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1.
目的:探讨siRNA 沉默整合素茁1 基因对子宫内膜癌细胞侵袭、转移的影响。方法:选取子宫内膜癌ECC-1细胞系(ER阳性)
和KLE细胞系(ER阴性),分别转染Integrin beta1 siRNA 质粒(Integrin beta1 siRNA 组)、无义序列siRNA质粒(无义序列对照组)和空载
质粒(空载对照组),利用实时荧光定量PCR 检测各组细胞中Integrin 茁1 mRNA的表达,Western blot 检测各组细胞中Integrin beta1、
beta-catenin 和C-Myc 蛋白的表达,Transwell 小室检测各组细胞迁移和侵袭能力,MTT 法检测各组细胞的增殖情况。结果:Integrin
beta1 siRNA 组ECC-1 细胞和KLE 细胞中Integrin beta1 mRNA 和蛋白相对表达量均低于无义序列对照组和空载对照组(P<0.05);
Integrin beta 1 siRNA组ECC-1 细胞和KLE细胞中beta-catenin 蛋白和C-Myc 蛋白相对表达量均低于无义序列对照组和空载对照组,
差异均有统计学意义(P<0.05);Integrin beta1 siRNA组ECC-1 细胞和KLE 细胞中迁移细胞数和侵袭细胞数均低于无义序列对照组
和空载对照组(P<0.05);Integrin beta1 siRNA 组ECC-1细胞和KLE 细胞的A 值均低于无义序列对照组和空载对照组(P<0.05)。结
论:特异性抑制Integrin beta1 基因可抑制子宫内膜癌细胞迁移、侵袭和增殖,可能与抑制Wnt信号传导有关。 相似文献
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Bin Zhu Chongwen Yang Hongrong Liu Lingpeng Cheng Feng Song Songjun Zeng Xiaojun Huang Gang Ji Ping Zhu 《Journal of molecular biology》2014
Many double-stranded RNA (dsRNA) viruses are capable of transcribing and capping RNA within a stable icosahedral viral capsid. The turret of turreted dsRNA viruses belonging to the family Reoviridae is formed by five copies of the turret protein, which contains domains with both 7-N-methyltransferase and 2′-O-methyltransferase activities, and serves to catalyze the methylation reactions during RNA capping. Cypovirus of the family Reoviridae provides a good model system for studying the methylation reactions in dsRNA viruses. Here, we present the structure of a transcribing cypovirus to a resolution of ~ 3.8 Å by cryo-electron microscopy. The binding sites for both S-adenosyl-l-methionine and RNA in the two methyltransferases of the turret were identified. Structural analysis of the turret in complex with RNA revealed a pathway through which the RNA molecule reaches the active sites of the two methyltransferases before it is released into the cytoplasm. The pathway shows that RNA capping reactions occur in the active sites of different turret protein monomers, suggesting that RNA capping requires concerted efforts by at least three turret protein monomers. Thus, the turret structure provides novel insights into the precise mechanisms of RNA methylation. 相似文献
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Nevena Cvetesic Mirna Bilus Ita Gruic-Sovulj 《The Journal of biological chemistry》2015,290(22):13981-13991
Aminoacyl-tRNA synthetases catalyze ATP-dependent covalent coupling of cognate amino acids and tRNAs for ribosomal protein synthesis. Escherichia coli isoleucyl-tRNA synthetase (IleRS) exploits both the tRNA-dependent pre- and post-transfer editing pathways to minimize errors in translation. However, the molecular mechanisms by which tRNAIle organizes the synthetic site to enhance pre-transfer editing, an idiosyncratic feature of IleRS, remains elusive. Here we show that tRNAIle affects both the synthetic and editing reactions localized within the IleRS synthetic site. In a complex with cognate tRNA, IleRS exhibits a 10-fold faster aminoacyl-AMP hydrolysis and a 10-fold drop in amino acid affinity relative to the free enzyme. Remarkably, the specificity against non-cognate valine was not improved by the presence of tRNA in either of these processes. Instead, amino acid specificity is determined by the protein component per se, whereas the tRNA promotes catalytic performance of the synthetic site, bringing about less error-prone and kinetically optimized isoleucyl-tRNAIle synthesis under cellular conditions. Finally, the extent to which tRNAIle modulates activation and pre-transfer editing is independent of the intactness of its 3′-end. This finding decouples aminoacylation and pre-transfer editing within the IleRS synthetic site and further demonstrates that the A76 hydroxyl groups participate in post-transfer editing only. The data are consistent with a model whereby the 3′-end of the tRNA remains free to sample different positions within the IleRS·tRNA complex, whereas the fine-tuning of the synthetic site is attained via conformational rearrangement of the enzyme through the interactions with the remaining parts of the tRNA body. 相似文献
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《Molecular cell》2020,77(5):1055-1065.e4
Download : Download video (66MB) 相似文献
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