.38±3.22)% to (29.87±3.46)%. Very significant differences were observed both at the transcription and posttranscription levels in the expression of the DNMT3b gene between the non-tranfection group and the antisense DN- MT3b gene eukaryotic expression plasmid transfection group (P<0.01). CONCLUSIONS: Transfection with the antisense DNMT3b gene eukaryotic expression plasmid can significantly reduce the expression level of the DNMT3b gene in the human biliary tract carcinoma cell line QBC-939. This study may provide a valid method to investigate the function of the DNMT3b gene and its role in biliary tract carcinoma.展开更多
从口蹄疫病毒(foot-and-m ou th d isease v irus,FM DV)细胞培养物中提取总RNA,经一步法RT-PCR获得了长约230 bp的3B基因片段,将PCR产物连接到pM D-18T载体上并测序,用B amHⅠ与H indⅢ双酶切后,将3B基因融合到pGEX-KG载体上形成表达质...从口蹄疫病毒(foot-and-m ou th d isease v irus,FM DV)细胞培养物中提取总RNA,经一步法RT-PCR获得了长约230 bp的3B基因片段,将PCR产物连接到pM D-18T载体上并测序,用B amHⅠ与H indⅢ双酶切后,将3B基因融合到pGEX-KG载体上形成表达质粒pGEX-KG-3B,转化到BL 21(DE 3)中在27℃诱导表达,将表达产物进行SDS-PAGE和蛋白质斑点EL ISA。结果表明3B基因主要以可溶形式高效表达,表达产物具有免疫原性。以纯化的表达产物为抗原建立了间接酶联免疫吸附试验(I-EL ISA)。方阵滴定其最佳包被浓度是6.1μg/孔,最佳血清稀释倍数为1∶80,通过测定36份FM DV阴性血清,确定了该方法的阳性判定标准。结果表明,该方法特异性强、重复性好;用3B-EL ISA方法与美国联合生物医学公司(U B I)生产的合成肽检测试剂盒U B I○RFM DV N S-EL ISA对比检测44份血清样品,符合率为93.1%。证明3B-EL ISA方法可用于口蹄疫的鉴别诊断。展开更多
目的构建反义DNA甲基化酶3b(DNM T 3b)基因片断真核表达载体,为研究DNM T 3b基因功能提供工具。方法根据DNM T 3b基因cDNA序列中编码序列设计PCR引物,在上下游引物5′端分别添加X baⅠ和K pnⅠ酶切位点,RT-PCR从胆管癌细胞QBC-939中获得...目的构建反义DNA甲基化酶3b(DNM T 3b)基因片断真核表达载体,为研究DNM T 3b基因功能提供工具。方法根据DNM T 3b基因cDNA序列中编码序列设计PCR引物,在上下游引物5′端分别添加X baⅠ和K pnⅠ酶切位点,RT-PCR从胆管癌细胞QBC-939中获得485bp的DNA片断;将该片断反向插入真核表达载体pcDNA 3.1(+)的多克隆位点,构建反义DNM T 3b基因片断真核表达载体,并用PCR、酶切法和DNA测序鉴定。结果PCR鉴定得到467bp特异条带,双酶切鉴定得到471bp片断和5.4kb载体片断,DNA测序说明插入片断序列正确。结论本研究构建的反义DNM T 3b基因片断真核表达载体可为进一步研究DNM T 3b基因功能提供实验工具。展开更多
目的构建SF3B1突变等位基因敲除的人葡萄膜黑色素瘤细胞模型,筛选靶向抑制SF3B1突变型葡萄膜黑色素瘤的药物。方法通过主成分分析法对来自TCGA数据库的葡萄膜黑色素瘤患者分成SF3B1野生型和突变型两组进行转录组可变剪接分析,研究SF3B1...目的构建SF3B1突变等位基因敲除的人葡萄膜黑色素瘤细胞模型,筛选靶向抑制SF3B1突变型葡萄膜黑色素瘤的药物。方法通过主成分分析法对来自TCGA数据库的葡萄膜黑色素瘤患者分成SF3B1野生型和突变型两组进行转录组可变剪接分析,研究SF3B1突变对可变剪接的影响。通过CRISPR-Cas9技术敲除Mel202细胞株的SF3B1突变等位基因,Sanger测序明确基因编辑的序列。MTT法和克隆形成实验检测Mel202细胞株和基因敲除mut-KO细胞株的增殖,RT-PCR琼脂糖电泳结合Sanger测序检测Mel202细胞株和基因敲除mut-KO细胞株的可变剪接事件。MTT法从上市药物库和生物活性化合物库筛选对SF3B1突变细胞具有选择性抑制活性的药物。结果选择性敲除Mel202细胞SF3B1突变等位基因促进了细胞的增殖(5.47±0.32 vs 10.17±0.27),改变了ZDHHC16和DYNLL1转录本的可变剪接。化合物库筛选结果显示13个化合物对SF3B1突变的Mel202细胞具有选择性的抑制活性(Fold change≥2),其中上市药物tetrandrine和lapatinib显示了较好的量效曲线。结论本研究为SF3B1突变的葡萄膜黑色素瘤患者提供了细胞筛选模型和潜在的个体化治疗药物。展开更多
BACKGROUND: Alterations in DNA methylation occur during the pathogenesis of human tumors. In this study, we investigated the influence of DNA methyltransferase 3b (DNMT3b) on fragile histidine trial (FHIT) expression ...BACKGROUND: Alterations in DNA methylation occur during the pathogenesis of human tumors. In this study, we investigated the influence of DNA methyltransferase 3b (DNMT3b) on fragile histidine trial (FHIT) expression and on DNA methylation of the FHIT promoter region in the hepatoma cell line SMMC-7721. METHODS: DNMT3b siRNA was used to down-regulate DNMT3b expression. DNMT3b and FHIT proteins were determined by Western blotting. Methylation-specific PCR was used to analyze the methylation status of the FHIT gene. RESULTS: After DNMT3b siRNA transfection, the expression of DNMT3b was inhibited in SMMC-7721 cells, and the expression of FHIT was significantly higher than that in the control group. There was no significant difference in methylation status between the DNMT3b siRNA transfected cells and control cells. CONCLUSION: DNMT3b may play an important role in regulation of FHIT expression in hepatoma SMMC-7721 cells, but not through methylation of the FHIT promoter. (Hepatobiliary Pancreat Dis Int 2009; 8: 273-277)展开更多
With 17% of all crop area, wheat is the staple food for 40% of the world’s population. Improvement in bread wheat quality and yield in the context of sustainable agriculture is needed in the next decades to meet human
基金This study was supported by a grant from Hi-Tech Research and Development Program of China (863 Program) (No. 2002AA214061).
文摘BACKGROUND: Hypermethylation of the promoter region is one of the major mechanisms of tumor suppressor gene inactivation. DNA methyltransferase 3b (DNMT3b), an enzyme that participates in the establishment of de novo methylation patterns, is highly expressed in many tumor cells and tissues, and it is closely associated with hypermethylation of the promoter of tumor suppressor genes. The aim of this study was to explore the effect of transfection with antisense DNMT3b gene eukaryotic expression plasmid on the expression of the DNMT3b gene in human biliary tract carcinoma cell. METHODS: The constructed antisense DNMT3b gene eukaryotic expression plasmid was transfected into the human biliary tract carcinoma cell line QBC-939 with lipofectamine transfection reagent, and positive cell clones were formed using G418 selection after transfection. The constructed recombinant plasmid was transfected into QBC-939 cells successfully and was confirmed by amplification of the exogenous neo^R gene with the polymerase chain reaction method. The expression of DNMT3b gene mRNA and protein was detected by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and flow cytometry respectively. RESULTS: Following transfection, the mRNA level of the DNMT3b gene decreased from 0.956±0.053 to 0.209±0.023, and the protein level of the DNMT3b gene also decreased from (75.38±3.22)% to (29.87±3.46)%. Very significant differences were observed both at the transcription and posttranscription levels in the expression of the DNMT3b gene between the non-tranfection group and the antisense DN- MT3b gene eukaryotic expression plasmid transfection group (P<0.01). CONCLUSIONS: Transfection with the antisense DNMT3b gene eukaryotic expression plasmid can significantly reduce the expression level of the DNMT3b gene in the human biliary tract carcinoma cell line QBC-939. This study may provide a valid method to investigate the function of the DNMT3b gene and its role in biliary tract carcinoma.
文摘从口蹄疫病毒(foot-and-m ou th d isease v irus,FM DV)细胞培养物中提取总RNA,经一步法RT-PCR获得了长约230 bp的3B基因片段,将PCR产物连接到pM D-18T载体上并测序,用B amHⅠ与H indⅢ双酶切后,将3B基因融合到pGEX-KG载体上形成表达质粒pGEX-KG-3B,转化到BL 21(DE 3)中在27℃诱导表达,将表达产物进行SDS-PAGE和蛋白质斑点EL ISA。结果表明3B基因主要以可溶形式高效表达,表达产物具有免疫原性。以纯化的表达产物为抗原建立了间接酶联免疫吸附试验(I-EL ISA)。方阵滴定其最佳包被浓度是6.1μg/孔,最佳血清稀释倍数为1∶80,通过测定36份FM DV阴性血清,确定了该方法的阳性判定标准。结果表明,该方法特异性强、重复性好;用3B-EL ISA方法与美国联合生物医学公司(U B I)生产的合成肽检测试剂盒U B I○RFM DV N S-EL ISA对比检测44份血清样品,符合率为93.1%。证明3B-EL ISA方法可用于口蹄疫的鉴别诊断。
文摘目的构建反义DNA甲基化酶3b(DNM T 3b)基因片断真核表达载体,为研究DNM T 3b基因功能提供工具。方法根据DNM T 3b基因cDNA序列中编码序列设计PCR引物,在上下游引物5′端分别添加X baⅠ和K pnⅠ酶切位点,RT-PCR从胆管癌细胞QBC-939中获得485bp的DNA片断;将该片断反向插入真核表达载体pcDNA 3.1(+)的多克隆位点,构建反义DNM T 3b基因片断真核表达载体,并用PCR、酶切法和DNA测序鉴定。结果PCR鉴定得到467bp特异条带,双酶切鉴定得到471bp片断和5.4kb载体片断,DNA测序说明插入片断序列正确。结论本研究构建的反义DNM T 3b基因片断真核表达载体可为进一步研究DNM T 3b基因功能提供实验工具。
文摘目的构建SF3B1突变等位基因敲除的人葡萄膜黑色素瘤细胞模型,筛选靶向抑制SF3B1突变型葡萄膜黑色素瘤的药物。方法通过主成分分析法对来自TCGA数据库的葡萄膜黑色素瘤患者分成SF3B1野生型和突变型两组进行转录组可变剪接分析,研究SF3B1突变对可变剪接的影响。通过CRISPR-Cas9技术敲除Mel202细胞株的SF3B1突变等位基因,Sanger测序明确基因编辑的序列。MTT法和克隆形成实验检测Mel202细胞株和基因敲除mut-KO细胞株的增殖,RT-PCR琼脂糖电泳结合Sanger测序检测Mel202细胞株和基因敲除mut-KO细胞株的可变剪接事件。MTT法从上市药物库和生物活性化合物库筛选对SF3B1突变细胞具有选择性抑制活性的药物。结果选择性敲除Mel202细胞SF3B1突变等位基因促进了细胞的增殖(5.47±0.32 vs 10.17±0.27),改变了ZDHHC16和DYNLL1转录本的可变剪接。化合物库筛选结果显示13个化合物对SF3B1突变的Mel202细胞具有选择性的抑制活性(Fold change≥2),其中上市药物tetrandrine和lapatinib显示了较好的量效曲线。结论本研究为SF3B1突变的葡萄膜黑色素瘤患者提供了细胞筛选模型和潜在的个体化治疗药物。
基金supported by a grant from the National Natural Science Foundation of China(No.30571814)
文摘BACKGROUND: Alterations in DNA methylation occur during the pathogenesis of human tumors. In this study, we investigated the influence of DNA methyltransferase 3b (DNMT3b) on fragile histidine trial (FHIT) expression and on DNA methylation of the FHIT promoter region in the hepatoma cell line SMMC-7721. METHODS: DNMT3b siRNA was used to down-regulate DNMT3b expression. DNMT3b and FHIT proteins were determined by Western blotting. Methylation-specific PCR was used to analyze the methylation status of the FHIT gene. RESULTS: After DNMT3b siRNA transfection, the expression of DNMT3b was inhibited in SMMC-7721 cells, and the expression of FHIT was significantly higher than that in the control group. There was no significant difference in methylation status between the DNMT3b siRNA transfected cells and control cells. CONCLUSION: DNMT3b may play an important role in regulation of FHIT expression in hepatoma SMMC-7721 cells, but not through methylation of the FHIT promoter. (Hepatobiliary Pancreat Dis Int 2009; 8: 273-277)
文摘With 17% of all crop area, wheat is the staple food for 40% of the world’s population. Improvement in bread wheat quality and yield in the context of sustainable agriculture is needed in the next decades to meet human
