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miRNAs的表达调控机制   总被引:2,自引:0,他引:2       下载免费PDF全文
microRNAs(miRNAs)是一类在转录后基因调控中发挥功能的非编码小RNAs,在发育、生长和分化等过程中发挥重要作用.至今已经在动物、植物和微生物等不同生物体中鉴定出来数千种miRNAs. miRNAs可以通过降解mRNA或抑制蛋白翻译的方式调节特异基因表达.生物体内约30%的基因都受miRNAs的调节.miRNAs的表达与功能受到转录因子、表观遗传学、多核苷酸多态性及其RNA编辑等多种因素的调节.此外,特异miRNA基因敲除的成功为研究miRNAs功能提供了有力的实验模型.  相似文献   

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周学  杜宜兰  金萍  马飞 《遗传》2015,37(9):855-864
MicroRNAs(miRNAs)是一类长度约为22nt的内源性非编码RNA,通过与靶基因转录本互补结合调控基因的表达。近年来,研究发现miRNA与癌症发生密切相关,miRNA可以直接充当癌基因或者抑癌基因而影响肿瘤的发生和生长。为更进一步揭示癌症相关miRNA的特征及靶基因的功能,文章通过数据库搜索及文献检索,在人类基因组中发现了475个癌症相关miRNA,系统地比较了癌症相关miRNA与非癌症miRNA以及基因内和基因间区癌症相关miRNA在保守性、SNP位点分布、癌谱及转录调控等特性。研究发现,癌症相关miRNA比非癌症miRNA保守性要强,发生SNP概率比较低,同时发现miRNA所涉及癌症数目与保守性成正相关。基因组定位分析发现,癌症相关miRNA比非癌症miRNA更倾向于成簇存在。进一步对宿主基因、癌症相关miRNA及作用的靶基因与癌症发生进行关联分析,发现一些非癌症miRNA的宿主基因倾向于被癌症miRNA作用。本研究结果为深入理解miRNA与癌症之间的关系,以及进一步为miRNA作为癌症诊断指示物提供理论依据。  相似文献   

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Scutellarin is an herbal agent which can exert anti-neuroinflammatory effects in activated microglia. However, it remains uncertain if it can inhibit microglia-mediated neuroinflammation by regulating miRNAs. This study sought to elucidate the upstream regulatory mechanisms by endogenous microRNAs and its target gene in activated microglia in lipopolysaccharide (LPS)-induced BV-2 microglia. Results show that scutellarin suppressed the expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and inducible nitric oxide synthase (iNOS) significantly in LPS-stimulated BV-2 microglia. As with the results of miRNAs function classification in vitro, the expression levels of mir-7036a-5p are upregulated in LPS-activated BV-2 microglia, but are downregulated by scutellarin. Rescue experiments indicated that mir-7036a-5p is a pro-inflammatory factor in activated BV-2 microglia. mir-7036a-5p agomir promoted the expression of phosphorylated tau proteins (p-tau), protein kinase C gamma type (PRKCG), extracellular regulated protein kinases (ERK1/2), but the is reversed by mir-7036a-5p antagomir in vitro. It is shown here that mir-7036a-5p is involved in microglia-mediated inflammation in LPS-induced BV-2 microglia. More important is the novel finding that scutellarin mitigated microglia inflammation by down-regulating the mir-7036a-5p/MAPT/PRKCG/ERK signaling pathway.  相似文献   

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程龙  黄翠芬  叶棋浓 《遗传》2010,32(3):191-197
雌激素受体α(ERα)在乳腺癌的发生发展中扮演重要角色,因而ERα成为乳腺癌治疗的分子靶标。ERα的表达水平在乳腺癌患者中差异较大,即使同一患者,在乳腺癌的不同阶段也可能有很大的差别。乳腺癌内分泌治疗的疗效以及预后都与ERα表达水平密切相关。影响ERα表达水平的分子机制复杂,众多调节分子在染色质、转录、转录后、翻译和翻译后等水平参与ERα表达水平的调节。在染色质和转录水平,许多分子通过直接或间接地与ERα启动子的相互作用改变ERα的转录;在转录后/翻译水平,一些microRNA通过诱导ERαmRNA的降解和/或抑制其翻译降低ERα的水平;在翻译后水平,许多分子通过泛素-蛋白酶体途径调节ERα蛋白水平。文章从不同水平,对这些调节分子的调节机制进行简要综述。  相似文献   

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肿瘤干细胞存在于多种类型肿瘤中,并与肿瘤的发生发展密切相关。肿瘤干细胞和胚胎干细胞在生物学特征上存在许多共同点,如自我更新,多潜能性分化等等。然而,肿瘤干细胞和胚胎干细胞又存在很大差异,主要表现在耐药性、致瘤力和转移活性上。肿瘤干细胞在临床研究中具有不可替代的重要性,然而其分子水平上的调节机制尚未被完整揭示。作为内源性非编码小RNA的一部分,miRNAs在细胞发生发展的调节过程中扮演着重要角色。大量研究表明,miRNAs参与肿瘤干细胞的调节,并参与肿瘤的发生与进展。探索miRNAs在肿瘤干细胞基因表达调控中的作用及作用机制,有助于肿瘤特异性生物学标志物及治疗靶点的确定。本文就miRNAs与肿瘤干细胞调节的相关研究进展进行综述。  相似文献   

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Chemotherapy is one of the major treatments of malignant carcinomas. However,its efficiency is affected by both intrinsic and acquired resistance to anticancer drugs. The cellular mechanisms of drug resistance include the overexpression of energy-dependent transporters that eject anticancer drugs from cells such as p-glycoprotein and multidrug resistance related protein (MRP),the mutation of drug targets,the activation of DNA repair pathways,the defects in cellular death pathways and so on. The genetic and ...  相似文献   

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Cutaneous neurogenic inflammation (CNI) is inflammation that is induced (or enhanced) in the skin by the release of neuropeptides from sensory nerve endings. Clinical manifestations are mainly sensory and vascular disorders such as pruritus and erythema. Transient receptor potential vanilloid 1 and ankyrin 1 (TRPV1 and TRPA1, respectively) are non-selective cation channels known to specifically participate in pain and CNI. Both TRPV1 and TRPA1 are co-expressed in a large subset of sensory nerves, where they integrate numerous noxious stimuli. It is now clear that the expression of both channels also extends far beyond the sensory nerves in the skin, occuring also in keratinocytes, mast cells, dendritic cells, and endothelial cells. In these non-neuronal cells, TRPV1 and TRPA1 also act as nociceptive sensors and potentiate the inflammatory process. This review discusses the role of TRPV1 and TRPA1 in the modulation of inflammatory genes that leads to or maintains CNI in sensory neurons and non-neuronal skin cells. In addition, this review provides a summary of current research on the intracellular sensitization pathways of both TRP channels by other endogenous inflammatory mediators that promote the self-maintenance of CNI.  相似文献   

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Inflammatory responses are essential for the clearance of pathogens and the repair of injured tissues; however, if these responses are not properly controlled chronic inflammation can occur. Chronic inflammation is now recognized as a contributing factor to many age‐associated diseases including metabolic disorders, arthritis, neurodegeneration, and cardiovascular disease. Due to the connection between chronic inflammation and these diseases, it is essential to understand underlying mechanisms behind this process. In this review, factors that contribute to chronic inflammation are discussed. Further, we emphasize the emerging roles of microRNAs (miRNAs) and other noncoding RNAs (ncRNA) in regulating chronic inflammatory states, making them important future diagnostic markers and therapeutic targets. Copyright Line: © 2015 The Authors BioEssays Published by Wiley‐VCH Verlag GmbH & Co. KGaA.  相似文献   

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目的 观察幽门螺杆菌(Helicobacter pylori, H. pylori)感染的慢性非萎缩性胃炎(no-atrophic gastritis,NAG)→萎缩性胃炎(chronic atrophic gastritis,CAG)→肠上皮化生(intestinal metaplasia,IM)→非典型增生(dysplasia,DYS)→胃癌(gastric cancer,GC)五个不同阶段miR-1、miR-20a、miR-34a、miR-423-5p表达变化规律及其与临床的关系。方法 收集胃镜及病理证实的上述胃癌发生五个不同阶段且H. pylori感染的患者(依次为44、47、43、50、45例),胃癌无H. pylori感染者46例,胃黏膜正常(normal gastric mucose,NGM)63例的血清标本,采用Real-time PCR法检测无H. pylori感染者miR-1、miR-20a、miR-34a、miR-423-5p表达。结果 H. pylori感染NAG→GC不同阶段,miR-1、miR-20a、miR-34a、miR-423-5p表达逐渐升高(P<0.05),GC阶段最高,miR-1、miR-20a CAG→GC阶段均高于NGM(P<0.05),与NGM比较差异有统计学意义(P<0.05);其表达程度与GC发生阶段呈正相关(P<0.001);GC组H. pylori感染者较无H. pylori感染者miR-1、miR-20a、miR-34a、miR-423-5p表达升高(P<0.05)。结论 H. pylori感染CAG→GC阶段miR-1、miR-20a、miR-34a、miR-423-5p表达升高,向胃癌演进中呈逐渐升高趋势,miR-1、miR-20a、miR-34a、miR-423-5p高表达可能是H. pylori感染后导致胃癌发生发展的重要机制,miR-1、miR-20a、miR-34a可作为诊断早期胃癌的标记物。  相似文献   

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