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Abstract
Long non-coding RNAs (lncRNAs) are over 200 nucleotides in length and are transcribed from the mammalian genome in a tissue-specific and developmentally regulated pattern. There is growing recognition that lncRNAs are novel biomarkers and/or key regulators of toxicological responses in humans and animal models. Lacking protein-coding capacity, the numerous types of lncRNAs possess a myriad of transcriptional regulatory functions that include cis and trans gene expression, transcription factor activity, chromatin remodeling, imprinting, and enhancer up-regulation. LncRNAs also influence mRNA processing, post-transcriptional regulation, and protein trafficking. Dysregulation of lncRNAs has been implicated in various human health outcomes such as various cancers, Alzheimer's disease, cardiovascular disease, autoimmune diseases, as well as intermediary metabolism such as glucose, lipid, and bile acid homeostasis. Interestingly, emerging evidence in the literature over the past five years has shown that lncRNA regulation is impacted by exposures to various chemicals such as polycyclic aromatic hydrocarbons, benzene, cadmium, chlorpyrifos-methyl, bisphenol A, phthalates, phenols, and bile acids. Recent technological advancements, including next-generation sequencing technologies and novel computational algorithms, have enabled the profiling and functional characterizations of lncRNAs on a genomic scale. In this review, we summarize the biogenesis and general biological functions of lncRNAs, highlight the important roles of lncRNAs in human diseases and especially during the toxicological responses to various xenobiotics, evaluate current methods for identifying aberrant lncRNA expression and molecular target interactions, and discuss the potential to implement these tools to address fundamental questions in toxicology.
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Affiliation(s)
- Joseph L Dempsey
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington 98105
| | - Julia Yue Cui
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington 98105
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103
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Wang XQD, Dostie J. Chromosome folding and its regulation in health and disease. Curr Opin Genet Dev 2016; 43:23-30. [PMID: 27940207 DOI: 10.1016/j.gde.2016.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 10/21/2016] [Accepted: 10/23/2016] [Indexed: 12/23/2022]
Abstract
There are many ways in which cells may not adequately behave or respond to their environment, and the molecular mechanisms leading to these defects are as diverse as they are many. In this review, we report on how spatial chromatin organization contributes to the proper expression of genes, relating how CTCF-one of its main architects-contributes to gene regulation. We also touch on the emerging role of long noncoding RNAs in shaping chromatin organization and activity. The HOX gene clusters have been used as paradigm in the study of various biological pathways, and the overview we provide gives emphasis to what research on these loci has revealed about chromatin architecture and its regulation in the control of gene expression.
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Affiliation(s)
- Xue Qing David Wang
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, 3655 Promenade Sir-William-Osler, Room 815A, Montréal, Québec, Canada H3G1Y6
| | - Josée Dostie
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, 3655 Promenade Sir-William-Osler, Room 815A, Montréal, Québec, Canada H3G1Y6.
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104
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Melé M, Mattioli K, Mallard W, Shechner DM, Gerhardinger C, Rinn JL. Chromatin environment, transcriptional regulation, and splicing distinguish lincRNAs and mRNAs. Genome Res 2016; 27:27-37. [PMID: 27927715 PMCID: PMC5204342 DOI: 10.1101/gr.214205.116] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 11/09/2016] [Indexed: 12/29/2022]
Abstract
While long intergenic noncoding RNAs (lincRNAs) and mRNAs share similar biogenesis pathways, these transcript classes differ in many regards. LincRNAs are less evolutionarily conserved, less abundant, and more tissue-specific, suggesting that their pre- and post-transcriptional regulation is different from that of mRNAs. Here, we perform an in-depth characterization of the features that contribute to lincRNA regulation in multiple human cell lines. We find that lincRNA promoters are depleted of transcription factor (TF) binding sites, yet enriched for some specific factors such as GATA and FOS relative to mRNA promoters. Surprisingly, we find that H3K9me3—a histone modification typically associated with transcriptional repression—is more enriched at the promoters of active lincRNA loci than at those of active mRNAs. Moreover, H3K9me3-marked lincRNA genes are more tissue-specific. The most discriminant differences between lincRNAs and mRNAs involve splicing. LincRNAs are less efficiently spliced, which cannot be explained by differences in U1 binding or the density of exonic splicing enhancers but may be partially attributed to lower U2AF65 binding and weaker splicing-related motifs. Conversely, the stability of lincRNAs and mRNAs is similar, differing only with regard to the location of stabilizing protein binding sites. Finally, we find that certain transcriptional properties are correlated with higher evolutionary conservation in both DNA and RNA motifs and are enriched in lincRNAs that have been functionally characterized.
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Affiliation(s)
- Marta Melé
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| | - Kaia Mattioli
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA.,Department of Biological and Biomedical Sciences, Harvard University, Boston, Massachusetts 02115, USA
| | - William Mallard
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| | - David M Shechner
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| | - Chiara Gerhardinger
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| | - John L Rinn
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.,Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA.,Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA
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106
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Abstract
The survival of all organisms is dependent on complex, coordinated responses to environmental cues. Non-coding RNAs have been identified as major players in regulation of gene expression, with recent evidence supporting roles for long non-coding (lnc)RNAs in both transcriptional and post-transcriptional control. Evidence from our laboratory shows that lncRNAs have the ability to form hybridized structures called R-loops with specific DNA target sequences in S. cerevisiae, thereby modulating gene expression. In this Point of View, we provide an overview of the nature of lncRNA-mediated control of gene expression in the context of our studies using the GAL gene cluster as a model for controlling the timing of transcription.
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Affiliation(s)
- Zachary T Beck
- a Department of Biochemistry , Purdue University , West Lafayette , IN , USA
| | - Zheng Xing
- a Department of Biochemistry , Purdue University , West Lafayette , IN , USA
| | - Elizabeth J Tran
- a Department of Biochemistry , Purdue University , West Lafayette , IN , USA.,b Purdue University Center for Cancer Research, Purdue University , West Lafayette , IN , USA
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107
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Abstract
We are beginning to understand the function of 3D genome architecture in the immune system. In this issue, Bunting et al. (2016) reported massive multi-layer genome reorganization from naive B cells to germinal center B cells, centered on a locus control region of Bcl6.
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Affiliation(s)
- Gangqing Hu
- Systems Biology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Keji Zhao
- Systems Biology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA.
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