151
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Wagner M, Vicinus B, Frick VO, Auchtor M, Rubie C, Jeanmonod P, Richards TA, Linder R, Weichert F. MicroRNA target prediction: theory and practice. Mol Genet Genomics 2014; 289:1085-101. [PMID: 24938624 DOI: 10.1007/s00438-014-0871-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 05/23/2014] [Indexed: 01/28/2023]
Abstract
The present study is one of the few that includes tissue samples in the evaluation of target prediction algorithms designed to detect microRNA (miRNA) sequences that might interact with particular messenger RNA (mRNA) sequences. Twelve different target prediction tools were used to find miRNA sequences that might interact with CCL20 gene expression. Different algorithms predicted controversial miRNA sequences for CCL20 regulation due to a different weighting of parameters. Hsa-miR-21 and hsa-miR-145 suggested by four or more programs were chosen for further investigation. Possible real interaction of these miRNA sequences with CCL20 gene expression was monitored using luciferase assays and expression analyses of tissue samples of colorectal adenocarcinoma by either qRT-PCR or ELISA. Folding status of seed-binding sites in complete mRNA and 3'UTR of CCL20 was predicted. Prediction of miRNA expression was attempted based on CCL20 expression data. Eight of the target prediction tools forecasted a role for hsa-miR-21 and four mentioned hsa-miR-145 in CCL20 gene regulation. Laboratory experimentation showed that CCL20 may serve as a target of hsa-miR-21 but not hsa-miR-145. Expression of the molecules resulted in no clear assertion. Folding of seed-binding sites was predicted to be relatively constant for the complete mRNA and 3'UTR. Predicting miRNA expression based on target gene expression was impossible. This might be attributable to the fact that effects of miRNA activity may oscillate between gene product repression and activation. Additional systematic studies are needed to address this issue.
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Affiliation(s)
- Mathias Wagner
- Department of Pathology, University of Saarland Medical School, Homburg Saar, Germany
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152
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Abstract
Efforts to understand the molecular basis of mycobacterial gene regulation are dominated by a protein-centric view. However, there is a growing appreciation that noncoding RNA, i.e., RNA that is not translated, plays a role in a wide variety of molecular mechanisms. Noncoding RNA comprises rRNA, tRNA, 4.5S RNA, RnpB, and transfer-messenger RNA, as well as a vast population of regulatory RNA, often dubbed "the dark matter of gene regulation." The regulatory RNA species comprise 5' and 3' untranslated regions and a rapidly expanding category of transcripts with the ability to base-pair with mRNAs or to interact with proteins. Regulatory RNA plays a central role in the bacterium's response to changes in the environment, and in this article we review emerging information on the presence and abundance of different types of noncoding RNA in mycobacteria.
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153
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Soreq L, Guffanti A, Salomonis N, Simchovitz A, Israel Z, Bergman H, Soreq H. Long non-coding RNA and alternative splicing modulations in Parkinson's leukocytes identified by RNA sequencing. PLoS Comput Biol 2014; 10:e1003517. [PMID: 24651478 PMCID: PMC3961179 DOI: 10.1371/journal.pcbi.1003517] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 01/31/2014] [Indexed: 12/22/2022] Open
Abstract
The continuously prolonged human lifespan is accompanied by increase in neurodegenerative diseases incidence, calling for the development of inexpensive blood-based diagnostics. Analyzing blood cell transcripts by RNA-Seq is a robust means to identify novel biomarkers that rapidly becomes a commonplace. However, there is lack of tools to discover novel exons, junctions and splicing events and to precisely and sensitively assess differential splicing through RNA-Seq data analysis and across RNA-Seq platforms. Here, we present a new and comprehensive computational workflow for whole-transcriptome RNA-Seq analysis, using an updated version of the software AltAnalyze, to identify both known and novel high-confidence alternative splicing events, and to integrate them with both protein-domains and microRNA binding annotations. We applied the novel workflow on RNA-Seq data from Parkinson's disease (PD) patients' leukocytes pre- and post- Deep Brain Stimulation (DBS) treatment and compared to healthy controls. Disease-mediated changes included decreased usage of alternative promoters and N-termini, 5′-end variations and mutually-exclusive exons. The PD regulated FUS and HNRNP A/B included prion-like domains regulated regions. We also present here a workflow to identify and analyze long non-coding RNAs (lncRNAs) via RNA-Seq data. We identified reduced lncRNA expression and selective PD-induced changes in 13 of over 6,000 detected leukocyte lncRNAs, four of which were inversely altered post-DBS. These included the U1 spliceosomal lncRNA and RP11-462G22.1, each entailing sequence complementarity to numerous microRNAs. Analysis of RNA-Seq from PD and unaffected controls brains revealed over 7,000 brain-expressed lncRNAs, of which 3,495 were co-expressed in the leukocytes including U1, which showed both leukocyte and brain increases. Furthermore, qRT-PCR validations confirmed these co-increases in PD leukocytes and two brain regions, the amygdala and substantia-nigra, compared to controls. This novel workflow allows deep multi-level inspection of RNA-Seq datasets and provides a comprehensive new resource for understanding disease transcriptome modifications in PD and other neurodegenerative diseases. Long non-coding RNAs (lncRNAs) comprise a novel, fascinating class of RNAs with largely unknown biological functions. Parkinson's-disease (PD) is the most frequent motor disorder, and Deep-brain-stimulation (DBS) treatment alleviates the symptoms, but early disease biomarkers are still unknown and new future genetic interference targets are urgently needed. Using RNA-sequencing technology and a novel computational workflow for in-depth exploration of whole-transcriptome RNA-seq datasets, we detected and analyzed lncRNAs in sequenced libraries from PD patients' leukocytes pre and post-treatment and the brain, adding this full profile resource of over 7,000 lncRNAs to the few human tissues-derived lncRNA datasets that are currently available. Our study includes sample-specific database construction, detecting disease-derived changes in known and novel lncRNAs, exons and junctions and predicting corresponding changes in Polyadenylation choices, protein domains and miRNA binding sites. We report widespread transcript structure variations at the splice junction and exons levels, including novel exons and junctions and alteration of lncRNAs followed by experimental validation in PD leukocytes and two PD brain regions compared with controls. Our results suggest lncRNAs involvement in neurodegenerative diseases, and specifically PD. This comprehensive workflow will be of use to the increasing number of laboratories producing RNA-Seq data in a wide range of biomedical studies.
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Affiliation(s)
- Lilach Soreq
- Department of Medical Neurobiology, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Alessandro Guffanti
- Department of Biological Chemistry, The Life Sciences Institute, The Hebrew University of Jerusalem, Jerusalem, Israel
- Genomnia srl, Lainate, Milan, Italy
| | - Nathan Salomonis
- Department of Pediatrics, Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
| | | | - Zvi Israel
- The Center for Functional and Restorative Neurosurgery, Department of Neurosurgery, Hadassah University Hospital, Jerusalem, Israel
| | - Hagai Bergman
- Department of Medical Neurobiology, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
- The Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hermona Soreq
- Department of Biological Chemistry, The Life Sciences Institute, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
- * E-mail:
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154
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Maurel M, Chevet E, Tavernier J, Gerlo S. Getting RIDD of RNA: IRE1 in cell fate regulation. Trends Biochem Sci 2014; 39:245-54. [PMID: 24657016 DOI: 10.1016/j.tibs.2014.02.008] [Citation(s) in RCA: 416] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 02/20/2014] [Accepted: 02/21/2014] [Indexed: 12/12/2022]
Abstract
Inositol-requiring enzyme 1 (IRE1) is the most conserved transducer of the unfolded protein response (UPR), a homeostatic response that preserves proteostasis. Intriguingly, via its endoribonuclease activity, IRE1 produces either adaptive or death signals. This occurs through both unconventional splicing of XBP1 mRNA and regulated IRE1-dependent decay of mRNA (RIDD). Whereas XBP1 mRNA splicing is cytoprotective in response to endoplasmic reticulum (ER) stress, RIDD has revealed many unexpected features. For instance, RIDD cleaves RNA at an XBP1-like consensus site but with an activity divergent from XBP1 mRNA splicing and can either preserve ER homeostasis or induce cell death. Here we review recent findings on RIDD and propose a model of how IRE1 RNase activity might control cell fate decisions.
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Affiliation(s)
- M Maurel
- Department of Medical Protein Research, VIB, Ghent, Belgium; Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
| | - E Chevet
- INSERM U1053, Université Bordeaux Segalen, 33000 Bordeaux, France; Centre Régional de Lutte Contre le Cancer Eugène Marquis, 35000 Rennes, France
| | - J Tavernier
- Department of Medical Protein Research, VIB, Ghent, Belgium; Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - S Gerlo
- Department of Medical Protein Research, VIB, Ghent, Belgium; Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
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155
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Sano M, Nakagawa M, Oishi A, Yasui Y, Katsube-Tanaka T. Diversification of 13S globulins, allergenic seed storage proteins, of common buckwheat. Food Chem 2014; 155:192-8. [PMID: 24594174 DOI: 10.1016/j.foodchem.2014.01.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 12/11/2013] [Accepted: 01/15/2014] [Indexed: 11/28/2022]
Abstract
The α polypeptide of the 13S globulin subunit of common buckwheat is the counterpart of the major allergenic β polypeptide. Trypsin digestibility varies between variants of the α polypeptide with and without a tandem repeat insert. To evaluate the intra-species diversity of 13S globulin, the comprehensive screening of a genomic DNA library was performed, resulting in the isolation of 14 and 3 genes for Met-poor and Met-rich subunits, respectively. Although most tandem repeat units were 45 bp in length, the two-repeat gene Glb2B and all one-repeat genes contained an additional 3 bp. Secondary structure predictions and polyacrylamide gel electrophoresis demonstrated that the sense strand of Glb2B-CCG, the additional 3 bp-deletion clone of Glb2B, formed a more rigid secondary structure than that of the wild-type. Thus, the large intra-species variation of 13S globulin revealed in this study and its diversification might be attributable to the unique nature of the tandem repeat sequences.
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Affiliation(s)
- Madoka Sano
- Graduate School of Agriculture, Kyoto University, Kitashirakawa, Kyoto 606-8502, Japan
| | - Mariko Nakagawa
- Graduate School of Agriculture, Kyoto University, Kitashirakawa, Kyoto 606-8502, Japan
| | - Akifumi Oishi
- Graduate School of Agriculture, Kyoto University, Kitashirakawa, Kyoto 606-8502, Japan
| | - Yasuo Yasui
- Graduate School of Agriculture, Kyoto University, Kitashirakawa, Kyoto 606-8502, Japan
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156
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Iida Y, Fujiwara K, Yoshioka Y, Tsuge T. Mutation of FVS1, encoding a protein with a sterile alpha motif domain, affects asexual reproduction in the fungal plant pathogen Fusarium oxysporum. FEMS Microbiol Lett 2014; 351:104-112. [PMID: 24330129 DOI: 10.1111/1574-6968.12356] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/24/2013] [Accepted: 12/10/2013] [Indexed: 11/30/2022] Open
Abstract
Fusarium oxysporum produces three kinds of asexual spores: microconidia, macroconidia and chlamydospores. We previously analysed expressed sequence tags during vegetative growth and conidiation in F. oxysporum and found 42 genes that were markedly upregulated during conidiation compared to vegetative growth. One of the genes, FVS1, encodes a protein with a sterile alpha motif (SAM) domain, which functions in protein-protein interactions that are involved in transcriptional or post-transcriptional regulation and signal transduction. Here, we made FVS1-disrupted mutants from the melon wilt pathogen F. oxysporum f. sp. melonis. Although the mutants produced all three kinds of asexual spores with normal morphology, they formed markedly fewer microconidia and macroconidia than the wild type. The mutants appeared to have a defect in the development of the conidiogenesis cells, conidiophores and phialides, required for the formation of microconidia and macroconidia. In contrast, chlamydospore formation was dramatically promoted in the mutants. The growth rates of the mutants on media were slightly reduced, indicating that FVS1 is also involved in, but not essential for, vegetative growth. We also observed that mutation of FVS1 caused defects in conidial germination and virulence, suggesting that the Fvs1 has pleiotropic functions in F. oxysporum.
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Affiliation(s)
- Yuichiro Iida
- Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan
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157
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Luo GZ, Yang W, Ma YK, Wang XJ. ISRNA: an integrative online toolkit for short reads from high-throughput sequencing data. ACTA ACUST UNITED AC 2013; 30:434-6. [PMID: 24300438 DOI: 10.1093/bioinformatics/btt678] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
UNLABELLED Integrative Short Reads NAvigator (ISRNA) is an online toolkit for analyzing high-throughput small RNA sequencing data. Besides the high-speed genome mapping function, ISRNA provides statistics for genomic location, length distribution and nucleotide composition bias analysis of sequence reads. Number of reads mapped to known microRNAs and other classes of short non-coding RNAs, coverage of short reads on genes, expression abundance of sequence reads as well as some other analysis functions are also supported. The versatile search functions enable users to select sequence reads according to their sub-sequences, expression abundance, genomic location, relationship to genes, etc. A specialized genome browser is integrated to visualize the genomic distribution of short reads. ISRNA also supports management and comparison among multiple datasets. AVAILABILITY ISRNA is implemented in Java/C++/Perl/MySQL and can be freely accessed at http://omicslab.genetics.ac.cn/ISRNA/.
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Affiliation(s)
- Guan-Zheng Luo
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences and Graduate University of Chinese Academy of Sciences, Beijing 100101, China
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158
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Shigdar S, Macdonald J, O'Connor M, Wang T, Xiang D, Al.Shamaileh H, Qiao L, Wei M, Zhou SF, Zhu Y, Kong L, Bhattacharya S, Li C, Duan W. Aptamers as theranostic agents: modifications, serum stability and functionalisation. SENSORS 2013; 13:13624-37. [PMID: 24152925 PMCID: PMC3859083 DOI: 10.3390/s131013624] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/24/2013] [Accepted: 09/27/2013] [Indexed: 02/07/2023]
Abstract
Aptamers, and the selection process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX) used to generate them, were first described more than twenty years ago. Since then, there have been numerous modifications to the selection procedures. This review discusses the use of modified bases as a means of enhancing serum stability and producing effective therapeutic tools, as well as functionalising these nucleic acids to be used as potential diagnostic agents.
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Affiliation(s)
- Sarah Shigdar
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
- Authors to whom correspondence should be addressed; E-Mails: (S.S.); (W.D.)
| | - Joanna Macdonald
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Michael O'Connor
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Tao Wang
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Dongxi Xiang
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Hadi Al.Shamaileh
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Liang Qiao
- Storr Liver Unit, at the Westmead Millennium Institute, The University of Sydney at the Westmead Hospital, Westmead NSW 2145, Australia; E-Mail:
| | - Ming Wei
- School of Medical Science and Griffith Health Institute, Griffith University, Gold Coast Campus, Southport 4222, Australia; E-Mail:
| | - Shu-Feng Zhou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL 33612, USA; E-Mail:
| | - Yimin Zhu
- Suzhou Key Laboratory of Nanobiomedicine, Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China; E-Mail:
| | - Lingxue Kong
- Institute for Frontier Materials, Deakin University, Waurn Ponds, Victoria 3217, Australia; E-Mail:
| | - Santanu Bhattacharya
- Department of Organic Chemistry, Indian Institute of Science, Bangalore 560 012, India; E-Mail:
| | - ChunGuang Li
- Centre for Complimentary Medicine Research, National Institute of Complementary Medicine, University of Western Sydney, Campbelltown Campus, Penrith, NSW 2751, Australia; E-Mail:
| | - Wei Duan
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
- Authors to whom correspondence should be addressed; E-Mails: (S.S.); (W.D.)
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159
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Yasuda K, Kotani T, Yamashita M. A cis-acting element in the coding region of cyclin B1 mRNA couples subcellular localization to translational timing. Dev Biol 2013; 382:517-29. [DOI: 10.1016/j.ydbio.2013.05.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 05/09/2013] [Accepted: 05/13/2013] [Indexed: 12/20/2022]
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160
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Matsumiya T, Xing F, Ebina M, Hayakari R, Imaizumi T, Yoshida H, Kikuchi H, Topham MK, Satoh K, Stafforini DM. Novel role for molecular transporter importin 9 in posttranscriptional regulation of IFN-ε expression. THE JOURNAL OF IMMUNOLOGY 2013; 191:1907-15. [PMID: 23851686 DOI: 10.4049/jimmunol.1201925] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
IFN-ε is a unique type I IFN whose constitutive expression in lung, brain, small intestine, and reproductive tissues is only partially understood. Our previous observation that posttranscriptional events participate in the regulation of IFN-ε mRNA expression led us to investigate whether the 5' and/or 3' untranslated regions (UTR) have regulatory functions. Surprisingly, we found that full-length IFN-ε 5'UTR markedly suppressed mRNA expression under basal conditions. Analysis of the secondary structure of this region predicted formation of two stable stem-loop structures, loops 1 and 2. Studies using luciferase constructs harboring various stretches of IFN-ε 5'UTR and mutant constructs in which the conformation of loop structures was disrupted showed that loop 1 is essential for regulation of mRNA expression. Incubation of HeLa cell extracts with agarose-bound RNAs harboring IFN-ε loop structures identified importin 9 (IPO9), a molecular transporter and chaperone, as a candidate that associates with these regions of the 5'UTR. IPO9 overexpression decreased, and IPO9 silencing increased basal IFN-ε expression. Our studies uncover a previously undescribed function for IPO9 as a specific, and negative, posttranscriptional regulator of IFN-ε expression, and they identify key roles for IFN-ε stem-loop structure 1 in this process. IPO9-mediated effects on 5'UTRs appear to extend to additional mRNAs, including hypoxia-inducible factor-1α, that can form specific loop structures.
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Affiliation(s)
- Tomoh Matsumiya
- Department of Vascular Biology, Institute of Brain Science, Hirosaki University Graduate School of Medicine, Hirosaki 036-8562, Japan.
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161
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Jeong DH, Thatcher SR, Brown RS, Zhai J, Park S, Rymarquis LA, Meyers BC, Green PJ. Comprehensive investigation of microRNAs enhanced by analysis of sequence variants, expression patterns, ARGONAUTE loading, and target cleavage. PLANT PHYSIOLOGY 2013; 162:1225-45. [PMID: 23709668 PMCID: PMC3707554 DOI: 10.1104/pp.113.219873] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
MicroRNAs (miRNAs) are a class of small RNAs that typically function by guiding the cleavage of target messenger RNAs. They have been shown to play major roles in a variety of plant processes, including development, and responses to pathogens and environmental stresses. To identify new miRNAs and regulation in Arabidopsis (Arabidopsis thaliana), 27 small RNA libraries were constructed and sequenced from various tissues, stresses, and small RNA biogenesis mutants, resulting in 95 million genome-matched sequences. The use of rdr2 to enrich the miRNA population greatly enhanced this analysis and led to the discovery of new miRNAs arising from both known and new precursors, increasing the total number of Arabidopsis miRNAs by about 10%. Parallel Analysis of RNA Ends data provide evidence that the majority guide target cleavage. Many libraries represented novel stress/tissue conditions, such as submergence-stressed flowers, which enabled the identification of new stress regulation of both miRNAs and their targets, all of which were validated in wild-type plants. By combining small RNA expression analysis with ARGONAUTE immunoprecipitation data and global target cleavage data from Parallel Analysis of RNA Ends, a much more complete picture of Arabidopsis miRNAs was obtained. In particular, the discovery of ARGONAUTE loading and target cleavage biases gave important insights into tissue-specific expression patterns, pathogen responses, and the role of sequence variation among closely related miRNA family members that would not be evident without this combinatorial approach.
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162
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Abstract
Many bioinformatics problems, such as sequence alignment, gene prediction, phylogenetic tree estimation and RNA secondary structure prediction, are often affected by the 'uncertainty' of a solution, that is, the probability of the solution is extremely small. This situation arises for estimation problems on high-dimensional discrete spaces in which the number of possible discrete solutions is immense. In the analysis of biological data or the development of prediction algorithms, this uncertainty should be handled carefully and appropriately. In this review, I will explain several methods to combat this uncertainty, presenting a number of examples in bioinformatics. The methods include (i) avoiding point estimation, (ii) maximum expected accuracy (MEA) estimations and (iii) several strategies to design a pipeline involving several prediction methods. I believe that the basic concepts and ideas described in this review will be generally useful for estimation problems in various areas of bioinformatics.
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163
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Directed evolution study unveiling key sequence factors that affect translation efficiency in Escherichia coli. J Biosci Bioeng 2013; 116:540-5. [PMID: 23790548 DOI: 10.1016/j.jbiosc.2013.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 05/08/2013] [Accepted: 05/08/2013] [Indexed: 11/23/2022]
Abstract
Synonymous mutations in protein coding genes significantly impact translation efficiency. We synthesized a pair of genes encoding green fluorescent protein that were separated by 160 synonymous mutations to investigate key factors that affect translation efficiency. One sequence was optimized for Escherichia coli (GFP(Eco)) and the other for Bacillus subtilis (GFP(Bsu)). When the genes were expressed in E. coli, GFP(Eco) fluoresced 12-fold stronger than GFP(Bsu), confirming the suboptimal nature of the GFP(Bsu) gene. We then employed directed evolution to improve the expression of GFP(Bsu). Random mutagenesis and DNA shuffling was used to generate mutant libraries, which were screened for fluorescence. A variant showing 6-fold fluorescence enhancement was identified, which contained a single mutation (G10A) in a rare codon for Gly-4. However, the substitution generated another type of rare codon, AGA, for Arg, suggesting that the improvement was caused by a factor other than the rare codon. We next applied saturation mutagenesis to Gly-4. The darkest variant contained a GGG codon (GFP(Bsu)-G) for Gly-4. Taking the location of the mutation into account, we hypothesized that destabilization of the mRNA secondary structure around the initiation codon improved the expression. We then randomized the nucleotide triplet in 5'-untranslated region (5'UTR) of GFP(Bsu), which is complementary to the Gly-4 codon. A variant showing 6-fold fluorescence enhancement was identified, which exhibited a destabilized secondary structure. When this 5'UTR sequence was combined with GFP(Bsu)-G, 22-fold fluorescent improvement was achieved. Collectively, the stability of the mRNA secondary structure around the initiation codon predominantly affected the translation efficiency.
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164
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Structural requirement in Clostridium perfringens collagenase mRNA 5' leader sequence for translational induction through small RNA-mRNA base pairing. J Bacteriol 2013; 195:2937-46. [PMID: 23585542 DOI: 10.1128/jb.00148-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The Gram-positive anaerobic bacterium Clostridium perfringens is pathogenic to humans and animals, and the production of its toxins is strictly regulated during the exponential phase. We recently found that the 5' leader sequence of the colA transcript encoding collagenase, which is a major toxin of this organism, is processed and stabilized in the presence of the small RNA VR-RNA. The primary colA 5'-untranslated region (5'UTR) forms a long stem-loop structure containing an internal bulge and masks its own ribosomal binding site. Here we found that VR-RNA directly regulates colA expression through base pairing with colA mRNA in vivo. However, when the internal bulge structure was closed by point mutations in colA mRNA, translation ceased despite the presence of VR-RNA. In addition, a mutation disrupting the colA stem-loop structure induced mRNA processing and ColA-FLAG translational activation in the absence of VR-RNA, indicating that the stem-loop and internal bulge structure of the colA 5' leader sequence is important for regulation by VR-RNA. On the other hand, processing was required for maximal ColA expression but was not essential for VR-RNA-dependent colA regulation. Finally, colA processing and translational activation were induced at a high temperature without VR-RNA. These results suggest that inhibition of the colA 5' leader structure through base pairing is the primary role of VR-RNA in colA regulation and that the colA 5' leader structure is a possible thermosensor.
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165
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Galipon J, Miki A, Oda A, Inada T, Ohta K. Stress-induced lncRNAs evade nuclear degradation and enter the translational machinery. Genes Cells 2013; 18:353-68. [PMID: 23489294 DOI: 10.1111/gtc.12042] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 01/14/2013] [Indexed: 12/29/2022]
Abstract
Long noncoding RNAs (lncRNAs) play important roles in the regulation of gene expression. In fission yeast, glucose starvation triggers a transcriptional cascade of polyadenylated lncRNAs in the upstream region of the fructose-1,6-bisphosphatase gene (fbp1(+) ), which is correlated with stepwise chromatin remodeling and necessary for the massive induction of fbp1(+) mRNA. Here, we show that these novel metabolic stress-induced lncRNAs (mlonRNAs) are 5'-capped, less stable than fbp1(+) mRNA and sensitive to a certain extent to the nuclear exosome cofactor Rrp6. However, most mlonRNAs seem to escape nuclear degradation and are exported to the cytoplasm, where they localize to polysomes precisely during glucose starvation-induced global translation inhibition. It is likely that ribosomes tend to accumulate in the upstream region of mlonRNAs. Although mlonRNAs contain an unusual amount of upstream AUGs (uAUGs) and small open reading frames (uORFs), they escape Upf1-mediated targeting to the non-sense-mediated decay (NMD) pathway. The deletion of Upf1 had no effect on mlonRNA stability, but considerably destabilized fbp1(+) mRNA, hinting toward a possible novel role of Upf1. Our findings suggest that the stability of mlonRNAs is distinctly regulated from mRNA and previously described noncoding transcripts.
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Affiliation(s)
- Josephine Galipon
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan
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Puton T, Kozlowski LP, Rother KM, Bujnicki JM. CompaRNA: a server for continuous benchmarking of automated methods for RNA secondary structure prediction. Nucleic Acids Res 2013; 41:4307-23. [PMID: 23435231 PMCID: PMC3627593 DOI: 10.1093/nar/gkt101] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We present a continuous benchmarking approach for the assessment of RNA secondary structure prediction methods implemented in the CompaRNA web server. As of 3 October 2012, the performance of 28 single-sequence and 13 comparative methods has been evaluated on RNA sequences/structures released weekly by the Protein Data Bank. We also provide a static benchmark generated on RNA 2D structures derived from the RNAstrand database. Benchmarks on both data sets offer insight into the relative performance of RNA secondary structure prediction methods on RNAs of different size and with respect to different types of structure. According to our tests, on the average, the most accurate predictions obtained by a comparative approach are generated by CentroidAlifold, MXScarna, RNAalifold and TurboFold. On the average, the most accurate predictions obtained by single-sequence analyses are generated by CentroidFold, ContextFold and IPknot. The best comparative methods typically outperform the best single-sequence methods if an alignment of homologous RNA sequences is available. This article presents the results of our benchmarks as of 3 October 2012, whereas the rankings presented online are continuously updated. We will gladly include new prediction methods and new measures of accuracy in the new editions of CompaRNA benchmarks.
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Affiliation(s)
- Tomasz Puton
- Bioinformatics Laboratory, Institute for Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, ul. Umultowska 89, 61-614 Poznan, Poland
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Molineros JE, Maiti AK, Sun C, Looger LL, Han S, Kim-Howard X, Glenn S, Adler A, Kelly JA, Niewold TB, Gilkeson GS, Brown EE, Alarcón GS, Edberg JC, Petri M, Ramsey-Goldman R, Reveille JD, Vilá LM, Freedman BI, Tsao BP, Criswell LA, Jacob CO, Moore JH, Vyse TJ, Langefeld CL, Guthridge JM, Gaffney PM, Moser KL, Scofield RH, Alarcón-Riquelme ME, Williams SM, Merrill JT, James JA, Kaufman KM, Kimberly RP, Harley JB, Nath SK. Admixture mapping in lupus identifies multiple functional variants within IFIH1 associated with apoptosis, inflammation, and autoantibody production. PLoS Genet 2013; 9:e1003222. [PMID: 23441136 PMCID: PMC3575474 DOI: 10.1371/journal.pgen.1003222] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 11/20/2012] [Indexed: 01/22/2023] Open
Abstract
Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease with a strong genetic component. African-Americans (AA) are at increased risk of SLE, but the genetic basis of this risk is largely unknown. To identify causal variants in SLE loci in AA, we performed admixture mapping followed by fine mapping in AA and European-Americans (EA). Through genome-wide admixture mapping in AA, we identified a strong SLE susceptibility locus at 2q22–24 (LOD = 6.28), and the admixture signal is associated with the European ancestry (ancestry risk ratio ∼1.5). Large-scale genotypic analysis on 19,726 individuals of African and European ancestry revealed three independently associated variants in the IFIH1 gene: an intronic variant, rs13023380 [Pmeta = 5.20×10−14; odds ratio, 95% confidence interval = 0.82 (0.78–0.87)], and two missense variants, rs1990760 (Ala946Thr) [Pmeta = 3.08×10−7; 0.88 (0.84–0.93)] and rs10930046 (Arg460His) [Pdom = 1.16×10−8; 0.70 (0.62–0.79)]. Both missense variants produced dramatic phenotypic changes in apoptosis and inflammation-related gene expression. We experimentally validated function of the intronic SNP by DNA electrophoresis, protein identification, and in vitro protein binding assays. DNA carrying the intronic risk allele rs13023380 showed reduced binding efficiency to a cellular protein complex including nucleolin and lupus autoantigen Ku70/80, and showed reduced transcriptional activity in vivo. Thus, in SLE patients, genetic susceptibility could create a biochemical imbalance that dysregulates nucleolin, Ku70/80, or other nucleic acid regulatory proteins. This could promote antibody hypermutation and auto-antibody generation, further destabilizing the cellular network. Together with molecular modeling, our results establish a distinct role for IFIH1 in apoptosis, inflammation, and autoantibody production, and explain the molecular basis of these three risk alleles for SLE pathogenesis. African-Americans (AA) are at increased risk of systemic lupus erythematosus (SLE), but the genetic basis of this risk increase is largely unknown. We used admixture mapping to localize disease-causing genetic variants that differ in frequency across populations. This approach is advantageous for localizing susceptibility genes in recently admixed populations like AA. Our genome-wide admixture scan identified seven admixture signals, and we followed the best signal at 2q22–24 with fine-mapping, imputation-based association analysis and experimental validation. We identified two independent coding variants and a non-coding variant within the IFIH1 gene associated with SLE. Together with molecular modeling, our results establish a distinct role for IFIH1 in apoptosis, inflammation, and autoantibody production, and explain the molecular basis of these three risk alleles for SLE pathogenesis.
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Affiliation(s)
- Julio E. Molineros
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Amit K. Maiti
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Celi Sun
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Loren L. Looger
- Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia, United States of America
| | - Shizhong Han
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Xana Kim-Howard
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Stuart Glenn
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Adam Adler
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Jennifer A. Kelly
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Timothy B. Niewold
- Mayo Clinic, Division of Rheumatology and Department of Immunology, Rochester, Minnesota, United States of America
| | - Gary S. Gilkeson
- Division of Rheumatology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Elizabeth E. Brown
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Graciela S. Alarcón
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jeffrey C. Edberg
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Michelle Petri
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Rosalind Ramsey-Goldman
- Division of Rheumatology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - John D. Reveille
- Department of Rheumatology and Clinical Immunogenetics, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Luis M. Vilá
- Department of Medicine, Division of Rheumatology, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
| | - Barry I. Freedman
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Betty P. Tsao
- Division of Rheumatology, Department of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Lindsey A. Criswell
- Rosalind Russell Medical Research Center for Arthritis, University of California San Francisco, San Francisco, California, United States of America
| | - Chaim O. Jacob
- Department of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Jason H. Moore
- Department of Genetics, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
| | - Timothy J. Vyse
- Division of Genetics and Molecular Medicine, King's College London, London, United Kingdom
- Division of Immunology, Infection and Inflammatory Diseases, Kings College London, London, United Kingdom
| | - Carl L. Langefeld
- Department of Biostatistical Sciences, Wake Forest University Health Sciences, Wake Forest, North Carolina, United States of America
| | - Joel M. Guthridge
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Patrick M. Gaffney
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Kathy L. Moser
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - R. Hal Scofield
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Marta E. Alarcón-Riquelme
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- Centro de Genómica e Investigación Oncológica (GENyO)–Pfizer/Universidad de Granada/Junta de Andalucía, Granada, Spain
| | | | - Scott M. Williams
- Department of Genetics, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Joan T. Merrill
- Clinical Pharmacology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Judith A. James
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Kenneth M. Kaufman
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
| | - Robert P. Kimberly
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - John B. Harley
- Cincinnati Children's Hospital Medical Center and the U.S. Department of Veterans Affairs Medical Center, Cincinnati, Ohio, United States of America
| | - Swapan K. Nath
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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168
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Yamamori K, Matsuo T, Iwakiri J, Kenmochi N, Yoshihara I. A detection method for intronic snoRNA genes using extended-weight-updating SOM with appearance probability of bases. ARTIFICIAL LIFE AND ROBOTICS 2013. [DOI: 10.1007/s10015-012-0072-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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169
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Hollensen AK, Bak RO, Haslund D, Mikkelsen JG. Suppression of microRNAs by dual-targeting and clustered Tough Decoy inhibitors. RNA Biol 2013; 10:406-14. [PMID: 23324610 DOI: 10.4161/rna.23543] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
MicroRNAs (miRNAs) are ubiquitous regulators of gene expression that contribute to almost any cellular process. Methods for managing of miRNA activity are attracting increasing attention in relation to diverse experimental and therapeutic applications. DNA-encoded miRNA inhibitors expressed from plasmid or virus-based vectors provide persistent miRNA suppression and options of tissue-directed micromanaging. In this report, we explore the potential of exploiting short, hairpin-shaped RNAs for simultaneous suppression of two or more miRNAs. Based on the "Tough Decoy" (TuD) design, we create dual-targeting hairpins carrying two miRNA recognition sites and demonstrate potent co-suppression of different pairs of unrelated miRNAs by a single DNA-encoded inhibitor RNA. In addition, enhanced miRNA suppression is achieved by expression of RNA polymerase II-transcribed inhibitors carrying clustered TuD hairpins with up to a total of eight miRNA recognition sites. Notably, by expressing clustered TuD inhibitors harboring a single recognition site for each of a total of six miRNAs, we document robust parallel suppression of multiple miRNAs by inhibitor RNA molecules encoded by a single expression cassette. These findings unveil a new potential of TuD-based miRNA inhibitors and pave the way for standardizing synchronized suppression of families or clusters of miRNAs.
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170
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Li SK, Ng PKS, Qin H, Lau JKY, Lau JPY, Tsui SKW, Chan TF, Lau TCK. Identification of small RNAs in Mycobacterium smegmatis using heterologous Hfq. RNA (NEW YORK, N.Y.) 2013; 19:74-84. [PMID: 23169799 PMCID: PMC3527728 DOI: 10.1261/rna.034116.112] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Accepted: 10/22/2012] [Indexed: 05/30/2023]
Abstract
Gene regulation by small RNAs (sRNAs) has been extensively studied in various bacteria. However, the presence and roles of sRNAs in mycobacteria remain largely unclear. Immunoprecipitation of RNA chaperone Hfq to enrich for sRNAs is one of the effective methods to isolate sRNAs. However, the lack of an identified mycobacterial hfq restricts the feasibility of this approach. We developed a novel method that takes advantage of the conserved inherent sRNAs-binding capability of heterologous Hfq from Escherichia coli to enrich sRNAs from Mycobacterium smegmatis, a model organism for studying Mycobacterium tuberculosis. We validated 12 trans-encoded and 12 cis-encoded novel sRNAs in M. smegmatis. Many of these sRNAs are differentially expressed at exponential phase compared with stationary phase, suggesting that sRNAs are involved in the growth of mycobacteria. Intriguingly, five of the cis-encoded novel sRNAs target known transposases. Phylogenetic conservation analysis shows that these sRNAs are pathogenicity dependent. We believe that our findings will serve as an important reference for future analysis of sRNAs regulation in mycobacteria and will contribute significantly to the development of sRNAs prediction programs. Moreover, this novel method of using heterologous Hfq for sRNAs enrichment can be of general use for the discovery of bacterial sRNAs in which no endogenous Hfq is identified.
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Affiliation(s)
- Sai-Kam Li
- Department of Biology and Chemistry, City University of Hong Kong, Hong Kong SAR
| | | | - Hao Qin
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong SAR
| | - Jeffrey Kwan-Yiu Lau
- Department of Biology and Chemistry, City University of Hong Kong, Hong Kong SAR
| | | | | | - Ting-Fung Chan
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong SAR
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171
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Haghighi MA, Mobarez AM, Salmanian AH, Moazeni M, Zali MR, Sadeghi M, Amani J. In silico experiment with an-antigen-toll like receptor-5 agonist fusion construct for immunogenic application to Helicobacter pylori. INDIAN JOURNAL OF HUMAN GENETICS 2013; 19:43-53. [PMID: 23901192 PMCID: PMC3722629 DOI: 10.4103/0971-6866.112885] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUNDS Helicobacter pylori colonize the gastric mucosa of half of the world's population. Although it is classified as a definitive type I carcinogen by World Health Organization, there is no effective vaccine against this bacterium. H. pylori evade the host immune response by avoiding toll-like detection, such as detection via toll-like receptor-5 (TLR-5). Thus, a chimeric construct consisting of selected epitopes from virulence factors that is incorporated into a TLR-5 ligand (Pseudomonas flagellin) could result in more potent innate and adaptive immune responses. MATERIALS AND METHODS Based on the histocompatibility antigens of BALB/c mice, in silico techniques were used to select several fragments from H. pylori virulence factors with a high density of B- and T-cell epitopes. RESULTS These segments consist of cytotoxin-associated geneA (residue 162-283), neutrophil activating protein (residue 30-135) and outer inflammatory protein A (residue 155-268). The secondary and tertiary structure of the chimeric constructs and other bioinformatics analyses such as stability, solubility, and antigenicity were performed. The chimeric construct containing antigenic segments of H. pylori proteins was fused with the D3 domain of Pseudomonas flagellin. This recombinant chimeric gene was optimized for expression in Escherichia coli. The in silico results showed that the conserved C- and N-terminal domains of flagellin and the antigenicity of selected fragments were retained. DISCUSSION In silico analysis showed that Pseudomonas flagellin is a suitable platform for incorporation of an antigenic construct from H. pylori. This strategy may be an effective tool for the control of H. pylori and other persistent infections.
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Affiliation(s)
- Mohamad Ali Haghighi
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ashraf Mohabati Mobarez
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ali Hatef Salmanian
- Department of Plant Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Mohamad Moazeni
- Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mohamad Reza Zali
- Gastroenterology and Liver Disease Research center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehdi Sadeghi
- Department of Biochemistry National Institute of Genetic Engineering and Biotechnology, Baqiyatallah Medical Science University, Tehran, Iran
| | - Jafar Amani
- Applied Microbiology Research Center, Baqiyatallah Medical Science University, Tehran, Iran
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172
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Ito Y, Shigemori S, Sato T, Shimazu T, Hatano K, Otani H, Kitazawa H, Shimosato T. Class I/II hybrid inhibitory oligodeoxynucleotide exerts Th1 and Th2 double immunosuppression. FEBS Open Bio 2012; 3:41-5. [PMID: 23847756 PMCID: PMC3668506 DOI: 10.1016/j.fob.2012.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 11/01/2012] [Accepted: 11/05/2012] [Indexed: 11/29/2022] Open
Abstract
We designed class I/II hybrid inhibitory oligodeoxynucleotides (iODNs), called iSG, and found that the sequence 5′-TTAGGG-3′, which has a six-base loop head structure, and a 3′-oligo (dG)3–5 tail sequence are important for potent immunosuppressive activity. Interestingly, splenocytes isolated from ovalbumin (OVA)-immunized mice and treated with iSG3 showed suppression of not only interleukin (IL)-6, IL-12p35, IL-12p40, and interferon (IFN) γ mRNA expression, but also IL-4 and IL-13 mRNA expression. Thus, both Th2 and Th1 immune responses can be strongly suppressed by iODNs in splenocytes from allergen-immunized mice, suggesting usefulness in the treatment of diseases induced by over-active immune activation.
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Key Words
- Class I iODN
- Class I/II hybrid iODN
- Class II iODN
- ELISA, enzyme-linked immunosorbent assay
- IFN, interferon
- IL, interleukin
- MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide
- ODN, oligodeoxynucleotide
- OVA, ovalbumin
- PO, phosphodiester
- PS, phosphorothioate
- STAT, signal transducer and activator of transcription
- TLR, Toll-like receptor
- Th1 cell, type 1 helper T cell
- Th2 cell, type 2 helper T cell
- iODN
- immunosuppression
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Affiliation(s)
- Yusuke Ito
- Graduate School of Agriculture, Shinshu University, Minamiminowa 399-4598, Japan
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173
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Bobbs AS, Saarela AV, Yatskievych TA, Antin PB. Fibroblast growth factor (FGF) signaling during gastrulation negatively modulates the abundance of microRNAs that regulate proteins required for cell migration and embryo patterning. J Biol Chem 2012; 287:38505-14. [PMID: 22995917 PMCID: PMC3493895 DOI: 10.1074/jbc.m112.400598] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 09/19/2012] [Indexed: 01/08/2023] Open
Abstract
FGF signaling plays a pivotal role in regulating cell movements and lineage induction during gastrulation. Here we identify 44 microRNAs that are expressed in the primitive streak region of gastrula stage chicken embryos. We show that the primary effect of FGF signaling on microRNA abundance is to negatively regulate the levels of miR-let-7b, -9, -19b, -107, -130b, and -218. LIN28B inhibits microRNA processing and is positively regulated by FGF signaling. Gain- and loss-of-function experiments show that LIN28B negatively regulates the expression of miR-19b, -130b, and let-7b, whereas negative modulation of miR-9, -107, and -218 appears to be independent of LIN28B function. Predicted mRNA targets of the FGF-regulated microRNAs are over-represented in serine/threonine and tyrosine kinase receptors, including ACVR1, ACVR2B, PDGFRA, TGFBR1, and TGFBR3. Luciferase assays show that these and other candidates are targeted by FGF-regulated microRNAs. PDGFRA, a receptor whose activity is required for cell migration through the primitive streak, is a target of miR-130b and -218 in vivo. These results identify a novel mechanism by which FGF signaling regulates gene expression by negatively modulating microRNA abundance through both LIN28B-dependent and LIN28B-independent pathways.
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Affiliation(s)
| | | | | | - Parker B. Antin
- From the Departments of Molecular and Cellular Biology and
- Cellular and Molecular Medicine, University of Arizona, Tucson, Arizona 85724
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174
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Ohuchi S, Mori Y, Nakamura Y. Evolution of an inhibitory RNA aptamer against T7 RNA polymerase. FEBS Open Bio 2012; 2:203-7. [PMID: 23650601 PMCID: PMC3642155 DOI: 10.1016/j.fob.2012.07.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/06/2012] [Accepted: 07/10/2012] [Indexed: 12/27/2022] Open
Abstract
Aptamers are promising gene components that can be used for the construction of synthetic gene circuits. In this study, we isolated an RNA aptamer that specifically inhibits transcription of T7 RNA polymerase (RNAP). The 38-nucleotide aptamer, which was a shortened variant of an initial SELEX isolate, showed moderate inhibitory activity. By stepwise doped-SELEX, we isolated evolved variants with strong inhibitory activity. A 29-nucleotide variant of a doped-SELEX isolate showed 50% inhibitory concentration at 11 nM under typical in vitro transcription conditions. Pull-down experiments revealed that the aptamer inhibited the association of T7 RNAP with T7 promoter DNA.
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Affiliation(s)
- Shoji Ohuchi
- Department of Basic Medical Sciences, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
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175
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Kato Y, Sato K, Asai K, Akutsu T. Rtips: fast and accurate tools for RNA 2D structure prediction using integer programming. Nucleic Acids Res 2012; 40:W29-34. [PMID: 22600734 PMCID: PMC3394313 DOI: 10.1093/nar/gks412] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We present a web-based tool set Rtips for fast and accurate prediction of RNA 2D complex structures. Rtips comprises two computational tools based on integer programming, IPknot for predicting RNA secondary structures with pseudoknots and RactIP for predicting RNA–RNA interactions with kissing hairpins. Both servers can run much faster than existing services with the same purpose on large data sets as well as being at least comparable in prediction accuracy. The Rtips web server along with the stand-alone programs is freely accessible at http://rna.naist.jp/.
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Affiliation(s)
- Yuki Kato
- Graduate School of Information Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
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176
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HEXIM1-binding elements on mRNAs identified through transcriptomic SELEX and computational screening. Biochimie 2012; 94:1900-9. [PMID: 22609015 DOI: 10.1016/j.biochi.2012.05.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Accepted: 05/04/2012] [Indexed: 11/20/2022]
Abstract
The positive transcription elongation factor b (P-TEFb) is one of the main regulatory factors of the transcription mediated by RNA polymerase II (RNAPII). P-TEFb promotes transcriptional elongation by phosphorylating its targets, which include the C-terminal domain of RNAPII. The activity of P-TEFb is negatively regulated by an RNA-binding protein HEXIM1 in association with 7SK snRNA. To search for other cellular RNAs that bind to HEXIM1, we used systematic evolution of ligands by exponential enrichment (SELEX) with the HeLa cDNA library as the initial pool source. We identified cad mRNA as a HEXIM1-binding RNA and confirmed their association in HeLa cells. In vitro mutational analysis showed that cad mRNA binds to HEXIM1 through its bulged stem structure located in exon 11. In addition, a computational search revealed other RNAs with similar stem structures, including brd4 and tcf3 mRNAs, both of which were shown to be coimmunoprecipitable with anti-HEXIM1 antibody in HeLa cells. Our findings suggest a possible role for HEXIM1 in the regulation of specific gene expressions.
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177
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Ohsaka Y, Nishino H. Polymorphisms in the 5′-UTR of PTEN and other gene polymorphisms in normal Japanese individuals. CYTOL GENET+ 2012. [DOI: 10.3103/s0095452712020028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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178
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Bahrami A, Clos LJ, Markley JL, Butcher SE, Eghbalnia HR. RNA-PAIRS: RNA probabilistic assignment of imino resonance shifts. JOURNAL OF BIOMOLECULAR NMR 2012; 52:289-302. [PMID: 22359049 PMCID: PMC3480180 DOI: 10.1007/s10858-012-9603-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 01/08/2012] [Indexed: 05/13/2023]
Abstract
The significant biological role of RNA has further highlighted the need for improving the accuracy, efficiency and the reach of methods for investigating RNA structure and function. Nuclear magnetic resonance (NMR) spectroscopy is vital to furthering the goals of RNA structural biology because of its distinctive capabilities. However, the dispersion pattern in the NMR spectra of RNA makes automated resonance assignment, a key step in NMR investigation of biomolecules, remarkably challenging. Herein we present RNA Probabilistic Assignment of Imino Resonance Shifts (RNA-PAIRS), a method for the automated assignment of RNA imino resonances with synchronized verification and correction of predicted secondary structure. RNA-PAIRS represents an advance in modeling the assignment paradigm because it seeds the probabilistic network for assignment with experimental NMR data, and predicted RNA secondary structure, simultaneously and from the start. Subsequently, RNA-PAIRS sets in motion a dynamic network that reverberates between predictions and experimental evidence in order to reconcile and rectify resonance assignments and secondary structure information. The procedure is halted when assignments and base-parings are deemed to be most consistent with observed crosspeaks. The current implementation of RNA-PAIRS uses an initial peak list derived from proton-nitrogen heteronuclear multiple quantum correlation ((1)H-(15)N 2D HMQC) and proton-proton nuclear Overhauser enhancement spectroscopy ((1)H-(1)H 2D NOESY) experiments. We have evaluated the performance of RNA-PAIRS by using it to analyze NMR datasets from 26 previously studied RNAs, including a 111-nucleotide complex. For moderately sized RNA molecules, and over a range of comparatively complex structural motifs, the average assignment accuracy exceeds 90%, while the average base pair prediction accuracy exceeded 93%. RNA-PAIRS yielded accurate assignments and base pairings consistent with imino resonances for a majority of the NMR resonances, even when the initial predictions are only modestly accurate. RNA-PAIRS is available as a public web-server at http://pine.nmrfam.wisc.edu/RNA/.
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Affiliation(s)
- Arash Bahrami
- National Magnetic Resonance Facility at Madison, Madison, WI, USA
| | - Lawrence J. Clos
- National Magnetic Resonance Facility at Madison, Madison, WI, USA
| | - John L. Markley
- National Magnetic Resonance Facility at Madison, Madison, WI, USA. Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Samuel E. Butcher
- National Magnetic Resonance Facility at Madison, Madison, WI, USA. Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Hamid R. Eghbalnia
- Department of Molecular and Cellular Physiology, University of Cincinnati, P.O. Box 670576, Cincinnati, OH 45267-0576, USA
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Miyagawa R, Tano K, Mizuno R, Nakamura Y, Ijiri K, Rakwal R, Shibato J, Masuo Y, Mayeda A, Hirose T, Akimitsu N. Identification of cis- and trans-acting factors involved in the localization of MALAT-1 noncoding RNA to nuclear speckles. RNA (NEW YORK, N.Y.) 2012; 18:738-51. [PMID: 22355166 PMCID: PMC3312561 DOI: 10.1261/rna.028639.111] [Citation(s) in RCA: 172] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2011] [Accepted: 12/15/2011] [Indexed: 05/26/2023]
Abstract
MALAT-1 noncoding RNA is localized to nuclear speckles despite its mRNA-like characteristics. Here, we report the identification of several key factors that promote the localization of MALAT-1 to nuclear speckles and also provide evidence that MALAT-1 is involved in the regulation of gene expression. Heterokaryon assays revealed that MALAT-1 does not shuttle between the nucleus and cytoplasm. RNAi-mediated repression of the nuclear speckle proteins, RNPS1, SRm160, or IBP160, which are well-known mRNA processing factors, resulted in the diffusion of MALAT-1 to the nucleoplasm. We demonstrated that MALAT-1 contains two distinct elements directing transcripts to nuclear speckles, which were also capable of binding to RNPS1 in vitro. Depletion of MALAT-1 represses the expression of several genes. Taken together, our results suggest that RNPS1, SRm160, and IBP160 contribute to the localization of MALAT-1 to nuclear speckles, where MALAT-1 could be involved in regulating gene expression.
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Affiliation(s)
- Ryu Miyagawa
- Radioisotope Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Keiko Tano
- Radioisotope Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Rie Mizuno
- Radioisotope Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Yo Nakamura
- Radioisotope Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Kenichi Ijiri
- Radioisotope Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Randeep Rakwal
- Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST) West, Tsukuba, Ibaraki 305-8569, Japan
| | - Junko Shibato
- Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST) West, Tsukuba, Ibaraki 305-8569, Japan
| | - Yoshinori Masuo
- Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST) West, Tsukuba, Ibaraki 305-8569, Japan
| | - Akila Mayeda
- Institute for Comprehensive Medical Science (ICMS), Fujita Health University, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Tetsuro Hirose
- Functional RNomics Team, Biomedicinal Information Research Center, AIST, Tokyo 135-0064, Japan
| | - Nobuyoshi Akimitsu
- Radioisotope Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
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180
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Bida JP, Maher LJ. Improved prediction of RNA tertiary structure with insights into native state dynamics. RNA (NEW YORK, N.Y.) 2012; 18:385-393. [PMID: 22279150 PMCID: PMC3285927 DOI: 10.1261/rna.027201.111] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 11/28/2011] [Indexed: 05/31/2023]
Abstract
The importance of RNA tertiary structure is evident from the growing number of published high resolution NMR and X-ray crystallographic structures of RNA molecules. These structures provide insights into function and create a knowledge base that is leveraged by programs such as Assemble, ModeRNA, RNABuilder, NAST, FARNA, Mc-Sym, RNA2D3D, and iFoldRNA for tertiary structure prediction and design. While these methods sample native-like RNA structures during simulations, all struggle to capture the native RNA conformation after scoring. We propose RSIM, an improved RNA fragment assembly method that preserves RNA global secondary structure while sampling conformations. This approach enhances the quality of predicted RNA tertiary structure, provides insights into the native state dynamics, and generates a powerful visualization of the RNA conformational space. RSIM is available for download from http://www.github.com/jpbida/rsim.
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Affiliation(s)
- John Paul Bida
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
| | - L. James Maher
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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181
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Sakuragi JI, Ode H, Sakuragi S, Shioda T, Sato H. A proposal for a new HIV-1 DLS structural model. Nucleic Acids Res 2012; 40:5012-22. [PMID: 22328732 PMCID: PMC3367192 DOI: 10.1093/nar/gks156] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The dimer initiation site/dimer linkage sequence (DIS/DLS) region of the human immunodeficiency virus type 1 (HIV-1) RNA genome is suggested to play essential roles at various stages of the viral life cycle. Through a novel assay we had recently developed, we reported on the necessary and sufficient region for RNA dimerization in the HIV-1 virion. Using this system, we performed further detailed mapping of the functional base pairs necessary for HIV-1 DLS structure. Interestingly, the study revealed a previously unnoticed stem formation between two distantly positioned regions. Based on this and other findings on functional base pairing in vivo, we propose new 3D models of the HIV-1 DLS which contain a unique pseudoknot-like conformation. Since this pseudoknot-like conformation appears to be thermodynamically stable, forms a foundational skeleton for the DLS and sterically restricts the spontaneous diversification of DLS conformations, its unique shape may contribute to the viral life cycle and potentially serve as a novel target for anti-HIV-1 therapies.
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Affiliation(s)
- Jun-ichi Sakuragi
- Department of Viral Infections, RIMD, Osaka Univ. 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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182
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Haraguchi T, Nakano H, Tagawa T, Ohki T, Ueno Y, Yoshida T, Iba H. A potent 2'-O-methylated RNA-based microRNA inhibitor with unique secondary structures. Nucleic Acids Res 2012; 40:e58. [PMID: 22259037 PMCID: PMC3333889 DOI: 10.1093/nar/gkr1317] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
MicroRNAs (miRNAs) are involved in various biological processes and human diseases. The development of strong low-molecular weight inhibitors of specific miRNAs is thus expected to be useful in providing tools for basic research or in generating promising new therapeutic drugs. We have previously described the development of ‘Tough Decoy (TuD) RNA’ molecules, which achieve the long-term suppression of specific miRNA activity in mammalian cells when expressed from a lentivirus vector. In our current study, we describe new synthetic miRNA inhibitors, designated as S-TuD (Synthetic TuD), which are composed of two fully 2′-O-methylated RNA strands. Each of these strands includes a miRNA-binding site. Following the hybridization of paired strands, the resultant S-TuD forms a secondary structure with two stems, which resembles the corresponding TuD RNA molecule. By analyzing the effects of S-TuD against miR-21, miR-200c, miR-16 and miR-106b, we have elucidated the critical design features of S-TuD molecules that will provide optimum inhibitory effects following transfection into human cell lines. We further show that the inhibitory effects of a single transfection of S-TuD-miR200c are quite long-lasting (>7 days) and induce partial EMT, the full establishment of which requires 11 days when using a lentivirus vector that expresses TuD-miR200c continuously.
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Affiliation(s)
- Takeshi Haraguchi
- Division of Host-Parasite Interaction, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
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183
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Dimonte S, Mercurio F, Svicher V, Perno CF, Ceccherini-Silberstein F. Genetic and structural analysis of HIV-1 Rev responsive element related to V38A and T18A enfuvirtide resistance mutations. Intervirology 2011; 55:385-90. [PMID: 22188777 DOI: 10.1159/000334696] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 10/24/2011] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND For the expression of late viral genes, HIV-1 efficiently exploits the nuclear export by using Rev viral protein, which specifically binds the RNA Rev Responsive Element (RRE). This region is contained within the gp120-gp41 encoding sequence. Enfuvirtide is the first approved HIV-1 fusion-inhibitor, and gp41 codons associated with primary enfuvirtide-resistance (amino-acids 36-45) are localized within the RRE structure. We previously found the co-presence of V38A+T18A resistance mutations in patients failing enfuvirtide. METHODS Collecting 476 and 135 HIV-1 B-subtype gp41 sequences from enfuvirtide-naïve and enfuvirtide-treated patients, respectively, two mutations previously found associated with enfuvirtide treatment, T18A and V38A, were analyzed. Moreover, the RNA secondary structure was displayed by CONTRAfold-software and the gp41 evolutionary pathways by a mutagenetic tree. RESULTS By modeling the RRE structure, we show that the T18 and V38 codons are base pairing within the RRE-stem-IIA, an important domain involved in Rev binding. While a structural RRE impairment in the presence of V38A alone was found, a restoration of the original RRE structure occurred in co-presence of V38A+T18A. By mutagenetic tree analysis, a compensatory evolution confirming our hypothesis on the structural modification mechanism was observed. CONCLUSION We show that enfuvirtide pressure may also affect specific RRE domains involved in Rev binding, thus requiring a compensatory evolution able to preserve the secondary structure of the RRE.
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Affiliation(s)
- Salvatore Dimonte
- University of Rome Tor Vergata, Rome, Italy. salvatore.dimonte @ uniroma2.it
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184
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Jeong DH, Park S, Zhai J, Gurazada SGR, De Paoli E, Meyers BC, Green PJ. Massive analysis of rice small RNAs: mechanistic implications of regulated microRNAs and variants for differential target RNA cleavage. THE PLANT CELL 2011; 23:4185-207. [PMID: 22158467 PMCID: PMC3269859 DOI: 10.1105/tpc.111.089045] [Citation(s) in RCA: 221] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Small RNAs have a variety of important roles in plant development, stress responses, and other processes. They exert their influence by guiding mRNA cleavage, translational repression, and chromatin modification. To identify previously unknown rice (Oryza sativa) microRNAs (miRNAs) and those regulated by environmental stress, 62 small RNA libraries were constructed from rice plants and used for deep sequencing with Illumina technology. The libraries represent several tissues from control plants and plants subjected to different environmental stress treatments. More than 94 million genome-matched reads were obtained, resulting in more than 16 million distinct small RNA sequences. This allowed an evaluation of ~400 annotated miRNAs with current criteria and the finding that among these, ~150 had small interfering RNA-like characteristics. Seventy-six new miRNAs were found, and miRNAs regulated in response to water stress, nutrient stress, or temperature stress were identified. Among the new examples of miRNA regulation were members of the same miRNA family that were differentially regulated in different organs and had distinct sequences Some of these distinct family members result in differential target cleavage and provide new insight about how an agriculturally important rice phenotype could be regulated in the panicle. This high-resolution analysis of rice miRNAs should be relevant to plant miRNAs in general, particularly in the Poaceae.
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185
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A distinct class of internal ribosomal entry site in members of the Kobuvirus and proposed Salivirus and Paraturdivirus genera of the Picornaviridae. J Virol 2011; 86:1468-86. [PMID: 22114340 DOI: 10.1128/jvi.05862-11] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The 5'-untranslated regions (5' UTRs) of picornavirus genomes contain an internal ribosomal entry site (IRES) that promotes the end-independent initiation of translation. Picornavirus IRESs are classified into four structurally distinct groups, each with different initiation factor requirements. Here, we identify a fifth IRES class in members of Kobuvirus, Salivirus, and Paraturdivirus genera of Picornaviridae: Aichi virus (AV), bovine kobuvirus (BKV), canine kobuvirus (CKoV), mouse kobuvirus (MKoV), sheep kobuvirus (SKV), salivirus A (SV-A), turdivirus 2 (TV2), and TV3. The 410-nucleotide (nt)-long AV IRES comprises four domains (I to L), including a hairpin (L) that overlaps a Yn-Xm-AUG (pyrimidine tract/spacer/initiation codon) motif. SV-A, CKoV, and MKoV also contain these four domains, whereas BKV, SKV, and TV2/TV3 5' UTRs contain domains that are related to domain I and equivalent to domains J and K but lack an AV-like domain L. These IRESs are located at different relative positions between a conserved 5'-terminal origin of replication and divergent coding sequences. Elements in these IRESs also occur elsewhere: domain J's apical subdomain, which contains a GNRA tetraloop, matches an element in type 1 IRESs, and eIF4G-binding motifs in domain K and in type 2 IRESs are identical. Other elements are unique, and their presence leads to unique initiation factor requirements. In vitro reconstitution experiments showed that like AV, but in contrast to other currently characterized IRESs, SV-A requires the DExH-box protein DHX29 during initiation, which likely ensures that the initiation codon sequestered in domain L is properly accommodated in the ribosomal mRNA-binding cleft.
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186
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Burroughs AM, Kawano M, Ando Y, Daub CO, Hayashizaki Y. pre-miRNA profiles obtained through application of locked nucleic acids and deep sequencing reveals complex 5'/3' arm variation including concomitant cleavage and polyuridylation patterns. Nucleic Acids Res 2011; 40:1424-37. [PMID: 22058130 PMCID: PMC3287202 DOI: 10.1093/nar/gkr903] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Recent research hints at an underappreciated complexity in pre-miRNA processing and regulation. Global profiling of pre-miRNA and its potential to increase understanding of the pre-miRNA landscape is impeded by overlap with highly expressed classes of other non coding (nc) RNA. Here, we present a data set excluding these RNA before sequencing through locked nucleic acids (LNA), greatly increasing pre-miRNA sequence counts with no discernable effect on pre-miRNA or mature miRNA sequencing. Analysis of profiles generated in total, nuclear and cytoplasmic cell fractions reveals that pre-miRNAs are subject to a wide range of regulatory processes involving loci-specific 3′- and 5′-end variation entailing complex cleavage patterns with co-occurring polyuridylation. Additionally, examination of nuclear-enriched flanking sequences of pre-miRNA, particularly those derived from polycistronic miRNA transcripts, provides insight into miRNA and miRNA-offset (moRNA) production, specifically identifying novel classes of RNA potentially functioning as moRNA precursors. Our findings point to particularly intricate regulation of the let-7 family in many ways reminiscent of DICER1-independent, pre-mir-451-like processing, introduce novel and unify known forms of pre-miRNA regulation and processing, and shed new light on overlooked products of miRNA processing pathways.
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Affiliation(s)
- A Maxwell Burroughs
- Omics Science Center, RIKEN Yokohama Institute, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa 230-0045, Japan.
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187
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Nishihara M, Hikage T, Yamada E, Nakatsuka T. A single-base substitution suppresses flower color mutation caused by a novel miniature inverted-repeat transposable element in gentian. Mol Genet Genomics 2011; 286:371-82. [DOI: 10.1007/s00438-011-0652-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 10/02/2011] [Indexed: 12/13/2022]
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188
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Siddiqui RA, Krawczak M, Platzer M, Sauermann U. Association of TLR7 variants with AIDS-like disease and AIDS vaccine efficacy in rhesus macaques. PLoS One 2011; 6:e25474. [PMID: 22022401 PMCID: PMC3192768 DOI: 10.1371/journal.pone.0025474] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 09/05/2011] [Indexed: 02/07/2023] Open
Abstract
In HIV infection, TLR7-triggered IFN-α production exerts a direct antiviral effect through the inhibition of viral replication, but may also be involved in immune pathogenesis leading to AIDS. TLR7 could also be an important mediator of vaccine efficacy. In this study, we analyzed polymorphisms in the X-linked TLR7 gene in the rhesus macaque model of AIDS. Upon resequencing of the TLR7 gene in 36 rhesus macaques of Indian origin, 12 polymorphic sites were detected. Next, we identified three tightly linked single nucleotide polymorphisms (SNP) as being associated with survival time. Genotyping of 119 untreated, simian immunodeficiency virus (SIV)-infected male rhesus macaques, including an 'MHC adjusted' subset, revealed that the three TLR7 SNPs are also significantly associated with set-point viral load. Surprisingly, this effect was not observed in 72 immunized SIV-infected male monkeys. We hypothesize (i) that SNP c.13G>A in the leader peptide is causative for the observed genotype-phenotype association and that (ii) the underlying mechanism is related to RNA secondary structure formation. Therefore, we investigated a fourth SNP (c.-17C>T), located 17 bp upstream of the ATG translation initiation codon, that is also potentially capable of influencing RNA structure. In c.13A carriers, neither set-point viral load nor survival time were related to the c.-17C>T genotype. In c.13G carriers, by contrast, the c.-17C allele was significantly associated with prolonged survival. Again, no such association was detected among immunized SIV-infected macaques. Our results highlight the dual role of TLR7 in immunodeficiency virus infection and vaccination and imply that it may be important to control human AIDS vaccine trials, not only for MHC genotype, but also for TLR7 genotype.
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Affiliation(s)
- Roman A. Siddiqui
- German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
- Genome Analysis, Leibniz Institute for Age Research–Fritz Lipmann Institute, Jena, Germany
| | - Michael Krawczak
- Institute of Medical Informatics and Statistics, Christian–Albrechts University, Kiel, Germany
| | - Matthias Platzer
- Genome Analysis, Leibniz Institute for Age Research–Fritz Lipmann Institute, Jena, Germany
| | - Ulrike Sauermann
- German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
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189
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Mutai H, Kouike H, Teruya E, Takahashi-Kodomari I, Kakishima H, Taiji H, Usami SI, Okuyama T, Matsunaga T. Systematic analysis of mitochondrial genes associated with hearing loss in the Japanese population: dHPLC reveals a new candidate mutation. BMC MEDICAL GENETICS 2011; 12:135. [PMID: 21989059 PMCID: PMC3207971 DOI: 10.1186/1471-2350-12-135] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 10/12/2011] [Indexed: 11/17/2022]
Abstract
Background Variants of mitochondrial DNA (mtDNA) have been evaluated for their association with hearing loss. Although ethnic background affects the spectrum of mtDNA variants, systematic mutational analysis of mtDNA in Japanese patients with hearing loss has not been reported. Methods Using denaturing high-performance liquid chromatography combined with direct sequencing and cloning-sequencing, Japanese patients with prelingual (N = 54) or postlingual (N = 80) sensorineural hearing loss not having pathogenic mutations of m.1555A > G and m.3243A > G nor GJB2 were subjected to mutational analysis of mtDNA genes (12S rRNA, tRNALeu(UUR), tRNASer(UCN), tRNALys, tRNAHis, tRNASer(AGY), and tRNAGlu). Results We discovered 15 variants in 12S rRNA and one homoplasmic m.7501A > G variant in tRNASer(UCN); no variants were detected in the other genes. Two criteria, namely the low frequency in the controls and the high conservation among animals, selected the m.904C > T and the m.1105T > C variants in 12S rRNA as candidate pathogenic mutations. Alterations in the secondary structures of the two variant transcripts as well as that of m.7501A > G in tRNASer(UCN) were predicted. Conclusions The m.904C > T variant was found to be a new candidate mutation associated with hearing loss. The m.1105T > C variant is unlikely to be pathogenic. The pathogenicity of the homoplasmic m.7501T > A variant awaits further study.
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Affiliation(s)
- Hideki Mutai
- Laboratory of Auditory Disorders, Division of Hearing and Balance Research, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
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190
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Kakui K, Katoh T, Hiruta SF, Kobayashi N, Kajihara H. Molecular Systematics of Tanaidacea (Crustacea: Peracarida) Based on 18S Sequence Data, with an Amendment of Suborder/Superfamily-Level Classification. Zoolog Sci 2011; 28:749-57. [DOI: 10.2108/zsj.28.749] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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191
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The mechanism of translation initiation on Aichivirus RNA mediated by a novel type of picornavirus IRES. EMBO J 2011; 30:4423-36. [PMID: 21873976 DOI: 10.1038/emboj.2011.306] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 08/01/2011] [Indexed: 01/17/2023] Open
Abstract
Picornavirus mRNAs contain IRESs that sustain their translation during infection, when host protein synthesis is shut off. The major classes of picornavirus IRESs (Types 1 and 2) have distinct structures and sequences, but initiation on both is determined by their specific interaction with eIF4G. We report here that Aichivirus (AV), a member of the Kobuvirus genus of Picornaviridae, contains an IRES that differs structurally from Type 1 and Type 2 IRESs. Its function similarly involves interaction with eIF4G, but its eIF4G-interacting domain is structurally distinct, although it contains an apical eIF4G-interacting motif similar to that in Type 2 IRESs. Like Type 1 and Type 2 IRESs, AV IRES function is enhanced by pyrimidine tract-binding protein (PTB), but the pattern of PTB's interaction with each of these IRESs is distinct. Unlike all known IRESs, the AV IRES is absolutely dependent on DHX29, a requirement imposed by sequestration of its initiation codon in a stable hairpin.
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192
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Nozaki H, Coleman AW. A NEW SPECIES OF VOLVOX SECT. MERRILLOSPHAERA (VOLVOCACEAE, CHLOROPHYCEAE) FROM TEXAS 1. JOURNAL OF PHYCOLOGY 2011; 47:673-679. [PMID: 27021996 DOI: 10.1111/j.1529-8817.2011.00975.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Smith (1944) divided the familiar genus Volvox L. into four sections, placing seven species that lacked cytoplasmic bridges between adult cells in the section Merrillosphaera. Herein, we describe a new member of the section Merrillosphaera originating from Texas (USA): Volvox ovalis Pocock ex Nozaki et A. W. Coleman sp. nov. Asexual spheroids of V. ovalis are ovoid or elliptical, with a monolayer of 1,000-2,000 somatic cells that are not linked by cytoplasmic bridges, an expanded anterior region, and 8-12 gonidia in the posterior region. Visibly asymmetric cleavage divisions do not occur in V. ovalis embryos as they do Volvox carteri F. Stein, Volvox obversus (W. Shaw) Printz, and Volvox africanus G. S. West, so the gonidia of the next generation are not yet recognizable in V. ovalis embryos prior to inversion. Molecular phylogenetic analyses of the five chloroplast genes and the internal transcribed spacer (ITS) regions of nuclear rDNA indicated that V. ovalis is closely related to Volvox spermatosphaera Powers (Powers 1908, as "spermatosphara") and/or Volvox tertius Art. Mey.; however, V. ovalis can be distinguished from V. spermatosphaera by its larger gonidia, and from V. tertius by visible differences in gonidial chloroplast morphology.
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Affiliation(s)
- Hisayoshi Nozaki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, JapanDepartment of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Annette W Coleman
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, JapanDepartment of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island 02912, USA
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193
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Hamada M, Yamada K, Sato K, Frith MC, Asai K. CentroidHomfold-LAST: accurate prediction of RNA secondary structure using automatically collected homologous sequences. Nucleic Acids Res 2011; 39:W100-6. [PMID: 21565800 PMCID: PMC3125741 DOI: 10.1093/nar/gkr290] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Although secondary structure predictions of an individual RNA sequence have been widely used in a number of sequence analyses of RNAs, accuracy is still limited. Recently, we proposed a method (called 'CentroidHomfold'), which includes information about homologous sequences into the prediction of the secondary structure of the target sequence, and showed that it substantially improved the performance of secondary structure predictions. CentroidHomfold, however, forces users to prepare homologous sequences of the target sequence. We have developed a Web application (CentroidHomfold-LAST) that predicts the secondary structure of the target sequence using automatically collected homologous sequences. LAST, which is a fast and sensitive local aligner, and CentroidHomfold are employed in the Web application. Computational experiments with a commonly-used data set indicated that CentroidHomfold-LAST substantially outperformed conventional secondary structure predictions including CentroidFold and RNAfold.
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Affiliation(s)
- Michiaki Hamada
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.
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194
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Setohigashi Y, Hamaji T, Hayama M, Matsuzaki R, Nozaki H. Uniparental inheritance of chloroplast DNA is strict in the isogamous volvocalean Gonium. PLoS One 2011; 6:e19545. [PMID: 21559302 PMCID: PMC3085477 DOI: 10.1371/journal.pone.0019545] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 03/31/2011] [Indexed: 11/19/2022] Open
Abstract
Background A problem has remained unresolved regarding the exceptions to the unilateral inheritance of chloroplast DNA (cpDNA) from MT+/female in Chlamydomonas and other volvocaleans demonstrated by the previous genetic analyses. For identification of the parental types of cpDNA, these studies used parents that have differences in restriction fragment length polymorphisms and exhibit partial sexual incompatibility. Methodology/Principal Findings In the present study, we used sexually compatible parents of the isogamous colonial volvocalean Gonium maiaprilis that seemed an ideal species to identify the pattern of cpDNA inheritance based on the length difference in the putative group I intron interrupted in the Rubisco large subunit gene and objective identification of mating types by the presence or absence of the minus-dominance (MID) gene. We examined patterns of inheritance of cpDNA and presence/absence of a MID ortholog (GmMID) in 107 F1 progeny of G. maiaprilis that were obtained by inducing germination of separated single zygotes. The results demonstrated no exception of the uniparental inheritance of cpDNA from the MT+ parent (lacking GmMID) in sexually compatible or genetically less divergent strains of G. maiaprilis. Conclusions/Significance The present data suggest that the uniparental inheritance of cpDNA is likely more strict in crossings of less diverged strains or sexually compatible parental volvocaleans, and some genetic inconsistency between the parents may cause exceptional uniparental inheritance of cpDNA.
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Affiliation(s)
- Yuka Setohigashi
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Takashi Hamaji
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Mahoko Hayama
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Ryo Matsuzaki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
| | - Hisayoshi Nozaki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
- * E-mail:
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195
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Hamada M, Kiryu H, Iwasaki W, Asai K. Generalized centroid estimators in bioinformatics. PLoS One 2011; 6:e16450. [PMID: 21365017 PMCID: PMC3041832 DOI: 10.1371/journal.pone.0016450] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 12/22/2010] [Indexed: 11/27/2022] Open
Abstract
In a number of estimation problems in bioinformatics, accuracy measures of the target problem are usually given, and it is important to design estimators that are suitable to those accuracy measures. However, there is often a discrepancy between an employed estimator and a given accuracy measure of the problem. In this study, we introduce a general class of efficient estimators for estimation problems on high-dimensional binary spaces, which represent many fundamental problems in bioinformatics. Theoretical analysis reveals that the proposed estimators generally fit with commonly-used accuracy measures (e.g. sensitivity, PPV, MCC and F-score) as well as it can be computed efficiently in many cases, and cover a wide range of problems in bioinformatics from the viewpoint of the principle of maximum expected accuracy (MEA). It is also shown that some important algorithms in bioinformatics can be interpreted in a unified manner. Not only the concept presented in this paper gives a useful framework to design MEA-based estimators but also it is highly extendable and sheds new light on many problems in bioinformatics.
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Affiliation(s)
- Michiaki Hamada
- Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan.
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196
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Ando Y, Maida Y, Morinaga A, Burroughs AM, Kimura R, Chiba J, Suzuki H, Masutomi K, Hayashizaki Y. Two-step cleavage of hairpin RNA with 5' overhangs by human DICER. BMC Mol Biol 2011; 12:6. [PMID: 21306637 PMCID: PMC3048551 DOI: 10.1186/1471-2199-12-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 02/09/2011] [Indexed: 12/21/2022] Open
Abstract
Background DICER is an RNase III family endoribonuclease that processes precursor microRNAs (pre-miRNAs) and long double-stranded RNAs, generating microRNA (miRNA) duplexes and short interfering RNA duplexes with 20~23 nucleotides (nts) in length. The typical form of pre-miRNA processed by the Drosha protein is a hairpin RNA with 2-nt 3' overhangs. On the other hand, production of mature miRNA from an endogenous hairpin RNA with 5' overhangs has also been reported, although the mechanism for this process is unknown. Results In this study, we show that human recombinant DICER protein (rDICER) processes a hairpin RNA with 5' overhangs in vitro and generates an intermediate duplex with a 29 nt-5' strand and a 23 nt-3' strand, which was eventually cleaved into a canonical miRNA duplex via a two-step cleavage. The previously identified endogenous pre-miRNA with 5' overhangs, pre-mmu-mir-1982 RNA, is also determined to be a substrate of rDICER through the same two-step cleavage. Conclusions The two-step cleavage of a hairpin RNA with 5' overhangs shows that DICER releases double-stranded RNAs after the first cleavage and binds them again in the inverse direction for a second cleavage. These findings have implications for how DICER may be able to interact with or process differing precursor structures.
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Affiliation(s)
- Yoshinari Ando
- RIKEN Omics Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
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197
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Sakurai M, Suzuki T. Biochemical identification of A-to-I RNA editing sites by the inosine chemical erasing (ICE) method. Methods Mol Biol 2011; 718:89-99. [PMID: 21370043 DOI: 10.1007/978-1-61779-018-8_5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Adenosine-to-inosine (A-to-I) RNA editing is a biologically important posttranscriptional processing event involved in the transcriptome diversification. The most conventional method of editing site identification is to compare the cDNA sequence with its corresponding genomic sequence; however, using this method, it is difficult to discriminate between guanosine residue that originated from inosine and errors or noise in the sequencing chromatograms. To address this issue, we developed the inosine chemical erasing (ICE) method to identify inosines in RNA strands utilizing inosine cyanoethylation and reverse transcription PCR. Since this method requires only a limited quantity of total RNA, it can be used in the genome-wide profiling of A-to-I editing sites in tissues and cells from various organisms, including clinical specimens.
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Affiliation(s)
- Masayuki Sakurai
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo, Japan
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198
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Abstract
The prediction of RNA structure can be a first important step for the functional characterization of novel ncRNAs. Especially for the very meaningful secondary structure, there is a multitude of computational prediction tools. They differ not only in algorithmic details and the underlying models but also in what exactly they are trying to predict. This chapter gives an overview of different programs that aim to predict RNA secondary structure. We will introduce the ViennaRNA software package and web server as a solution that implements most of the varieties of RNA secondary structure prediction that have been published over the years. We focus on algorithms going beyond the mere prediction of a static structure.
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Affiliation(s)
- Stephan H Bernhart
- Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria.
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199
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Hamada M, Sato K, Asai K. Prediction of RNA secondary structure by maximizing pseudo-expected accuracy. BMC Bioinformatics 2010; 11:586. [PMID: 21118522 PMCID: PMC3003279 DOI: 10.1186/1471-2105-11-586] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 11/30/2010] [Indexed: 12/17/2022] Open
Abstract
Background Recent studies have revealed the importance of considering the entire distribution of possible secondary structures in RNA secondary structure predictions; therefore, a new type of estimator is proposed including the maximum expected accuracy (MEA) estimator. The MEA-based estimators have been designed to maximize the expected accuracy of the base-pairs and have achieved the highest level of accuracy. Those methods, however, do not give the single best prediction of the structure, but employ parameters to control the trade-off between the sensitivity and the positive predictive value (PPV). It is unclear what parameter value we should use, and even the well-trained default parameter value does not, in general, give the best result in popular accuracy measures to each RNA sequence. Results Instead of using the expected values of the popular accuracy measures for RNA secondary structure prediction, which is difficult to be calculated, the pseudo-expected accuracy, which can easily be computed from base-pairing probabilities, is introduced. It is shown that the pseudo-expected accuracy is a good approximation in terms of sensitivity, PPV, MCC, or F-score. The pseudo-expected accuracy can be approximately maximized for each RNA sequence by stochastic sampling. It is also shown that well-balanced secondary structures between sensitivity and PPV can be predicted with a small computational overhead by combining the pseudo-expected accuracy of MCC or F-score with the γ-centroid estimator. Conclusions This study gives not only a method for predicting the secondary structure that balances between sensitivity and PPV, but also a general method for approximately maximizing the (pseudo-)expected accuracy with respect to various evaluation measures including MCC and F-score.
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Affiliation(s)
- Michiaki Hamada
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, Japan.
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200
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Hamada M, Sato K, Asai K. Improving the accuracy of predicting secondary structure for aligned RNA sequences. Nucleic Acids Res 2010; 39:393-402. [PMID: 20843778 PMCID: PMC3025558 DOI: 10.1093/nar/gkq792] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Considerable attention has been focused on predicting the secondary structure for aligned RNA sequences since it is useful not only for improving the limiting accuracy of conventional secondary structure prediction but also for finding non-coding RNAs in genomic sequences. Although there exist many algorithms of predicting secondary structure for aligned RNA sequences, further improvement of the accuracy is still awaited. In this article, toward improving the accuracy, a theoretical classification of state-of-the-art algorithms of predicting secondary structure for aligned RNA sequences is presented. The classification is based on the viewpoint of maximum expected accuracy (MEA), which has been successfully applied in various problems in bioinformatics. The classification reveals several disadvantages of the current algorithms but we propose an improvement of a previously introduced algorithm (CentroidAlifold). Finally, computational experiments strongly support the theoretical classification and indicate that the improved CentroidAlifold substantially outperforms other algorithms.
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Affiliation(s)
- Michiaki Hamada
- Mizuho Information & Research Institute, Inc, Chiyoda-ku, Tokyo, Japan.
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