The Role of MicroRNAs in the Regulation of Gene Expression

MicroRNA 在基因表达调控中的作用

• 批准号: 7592798
• 负责人: natasha caplen
• 金额: $ 34.91万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7592798
• 关键词: 3' Untranslated Regions; 8q24; ABCC1 gene; Address; Affect; Area; Breast Cancer Cell; Burkitt Lymphoma; CCR; Cancer Biology; Cancer cell line; Code; Collaborations; DNA Sequence Rearrangement; Data; Diagnosis; Follow-Up Studies; Gene Expression; Gene Expression Regulation; Gene Silencing; Genetic; Genomic Instability; Genomics; Head; Human; Human Chromosomes; Iowa; Letters; Location; Malignant Neoplasms; Malignant neoplasm of lung; Mammalian Cell; Maps; Mediating; Messenger RNA; MicroRNAs; Microarray Analysis; Molecular Genetics; Mus; Normal tissue morphology; Numbers; Paper; Pathway interactions; Pattern; Process; Publishing; RNA; RNA Interference; Reporting; Role; Site; Small Interfering RNA; Small RNA; Solid Neoplasm; System; Technology; Thinking; Transcript; United States National Institutes of Health; Universities; Work; base; cancer cell; cancer type; carcinogenesis; mouse genome; novel; outcome forecast

In mammalian cells, RNA interference (RNAi) can be mediated by synthetic duplex RNAs, termed small interfering RNAs (siRNAs, by mediating the cleavage of completely complementary mRNA transcripts. MicroRNAs (miRNAs) are endogenous small RNAs that assist in translationally repressing mRNAs with regions of partial complementarity, but may also reduce transcript levels. Since miRNAs are thought to predominantly interact with the 3 untranslated regions (UTRs) of transcripts but little experimental data exists to support this, we sought to ask if mismatched siRNAs mimicking miRNAs affect cognate mRNA levels as a function of target site location. Our studies found that mismatched siRNAs targeting the 3 UTRs of two endogenous transcripts yield a greater reduction in mRNA levels than those targeting the coding region. Our findings demonstrated the importance of target site location within endogenous mRNAs for small RNAs associated with RNAi and these studies were published in FEBS Letters in 2006. To address if altered miRNA expression can contribute to the cancer process Dr. Caplen, (Section head, Gene Silencing Section (GSS), Genetics Branch), became involved in a study conducted by Dr. Curt Harriss group at CCR (Lab. of Human Carcinogenesis, (LHC), CCR, NCI) in collaboration with Dr. Carlo Croce, University of Iowa. Dr. Carlo Croce and others have previously shown that different types of cancer are associated with unique microRNA patterns, and that these patterns may be valuable in diagnosing and ascertaining prognosis. In this collaborative study (Yanaihara et al., 2006 Cancer Cell 9: 189-198), differential microRNA expression data from 104 pairs of primary lung cancers matched against adjacent normal tissue confirmed the deregulation of microRNAs in lung cancer reported in earlier papers, and uncovered a new microRNA marker associated with poor prognosis, hsa-miR-155. To further study the role of miRNA expression in cancer we have now established our own miRNA microarray based analysis within GSS using a commercial array platform (Ambion/ABI) and have begun extensive analysis of the miRNA expression breast cancer cell lines. This work has identified a number of miRNAs differential expressed in different breast cancer cell line. Follow up studies are focused on characterizing the putative targets of these differentially expressed miRNAs. Finally, we have examined a genomic region, human chromosome 8q24, commonly associated with Burkitts lymphoma and some solid tumors as a result of genetic rearrangements and/or deletions and amplifications for evidence of the presence of previously unidentified miRNAs. A number of studies have suggested that miRNAs may be clustered within known areas of genomic instability and we have recently reviewed this particular subject area with a special emphasis on the mouse genome (Huppi et al., Seminars in Cancer Biology). In collaboration with Drs. Natalia Volfovsky and Bob Stephens (ABCC, NCI-Fredrick/SAIC Frederick Inc. NCI, NIH) 12 possible miRNA precursor sequences were identified as mapping to within the human chr. 8q24 region, of which, 7 were experimentally verified. Further molecular and genetic studies investigating these novel miRNAs are on going in both human and mouse systems.

在哺乳动物细胞中，RNA干扰（RNAi）可以由合成的双工RNA介导，称为小干扰RNA (sirna)，通过介导完全互补的mRNA转录物的切割。MicroRNAs （miRNAs）是内源性小rna，有助于翻译抑制部分互补区域的mrna，但也可能降低转录水平。由于mirna被认为主要与转录本的3个非翻译区（UTRs）相互作用，但很少有实验数据支持这一点，我们试图询问是否不匹配的sirna模仿mirna影响同源mRNA水平作为靶位点位置的功能。我们的研究发现，靶向两种内源性转录物的3个utr的错配sirna比靶向编码区的sirna产生更大的mRNA水平降低。我们的研究结果证明了内源性mrna中与RNAi相关的小rna的靶位点位置的重要性，这些研究发表在2006年的FEBS Letters上。为了研究miRNA表达的改变是否会导致癌症的发生，基因沉默组（GSS），遗传学分部的组长Caplen博士参与了CCR实验室的Curt harris博士小组进行的一项研究。人类致癌，（LHC）， CCR， NCI)与爱荷华大学Carlo Croce博士合作。Carlo Croce博士和其他人先前已经表明，不同类型的癌症与独特的microRNA模式相关，并且这些模式可能对诊断和确定预后有价值。在这项合作研究中（Yanaihara et al., 2006 Cancer Cell 9: 189-198），来自104对与邻近正常组织匹配的原发性肺癌的差异microRNA表达数据证实了早期文献报道的microRNA在肺癌中的失调，并发现了一种新的与不良预后相关的microRNA标志物hsa-miR-155。为了进一步研究miRNA表达在癌症中的作用，我们现在使用商业阵列平台（Ambion/ABI）在GSS中建立了自己的基于miRNA微阵列的分析，并开始广泛分析miRNA表达的乳腺癌细胞系。这项工作已经确定了一些mirna在不同乳腺癌细胞系中的差异表达。后续研究的重点是表征这些差异表达的mirna的假设靶点。最后，我们研究了一个基因组区域，人类染色体8q24，它通常与伯基茨淋巴瘤和一些实体瘤有关，这是遗传重排和/或缺失的结果，并扩增了先前未识别的miRNAs存在的证据。许多研究表明，mirna可能聚集在已知的基因组不稳定区域，我们最近回顾了这一特定的主题领域，特别强调了小鼠基因组（Huppi等人，癌症生物学研讨会）。在与博士合作。Natalia Volfovsky和Bob Stephens （ABCC, nci - Frederick /SAIC Frederick Inc.）NCI， NIH)鉴定出12个可能的miRNA前体序列映射到人类chr内。8q24区域，其中有7个得到了实验验证。对这些新型mirna的进一步分子和遗传学研究正在人类和小鼠系统中进行。