RNA editing of microRNA prevents RNA-induced silencing complex recognition of target mRNA.

PubMed

Cui, Yalei; Huang, Tianzhi; Zhang, Xiaobo

2015-12-01

MicroRNAs (miRNAs) integrate with Argonaut (Ago) to create the RNA-induced silencing complex, and regulate gene expression by silencing target mRNAs. RNA editing of miRNA may affect miRNA processing, assembly of the Ago complex and target mRNA binding. However, the function of edited miRNA, assembled within the Ago complex, has not been extensively investigated. In this study, sequence analysis of the Ago complex of Marsupenaeus japonicus shrimp infected with white spot syndrome virus (WSSV) revealed that host ADAR (adenosine deaminase acting on RNA) catalysed A-to-I RNA editing of a viral miRNA (WSSV-miR-N12) at the +16 site. This editing of the non-seed sequence did not affect association of the edited miRNA with the Ago protein, but inhibited interaction between the miRNA and its target gene (wsv399). The WSSV early gene wsv399 inhibited WSSV infection. As a result, the RNA editing of miRNA caused virus latency. Our results highlight a novel example of miRNA editing in the miRNA-induced silencing complex. © 2015 The Authors.

External Guide Sequences Targeting the aac(6′)-Ib mRNA Induce Inhibition of Amikacin Resistance▿

PubMed Central

Bistué, Alfonso J. C. Soler; Ha, Hongphuc; Sarno, Renee; Don, Michelle; Zorreguieta, Angeles; Tolmasky, Marcelo E.

2007-01-01

The dissemination of AAC(6′)-I-type acetyltransferases have rendered amikacin and other aminoglycosides all but useless in some parts of the world. Antisense technologies could be an alternative to extend the life of these antibiotics. External guide sequences are short antisense oligoribonucleotides that induce RNase P-mediated cleavage of a target RNA by forming a precursor tRNA-like complex. Thirteen-nucleotide external guide sequences complementary to locations within five regions accessible for interaction with antisense oligonucleotides in the mRNA that encodes AAC(6′)-Ib were analyzed. While small variations in the location targeted by different external guide sequences resulted in big changes in efficiency of binding to native aac(6′)-Ib mRNA, most of them induced high levels of RNase P-mediated cleavage in vitro. Recombinant plasmids coding for selected external guide sequences were introduced into Escherichia coli harboring aac(6′)-Ib, and the transformant strains were tested to determine their resistance to amikacin. The two external guide sequences that showed the strongest binding efficiency to the mRNA in vitro, EGSC3 and EGSA2, interfered with expression of the resistance phenotype at different degrees. Growth curve experiments showed that E. coli cells harboring a plasmid coding for EGSC3, the external guide sequence with the highest mRNA binding affinity in vitro, did not grow for at least 300 min in the presence of 15 μg of amikacin/ml. EGSA2, which had a lower mRNA-binding affinity in vitro than EGSC3, inhibited the expression of amikacin resistance at a lesser level; growth of E. coli harboring a plasmid coding for EGSA2, in the presence of 15 μg of amikacin/ml was undetectable for 200 min but reached an optical density at 600 nm of 0.5 after 5 h of incubation. Our results indicate that the use of external guide sequences could be a viable strategy to preserve the efficacy of amikacin. PMID:17387154

Embedding siRNA sequences targeting Apolipoprotein B100 in shRNA and miRNA scaffolds results in differential processing and in vivo efficacy

PubMed Central

Maczuga, Piotr; Lubelski, Jacek; van Logtenstein, Richard; Borel, Florie; Blits, Bas; Fakkert, Erwin; Costessi, Adalberto; Butler, Derek; van Deventer, Sander; Petry, Harald; Koornneef, Annemart; Konstantinova, Pavlina

2013-01-01

Overexpression of short hairpin RNA (shRNA) often causes cytotoxicity and using microRNA (miRNA) scaffolds can circumvent this problem. In this study, identically predicted small interfering RNA (siRNA) sequences targeting apolipoprotein B100 (siApoB) were embedded in shRNA (shApoB) or miRNA (miApoB) scaffolds and a direct comparison of the processing and long-term in vivo efficacy was performed. Next generation sequencing of small RNAs originating from shApoB- or miApoB-transfected cells revealed substantial differences in processing, resulting in different siApoB length, 5′ and 3′ cleavage sites and abundance of the guide or passenger strands. Murine liver transduction with adeno-associated virus (AAV) vectors expressing shApoB or miApoB resulted in high levels of siApoB expression associated with strong decrease of plasma ApoB protein and cholesterol. Expression of miApoB from the liver-specific LP1 promoter was restricted to the liver, while the H1 promoter-expressed shApoB was ectopically present. Delivery of 1 × 1011 genome copies AAV-shApoB or AAV-miApoB led to a gradual loss of ApoB and plasma cholesterol inhibition, which was circumvented by delivering a 20-fold lower vector dose. In conclusion, incorporating identical siRNA sequences in shRNA or miRNA scaffolds results in differential processing patterns and in vivo efficacy that may have serious consequences for future RNAi-based therapeutics. PMID:23089734

Comparative Analysis of Fruit Ripening-Related miRNAs and Their Targets in Blueberry Using Small RNA and Degradome Sequencing

PubMed Central

Hou, Yanming; Zhai, Lulu; Li, Xuyan; Xue, Yu; Wang, Jingjing; Yang, Pengjie; Cao, Chunmei; Li, Hongxue; Cui, Yuhai; Bian, Shaomin

2017-01-01

MicroRNAs (miRNAs) play vital roles in the regulation of fruit development and ripening. Blueberry is an important small berry fruit crop with economical and nutritional value. However, nothing is known about the miRNAs and their targets involved in blueberry fruit ripening. In this study, using high-throughput sequencing of small RNAs, 84 known miRNAs belonging to 28 families and 16 novel miRNAs were identified in white fruit (WF) and blue fruit (BF) libraries, which represent fruit ripening onset and in progress, respectively. Among them, 41 miRNAs were shown to be differentially expressed during fruit maturation, and 16 miRNAs representing 16 families were further chosen to validate the sRNA sequencing data by stem-loop qRT-PCR. Meanwhile, 178 targets were identified for 41 known and 7 novel miRNAs in WF and BF libraries using degradome sequencing, and targets of miR160 were validated using RLM-RACE (RNA Ligase-Mediated (RLM)-Rapid Amplification of cDNA Ends) approach. Moreover, the expression patterns of 6 miRNAs and their targets were examined during fruit development and ripening. Finally, integrative analysis of miRNAs and their targets revealed a complex miRNA-mRNA regulatory network involving a wide variety of biological processes. The findings will facilitate future investigations of the miRNA-mediated mechanisms that regulate fruit development and ripening in blueberry. PMID:29257112

Signal sequence-independent targeting of MID2 mRNA to the endoplasmic reticulum by the yeast RNA-binding protein Khd1p.

PubMed

Syed, Muhammad Ibrahim; Moorthy, Balaji T; Jenner, Andreas; Fetka, Ingrid; Jansen, Ralf-Peter

2018-05-17

Localization of mRNAs depends on specific RNA-binding proteins (RBPs) and critically contributes not only to cell polarization but also to basal cell function. The yeast RBP Khd1p binds to several hundred mRNAs, the majority of which encodes secreted or membrane proteins. We demonstrate that a subfraction of Khd1p associates with artificial liposomes and endoplasmic reticulum (ER), and that Khd1p endomembrane association is partially dependent on its binding to RNA. ER targeting of at least two mRNAs, MID2 and SLG1/WSC1, requires KHD1 but is independent of their translation. Together, our results suggest interdependence of Khd1p and mRNA for their targeting to the ER and presents additional evidence for signal sequence-independent, RBP-mediated mRNA targeting. © 2018 Federation of European Biochemical Societies.

Direct detection of RNA in vitro and in situ by target-primed RCA: The impact of E. coli RNase III on the detection efficiency of RNA sequences distanced far from the 3'-end.

PubMed

Merkiene, Egle; Gaidamaviciute, Edita; Riauba, Laurynas; Janulaitis, Arvydas; Lagunavicius, Arunas

2010-08-01

We improved the target RNA-primed RCA technique for direct detection and analysis of RNA in vitro and in situ. Previously we showed that the 3' --> 5' single-stranded RNA exonucleolytic activity of Phi29 DNA polymerase converts the target RNA into a primer and uses it for RCA initiation. However, in some cases, the single-stranded RNA exoribonucleolytic activity of the polymerase is hindered by strong double-stranded structures at the 3'-end of target RNAs. We demonstrate that in such hampered cases, the double-stranded RNA-specific Escherichia coli RNase III efficiently assists Phi29 DNA polymerase in converting the target RNA into a primer. These observations extend the target RNA-primed RCA possibilities to test RNA sequences distanced far from the 3'-end and customize this technique for the inner RNA sequence analysis.

Frnakenstein: multiple target inverse RNA folding.

PubMed

Lyngsø, Rune B; Anderson, James W J; Sizikova, Elena; Badugu, Amarendra; Hyland, Tomas; Hein, Jotun

2012-10-09

RNA secondary structure prediction, or folding, is a classic problem in bioinformatics: given a sequence of nucleotides, the aim is to predict the base pairs formed in its three dimensional conformation. The inverse problem of designing a sequence folding into a particular target structure has only more recently received notable interest. With a growing appreciation and understanding of the functional and structural properties of RNA motifs, and a growing interest in utilising biomolecules in nano-scale designs, the interest in the inverse RNA folding problem is bound to increase. However, whereas the RNA folding problem from an algorithmic viewpoint has an elegant and efficient solution, the inverse RNA folding problem appears to be hard. In this paper we present a genetic algorithm approach to solve the inverse folding problem. The main aims of the development was to address the hitherto mostly ignored extension of solving the inverse folding problem, the multi-target inverse folding problem, while simultaneously designing a method with superior performance when measured on the quality of designed sequences. The genetic algorithm has been implemented as a Python program called Frnakenstein. It was benchmarked against four existing methods and several data sets totalling 769 real and predicted single structure targets, and on 292 two structure targets. It performed as well as or better at finding sequences which folded in silico into the target structure than all existing methods, without the heavy bias towards CG base pairs that was observed for all other top performing methods. On the two structure targets it also performed well, generating a perfect design for about 80% of the targets. Our method illustrates that successful designs for the inverse RNA folding problem does not necessarily have to rely on heavy biases in base pair and unpaired base distributions. The design problem seems to become more difficult on larger structures when the target structures are

Frnakenstein: multiple target inverse RNA folding

PubMed Central

2012-01-01

Background RNA secondary structure prediction, or folding, is a classic problem in bioinformatics: given a sequence of nucleotides, the aim is to predict the base pairs formed in its three dimensional conformation. The inverse problem of designing a sequence folding into a particular target structure has only more recently received notable interest. With a growing appreciation and understanding of the functional and structural properties of RNA motifs, and a growing interest in utilising biomolecules in nano-scale designs, the interest in the inverse RNA folding problem is bound to increase. However, whereas the RNA folding problem from an algorithmic viewpoint has an elegant and efficient solution, the inverse RNA folding problem appears to be hard. Results In this paper we present a genetic algorithm approach to solve the inverse folding problem. The main aims of the development was to address the hitherto mostly ignored extension of solving the inverse folding problem, the multi-target inverse folding problem, while simultaneously designing a method with superior performance when measured on the quality of designed sequences. The genetic algorithm has been implemented as a Python program called Frnakenstein. It was benchmarked against four existing methods and several data sets totalling 769 real and predicted single structure targets, and on 292 two structure targets. It performed as well as or better at finding sequences which folded in silico into the target structure than all existing methods, without the heavy bias towards CG base pairs that was observed for all other top performing methods. On the two structure targets it also performed well, generating a perfect design for about 80% of the targets. Conclusions Our method illustrates that successful designs for the inverse RNA folding problem does not necessarily have to rely on heavy biases in base pair and unpaired base distributions. The design problem seems to become more difficult on larger structures

SSMART: Sequence-structure motif identification for RNA-binding proteins.

PubMed

Munteanu, Alina; Mukherjee, Neelanjan; Ohler, Uwe

2018-06-11

RNA-binding proteins (RBPs) regulate every aspect of RNA metabolism and function. There are hundreds of RBPs encoded in the eukaryotic genomes, and each recognize its RNA targets through a specific mixture of RNA sequence and structure properties. For most RBPs, however, only a primary sequence motif has been determined, while the structure of the binding sites is uncharacterized. We developed SSMART, an RNA motif finder that simultaneously models the primary sequence and the structural properties of the RNA targets sites. The sequence-structure motifs are represented as consensus strings over a degenerate alphabet, extending the IUPAC codes for nucleotides to account for secondary structure preferences. Evaluation on synthetic data showed that SSMART is able to recover both sequence and structure motifs implanted into 3'UTR-like sequences, for various degrees of structured/unstructured binding sites. In addition, we successfully used SSMART on high-throughput in vivo and in vitro data, showing that we not only recover the known sequence motif, but also gain insight into the structural preferences of the RBP. Availability: SSMART is freely available at https://ohlerlab.mdc-berlin.de/software/SSMART_137/. Supplementary data are available at Bioinformatics online.

Deep sequencing of cardiac microRNA-mRNA interactomes in clinical and experimental cardiomyopathy

PubMed Central

Matkovich, Scot J.; Dorn, Gerald W.

2018-01-01

Summary MicroRNAs are a family of short (~21 nucleotide) noncoding RNAs that serve key roles in cellular growth and differentiation and the response of the heart to stress stimuli. As the sequence-specific recognition element of RNA-induced silencing complexes (RISCs), microRNAs bind mRNAs and prevent their translation via mechanisms that may include transcript degradation and/or prevention of ribosome binding. Short microRNA sequences and the ability of microRNAs to bind to mRNA sites having only partial/imperfect sequence complementarity complicates purely computational analyses of microRNA-mRNA interactomes. Furthermore, computational microRNA target prediction programs typically ignore biological context, and therefore the principal determinants of microRNA-mRNA binding: the presence and quantity of each. To address these deficiencies we describe an empirical method, developed via studies of stressed and failing hearts, to determine disease-induced changes in microRNAs, mRNAs, and the mRNAs targeted to the RISC, without cross-linking mRNAs to RISC proteins. Deep sequencing methods are used to determine RNA abundances, delivering unbiased, quantitative RNA data limited only by their annotation in the genome of interest. We describe the laboratory bench steps required to perform these experiments, experimental design strategies to achieve an appropriate number of sequencing reads per biological replicate, and computer-based processing tools and procedures to convert large raw sequencing data files into gene expression measures useful for differential expression analyses. PMID:25836573

Deep sequencing of cardiac microRNA-mRNA interactomes in clinical and experimental cardiomyopathy.

PubMed

Matkovich, Scot J; Dorn, Gerald W

2015-01-01

MicroRNAs are a family of short (~21 nucleotide) noncoding RNAs that serve key roles in cellular growth and differentiation and the response of the heart to stress stimuli. As the sequence-specific recognition element of RNA-induced silencing complexes (RISCs), microRNAs bind mRNAs and prevent their translation via mechanisms that may include transcript degradation and/or prevention of ribosome binding. Short microRNA sequences and the ability of microRNAs to bind to mRNA sites having only partial/imperfect sequence complementarity complicate purely computational analyses of microRNA-mRNA interactomes. Furthermore, computational microRNA target prediction programs typically ignore biological context, and therefore the principal determinants of microRNA-mRNA binding: the presence and quantity of each. To address these deficiencies we describe an empirical method, developed via studies of stressed and failing hearts, to determine disease-induced changes in microRNAs, mRNAs, and the mRNAs targeted to the RISC, without cross-linking mRNAs to RISC proteins. Deep sequencing methods are used to determine RNA abundances, delivering unbiased, quantitative RNA data limited only by their annotation in the genome of interest. We describe the laboratory bench steps required to perform these experiments, experimental design strategies to achieve an appropriate number of sequencing reads per biological replicate, and computer-based processing tools and procedures to convert large raw sequencing data files into gene expression measures useful for differential expression analyses.

Investigation of Experimental Factors That Underlie BRCA1/2 mRNA Isoform Expression Variation: Recommendations for Utilizing Targeted RNA Sequencing to Evaluate Potential Spliceogenic Variants.

PubMed

Lattimore, Vanessa L; Pearson, John F; Currie, Margaret J; Spurdle, Amanda B; Robinson, Bridget A; Walker, Logan C

2018-01-01

PCR-based RNA splicing assays are commonly used in diagnostic and research settings to assess the potential effects of variants of uncertain clinical significance in BRCA1 and BRCA2 . The Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA) consortium completed a multicentre investigation to evaluate differences in assay design and the integrity of published data, raising a number of methodological questions associated with cell culture conditions and PCR-based protocols. We utilized targeted RNA-seq to re-assess BRCA1 and BRCA2 mRNA isoform expression patterns in lymphoblastoid cell lines (LCLs) previously used in the multicentre ENIGMA study. Capture of the targeted cDNA sequences was carried out using 34 BRCA1 and 28 BRCA2 oligonucleotides from the Illumina Truseq Targeted RNA Expression platform. Our results show that targeted RNA-seq analysis of LCLs overcomes many of the methodology limitations associated with PCR-based assays leading us to make the following observations and recommendations: (1) technical replicates ( n  > 2) of variant carriers to capture methodology induced variability associated with RNA-seq assays, (2) LCLs can undergo multiple freeze/thaw cycles and can be cultured up to 2 weeks without noticeably influencing isoform expression levels, (3) nonsense-mediated decay inhibitors are essential prior to splicing assays for comprehensive mRNA isoform detection, (4) quantitative assessment of exon:exon junction levels across BRCA1 and BRCA2 can help distinguish between normal and aberrant isoform expression patterns. Experimentally derived recommendations from this study will facilitate the application of targeted RNA-seq platforms for the quantitation of BRCA1 and BRCA2 mRNA aberrations associated with sequence variants of uncertain clinical significance.

Investigation of Experimental Factors That Underlie BRCA1/2 mRNA Isoform Expression Variation: Recommendations for Utilizing Targeted RNA Sequencing to Evaluate Potential Spliceogenic Variants

PubMed Central

Lattimore, Vanessa L.; Pearson, John F.; Currie, Margaret J.; Spurdle, Amanda B.; Robinson, Bridget A.; Walker, Logan C.

2018-01-01

PCR-based RNA splicing assays are commonly used in diagnostic and research settings to assess the potential effects of variants of uncertain clinical significance in BRCA1 and BRCA2. The Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA) consortium completed a multicentre investigation to evaluate differences in assay design and the integrity of published data, raising a number of methodological questions associated with cell culture conditions and PCR-based protocols. We utilized targeted RNA-seq to re-assess BRCA1 and BRCA2 mRNA isoform expression patterns in lymphoblastoid cell lines (LCLs) previously used in the multicentre ENIGMA study. Capture of the targeted cDNA sequences was carried out using 34 BRCA1 and 28 BRCA2 oligonucleotides from the Illumina Truseq Targeted RNA Expression platform. Our results show that targeted RNA-seq analysis of LCLs overcomes many of the methodology limitations associated with PCR-based assays leading us to make the following observations and recommendations: (1) technical replicates (n > 2) of variant carriers to capture methodology induced variability associated with RNA-seq assays, (2) LCLs can undergo multiple freeze/thaw cycles and can be cultured up to 2 weeks without noticeably influencing isoform expression levels, (3) nonsense-mediated decay inhibitors are essential prior to splicing assays for comprehensive mRNA isoform detection, (4) quantitative assessment of exon:exon junction levels across BRCA1 and BRCA2 can help distinguish between normal and aberrant isoform expression patterns. Experimentally derived recommendations from this study will facilitate the application of targeted RNA-seq platforms for the quantitation of BRCA1 and BRCA2 mRNA aberrations associated with sequence variants of uncertain clinical significance. PMID:29774201

Primer-independent RNA sequencing with bacteriophage phi6 RNA polymerase and chain terminators.

PubMed

Makeyev, E V; Bamford, D H

2001-05-01

Here we propose a new general method for directly determining RNA sequence based on the use of the RNA-dependent RNA polymerase from bacteriophage phi6 and the chain terminators (RdRP sequencing). The following properties of the polymerase render it appropriate for this application: (1) the phi6 polymerase can replicate a number of single-stranded RNA templates in vitro. (2) In contrast to the primer-dependent DNA polymerases utilized in the sequencing procedure by Sanger et al. (Proc Natl Acad Sci USA, 1977, 74:5463-5467), it initiates nascent strand synthesis without a primer, starting the polymerization on the very 3'-terminus of the template. (3) The polymerase can incorporate chain-terminating nucleotide analogs into the nascent RNA chain to produce a set of base-specific termination products. Consequently, 3' proximal or even complete sequence of many target RNA molecules can be rapidly deduced without prior sequence information. The new technique proved useful for sequencing several synthetic ssRNA templates. Furthermore, using genomic segments of the bluetongue virus we show that RdRP sequencing can also be applied to naturally occurring dsRNA templates. This suggests possible uses of the method in the RNA virus research and diagnostics.

Identification of MicroRNA Targets of Capsicum spp. Using MiRTrans—a Trans-Omics Approach

PubMed Central

Zhang, Lu; Qin, Cheng; Mei, Junpu; Chen, Xiaocui; Wu, Zhiming; Luo, Xirong; Cheng, Jiaowen; Tang, Xiangqun; Hu, Kailin; Li, Shuai C.

2017-01-01

The microRNA (miRNA) can regulate the transcripts that are involved in eukaryotic cell proliferation, differentiation, and metabolism. Especially for plants, our understanding of miRNA targets, is still limited. Early attempts of prediction on sequence alignments have been plagued by enormous false positives. It is helpful to improve target prediction specificity by incorporating the other data sources such as the dependency between miRNA and transcript expression or even cleaved transcripts by miRNA regulations, which are referred to as trans-omics data. In this paper, we developed MiRTrans (Prediction of MiRNA targets by Trans-omics data) to explore miRNA targets by incorporating miRNA sequencing, transcriptome sequencing, and degradome sequencing. MiRTrans consisted of three major steps. First, the target transcripts of miRNAs were predicted by scrutinizing their sequence characteristics and collected as an initial potential targets pool. Second, false positive targets were eliminated if the expression of miRNA and its targets were weakly correlated by lasso regression. Third, degradome sequencing was utilized to capture the miRNA targets by examining the cleaved transcripts that regulated by miRNAs. Finally, the predicted targets from the second and third step were combined by Fisher's combination test. MiRTrans was applied to identify the miRNA targets for Capsicum spp. (i.e., pepper). It can generate more functional miRNA targets than sequence-based predictions by evaluating functional enrichment. MiRTrans identified 58 miRNA-transcript pairs with high confidence from 18 miRNA families conserved in eudicots. Most of these targets were transcription factors; this lent support to the role of miRNA as key regulator in pepper. To our best knowledge, this work is the first attempt to investigate the miRNA targets of pepper, as well as their regulatory networks. Surprisingly, only a small proportion of miRNA-transcript pairs were shared between degradome sequencing

Artificial small RNA for sequence specific cleavage of target RNA through RNase III endonuclease Dicer

PubMed Central

Liu, Yali; Liu, Li; Zhan, Yonghao; Zhuang, Chengle; Lin, Junhao; Chen, Mingwei; Li, Jianfa; Cai, Zhiming; Huang, Weiren; Zhang, Yong

2016-01-01

CRISPR-Cas9 system uses a guide RNA which functions in conjunction with Cas9 proteins to target a DNA and cleaves double-strand DNA. This phenomenon raises a question whether an artificial small RNA (asRNA), composed of a Dicer–binding RNA element and an antisense RNA, could also be used to induce Dicer to process and degrade a specific RNA. If so, we could develop a new method which is named DICERi for gene silencing or RNA editing. To prove the feasibility of asRNA, we selected MALAT-1 as target and used Hela and MDA-MB-231 cells as experimental models. The results of qRT-PCR showed that the introduction of asRNA decreased the relative expression level of target gene significantly. Next, we analyzed cell proliferation using CCK-8 and EdU staining assays, and then cell migration using wound scratch and Transwell invasion assays. We found that cell proliferation and cell migration were both suppressed remarkably after asRNA was expressed in Hela and MDA-MB-231 cells. Cell apoptosis was also detected through Hoechst staining and ELISA assays and the data indicated that he numbers of apoptotic cell in experimental groups significantly increased compared with negative controls. In order to prove that the gene silencing effects were caused by Dicer, we co-transfected shRNA silencing Dicer and asRNA. The relative expression levels of Dicer and MALAT-1 were both detected and the results indicated that when the cleavage role of Dicer was silenced, the relative expression level of MALAT-1 was not affected after the introduction of asRNA. All the above results demonstrated that these devices directed by Dicer effectively excised target RNA and repressed the target genes, thus causing phenotypic changes. Our works adds a new dimension to gene regulating technologies and may have broad applications in construction of gene circuits. PMID:27231846

Artificial small RNA for sequence specific cleavage of target RNA through RNase III endonuclease Dicer.

PubMed

Xu, Wen; Liu, Yuchen; Liu, Yali; Liu, Li; Zhan, Yonghao; Zhuang, Chengle; Lin, Junhao; Chen, Mingwei; Li, Jianfa; Cai, Zhiming; Huang, Weiren; Zhang, Yong

2016-08-23

CRISPR-Cas9 system uses a guide RNA which functions in conjunction with Cas9 proteins to target a DNA and cleaves double-strand DNA. This phenomenon raises a question whether an artificial small RNA (asRNA), composed of a Dicer-binding RNA element and an antisense RNA, could also be used to induce Dicer to process and degrade a specific RNA. If so, we could develop a new method which is named DICERi for gene silencing or RNA editing. To prove the feasibility of asRNA, we selected MALAT-1 as target and used Hela and MDA-MB-231 cells as experimental models. The results of qRT-PCR showed that the introduction of asRNA decreased the relative expression level of target gene significantly. Next, we analyzed cell proliferation using CCK-8 and EdU staining assays, and then cell migration using wound scratch and Transwell invasion assays. We found that cell proliferation and cell migration were both suppressed remarkably after asRNA was expressed in Hela and MDA-MB-231 cells. Cell apoptosis was also detected through Hoechst staining and ELISA assays and the data indicated that he numbers of apoptotic cell in experimental groups significantly increased compared with negative controls. In order to prove that the gene silencing effects were caused by Dicer, we co-transfected shRNA silencing Dicer and asRNA. The relative expression levels of Dicer and MALAT-1 were both detected and the results indicated that when the cleavage role of Dicer was silenced, the relative expression level of MALAT-1 was not affected after the introduction of asRNA. All the above results demonstrated that these devices directed by Dicer effectively excised target RNA and repressed the target genes, thus causing phenotypic changes. Our works adds a new dimension to gene regulating technologies and may have broad applications in construction of gene circuits.

Prediction of miRNA targets.

PubMed

Oulas, Anastasis; Karathanasis, Nestoras; Louloupi, Annita; Pavlopoulos, Georgios A; Poirazi, Panayiota; Kalantidis, Kriton; Iliopoulos, Ioannis

2015-01-01

Computational methods for miRNA target prediction are currently undergoing extensive review and evaluation. There is still a great need for improvement of these tools and bioinformatics approaches are looking towards high-throughput experiments in order to validate predictions. The combination of large-scale techniques with computational tools will not only provide greater credence to computational predictions but also lead to the better understanding of specific biological questions. Current miRNA target prediction tools utilize probabilistic learning algorithms, machine learning methods and even empirical biologically defined rules in order to build models based on experimentally verified miRNA targets. Large-scale protein downregulation assays and next-generation sequencing (NGS) are now being used to validate methodologies and compare the performance of existing tools. Tools that exhibit greater correlation between computational predictions and protein downregulation or RNA downregulation are considered the state of the art. Moreover, efficiency in prediction of miRNA targets that are concurrently verified experimentally provides additional validity to computational predictions and further highlights the competitive advantage of specific tools and their efficacy in extracting biologically significant results. In this review paper, we discuss the computational methods for miRNA target prediction and provide a detailed comparison of methodologies and features utilized by each specific tool. Moreover, we provide an overview of current state-of-the-art high-throughput methods used in miRNA target prediction.

Deep sequencing of Salmonella RNA associated with heterologous Hfq proteins in vivo reveals small RNAs as a major target class and identifies RNA processing phenotypes.

PubMed

Sittka, Alexandra; Sharma, Cynthia M; Rolle, Katarzyna; Vogel, Jörg

2009-01-01

The bacterial Sm-like protein, Hfq, is a key factor for the stability and function of small non-coding RNAs (sRNAs) in Escherichia coli. Homologues of this protein have been predicted in many distantly related organisms yet their functional conservation as sRNA-binding proteins has not entirely been clear. To address this, we expressed in Salmonella the Hfq proteins of two eubacteria (Neisseria meningitides, Aquifex aeolicus) and an archaeon (Methanocaldococcus jannaschii), and analyzed the associated RNA by deep sequencing. This in vivo approach identified endogenous Salmonella sRNAs as a major target of the foreign Hfq proteins. New Salmonella sRNA species were also identified, and some of these accumulated specifically in the presence of a foreign Hfq protein. In addition, we observed specific RNA processing defects, e.g., suppression of precursor processing of SraH sRNA by Methanocaldococcus Hfq, or aberrant accumulation of extracytoplasmic target mRNAs of the Salmonella GcvB, MicA or RybB sRNAs. Taken together, our study provides evidence of a conserved inherent sRNA-binding property of Hfq, which may facilitate the lateral transmission of regulatory sRNAs among distantly related species. It also suggests that the expression of heterologous RNA-binding proteins combined with deep sequencing analysis of RNA ligands can be used as a molecular tool to dissect individual steps of RNA metabolism in vivo.

BioVLAB-MMIA-NGS: microRNA-mRNA integrated analysis using high-throughput sequencing data.

PubMed

Chae, Heejoon; Rhee, Sungmin; Nephew, Kenneth P; Kim, Sun

2015-01-15

It is now well established that microRNAs (miRNAs) play a critical role in regulating gene expression in a sequence-specific manner, and genome-wide efforts are underway to predict known and novel miRNA targets. However, the integrated miRNA-mRNA analysis remains a major computational challenge, requiring powerful informatics systems and bioinformatics expertise. The objective of this study was to modify our widely recognized Web server for the integrated mRNA-miRNA analysis (MMIA) and its subsequent deployment on the Amazon cloud (BioVLAB-MMIA) to be compatible with high-throughput platforms, including next-generation sequencing (NGS) data (e.g. RNA-seq). We developed a new version called the BioVLAB-MMIA-NGS, deployed on both Amazon cloud and on a high-performance publicly available server called MAHA. By using NGS data and integrating various bioinformatics tools and databases, BioVLAB-MMIA-NGS offers several advantages. First, sequencing data is more accurate than array-based methods for determining miRNA expression levels. Second, potential novel miRNAs can be detected by using various computational methods for characterizing miRNAs. Third, because miRNA-mediated gene regulation is due to hybridization of an miRNA to its target mRNA, sequencing data can be used to identify many-to-many relationship between miRNAs and target genes with high accuracy. http://epigenomics.snu.ac.kr/biovlab_mmia_ngs/. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Individual microRNAs (miRNAs) display distinct mRNA targeting "rules".

PubMed

Wang, Wang-Xia; Wilfred, Bernard R; Xie, Kevin; Jennings, Mary H; Hu, Yanling Hu; Stromberg, Arnold J; Nelson, Peter T

2010-01-01

MicroRNAs (miRNAs) guide Argonaute (AGO)-containing microribonucleoprotein (miRNP) complexes to target mRNAs.It has been assumed that miRNAs behave similarly to each other with regard to mRNA target recognition. The usual assumptions, which are based on prior studies, are that miRNAs target preferentially sequences in the 3'UTR of mRNAs,guided by the 5' "seed" portion of the miRNAs. Here we isolated AGO- and miRNA-containing miRNPs from human H4 tumor cells by co-immunoprecipitation (co-IP) with anti-AGO antibody. Cells were transfected with miR-107, miR-124,miR-128, miR-320, or a negative control miRNA. Co-IPed RNAs were subjected to downstream high-density Affymetrix Human Gene 1.0 ST microarray analyses using an assay we validated previously-a "RIP-Chip" experimental design. RIP-Chip data provided a list of mRNAs recruited into the AGO-miRNP in correlation to each miRNA. These experimentally identified miRNA targets were analyzed for complementary six nucleotide "seed" sequences within the transfected miRNAs. We found that miR-124 targets tended to have sequences in the 3'UTR that would be recognized by the 5' seed of miR-124, as described in previous studies. By contrast, miR-107 targets tended to have 'seed' sequences in the mRNA open reading frame, but not the 3' UTR. Further, mRNA targets of miR-128 and miR-320 are less enriched for 6-mer seed sequences in comparison to miR-107 and miR-124. In sum, our data support the importance of the 5' seed in determining binding characteristics for some miRNAs; however, the "binding rules" are complex, and individual miRNAs can have distinct sequence determinants that lead to mRNA targeting.

About miRNAs, miRNA seeds, target genes and target pathways.

PubMed

Kehl, Tim; Backes, Christina; Kern, Fabian; Fehlmann, Tobias; Ludwig, Nicole; Meese, Eckart; Lenhof, Hans-Peter; Keller, Andreas

2017-12-05

miRNAs are typically repressing gene expression by binding to the 3' UTR, leading to degradation of the mRNA. This process is dominated by the eight-base seed region of the miRNA. Further, miRNAs are known not only to target genes but also to target significant parts of pathways. A logical line of thoughts is: miRNAs with similar (seed) sequence target similar sets of genes and thus similar sets of pathways. By calculating similarity scores for all 3.25 million pairs of 2,550 human miRNAs, we found that this pattern frequently holds, while we also observed exceptions. Respective results were obtained for both, predicted target genes as well as experimentally validated targets. We note that miRNAs target gene set similarity follows a bimodal distribution, pointing at a set of 282 miRNAs that seems to target genes with very high specificity. Further, we discuss miRNAs with different (seed) sequences that nonetheless regulate similar gene sets or pathways. Most intriguingly, we found miRNA pairs that regulate different gene sets but similar pathways such as miR-6886-5p and miR-3529-5p. These are jointly targeting different parts of the MAPK signaling cascade. The main goal of this study is to provide a general overview on the results, to highlight a selection of relevant results on miRNAs, miRNA seeds, target genes and target pathways and to raise awareness for artifacts in respective comparisons. The full set of information that allows to infer detailed results on each miRNA has been included in miRPathDB, the miRNA target pathway database (https://mpd.bioinf.uni-sb.de).

Messenger RNA biomarker signatures for forensic body fluid identification revealed by targeted RNA sequencing.

PubMed

Hanson, E; Ingold, S; Haas, C; Ballantyne, J

2018-05-01

The recovery of a DNA profile from the perpetrator or victim in criminal investigations can provide valuable 'source level' information for investigators. However, a DNA profile does not reveal the circumstances by which biological material was transferred. Some contextual information can be obtained by a determination of the tissue or fluid source of origin of the biological material as it is potentially indicative of some behavioral activity on behalf of the individual that resulted in its transfer from the body. Here, we sought to improve upon established RNA based methods for body fluid identification by developing a targeted multiplexed next generation mRNA sequencing assay comprising a panel of approximately equal sized gene amplicons. The multiplexed biomarker panel includes several highly specific gene targets with the necessary specificity to definitively identify most forensically relevant biological fluids and tissues (blood, semen, saliva, vaginal secretions, menstrual blood and skin). In developing the biomarker panel we evaluated 66 gene targets, with a progressive iteration of testing target combinations that exhibited optimal sensitivity and specificity using a training set of forensically relevant body fluid samples. The current assay comprises 33 targets: 6 blood, 6 semen, 6 saliva, 4 vaginal secretions, 5 menstrual blood and 6 skin markers. We demonstrate the sensitivity and specificity of the assay and the ability to identify body fluids in single source and admixed stains. A 16 sample blind test was carried out by one lab with samples provided by the other participating lab. The blinded lab correctly identified the body fluids present in 15 of the samples with the major component identified in the 16th. Various classification methods are being investigated to permit inference of the body fluid/tissue in dried physiological stains. These include the percentage of reads in a sample that are due to each of the 6 tissues/body fluids tested and

Short RNA indicator sequences are not completely degraded by autoclaving

PubMed Central

Unnithan, Veena V.; Unc, Adrian; Joe, Valerisa; Smith, Geoffrey B.

2014-01-01

Short indicator RNA sequences (<100 bp) persist after autoclaving and are recovered intact by molecular amplification. Primers targeting longer sequences are most likely to produce false positives due to amplification errors easily verified by melting curves analyses. If short indicator RNA sequences are used for virus identification and quantification then post autoclave RNA degradation methodology should be employed, which may include further autoclaving. PMID:24518856

Structural basis for microRNA targeting

DOE PAGES

Schirle, Nicole T.; Sheu-Gruttadauria, Jessica; MacRae, Ian J.

2014-10-31

MicroRNAs (miRNAs) control expression of thousands of genes in plants and animals. miRNAs function by guiding Argonaute proteins to complementary sites in messenger RNAs (mRNAs) targeted for repression. In this paper, we determined crystal structures of human Argonaute-2 (Ago2) bound to a defined guide RNA with and without target RNAs representing miRNA recognition sites. These structures suggest a stepwise mechanism, in which Ago2 primarily exposes guide nucleotides (nt) 2 to 5 for initial target pairing. Pairing to nt 2 to 5 promotes conformational changes that expose nt 2 to 8 and 13 to 16 for further target recognition. Interactions withmore » the guide-target minor groove allow Ago2 to interrogate target RNAs in a sequence-independent manner, whereas an adenosine binding-pocket opposite guide nt 1 further facilitates target recognition. Spurious slicing of miRNA targets is avoided through an inhibitory coordination of one catalytic magnesium ion. Finally, these results explain the conserved nucleotide-pairing patterns in animal miRNA target sites first observed over two decades ago.« less

An mRNA-Derived Noncoding RNA Targets and Regulates the Ribosome

PubMed Central

Pircher, Andreas; Bakowska-Zywicka, Kamilla; Schneider, Lukas; Zywicki, Marek; Polacek, Norbert

2014-01-01

Summary The structural and functional repertoire of small non-protein-coding RNAs (ncRNAs) is central for establishing gene regulation networks in cells and organisms. Here, we show that an mRNA-derived 18-nucleotide-long ncRNA is capable of downregulating translation in Saccharomyces cerevisiae by targeting the ribosome. This 18-mer ncRNA binds to polysomes upon salt stress and is crucial for efficient growth under hyperosmotic conditions. Although the 18-mer RNA originates from the TRM10 locus, which encodes a tRNA methyltransferase, genetic analyses revealed the 18-mer RNA nucleotide sequence, rather than the mRNA-encoded enzyme, as the translation regulator. Our data reveal the ribosome as a target for a small regulatory ncRNA and demonstrate the existence of a yet unkown mechanism of translation regulation. Ribosome-targeted small ncRNAs are found in all domains of life and represent a prevalent but so far largely unexplored class of regulatory molecules. PMID:24685157

A weighted sampling algorithm for the design of RNA sequences with targeted secondary structure and nucleotide distribution.

PubMed

Reinharz, Vladimir; Ponty, Yann; Waldispühl, Jérôme

2013-07-01

The design of RNA sequences folding into predefined secondary structures is a milestone for many synthetic biology and gene therapy studies. Most of the current software uses similar local search strategies (i.e. a random seed is progressively adapted to acquire the desired folding properties) and more importantly do not allow the user to control explicitly the nucleotide distribution such as the GC-content in their sequences. However, the latter is an important criterion for large-scale applications as it could presumably be used to design sequences with better transcription rates and/or structural plasticity. In this article, we introduce IncaRNAtion, a novel algorithm to design RNA sequences folding into target secondary structures with a predefined nucleotide distribution. IncaRNAtion uses a global sampling approach and weighted sampling techniques. We show that our approach is fast (i.e. running time comparable or better than local search methods), seedless (we remove the bias of the seed in local search heuristics) and successfully generates high-quality sequences (i.e. thermodynamically stable) for any GC-content. To complete this study, we develop a hybrid method combining our global sampling approach with local search strategies. Remarkably, our glocal methodology overcomes both local and global approaches for sampling sequences with a specific GC-content and target structure. IncaRNAtion is available at csb.cs.mcgill.ca/incarnation/. Supplementary data are available at Bioinformatics online.

Integrating RNA sequencing into neuro-oncology practice.

PubMed

Rogawski, David S; Vitanza, Nicholas A; Gauthier, Angela C; Ramaswamy, Vijay; Koschmann, Carl

2017-11-01

Malignant tumors of the central nervous system (CNS) cause substantial morbidity and mortality, yet efforts to optimize chemo- and radiotherapy have largely failed to improve dismal prognoses. Over the past decade, RNA sequencing (RNA-seq) has emerged as a powerful tool to comprehensively characterize the transcriptome of CNS tumor cells in one high-throughput step, leading to improved understanding of CNS tumor biology and suggesting new routes for targeted therapies. RNA-seq has been instrumental in improving the diagnostic classification of brain tumors, characterizing oncogenic fusion genes, and shedding light on intratumor heterogeneity. Currently, RNA-seq is beginning to be incorporated into regular neuro-oncology practice in the form of precision neuro-oncology programs, which use information from tumor sequencing to guide implementation of personalized targeted therapies. These programs show great promise in improving patient outcomes for tumors where single agent trials have been ineffective. As RNA-seq is a relatively new technique, many further applications yielding new advances in CNS tumor research and management are expected in the coming years. Copyright © 2017 Elsevier Inc. All rights reserved.

Impact of target mRNA structure on siRNA silencing efficiency: A large-scale study.

PubMed

Gredell, Joseph A; Berger, Angela K; Walton, S Patrick

2008-07-01

The selection of active siRNAs is generally based on identifying siRNAs with certain sequence and structural properties. However, the efficiency of RNA interference has also been shown to depend on the structure of the target mRNA, primarily through studies using exogenous transcripts with well-defined secondary structures in the vicinity of the target sequence. While these studies provide a means for examining the impact of target sequence and structure independently, the predicted secondary structures for these transcripts are often not reflective of structures that form in full-length, native mRNAs where interactions can occur between relatively remote segments of the mRNAs. Here, using a combination of experimental results and analysis of a large dataset, we demonstrate that the accessibility of certain local target structures on the mRNA is an important determinant in the gene silencing ability of siRNAs. siRNAs targeting the enhanced green fluorescent protein were chosen using a minimal siRNA selection algorithm followed by classification based on the predicted minimum free energy structures of the target transcripts. Transfection into HeLa and HepG2 cells revealed that siRNAs targeting regions of the mRNA predicted to have unpaired 5'- and 3'-ends resulted in greater gene silencing than regions predicted to have other types of secondary structure. These results were confirmed by analysis of gene silencing data from previously published siRNAs, which showed that mRNA target regions unpaired at either the 5'-end or 3'-end were silenced, on average, approximately 10% more strongly than target regions unpaired in the center or primarily paired throughout. We found this effect to be independent of the structure of the siRNA guide strand. Taken together, these results suggest minimal requirements for nucleation of hybridization between the siRNA guide strand and mRNA and that both mRNA and guide strand structure should be considered when choosing candidate si

Impact of target mRNA structure on siRNA silencing efficiency: a large-scale study

PubMed Central

Gredell, Joseph A.; Berger, Angela K.; Walton, S. Patrick

2009-01-01

The selection of active siRNAs is generally based on identifying siRNAs with certain sequence and structural properties. However, the efficiency of RNA interference has also been shown to depend on the structure of the target mRNA, primarily through studies using exogenous transcripts with well-defined secondary structures in the vicinity of the target sequence. While these studies provide a means for examining the impact of target sequence and structure independently, the predicted secondary structures for these transcripts are often not reflective of structures that form in full-length, native mRNAs where interactions can occur between relatively remote segments of the mRNAs. Here, using a combination of experimental results and analysis of a large dataset, we demonstrate that the accessibility of certain local target structures on the mRNA is an important determinant in the gene silencing ability of siRNAs. siRNAs targeting the enhanced green fluorescent protein were chosen using a minimal siRNA selection algorithm followed by classification based on the predicted minimum free energy structures of the target transcripts. Transfection into HeLa and HepG2 cells revealed that siRNAs targeting regions of the mRNA predicted to have unpaired 5’- and 3’-ends resulted in greater gene silencing than regions predicted to have other types of secondary structure. These results were confirmed by analysis of gene silencing data from previously published siRNAs, which showed that mRNA target regions unpaired at either the 5’-end or 3’-end were silenced, on average, ~10% more strongly than target regions unpaired in the center or primarily paired throughout. We found this effect to be independent of the structure of the siRNA guide strand. Taken together, these results suggest minimal requirements for nucleation of hybridization between the siRNA guide strand and mRNA and that both mRNA and guide strand structure should be considered when choosing candidate siRNAs. PMID

A Simple Method for Amplifying RNA Targets (SMART)

PubMed Central

McCalla, Stephanie E.; Ong, Carmichael; Sarma, Aartik; Opal, Steven M.; Artenstein, Andrew W.; Tripathi, Anubhav

2012-01-01

We present a novel and simple method for amplifying RNA targets (named by its acronym, SMART), and for detection, using engineered amplification probes that overcome existing limitations of current RNA-based technologies. This system amplifies and detects optimal engineered ssDNA probes that hybridize to target RNA. The amplifiable probe-target RNA complex is captured on magnetic beads using a sequence-specific capture probe and is separated from unbound probe using a novel microfluidic technique. Hybridization sequences are not constrained as they are in conventional target-amplification reactions such as nucleic acid sequence amplification (NASBA). Our engineered ssDNA probe was amplified both off-chip and in a microchip reservoir at the end of the separation microchannel using isothermal NASBA. Optimal solution conditions for ssDNA amplification were investigated. Although KCl and MgCl2 are typically found in NASBA reactions, replacing 70 mmol/L of the 82 mmol/L total chloride ions with acetate resulted in optimal reaction conditions, particularly for low but clinically relevant probe concentrations (≤100 fmol/L). With the optimal probe design and solution conditions, we also successfully removed the initial heating step of NASBA, thus achieving a true isothermal reaction. The SMART assay using a synthetic model influenza DNA target sequence served as a fundamental demonstration of the efficacy of the capture and microfluidic separation system, thus bridging our system to a clinically relevant detection problem. PMID:22691910

Diversity, expression and mRNA targeting abilities of Argonaute-targeting miRNAs among selected vascular plants.

PubMed

Jagtap, Soham; Shivaprasad, Padubidri V

2014-12-02

Micro (mi)RNAs are important regulators of plant development. Across plant lineages, Dicer-like 1 (DCL1) proteins process long ds-like structures to produce micro (mi) RNA duplexes in a stepwise manner. These miRNAs are incorporated into Argonaute (AGO) proteins and influence expression of RNAs that have sequence complementarity with miRNAs. Expression levels of AGOs are greatly regulated by plants in order to minimize unwarranted perturbations using miRNAs to target mRNAs coding for AGOs. AGOs may also have high promoter specificity-sometimes expression of AGO can be limited to just a few cells in a plant. Viral pathogens utilize various means to counter antiviral roles of AGOs including hijacking the host encoded miRNAs to target AGOs. Two host encoded miRNAs namely miR168 and miR403 that target AGOs have been described in the model plant Arabidopsis and such a mechanism is thought to be well conserved across plants because AGO sequences are well conserved. We show that the interaction between AGO mRNAs and miRNAs is species-specific due to the diversity in sequences of two miRNAs that target AGOs, sequence diversity among corresponding target regions in AGO mRNAs and variable expression levels of these miRNAs among vascular plants. We used miRNA sequences from 68 plant species representing 31 plant families for this analysis. Sequences of miR168 and miR403 are not conserved among plant lineages, but surprisingly they differ drastically in their sequence diversity and expression levels even among closely related plants. Variation in miR168 expression among plants correlates well with secondary structures/length of loop sequences of their precursors. Our data indicates a complex AGO targeting interaction among plant lineages due to miRNA sequence diversity and sequences of miRNA targeting regions among AGO mRNAs, thus leading to the assumption that the perturbations by viruses that use host miRNAs to target antiviral AGOs can only be species-specific. We also show

Deep sequencing and in silico analysis of small RNA library reveals novel miRNA from leaf Persicaria minor transcriptome.

PubMed

Samad, Abdul Fatah A; Nazaruddin, Nazaruddin; Murad, Abdul Munir Abdul; Jani, Jaeyres; Zainal, Zamri; Ismail, Ismanizan

2018-03-01

In current era, majority of microRNA (miRNA) are being discovered through computational approaches which are more confined towards model plants. Here, for the first time, we have described the identification and characterization of novel miRNA in a non-model plant, Persicaria minor ( P . minor ) using computational approach. Unannotated sequences from deep sequencing were analyzed based on previous well-established parameters. Around 24 putative novel miRNAs were identified from 6,417,780 reads of the unannotated sequence which represented 11 unique putative miRNA sequences. PsRobot target prediction tool was deployed to identify the target transcripts of putative novel miRNAs. Most of the predicted target transcripts (mRNAs) were known to be involved in plant development and stress responses. Gene ontology showed that majority of the putative novel miRNA targets involved in cellular component (69.07%), followed by molecular function (30.08%) and biological process (0.85%). Out of 11 unique putative miRNAs, 7 miRNAs were validated through semi-quantitative PCR. These novel miRNAs discoveries in P . minor may develop and update the current public miRNA database.

Delivery of siRNA using ternary complexes containing branched cationic peptides: the role of peptide sequence, branching and targeting.

PubMed

Kudsiova, Laila; Welser, Katharina; Campbell, Frederick; Mohammadi, Atefeh; Dawson, Natalie; Cui, Lili; Hailes, Helen C; Lawrence, M Jayne; Tabor, Alethea B

2016-03-01

Ternary nanocomplexes, composed of bifunctional cationic peptides, lipids and siRNA, as delivery vehicles for siRNA have been investigated. The study is the first to determine the optimal sequence and architecture of the bifunctional cationic peptide used for siRNA packaging and delivery using lipopolyplexes. Specifically three series of cationic peptides of differing sequence, degrees of branching and cell-targeting sequences were co-formulated with siRNA and vesicles prepared from a 1 : 1 molar ratio of the cationic lipid DOTMA and the helper lipid, DOPE. The level of siRNA knockdown achieved in the human alveolar cell line, A549-luc cells, in both reduced serum and in serum supplemented media was evaluated, and the results correlated to the nanocomplex structure (established using a range of physico-chemical tools, namely small angle neutron scattering, transmission electron microscopy, dynamic light scattering and zeta potential measurement); the conformational properties of each component (circular dichroism); the degree of protection of the siRNA in the lipopolyplex (using gel shift assays) and to the cellular uptake, localisation and toxicity of the nanocomplexes (confocal microscopy). Although the size, charge, structure and stability of the various lipopolyplexes were broadly similar, it was clear that lipopolyplexes formulated from branched peptides containing His-Lys sequences perform best as siRNA delivery agents in serum, with protection of the siRNA in serum balanced against efficient release of the siRNA into the cytoplasm of the cell.

Evaluation and control of miRNA-like off-target repression for RNA interference.

PubMed

Seok, Heeyoung; Lee, Haejeong; Jang, Eun-Sook; Chi, Sung Wook

2018-03-01

RNA interference (RNAi) has been widely adopted to repress specific gene expression and is easily achieved by designing small interfering RNAs (siRNAs) with perfect sequence complementarity to the intended target mRNAs. Although siRNAs direct Argonaute (Ago), a core component of the RNA-induced silencing complex (RISC), to recognize and silence target mRNAs, they also inevitably function as microRNAs (miRNAs) and suppress hundreds of off-targets. Such miRNA-like off-target repression is potentially detrimental, resulting in unwanted toxicity and phenotypes. Despite early recognition of the severity of miRNA-like off-target repression, this effect has often been overlooked because of difficulties in recognizing and avoiding off-targets. However, recent advances in genome-wide methods and knowledge of Ago-miRNA target interactions have set the stage for properly evaluating and controlling miRNA-like off-target repression. Here, we describe the intrinsic problems of miRNA-like off-target effects caused by canonical and noncanonical interactions. We particularly focus on various genome-wide approaches and chemical modifications for the evaluation and prevention of off-target repression to facilitate the use of RNAi with secured specificity.

Probing Xist RNA Structure in Cells Using Targeted Structure-Seq

PubMed Central

Rutenberg-Schoenberg, Michael; Simon, Matthew D.

2015-01-01

The long non-coding RNA (lncRNA) Xist is a master regulator of X-chromosome inactivation in mammalian cells. Models for how Xist and other lncRNAs function depend on thermodynamically stable secondary and higher-order structures that RNAs can form in the context of a cell. Probing accessible RNA bases can provide data to build models of RNA conformation that provide insight into RNA function, molecular evolution, and modularity. To study the structure of Xist in cells, we built upon recent advances in RNA secondary structure mapping and modeling to develop Targeted Structure-Seq, which combines chemical probing of RNA structure in cells with target-specific massively parallel sequencing. By enriching for signals from the RNA of interest, Targeted Structure-Seq achieves high coverage of the target RNA with relatively few sequencing reads, thus providing a targeted and scalable approach to analyze RNA conformation in cells. We use this approach to probe the full-length Xist lncRNA to develop new models for functional elements within Xist, including the repeat A element in the 5’-end of Xist. This analysis also identified new structural elements in Xist that are evolutionarily conserved, including a new element proximal to the C repeats that is important for Xist function. PMID:26646615

Chromatin-associated RNA sequencing (ChAR-seq) maps genome-wide RNA-to-DNA contacts

PubMed Central

Jukam, David; Teran, Nicole A; Risca, Viviana I; Smith, Owen K; Johnson, Whitney L; Skotheim, Jan M; Greenleaf, William James

2018-01-01

RNA is a critical component of chromatin in eukaryotes, both as a product of transcription, and as an essential constituent of ribonucleoprotein complexes that regulate both local and global chromatin states. Here, we present a proximity ligation and sequencing method called Chromatin-Associated RNA sequencing (ChAR-seq) that maps all RNA-to-DNA contacts across the genome. Using Drosophila cells, we show that ChAR-seq provides unbiased, de novo identification of targets of chromatin-bound RNAs including nascent transcripts, chromosome-specific dosage compensation ncRNAs, and genome-wide trans-associated RNAs involved in co-transcriptional RNA processing. PMID:29648534

shRNA target prediction informed by comprehensive enquiry (SPICE): a supporting system for high-throughput screening of shRNA library.

PubMed

Kamatuka, Kenta; Hattori, Masahiro; Sugiyama, Tomoyasu

2016-12-01

RNA interference (RNAi) screening is extensively used in the field of reverse genetics. RNAi libraries constructed using random oligonucleotides have made this technology affordable. However, the new methodology requires exploration of the RNAi target gene information after screening because the RNAi library includes non-natural sequences that are not found in genes. Here, we developed a web-based tool to support RNAi screening. The system performs short hairpin RNA (shRNA) target prediction that is informed by comprehensive enquiry (SPICE). SPICE automates several tasks that are laborious but indispensable to evaluate the shRNAs obtained by RNAi screening. SPICE has four main functions: (i) sequence identification of shRNA in the input sequence (the sequence might be obtained by sequencing clones in the RNAi library), (ii) searching the target genes in the database, (iii) demonstrating biological information obtained from the database, and (iv) preparation of search result files that can be utilized in a local personal computer (PC). Using this system, we demonstrated that genes targeted by random oligonucleotide-derived shRNAs were not different from those targeted by organism-specific shRNA. The system facilitates RNAi screening, which requires sequence analysis after screening. The SPICE web application is available at http://www.spice.sugysun.org/.

Modified Cross-Linking, Ligation, and Sequencing of Hybrids (qCLASH) Identifies Kaposi's Sarcoma-Associated Herpesvirus MicroRNA Targets in Endothelial Cells.

PubMed

Gay, Lauren A; Sethuraman, Sunantha; Thomas, Merin; Turner, Peter C; Renne, Rolf

2018-04-15

Kaposi's sarcoma (KS) tumors are derived from endothelial cells and express Kaposi's sarcoma-associated herpesvirus (KSHV) microRNAs (miRNAs). Although miRNA targets have been identified in B cell lymphoma-derived cells and epithelial cells, little has been done to characterize the KSHV miRNA targetome in endothelial cells. A recent innovation in the identification of miRNA targetomes, cross-linking, ligation, and sequencing of hybrids (CLASH), unambiguously identifies miRNAs and their targets by ligating the two species while both species are still bound within the RNA-induced silencing complex (RISC). We developed a streamlined quick CLASH (qCLASH) protocol that requires a lower cell input than the original method and therefore has the potential to be used on patient biopsy samples. Additionally, we developed a fast-growing, KSHV-negative endothelial cell line derived from telomerase-immortalized vein endothelial long-term culture (TIVE-LTC) cells. qCLASH was performed on uninfected cells and cells infected with either wild-type KSHV or a mutant virus lacking miR-K12-11/11*. More than 1,400 cellular targets of KSHV miRNAs were identified. Many of the targets identified by qCLASH lacked a canonical seed sequence match. Additionally, most target regions in mRNAs originated from the coding DNA sequence (CDS) rather than the 3' untranslated region (UTR). This set of genes includes some that were previously identified in B cells and some new genes that warrant further study. Pathway analysis of endothelial cell targets showed enrichment in cell cycle control, apoptosis, and glycolysis pathways, among others. Characterization of these new targets and the functional consequences of their repression will be important in furthering our understanding of the role of KSHV miRNAs in oncogenesis. IMPORTANCE KS lesions consist of endothelial cells latently infected with KSHV. Cells that make up these lesions express KSHV miRNAs. Identification of the targets of KSHV miRNAs will

Comprehensive analysis of RNA-protein interactions by high-throughput sequencing-RNA affinity profiling.

PubMed

Tome, Jacob M; Ozer, Abdullah; Pagano, John M; Gheba, Dan; Schroth, Gary P; Lis, John T

2014-06-01

RNA-protein interactions play critical roles in gene regulation, but methods to quantitatively analyze these interactions at a large scale are lacking. We have developed a high-throughput sequencing-RNA affinity profiling (HiTS-RAP) assay by adapting a high-throughput DNA sequencer to quantify the binding of fluorescently labeled protein to millions of RNAs anchored to sequenced cDNA templates. Using HiTS-RAP, we measured the affinity of mutagenized libraries of GFP-binding and NELF-E-binding aptamers to their respective targets and identified critical regions of interaction. Mutations additively affected the affinity of the NELF-E-binding aptamer, whose interaction depended mainly on a single-stranded RNA motif, but not that of the GFP aptamer, whose interaction depended primarily on secondary structure.

DNA targeting specificity of RNA-guided Cas9 nucleases.

PubMed

Hsu, Patrick D; Scott, David A; Weinstein, Joshua A; Ran, F Ann; Konermann, Silvana; Agarwala, Vineeta; Li, Yinqing; Fine, Eli J; Wu, Xuebing; Shalem, Ophir; Cradick, Thomas J; Marraffini, Luciano A; Bao, Gang; Zhang, Feng

2013-09-01

The Streptococcus pyogenes Cas9 (SpCas9) nuclease can be efficiently targeted to genomic loci by means of single-guide RNAs (sgRNAs) to enable genome editing. Here, we characterize SpCas9 targeting specificity in human cells to inform the selection of target sites and avoid off-target effects. Our study evaluates >700 guide RNA variants and SpCas9-induced indel mutation levels at >100 predicted genomic off-target loci in 293T and 293FT cells. We find that SpCas9 tolerates mismatches between guide RNA and target DNA at different positions in a sequence-dependent manner, sensitive to the number, position and distribution of mismatches. We also show that SpCas9-mediated cleavage is unaffected by DNA methylation and that the dosage of SpCas9 and sgRNA can be titrated to minimize off-target modification. To facilitate mammalian genome engineering applications, we provide a web-based software tool to guide the selection and validation of target sequences as well as off-target analyses.

Prediction of effective RNA interference targets and pathway-related genes in lepidopteran insects by RNA sequencing analysis.

PubMed

Guan, Ruo-Bing; Li, Hai-Chao; Miao, Xue-Xia

2018-06-01

When using RNA interference (RNAi) to study gene functions in Lepidoptera insects, we discovered that some genes could not be suppressed; instead, their expression levels could be up-regulated by double-stranded RNA (dsRNA). To predict which genes could be easily silenced, we treated the Asian corn borer (Ostrinia furnacalis) with dsGFP (green fluorescent protein) and dsMLP (muscle lim protein). A transcriptome sequence analysis was conducted using the cDNAs 6 h after treatment with dsRNA. The results indicated that 160 genes were up-regulated and 44 genes were down-regulated by the two dsRNAs. Then, 50 co-up-regulated, 25 co-down-regulated and 43 unaffected genes were selected to determine their RNAi responses. All the 25 down-regulated genes were knocked down by their corresponding dsRNA. However, several of the up-regulated and unaffected genes were up-regulated when treated with their corresponding dsRNAs instead of being knocked down. The genes up-regulated by the dsGFP treatment may be involved in insect immune responses or the RNAi pathway. When the immune-related genes were excluded, only seven genes were induced by dsGFP, including ago-2 and dicer-2. These results not only provide a reference for efficient RNAi target predications, but also provide some potential RNAi pathway-related genes for further study. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Target mimicry provides a new mechanism for regulation of microRNA activity.

PubMed

Franco-Zorrilla, José Manuel; Valli, Adrián; Todesco, Marco; Mateos, Isabel; Puga, María Isabel; Rubio-Somoza, Ignacio; Leyva, Antonio; Weigel, Detlef; García, Juan Antonio; Paz-Ares, Javier

2007-08-01

MicroRNAs (miRNA) regulate key aspects of development and physiology in animals and plants. These regulatory RNAs act as guides of effector complexes to recognize specific mRNA sequences based on sequence complementarity, resulting in translational repression or site-specific cleavage. In plants, most miRNA targets are cleaved and show almost perfect complementarity with the miRNAs around the cleavage site. Here, we examined the non-protein coding gene IPS1 (INDUCED BY PHOSPHATE STARVATION 1) from Arabidopsis thaliana. IPS1 contains a motif with sequence complementarity to the phosphate (Pi) starvation-induced miRNA miR-399, but the pairing is interrupted by a mismatched loop at the expected miRNA cleavage site. We show that IPS1 RNA is not cleaved but instead sequesters miR-399. Thus, IPS1 overexpression results in increased accumulation of the miR-399 target PHO2 mRNA and, concomitantly, in reduced shoot Pi content. Engineering of IPS1 to be cleavable abolishes its inhibitory activity on miR-399. We coin the term 'target mimicry' to define this mechanism of inhibition of miRNA activity. Target mimicry can be generalized beyond the control of Pi homeostasis, as demonstrated using artificial target mimics.

Whole-Genome Thermodynamic Analysis Reduces siRNA Off-Target Effects

PubMed Central

Chen, Xi; Liu, Peng; Chou, Hui-Hsien

2013-01-01

Small interfering RNAs (siRNAs) are important tools for knocking down targeted genes, and have been widely applied to biological and biomedical research. To design siRNAs, two important aspects must be considered: the potency in knocking down target genes and the off-target effect on any nontarget genes. Although many studies have produced useful tools to design potent siRNAs, off-target prevention has mostly been delegated to sequence-level alignment tools such as BLAST. We hypothesize that whole-genome thermodynamic analysis can identify potential off-targets with higher precision and help us avoid siRNAs that may have strong off-target effects. To validate this hypothesis, two siRNA sets were designed to target three human genes IDH1, ITPR2 and TRIM28. They were selected from the output of two popular siRNA design tools, siDirect and siDesign. Both siRNA design tools have incorporated sequence-level screening to avoid off-targets, thus their output is believed to be optimal. However, one of the sets we tested has off-target genes predicted by Picky, a whole-genome thermodynamic analysis tool. Picky can identify off-target genes that may hybridize to a siRNA within a user-specified melting temperature range. Our experiments validated that some off-target genes predicted by Picky can indeed be inhibited by siRNAs. Similar experiments were performed using commercially available siRNAs and a few off-target genes were also found to be inhibited as predicted by Picky. In summary, we demonstrate that whole-genome thermodynamic analysis can identify off-target genes that are missed in sequence-level screening. Because Picky prediction is deterministic according to thermodynamics, if a siRNA candidate has no Picky predicted off-targets, it is unlikely to cause off-target effects. Therefore, we recommend including Picky as an additional screening step in siRNA design. PMID:23484018

Identification of human microRNA targets from isolated argonaute protein complexes.

PubMed

Beitzinger, Michaela; Peters, Lasse; Zhu, Jia Yun; Kremmer, Elisabeth; Meister, Gunter

2007-06-01

MicroRNAs (miRNAs) constitute a class of small non-coding RNAs that regulate gene expression on the level of translation and/or mRNA stability. Mammalian miRNAs associate with members of the Argonaute (Ago) protein family and bind to partially complementary sequences in the 3' untranslated region (UTR) of specific target mRNAs. Computer algorithms based on factors such as free binding energy or sequence conservation have been used to predict miRNA target mRNAs. Based on such predictions, up to one third of all mammalian mRNAs seem to be under miRNA regulation. However, due to the low degree of complementarity between the miRNA and its target, such computer programs are often imprecise and therefore not very reliable. Here we report the first biochemical identification approach of miRNA targets from human cells. Using highly specific monoclonal antibodies against members of the Ago protein family, we co-immunoprecipitate Ago-bound mRNAs and identify them by cloning. Interestingly, most of the identified targets are also predicted by different computer programs. Moreover, we randomly analyzed six different target candidates and were able to experimentally validate five as miRNA targets. Our data clearly indicate that miRNA targets can be experimentally identified from Ago complexes and therefore provide a new tool to directly analyze miRNA function.

Development of a microcapillary column for detecting targeted messenger RNA molecules.

PubMed

Ohnishi, Michihiro

2006-03-24

A capillary column in a rapid-flow system has been developed for detecting targeted messenger RNA (mRNA) molecules. The column has a structure made of two beds-one bed of porous microbeads and one bed of microbeads with a polythymidine base sequence. The targeted eukaryotic mRNA molecules are detected by two-step hybridization (sandwich hybridization) composed of polyadenosine selection of mRNA molecules and formation of a probe-target (targeted mRNA) hybrid. The sandwich hybridization, which is accomplished within 1 h, was tested using synthetic polydeoxynucleotides. Ten picomoles of the targeted polydeoxynucleotide were detected.

Literature-based condition-specific miRNA-mRNA target prediction.

PubMed

Oh, Minsik; Rhee, Sungmin; Moon, Ji Hwan; Chae, Heejoon; Lee, Sunwon; Kang, Jaewoo; Kim, Sun

2017-01-01

miRNAs are small non-coding RNAs that regulate gene expression by binding to the 3'-UTR of genes. Many recent studies have reported that miRNAs play important biological roles by regulating specific mRNAs or genes. Many sequence-based target prediction algorithms have been developed to predict miRNA targets. However, these methods are not designed for condition-specific target predictions and produce many false positives; thus, expression-based target prediction algorithms have been developed for condition-specific target predictions. A typical strategy to utilize expression data is to leverage the negative control roles of miRNAs on genes. To control false positives, a stringent cutoff value is typically set, but in this case, these methods tend to reject many true target relationships, i.e., false negatives. To overcome these limitations, additional information should be utilized. The literature is probably the best resource that we can utilize. Recent literature mining systems compile millions of articles with experiments designed for specific biological questions, and the systems provide a function to search for specific information. To utilize the literature information, we used a literature mining system, BEST, that automatically extracts information from the literature in PubMed and that allows the user to perform searches of the literature with any English words. By integrating omics data analysis methods and BEST, we developed Context-MMIA, a miRNA-mRNA target prediction method that combines expression data analysis results and the literature information extracted based on the user-specified context. In the pathway enrichment analysis using genes included in the top 200 miRNA-targets, Context-MMIA outperformed the four existing target prediction methods that we tested. In another test on whether prediction methods can re-produce experimentally validated target relationships, Context-MMIA outperformed the four existing target prediction methods. In summary

CRISPRdirect: software for designing CRISPR/Cas guide RNA with reduced off-target sites

PubMed Central

Naito, Yuki; Hino, Kimihiro; Bono, Hidemasa; Ui-Tei, Kumiko

2015-01-01

Summary: CRISPRdirect is a simple and functional web server for selecting rational CRISPR/Cas targets from an input sequence. The CRISPR/Cas system is a promising technique for genome engineering which allows target-specific cleavage of genomic DNA guided by Cas9 nuclease in complex with a guide RNA (gRNA), that complementarily binds to a ∼20 nt targeted sequence. The target sequence requirements are twofold. First, the 5′-NGG protospacer adjacent motif (PAM) sequence must be located adjacent to the target sequence. Second, the target sequence should be specific within the entire genome in order to avoid off-target editing. CRISPRdirect enables users to easily select rational target sequences with minimized off-target sites by performing exhaustive searches against genomic sequences. The server currently incorporates the genomic sequences of human, mouse, rat, marmoset, pig, chicken, frog, zebrafish, Ciona, fruit fly, silkworm, Caenorhabditis elegans, Arabidopsis, rice, Sorghum and budding yeast. Availability: Freely available at http://crispr.dbcls.jp/. Contact: y-naito@dbcls.rois.ac.jp Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25414360

RNA-guided genome editing for target gene mutations in wheat.

PubMed

Upadhyay, Santosh Kumar; Kumar, Jitesh; Alok, Anshu; Tuli, Rakesh

2013-12-09

The clustered, regularly interspaced, short palindromic repeats (CRISPR) and CRISPR-associated protein (Cas) system has been used as an efficient tool for genome editing. We report the application of CRISPR-Cas-mediated genome editing to wheat (Triticum aestivum), the most important food crop plant with a very large and complex genome. The mutations were targeted in the inositol oxygenase (inox) and phytoene desaturase (pds) genes using cell suspension culture of wheat and in the pds gene in leaves of Nicotiana benthamiana. The expression of chimeric guide RNAs (cgRNA) targeting single and multiple sites resulted in indel mutations in all the tested samples. The expression of Cas9 or sgRNA alone did not cause any mutation. The expression of duplex cgRNA with Cas9 targeting two sites in the same gene resulted in deletion of DNA fragment between the targeted sequences. Multiplexing the cgRNA could target two genes at one time. Target specificity analysis of cgRNA showed that mismatches at the 3' end of the target site abolished the cleavage activity completely. The mismatches at the 5' end reduced cleavage, suggesting that the off target effects can be abolished in vivo by selecting target sites with unique sequences at 3' end. This approach provides a powerful method for genome engineering in plants.

Detection of canonical A-to-G editing events at 3' UTRs and microRNA target sites in human lungs using next-generation sequencing.

PubMed

Soundararajan, Ramani; Stearns, Timothy M; Griswold, Anthony L; Mehta, Arpit; Czachor, Alexander; Fukumoto, Jutaro; Lockey, Richard F; King, Benjamin L; Kolliputi, Narasaiah

2015-11-03

RNA editing is a post-transcriptional modification of RNA. The majority of these changes result from adenosine deaminase acting on RNA (ADARs) catalyzing the conversion of adenosine residues to inosine in double-stranded RNAs (dsRNAs). Massively parallel sequencing has enabled the identification of RNA editing sites in human transcriptomes. In this study, we sequenced DNA and RNA from human lungs and identified RNA editing sites with high confidence via a computational pipeline utilizing stringent analysis thresholds. We identified a total of 3,447 editing sites that overlapped in three human lung samples, and with 50% of these sites having canonical A-to-G base changes. Approximately 27% of the edited sites overlapped with Alu repeats, and showed A-to-G clustering (>3 clusters in 100 bp). The majority of edited sites mapped to either 3' untranslated regions (UTRs) or introns close to splice sites; whereas, only few sites were in exons resulting in non-synonymous amino acid changes. Interestingly, we identified 652 A-to-G editing events in the 3' UTR of 205 target genes that mapped to 932 potential miRNA target binding sites. Several of these miRNA edited sites were validated in silico. Additionally, we validated several A-to-G edited sites by Sanger sequencing. Altogether, our study suggests a role for RNA editing in miRNA-mediated gene regulation and splicing in human lungs. In this study, we have generated a RNA editome of human lung tissue that can be compared with other RNA editomes across different lung tissues to delineate a role for RNA editing in normal and diseased states.

mESAdb: microRNA Expression and Sequence Analysis Database

PubMed Central

Kaya, Koray D.; Karakülah, Gökhan; Yakıcıer, Cengiz M.; Acar, Aybar C.; Konu, Özlen

2011-01-01

microRNA expression and sequence analysis database (http://konulab.fen.bilkent.edu.tr/mirna/) (mESAdb) is a regularly updated database for the multivariate analysis of sequences and expression of microRNAs from multiple taxa. mESAdb is modular and has a user interface implemented in PHP and JavaScript and coupled with statistical analysis and visualization packages written for the R language. The database primarily comprises mature microRNA sequences and their target data, along with selected human, mouse and zebrafish expression data sets. mESAdb analysis modules allow (i) mining of microRNA expression data sets for subsets of microRNAs selected manually or by motif; (ii) pair-wise multivariate analysis of expression data sets within and between taxa; and (iii) association of microRNA subsets with annotation databases, HUGE Navigator, KEGG and GO. The use of existing and customized R packages facilitates future addition of data sets and analysis tools. Furthermore, the ability to upload and analyze user-specified data sets makes mESAdb an interactive and expandable analysis tool for microRNA sequence and expression data. PMID:21177657

mESAdb: microRNA expression and sequence analysis database.

PubMed

Kaya, Koray D; Karakülah, Gökhan; Yakicier, Cengiz M; Acar, Aybar C; Konu, Ozlen

2011-01-01

microRNA expression and sequence analysis database (http://konulab.fen.bilkent.edu.tr/mirna/) (mESAdb) is a regularly updated database for the multivariate analysis of sequences and expression of microRNAs from multiple taxa. mESAdb is modular and has a user interface implemented in PHP and JavaScript and coupled with statistical analysis and visualization packages written for the R language. The database primarily comprises mature microRNA sequences and their target data, along with selected human, mouse and zebrafish expression data sets. mESAdb analysis modules allow (i) mining of microRNA expression data sets for subsets of microRNAs selected manually or by motif; (ii) pair-wise multivariate analysis of expression data sets within and between taxa; and (iii) association of microRNA subsets with annotation databases, HUGE Navigator, KEGG and GO. The use of existing and customized R packages facilitates future addition of data sets and analysis tools. Furthermore, the ability to upload and analyze user-specified data sets makes mESAdb an interactive and expandable analysis tool for microRNA sequence and expression data.

RISE: a database of RNA interactome from sequencing experiments

PubMed Central

Gong, Jing; Shao, Di; Xu, Kui

2018-01-01

Abstract We present RISE (http://rise.zhanglab.net), a database of RNA Interactome from Sequencing Experiments. RNA-RNA interactions (RRIs) are essential for RNA regulation and function. RISE provides a comprehensive collection of RRIs that mainly come from recent transcriptome-wide sequencing-based experiments like PARIS, SPLASH, LIGR-seq, and MARIO, as well as targeted studies like RIA-seq, RAP-RNA and CLASH. It also includes interactions aggregated from other primary databases and publications. The RISE database currently contains 328,811 RNA-RNA interactions mainly in human, mouse and yeast. While most existing RNA databases mainly contain interactions of miRNA targeting, notably, more than half of the RRIs in RISE are among mRNA and long non-coding RNAs. We compared different RRI datasets in RISE and found limited overlaps in interactions resolved by different techniques and in different cell lines. It may suggest technology preference and also dynamic natures of RRIs. We also analyzed the basic features of the human and mouse RRI networks and found that they tend to be scale-free, small-world, hierarchical and modular. The analysis may nominate important RNAs or RRIs for further investigation. Finally, RISE provides a Circos plot and several table views for integrative visualization, with extensive molecular and functional annotations to facilitate exploration of biological functions for any RRI of interest. PMID:29040625

Targets of small interfering RNA restriction during human immunodeficiency virus type 1 replication.

PubMed

Gao, Yong; Lobritz, Michael A; Roth, Justin; Abreha, Measho; Nelson, Kenneth N; Nankya, Immaculate; Moore-Dudley, Dawn M; Abraha, Awet; Gerson, Stanton L; Arts, Eric J

2008-03-01

Small interfering RNAs (siRNAs) have been shown to effectively inhibit human immunodeficiency virus type 1 (HIV-1) replication in vitro. The mechanism(s) for this inhibition is poorly understood, as siRNAs may interact with multiple HIV-1 RNA species during different steps of the retroviral life cycle. To define susceptible HIV-1 RNA species, siRNAs were first designed to specifically inhibit two divergent primary HIV-1 isolates via env and gag gene targets. A self-inactivating lentiviral vector harboring these target sequences confirmed that siRNA cannot degrade incoming genomic RNA. Disruption of the incoming core structure by rhesus macaque TRIM5alpha did, however, provide siRNA-RNA-induced silencing complex access to HIV-1 genomic RNA and promoted degradation. In the absence of accelerated core disruption, only newly transcribed HIV-1 mRNA in the cytoplasm is sensitive to siRNA degradation. Inhibitors of HIV-1 mRNA nuclear export, such as leptomycin B and camptothecin, blocked siRNA restriction. All HIV-1 RNA regions and transcripts found 5' of the target sequence, including multiply spliced HIV-1 RNA, were degraded by unidirectional 3'-to-5' siRNA amplification and spreading. In contrast, HIV-1 RNA 3' of the target sequence was not susceptible to siRNA. Even in the presence of siRNA, full-length HIV-1 RNA is still encapsidated into newly assembled viruses. These findings suggest that siRNA can target only a relatively "naked" cytoplasmic HIV-1 RNA despite the involvement of viral RNA at nearly every step in the retroviral life cycle. Protection of HIV-1 RNA within the core following virus entry, during encapsidation/virus assembly, or within the nucleus may reflect virus evolution in response to siRNA, TRIM5alpha, or other host restriction factors.

A quick reality check for microRNA target prediction.

PubMed

Kast, Juergen

2011-04-01

The regulation of protein abundance by microRNA (miRNA)-mediated repression of mRNA translation is a rapidly growing area of interest in biochemical research. In animal cells, the miRNA seed sequence does not perfectly match that of the mRNA it targets, resulting in a large number of possible miRNA targets and varied extents of repression. Several software tools are available for the prediction of miRNA targets, yet the overlap between them is limited. Jovanovic et al. have developed and applied a targeted, quantitative approach to validate predicted miRNA target proteins. Using a proteome database, they have set up and tested selected reaction monitoring assays for approximately 20% of more than 800 predicted let-7 targets, as well as control genes in Caenorhabditis elegans. Their results demonstrate that such assays can be developed quickly and with relative ease, and applied in a high-throughput setup to verify known and identify novel miRNA targets. They also show, however, that the choice of the biological system and material has a noticeable influence on the frequency, extent and direction of the observed changes. Nonetheless, selected reaction monitoring assays, such as those developed by Jovanovic et al., represent an attractive new tool in the study of miRNA function at the organism level.

Detection of canonical A-to-G editing events at 3′ UTRs and microRNA target sites in human lungs using next-generation sequencing

PubMed Central

Soundararajan, Ramani; Stearns, Timothy M.; Griswold, Anthony J.; Mehta, Arpit; Czachor, Alexander; Fukumoto, Jutaro; Lockey, Richard F.; King, Benjamin L.; Kolliputi, Narasaiah

2015-01-01

RNA editing is a post-transcriptional modification of RNA. The majority of these changes result from adenosine deaminase acting on RNA (ADARs) catalyzing the conversion of adenosine residues to inosine in double-stranded RNAs (dsRNAs). Massively parallel sequencing has enabled the identification of RNA editing sites in human transcriptomes. In this study, we sequenced DNA and RNA from human lungs and identified RNA editing sites with high confidence via a computational pipeline utilizing stringent analysis thresholds. We identified a total of 3,447 editing sites that overlapped in three human lung samples, and with 50% of these sites having canonical A-to-G base changes. Approximately 27% of the edited sites overlapped with Alu repeats, and showed A-to-G clustering (>3 clusters in 100 bp). The majority of edited sites mapped to either 3′ untranslated regions (UTRs) or introns close to splice sites; whereas, only few sites were in exons resulting in non-synonymous amino acid changes. Interestingly, we identified 652 A-to-G editing events in the 3′ UTR of 205 target genes that mapped to 932 potential miRNA target binding sites. Several of these miRNA edited sites were validated in silico. Additionally, we validated several A-to-G edited sites by Sanger sequencing. Altogether, our study suggests a role for RNA editing in miRNA-mediated gene regulation and splicing in human lungs. In this study, we have generated a RNA editome of human lung tissue that can be compared with other RNA editomes across different lung tissues to delineate a role for RNA editing in normal and diseased states. PMID:26486088

incaRNAfbinv: a web server for the fragment-based design of RNA sequences

PubMed Central

Drory Retwitzer, Matan; Reinharz, Vladimir; Ponty, Yann; Waldispühl, Jérôme; Barash, Danny

2016-01-01

Abstract In recent years, new methods for computational RNA design have been developed and applied to various problems in synthetic biology and nanotechnology. Lately, there is considerable interest in incorporating essential biological information when solving the inverse RNA folding problem. Correspondingly, RNAfbinv aims at including biologically meaningful constraints and is the only program to-date that performs a fragment-based design of RNA sequences. In doing so it allows the design of sequences that do not necessarily exactly fold into the target, as long as the overall coarse-grained tree graph shape is preserved. Augmented by the weighted sampling algorithm of incaRNAtion, our web server called incaRNAfbinv implements the method devised in RNAfbinv and offers an interactive environment for the inverse folding of RNA using a fragment-based design approach. It takes as input: a target RNA secondary structure; optional sequence and motif constraints; optional target minimum free energy, neutrality and GC content. In addition to the design of synthetic regulatory sequences, it can be used as a pre-processing step for the detection of novel natural occurring RNAs. The two complementary methodologies RNAfbinv and incaRNAtion are merged together and fully implemented in our web server incaRNAfbinv, available at http://www.cs.bgu.ac.il/incaRNAfbinv. PMID:27185893

Discriminative Prediction of A-To-I RNA Editing Events from DNA Sequence

PubMed Central

Sun, Jiangming; Singh, Pratibha; Bagge, Annika; Valtat, Bérengère; Vikman, Petter; Spégel, Peter; Mulder, Hindrik

2016-01-01

RNA editing is a post-transcriptional alteration of RNA sequences that, via insertions, deletions or base substitutions, can affect protein structure as well as RNA and protein expression. Recently, it has been suggested that RNA editing may be more frequent than previously thought. A great impediment, however, to a deeper understanding of this process is the paramount sequencing effort that needs to be undertaken to identify RNA editing events. Here, we describe an in silico approach, based on machine learning, that ameliorates this problem. Using 41 nucleotide long DNA sequences, we show that novel A-to-I RNA editing events can be predicted from known A-to-I RNA editing events intra- and interspecies. The validity of the proposed method was verified in an independent experimental dataset. Using our approach, 203 202 putative A-to-I RNA editing events were predicted in the whole human genome. Out of these, 9% were previously reported. The remaining sites require further validation, e.g., by targeted deep sequencing. In conclusion, the approach described here is a useful tool to identify potential A-to-I RNA editing events without the requirement of extensive RNA sequencing. PMID:27764195

Targeting a KH-domain protein with RNA decoys.

PubMed

Makeyev, Aleksandr V; Eastmond, Dawn L; Liebhaber, Stephen A

2002-09-01

RNA-binding proteins are involved in the regulation of many aspects of eukaryotic gene expression. Targeted interference with RNA-protein interactions could offer novel approaches to modulation of expression profiles, alteration of developmental pathways, and reversal of certain disease processes. Here we investigate a decoy strategy for the study of the alphaCP subgroup of KH-domain RNA-binding proteins. These poly(C)-binding proteins have been implicated in a wide spectrum of posttranscriptional controls. Three categories of RNA decoys to alphaCPs were studied: poly(C) homopolymers, native mRNA-binding sites, and a high-affinity structure selected from a combinatorial library. Native chemistry was found to be essential for alphaCP decoy action. Because alphaCP proteins are found in both the nucleus and cytoplasm, decoy cassettes were incorporated within both nuclear (U1 snRNA) and cytoplasmic (VA1 RNA) RNA frameworks. Several sequences demonstrated optimal decoy properties when assayed for protein-binding and decoy bioactivity in vitro. A subset of these transcripts was shown to mediate targeted inhibition of alphaCP-dependent translation when expressed in either the nucleus or cytoplasm of transfected cells. Significantly, these studies establish the feasibility of developing RNA decoys that can selectively target biologic functions of abundant and widely expressed RNA binding proteins.

Targeting a KH-domain protein with RNA decoys.

PubMed Central

Makeyev, Aleksandr V; Eastmond, Dawn L; Liebhaber, Stephen A

2002-01-01

RNA-binding proteins are involved in the regulation of many aspects of eukaryotic gene expression. Targeted interference with RNA-protein interactions could offer novel approaches to modulation of expression profiles, alteration of developmental pathways, and reversal of certain disease processes. Here we investigate a decoy strategy for the study of the alphaCP subgroup of KH-domain RNA-binding proteins. These poly(C)-binding proteins have been implicated in a wide spectrum of posttranscriptional controls. Three categories of RNA decoys to alphaCPs were studied: poly(C) homopolymers, native mRNA-binding sites, and a high-affinity structure selected from a combinatorial library. Native chemistry was found to be essential for alphaCP decoy action. Because alphaCP proteins are found in both the nucleus and cytoplasm, decoy cassettes were incorporated within both nuclear (U1 snRNA) and cytoplasmic (VA1 RNA) RNA frameworks. Several sequences demonstrated optimal decoy properties when assayed for protein-binding and decoy bioactivity in vitro. A subset of these transcripts was shown to mediate targeted inhibition of alphaCP-dependent translation when expressed in either the nucleus or cytoplasm of transfected cells. Significantly, these studies establish the feasibility of developing RNA decoys that can selectively target biologic functions of abundant and widely expressed RNA binding proteins. PMID:12358435

psRNATarget: a plant small RNA target analysis server

PubMed Central

Dai, Xinbin; Zhao, Patrick Xuechun

2011-01-01

Plant endogenous non-coding short small RNAs (20–24 nt), including microRNAs (miRNAs) and a subset of small interfering RNAs (ta-siRNAs), play important role in gene expression regulatory networks (GRNs). For example, many transcription factors and development-related genes have been reported as targets of these regulatory small RNAs. Although a number of miRNA target prediction algorithms and programs have been developed, most of them were designed for animal miRNAs which are significantly different from plant miRNAs in the target recognition process. These differences demand the development of separate plant miRNA (and ta-siRNA) target analysis tool(s). We present psRNATarget, a plant small RNA target analysis server, which features two important analysis functions: (i) reverse complementary matching between small RNA and target transcript using a proven scoring schema, and (ii) target-site accessibility evaluation by calculating unpaired energy (UPE) required to ‘open’ secondary structure around small RNA’s target site on mRNA. The psRNATarget incorporates recent discoveries in plant miRNA target recognition, e.g. it distinguishes translational and post-transcriptional inhibition, and it reports the number of small RNA/target site pairs that may affect small RNA binding activity to target transcript. The psRNATarget server is designed for high-throughput analysis of next-generation data with an efficient distributed computing back-end pipeline that runs on a Linux cluster. The server front-end integrates three simplified user-friendly interfaces to accept user-submitted or preloaded small RNAs and transcript sequences; and outputs a comprehensive list of small RNA/target pairs along with the online tools for batch downloading, key word searching and results sorting. The psRNATarget server is freely available at http://plantgrn.noble.org/psRNATarget/. PMID:21622958

Assembly and analysis of eukaryotic Argonaute–RNA complexes in microRNA-target recognition

PubMed Central

Gan, Hin Hark; Gunsalus, Kristin C.

2015-01-01

Experimental studies have uncovered a variety of microRNA (miRNA)–target duplex structures that include perfect, imperfect and seedless duplexes. However, non-canonical binding modes from imperfect/seedless duplexes are not well predicted by computational approaches, which rely primarily on sequence and secondary structural features, nor have their tertiary structures been characterized because solved structures to date are limited to near perfect, straight duplexes in Argonautes (Agos). Here, we use structural modeling to examine the role of Ago dynamics in assembling viable eukaryotic miRNA-induced silencing complexes (miRISCs). We show that combinations of low-frequency, global modes of motion of Ago domains are required to accommodate RNA duplexes in model human and C. elegans Ago structures. Models of viable miRISCs imply that Ago adopts variable conformations at distinct target sites that generate distorted, imperfect miRNA-target duplexes. Ago's ability to accommodate a duplex is dependent on the region where structural distortions occur: distortions in solvent-exposed seed and 3′-end regions are less likely to produce steric clashes than those in the central duplex region. Energetic analyses of assembled miRISCs indicate that target recognition is also driven by favorable Ago-duplex interactions. Such structural insights into Ago loading and target recognition mechanisms may provide a more accurate assessment of miRNA function. PMID:26432829

Methods to enable the design of bioactive small molecules targeting RNA.

PubMed

Disney, Matthew D; Yildirim, Ilyas; Childs-Disney, Jessica L

2014-02-21

RNA is an immensely important target for small molecule therapeutics or chemical probes of function. However, methods that identify, annotate, and optimize RNA-small molecule interactions that could enable the design of compounds that modulate RNA function are in their infancies. This review describes recent approaches that have been developed to understand and optimize RNA motif-small molecule interactions, including structure-activity relationships through sequencing (StARTS), quantitative structure-activity relationships (QSAR), chemical similarity searching, structure-based design and docking, and molecular dynamics (MD) simulations. Case studies described include the design of small molecules targeting RNA expansions, the bacterial A-site, viral RNAs, and telomerase RNA. These approaches can be combined to afford a synergistic method to exploit the myriad of RNA targets in the transcriptome.

RNA therapeutics targeting osteoclast-mediated excessive bone resorption

PubMed Central

Wang, Yuwei; Grainger, David W

2011-01-01

RNA interference (RNAi) is a sequence-specific post-transcriptional gene silencing technique developed with dramatically increasing utility for both scientific and therapeutic purposes. Short interfering RNA (siRNA) is currently exploited to regulate protein expression relevant to many therapeutic applications, and commonly used as a tool for elucidating disease-associated genes. Osteoporosis and their associated osteoporotic fragility fractures in both men and women are rapidly becoming a global healthcare crisis as average life expectancy increases worldwide. New therapeutics are needed for this increasing patient population. This review describes the diversity of molecular targets suitable for RNAi-based gene knock-down in osteoclasts to control osteoclast-mediated excessive bone resorption. We identify strategies for developing targeted siRNA delivery and efficient gene silencing, and describe opportunities and challenges of introducing siRNA as a therapeutic approach to hard and connective tissue disorders. PMID:21945356

TargetM6A: Identifying N6-Methyladenosine Sites From RNA Sequences via Position-Specific Nucleotide Propensities and a Support Vector Machine.

PubMed

Li, Guang-Qing; Liu, Zi; Shen, Hong-Bin; Yu, Dong-Jun

2016-10-01

As one of the most ubiquitous post-transcriptional modifications of RNA, N 6 -methyladenosine ( [Formula: see text]) plays an essential role in many vital biological processes. The identification of [Formula: see text] sites in RNAs is significantly important for both basic biomedical research and practical drug development. In this study, we designed a computational-based method, called TargetM6A, to rapidly and accurately target [Formula: see text] sites solely from the primary RNA sequences. Two new features, i.e., position-specific nucleotide/dinucleotide propensities (PSNP/PSDP), are introduced and combined with the traditional nucleotide composition (NC) feature to formulate RNA sequences. The extracted features are further optimized to obtain a much more compact and discriminative feature subset by applying an incremental feature selection (IFS) procedure. Based on the optimized feature subset, we trained TargetM6A on the training dataset with a support vector machine (SVM) as the prediction engine. We compared the proposed TargetM6A method with existing methods for predicting [Formula: see text] sites by performing stringent jackknife tests and independent validation tests on benchmark datasets. The experimental results show that the proposed TargetM6A method outperformed the existing methods for predicting [Formula: see text] sites and remarkably improved the prediction performances, with MCC = 0.526 and AUC = 0.818. We also provided a user-friendly web server for TargetM6A, which is publicly accessible for academic use at http://csbio.njust.edu.cn/bioinf/TargetM6A.

Comparison of small molecules and oligonucleotides that target a toxic, non-coding RNA.

PubMed

Costales, Matthew G; Rzuczek, Suzanne G; Disney, Matthew D

2016-06-01

Potential RNA targets for chemical probes and therapeutic modalities are pervasive in the transcriptome. Oligonucleotide-based therapeutics are commonly used to target RNA sequence. Small molecules are emerging as a modality to target RNA structures selectively, but their development is still in its infancy. In this work, we compare the activity of oligonucleotides and several classes of small molecules that target the non-coding r(CCUG) repeat expansion (r(CCUG)(exp)) that causes myotonic dystrophy type 2 (DM2), an incurable disease that is the second-most common cause of adult onset muscular dystrophy. Small molecule types investigated include monomers, dimers, and multivalent compounds synthesized on-site by using RNA-templated click chemistry. Oligonucleotides investigated include phosphorothioates that cleave their target and vivo-morpholinos that modulate target RNA activity via binding. We show that compounds assembled on-site that recognize structure have the highest potencies amongst small molecules and are similar in potency to a vivo-morpholino modified oligonucleotide that targets sequence. These studies are likely to impact the design of therapeutic modalities targeting other repeats expansions that cause fragile X syndrome and amyotrophic lateral sclerosis, for example. Copyright © 2016. Published by Elsevier Ltd.

TargetSpy: a supervised machine learning approach for microRNA target prediction.

PubMed

Sturm, Martin; Hackenberg, Michael; Langenberger, David; Frishman, Dmitrij

2010-05-28

Virtually all currently available microRNA target site prediction algorithms require the presence of a (conserved) seed match to the 5' end of the microRNA. Recently however, it has been shown that this requirement might be too stringent, leading to a substantial number of missed target sites. We developed TargetSpy, a novel computational approach for predicting target sites regardless of the presence of a seed match. It is based on machine learning and automatic feature selection using a wide spectrum of compositional, structural, and base pairing features covering current biological knowledge. Our model does not rely on evolutionary conservation, which allows the detection of species-specific interactions and makes TargetSpy suitable for analyzing unconserved genomic sequences.In order to allow for an unbiased comparison of TargetSpy to other methods, we classified all algorithms into three groups: I) no seed match requirement, II) seed match requirement, and III) conserved seed match requirement. TargetSpy predictions for classes II and III are generated by appropriate postfiltering. On a human dataset revealing fold-change in protein production for five selected microRNAs our method shows superior performance in all classes. In Drosophila melanogaster not only our class II and III predictions are on par with other algorithms, but notably the class I (no-seed) predictions are just marginally less accurate. We estimate that TargetSpy predicts between 26 and 112 functional target sites without a seed match per microRNA that are missed by all other currently available algorithms. Only a few algorithms can predict target sites without demanding a seed match and TargetSpy demonstrates a substantial improvement in prediction accuracy in that class. Furthermore, when conservation and the presence of a seed match are required, the performance is comparable with state-of-the-art algorithms. TargetSpy was trained on mouse and performs well in human and drosophila

TargetSpy: a supervised machine learning approach for microRNA target prediction

PubMed Central

2010-01-01

Background Virtually all currently available microRNA target site prediction algorithms require the presence of a (conserved) seed match to the 5' end of the microRNA. Recently however, it has been shown that this requirement might be too stringent, leading to a substantial number of missed target sites. Results We developed TargetSpy, a novel computational approach for predicting target sites regardless of the presence of a seed match. It is based on machine learning and automatic feature selection using a wide spectrum of compositional, structural, and base pairing features covering current biological knowledge. Our model does not rely on evolutionary conservation, which allows the detection of species-specific interactions and makes TargetSpy suitable for analyzing unconserved genomic sequences. In order to allow for an unbiased comparison of TargetSpy to other methods, we classified all algorithms into three groups: I) no seed match requirement, II) seed match requirement, and III) conserved seed match requirement. TargetSpy predictions for classes II and III are generated by appropriate postfiltering. On a human dataset revealing fold-change in protein production for five selected microRNAs our method shows superior performance in all classes. In Drosophila melanogaster not only our class II and III predictions are on par with other algorithms, but notably the class I (no-seed) predictions are just marginally less accurate. We estimate that TargetSpy predicts between 26 and 112 functional target sites without a seed match per microRNA that are missed by all other currently available algorithms. Conclusion Only a few algorithms can predict target sites without demanding a seed match and TargetSpy demonstrates a substantial improvement in prediction accuracy in that class. Furthermore, when conservation and the presence of a seed match are required, the performance is comparable with state-of-the-art algorithms. TargetSpy was trained on mouse and performs well

Single-cell mRNA cytometry via sequence-specific nanoparticle clustering and trapping

NASA Astrophysics Data System (ADS)

Labib, Mahmoud; Mohamadi, Reza M.; Poudineh, Mahla; Ahmed, Sharif U.; Ivanov, Ivaylo; Huang, Ching-Lung; Moosavi, Maral; Sargent, Edward H.; Kelley, Shana O.

2018-05-01

Cell-to-cell variation in gene expression creates a need for techniques that can characterize expression at the level of individual cells. This is particularly true for rare circulating tumour cells, in which subtyping and drug resistance are of intense interest. Here we describe a method for cell analysis—single-cell mRNA cytometry—that enables the isolation of rare cells from whole blood as a function of target mRNA sequences. This approach uses two classes of magnetic particles that are labelled to selectively hybridize with different regions of the target mRNA. Hybridization leads to the formation of large magnetic clusters that remain localized within the cells of interest, thereby enabling the cells to be magnetically separated. Targeting specific intracellular mRNAs enablescirculating tumour cells to be distinguished from normal haematopoietic cells. No polymerase chain reaction amplification is required to determine RNA expression levels and genotype at the single-cell level, and minimal cell manipulation is required. To demonstrate this approach we use single-cell mRNA cytometry to detect clinically important sequences in prostate cancer specimens.

Target mimics: an embedded layer of microRNA-involved gene regulatory networks in plants.

PubMed

Meng, Yijun; Shao, Chaogang; Wang, Huizhong; Jin, Yongfeng

2012-05-21

MicroRNAs (miRNAs) play an essential role in gene regulation in plants. At the same time, the expression of miRNA genes is also tightly controlled. Recently, a novel mechanism called "target mimicry" was discovered, providing another layer for modulating miRNA activities. However, except for the artificial target mimics manipulated for functional studies on certain miRNA genes, only one example, IPS1 (Induced by Phosphate Starvation 1)-miR399 was experimentally confirmed in planta. To date, few analyses for comprehensive identification of natural target mimics have been performed in plants. Thus, limited evidences are available to provide detailed information for interrogating the questionable issue whether target mimicry was widespread in planta, and implicated in certain biological processes. In this study, genome-wide computational prediction of endogenous miRNA mimics was performed in Arabidopsis and rice, and dozens of target mimics were identified. In contrast to a recent report, the densities of target mimic sites were found to be much higher within the untranslated regions (UTRs) when compared to those within the coding sequences (CDSs) in both plants. Some novel sequence characteristics were observed for the miRNAs that were potentially regulated by the target mimics. GO (Gene Ontology) term enrichment analysis revealed some functional insights into the predicted mimics. After degradome sequencing data-based identification of miRNA targets, the regulatory networks constituted by target mimics, miRNAs and their downstream targets were constructed, and some intriguing subnetworks were further exploited. These results together suggest that target mimicry may be widely implicated in regulating miRNA activities in planta, and we hope this study could expand the current understanding of miRNA-involved regulatory networks.

Application of Stochastic Labeling with Random-Sequence Barcodes for Simultaneous Quantification and Sequencing of Environmental 16S rRNA Genes.

PubMed

Hoshino, Tatsuhiko; Inagaki, Fumio

2017-01-01

Next-generation sequencing (NGS) is a powerful tool for analyzing environmental DNA and provides the comprehensive molecular view of microbial communities. For obtaining the copy number of particular sequences in the NGS library, however, additional quantitative analysis as quantitative PCR (qPCR) or digital PCR (dPCR) is required. Furthermore, number of sequences in a sequence library does not always reflect the original copy number of a target gene because of biases caused by PCR amplification, making it difficult to convert the proportion of particular sequences in the NGS library to the copy number using the mass of input DNA. To address this issue, we applied stochastic labeling approach with random-tag sequences and developed a NGS-based quantification protocol, which enables simultaneous sequencing and quantification of the targeted DNA. This quantitative sequencing (qSeq) is initiated from single-primer extension (SPE) using a primer with random tag adjacent to the 5' end of target-specific sequence. During SPE, each DNA molecule is stochastically labeled with the random tag. Subsequently, first-round PCR is conducted, specifically targeting the SPE product, followed by second-round PCR to index for NGS. The number of random tags is only determined during the SPE step and is therefore not affected by the two rounds of PCR that may introduce amplification biases. In the case of 16S rRNA genes, after NGS sequencing and taxonomic classification, the absolute number of target phylotypes 16S rRNA gene can be estimated by Poisson statistics by counting random tags incorporated at the end of sequence. To test the feasibility of this approach, the 16S rRNA gene of Sulfolobus tokodaii was subjected to qSeq, which resulted in accurate quantification of 5.0 × 103 to 5.0 × 104 copies of the 16S rRNA gene. Furthermore, qSeq was applied to mock microbial communities and environmental samples, and the results were comparable to those obtained using digital PCR and

Whole genome analysis of CRISPR Cas9 sgRNA off-target homologies via an efficient computational algorithm.

PubMed

Zhou, Hong; Zhou, Michael; Li, Daisy; Manthey, Joseph; Lioutikova, Ekaterina; Wang, Hong; Zeng, Xiao

2017-11-17

The beauty and power of the genome editing mechanism, CRISPR Cas9 endonuclease system, lies in the fact that it is RNA-programmable such that Cas9 can be guided to any genomic loci complementary to a 20-nt RNA, single guide RNA (sgRNA), to cleave double stranded DNA, allowing the introduction of wanted mutations. Unfortunately, it has been reported repeatedly that the sgRNA can also guide Cas9 to off-target sites where the DNA sequence is homologous to sgRNA. Using human genome and Streptococcus pyogenes Cas9 (SpCas9) as an example, this article mathematically analyzed the probabilities of off-target homologies of sgRNAs and discovered that for large genome size such as human genome, potential off-target homologies are inevitable for sgRNA selection. A highly efficient computationl algorithm was developed for whole genome sgRNA design and off-target homology searches. By means of a dynamically constructed sequence-indexed database and a simplified sequence alignment method, this algorithm achieves very high efficiency while guaranteeing the identification of all existing potential off-target homologies. Via this algorithm, 1,876,775 sgRNAs were designed for the 19,153 human mRNA genes and only two sgRNAs were found to be free of off-target homology. By means of the novel and efficient sgRNA homology search algorithm introduced in this article, genome wide sgRNA design and off-target analysis were conducted and the results confirmed the mathematical analysis that for a sgRNA sequence, it is almost impossible to escape potential off-target homologies. Future innovations on the CRISPR Cas9 gene editing technology need to focus on how to eliminate the Cas9 off-target activity.

Methods to enable the design of bioactive small molecules targeting RNA

PubMed Central

Disney, Matthew D.; Yildirim, Ilyas; Childs-Disney, Jessica L.

2014-01-01

RNA is an immensely important target for small molecule therapeutics or chemical probes of function. However, methods that identify, annotate, and optimize RNA-small molecule interactions that could enable the design of compounds that modulate RNA function are in their infancies. This review describes recent approaches that have been developed to understand and optimize RNA motif-small molecule interactions, including Structure-Activity Relationships Through Sequencing (StARTS), quantitative structure-activity relationships (QSAR), chemical similarity searching, structure-based design and docking, and molecular dynamics (MD) simulations. Case studies described include the design of small molecules targeting RNA expansions, the bacterial A-site, viral RNAs, and telomerase RNA. These approaches can be combined to afford a synergistic method to exploit the myriad of RNA targets in the transcriptome. PMID:24357181

eRNA: a graphic user interface-based tool optimized for large data analysis from high-throughput RNA sequencing.

PubMed

Yuan, Tiezheng; Huang, Xiaoyi; Dittmar, Rachel L; Du, Meijun; Kohli, Manish; Boardman, Lisa; Thibodeau, Stephen N; Wang, Liang

2014-03-05

RNA sequencing (RNA-seq) is emerging as a critical approach in biological research. However, its high-throughput advantage is significantly limited by the capacity of bioinformatics tools. The research community urgently needs user-friendly tools to efficiently analyze the complicated data generated by high throughput sequencers. We developed a standalone tool with graphic user interface (GUI)-based analytic modules, known as eRNA. The capacity of performing parallel processing and sample management facilitates large data analyses by maximizing hardware usage and freeing users from tediously handling sequencing data. The module miRNA identification" includes GUIs for raw data reading, adapter removal, sequence alignment, and read counting. The module "mRNA identification" includes GUIs for reference sequences, genome mapping, transcript assembling, and differential expression. The module "Target screening" provides expression profiling analyses and graphic visualization. The module "Self-testing" offers the directory setups, sample management, and a check for third-party package dependency. Integration of other GUIs including Bowtie, miRDeep2, and miRspring extend the program's functionality. eRNA focuses on the common tools required for the mapping and quantification analysis of miRNA-seq and mRNA-seq data. The software package provides an additional choice for scientists who require a user-friendly computing environment and high-throughput capacity for large data analysis. eRNA is available for free download at https://sourceforge.net/projects/erna/?source=directory.

RNA Sequencing Identifies New RNase III Cleavage Sites in Escherichia coli and Reveals Increased Regulation of mRNA

DOE PAGES

Gordon, Gina C.; Cameron, Jeffrey C.; Pfleger, Brian F.

2017-03-28

Ribonucleases facilitate rapid turnover of RNA, providing cells with another mechanism to adjust transcript and protein levels in response to environmental conditions. While many examples have been documented, a comprehensive list of RNase targets is not available. To address this knowledge gap, we compared levels of RNA sequencing coverage of Escherichia coli and a corresponding RNase III mutant to expand the list of known RNase III targets. RNase III is a widespread endoribonuclease that binds and cleaves double-stranded RNA in many critical transcripts. RNase III cleavage at novel sites found in aceEF, proP, tnaC, dctA, pheM, sdhC, yhhQ, glpT, aceK,more » and gluQ accelerated RNA decay, consistent with previously described targets wherein RNase III cleavage initiates rapid degradation of secondary messages by other RNases. In contrast, cleavage at three novel sites in the ahpF, pflB, and yajQ transcripts led to stabilized secondary transcripts. Two other novel sites in hisL and pheM overlapped with transcriptional attenuators that likely serve to ensure turnover of these highly structured RNAs. Many of the new RNase III target sites are located on transcripts encoding metabolic enzymes. For instance, two novel RNase III sites are located within transcripts encoding enzymes near a key metabolic node connecting glycolysis and the tricarboxylic acid (TCA) cycle. Pyruvate dehydrogenase activity was increased in an rnc deletion mutant compared to the wild-type (WT) strain in early stationary phase, confirming the novel link between RNA turnover and regulation of pathway activity. Identification of these novel sites suggests that mRNA turnover may be an underappreciated mode of regulating metabolism. IMPORTANCE: The concerted action and overlapping functions of endoribonucleases, exoribonucleases, and RNA processing enzymes complicate the study of global RNA turnover and recycling of specific transcripts. More information about RNase specificity and activity is

RNA Sequencing Identifies New RNase III Cleavage Sites in Escherichia coli and Reveals Increased Regulation of mRNA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordon, Gina C.; Cameron, Jeffrey C.; Pfleger, Brian F.

Ribonucleases facilitate rapid turnover of RNA, providing cells with another mechanism to adjust transcript and protein levels in response to environmental conditions. While many examples have been documented, a comprehensive list of RNase targets is not available. To address this knowledge gap, we compared levels of RNA sequencing coverage of Escherichia coli and a corresponding RNase III mutant to expand the list of known RNase III targets. RNase III is a widespread endoribonuclease that binds and cleaves double-stranded RNA in many critical transcripts. RNase III cleavage at novel sites found in aceEF, proP, tnaC, dctA, pheM, sdhC, yhhQ, glpT, aceK,more » and gluQ accelerated RNA decay, consistent with previously described targets wherein RNase III cleavage initiates rapid degradation of secondary messages by other RNases. In contrast, cleavage at three novel sites in the ahpF, pflB, and yajQ transcripts led to stabilized secondary transcripts. Two other novel sites in hisL and pheM overlapped with transcriptional attenuators that likely serve to ensure turnover of these highly structured RNAs. Many of the new RNase III target sites are located on transcripts encoding metabolic enzymes. For instance, two novel RNase III sites are located within transcripts encoding enzymes near a key metabolic node connecting glycolysis and the tricarboxylic acid (TCA) cycle. Pyruvate dehydrogenase activity was increased in an rnc deletion mutant compared to the wild-type (WT) strain in early stationary phase, confirming the novel link between RNA turnover and regulation of pathway activity. Identification of these novel sites suggests that mRNA turnover may be an underappreciated mode of regulating metabolism. IMPORTANCE: The concerted action and overlapping functions of endoribonucleases, exoribonucleases, and RNA processing enzymes complicate the study of global RNA turnover and recycling of specific transcripts. More information about RNase specificity and activity is

Current siRNA Targets in Atherosclerosis and Aortic Aneurysm

PubMed Central

Pradhan-Nabzdyk, Leena; Huang, Chenyu; Logerfo, Frank W.; Nabzdyk, Christoph S.

2014-01-01

Atherosclerosis (ATH) and aortic aneurysms (AA) remain challenging chronic diseases that confer high morbidity and mortality despite advances in medical, interventional, and surgical care. RNA interference represents a promising technology that may be utilized to silence genes contributing to ATH and AA. Despite positive results in preclinical and some clinical feasibility studies, challenges such as target/sequence validation, tissue specificity, transfection efficiency, and mitigation of unwanted off-target effects remain to be addressed. In this review the most current targets and some novel approaches in siRNA delivery are being discussed. Due to the plethora of investigated targets, only studies published between 2010 and 2014 were included. PMID:24882715

SMARTIV: combined sequence and structure de-novo motif discovery for in-vivo RNA binding data.

PubMed

Polishchuk, Maya; Paz, Inbal; Yakhini, Zohar; Mandel-Gutfreund, Yael

2018-05-25

Gene expression regulation is highly dependent on binding of RNA-binding proteins (RBPs) to their RNA targets. Growing evidence supports the notion that both RNA primary sequence and its local secondary structure play a role in specific Protein-RNA recognition and binding. Despite the great advance in high-throughput experimental methods for identifying sequence targets of RBPs, predicting the specific sequence and structure binding preferences of RBPs remains a major challenge. We present a novel webserver, SMARTIV, designed for discovering and visualizing combined RNA sequence and structure motifs from high-throughput RNA-binding data, generated from in-vivo experiments. The uniqueness of SMARTIV is that it predicts motifs from enriched k-mers that combine information from ranked RNA sequences and their predicted secondary structure, obtained using various folding methods. Consequently, SMARTIV generates Position Weight Matrices (PWMs) in a combined sequence and structure alphabet with assigned P-values. SMARTIV concisely represents the sequence and structure motif content as a single graphical logo, which is informative and easy for visual perception. SMARTIV was examined extensively on a variety of high-throughput binding experiments for RBPs from different families, generated from different technologies, showing consistent and accurate results. Finally, SMARTIV is a user-friendly webserver, highly efficient in run-time and freely accessible via http://smartiv.technion.ac.il/.

Comprehensive evaluation of AmpliSeq transcriptome, a novel targeted whole transcriptome RNA sequencing methodology for global gene expression analysis.

PubMed

Li, Wenli; Turner, Amy; Aggarwal, Praful; Matter, Andrea; Storvick, Erin; Arnett, Donna K; Broeckel, Ulrich

2015-12-16

Whole transcriptome sequencing (RNA-seq) represents a powerful approach for whole transcriptome gene expression analysis. However, RNA-seq carries a few limitations, e.g., the requirement of a significant amount of input RNA and complications led by non-specific mapping of short reads. The Ion AmpliSeq Transcriptome Human Gene Expression Kit (AmpliSeq) was recently introduced by Life Technologies as a whole-transcriptome, targeted gene quantification kit to overcome these limitations of RNA-seq. To assess the performance of this new methodology, we performed a comprehensive comparison of AmpliSeq with RNA-seq using two well-established next-generation sequencing platforms (Illumina HiSeq and Ion Torrent Proton). We analyzed standard reference RNA samples and RNA samples obtained from human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs). Using published data from two standard RNA reference samples, we observed a strong concordance of log2 fold change for all genes when comparing AmpliSeq to Illumina HiSeq (Pearson's r = 0.92) and Ion Torrent Proton (Pearson's r = 0.92). We used ROC, Matthew's correlation coefficient and RMSD to determine the overall performance characteristics. All three statistical methods demonstrate AmpliSeq as a highly accurate method for differential gene expression analysis. Additionally, for genes with high abundance, AmpliSeq outperforms the two RNA-seq methods. When analyzing four closely related hiPSC-CM lines, we show that both AmpliSeq and RNA-seq capture similar global gene expression patterns consistent with known sources of variations. Our study indicates that AmpliSeq excels in the limiting areas of RNA-seq for gene expression quantification analysis. Thus, AmpliSeq stands as a very sensitive and cost-effective approach for very large scale gene expression analysis and mRNA marker screening with high accuracy.

The Mechanism of Synchronous Precise Regulation of Two Shrimp White Spot Syndrome Virus Targets by a Viral MicroRNA

PubMed Central

He, Yaodong; Ma, Tiantian; Zhang, Xiaobo

2017-01-01

MicroRNAs (miRNAs), important factors in animal innate immunity, suppress the expressions of their target genes by binding to target mRNA’s 3′ untranslated regions (3′UTRs). However, the mechanism of synchronous regulation of multiple targets by a single miRNA remains unclear. In this study, the interaction between a white spot syndrome virus (WSSV) miRNA (WSSV-miR-N32) and its two viral targets (wsv459 and wsv322) was characterized in WSSV-infected shrimp. The outcomes indicated that WSSV-encoded miRNA (WSSV-miR-N32) significantly inhibited virus infection by simultaneously targeting wsv459 and wsv322. The silencing of wsv459 or wsv322 by siRNA led to significant decrease of WSSV copies in shrimp, showing that the two viral genes were required for WSSV infection. WSSV-miR-N32 could mediate 5′–3′ exonucleolytic digestion of its target mRNAs, which stopped at the sites of target mRNA 3′UTRs close to the sequence complementary to the miRNA seed sequence. The complementary bases (to the target mRNA sequence) of a miRNA 9th–18th non-seed sequence were essential for the miRNA targeting. Therefore, our findings presented novel insights into the mechanism of miRNA-mediated suppression of target gene expressions, which would be helpful for understanding the roles of miRNAs in innate immunity of invertebrate. PMID:29230209

Sequence, Structure, and Context Preferences of Human RNA Binding Proteins.

PubMed

Dominguez, Daniel; Freese, Peter; Alexis, Maria S; Su, Amanda; Hochman, Myles; Palden, Tsultrim; Bazile, Cassandra; Lambert, Nicole J; Van Nostrand, Eric L; Pratt, Gabriel A; Yeo, Gene W; Graveley, Brenton R; Burge, Christopher B

2018-06-07

RNA binding proteins (RBPs) orchestrate the production, processing, and function of mRNAs. Here, we present the affinity landscapes of 78 human RBPs using an unbiased assay that determines the sequence, structure, and context preferences of these proteins in vitro by deep sequencing of bound RNAs. These data enable construction of "RNA maps" of RBP activity without requiring crosslinking-based assays. We found an unexpectedly low diversity of RNA motifs, implying frequent convergence of binding specificity toward a relatively small set of RNA motifs, many with low compositional complexity. Offsetting this trend, however, we observed extensive preferences for contextual features distinct from short linear RNA motifs, including spaced "bipartite" motifs, biased flanking nucleotide composition, and bias away from or toward RNA structure. Our results emphasize the importance of contextual features in RNA recognition, which likely enable targeting of distinct subsets of transcripts by different RBPs that recognize the same linear motif. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Preparation of highly multiplexed small RNA sequencing libraries.

PubMed

Persson, Helena; Søkilde, Rolf; Pirona, Anna Chiara; Rovira, Carlos

2017-08-01

MicroRNAs (miRNAs) are ~22-nucleotide-long small non-coding RNAs that regulate the expression of protein-coding genes by base pairing to partially complementary target sites, preferentially located in the 3´ untranslated region (UTR) of target mRNAs. The expression and function of miRNAs have been extensively studied in human disease, as well as the possibility of using these molecules as biomarkers for prognostication and treatment guidance. To identify and validate miRNAs as biomarkers, their expression must be screened in large collections of patient samples. Here, we develop a scalable protocol for the rapid and economical preparation of a large number of small RNA sequencing libraries using dual indexing for multiplexing. Combined with the use of off-the-shelf reagents, more samples can be sequenced simultaneously on large-scale sequencing platforms at a considerably lower cost per sample. Sample preparation is simplified by pooling libraries prior to gel purification, which allows for the selection of a narrow size range while minimizing sample variation. A comparison with publicly available data from benchmarking of miRNA analysis platforms showed that this method captures absolute and differential expression as effectively as commercially available alternatives.

Combined Targeted DNA Sequencing in Non-Small Cell Lung Cancer (NSCLC) Using UNCseq and NGScopy, and RNA Sequencing Using UNCqeR for the Detection of Genetic Aberrations in NSCLC

PubMed Central

Walter, Vonn; Patel, Nirali M.; Eberhard, David A.; Hayward, Michele C.; Salazar, Ashley H.; Jo, Heejoon; Soloway, Matthew G.; Wilkerson, Matthew D.; Parker, Joel S.; Yin, Xiaoying; Zhang, Guosheng; Siegel, Marni B.; Rosson, Gary B.; Earp, H. Shelton; Sharpless, Norman E.; Gulley, Margaret L.; Weck, Karen E.

2015-01-01

The recent FDA approval of the MiSeqDx platform provides a unique opportunity to develop targeted next generation sequencing (NGS) panels for human disease, including cancer. We have developed a scalable, targeted panel-based assay termed UNCseq, which involves a NGS panel of over 200 cancer-associated genes and a standardized downstream bioinformatics pipeline for detection of single nucleotide variations (SNV) as well as small insertions and deletions (indel). In addition, we developed a novel algorithm, NGScopy, designed for samples with sparse sequencing coverage to detect large-scale copy number variations (CNV), similar to human SNP Array 6.0 as well as small-scale intragenic CNV. Overall, we applied this assay to 100 snap-frozen lung cancer specimens lacking same-patient germline DNA (07–0120 tissue cohort) and validated our results against Sanger sequencing, SNP Array, and our recently published integrated DNA-seq/RNA-seq assay, UNCqeR, where RNA-seq of same-patient tumor specimens confirmed SNV detected by DNA-seq, if RNA-seq coverage depth was adequate. In addition, we applied the UNCseq assay on an independent lung cancer tumor tissue collection with available same-patient germline DNA (11–1115 tissue cohort) and confirmed mutations using assays performed in a CLIA-certified laboratory. We conclude that UNCseq can identify SNV, indel, and CNV in tumor specimens lacking germline DNA in a cost-efficient fashion. PMID:26076459

Mechanism of duplex DNA destabilization by RNA-guided Cas9 nuclease during target interrogation.

PubMed

Mekler, Vladimir; Minakhin, Leonid; Severinov, Konstantin

2017-05-23

The prokaryotic clustered regularly interspaced short palindromic repeats (CRISPR)-associated 9 (Cas9) endonuclease cleaves double-stranded DNA sequences specified by guide RNA molecules and flanked by a protospacer adjacent motif (PAM) and is widely used for genome editing in various organisms. The RNA-programmed Cas9 locates the target site by scanning genomic DNA. We sought to elucidate the mechanism of initial DNA interrogation steps that precede the pairing of target DNA with guide RNA. Using fluorometric and biochemical assays, we studied Cas9/guide RNA complexes with model DNA substrates that mimicked early intermediates on the pathway to the final Cas9/guide RNA-DNA complex. The results show that Cas9/guide RNA binding to PAM favors separation of a few PAM-proximal protospacer base pairs allowing initial target interrogation by guide RNA. The duplex destabilization is mediated, in part, by Cas9/guide RNA affinity for unpaired segments of nontarget strand DNA close to PAM. Furthermore, our data indicate that the entry of double-stranded DNA beyond a short threshold distance from PAM into the Cas9/single-guide RNA (sgRNA) interior is hindered. We suggest that the interactions unfavorable for duplex DNA binding promote DNA bending in the PAM-proximal region during early steps of Cas9/guide RNA-DNA complex formation, thus additionally destabilizing the protospacer duplex. The mechanism that emerges from our analysis explains how the Cas9/sgRNA complex is able to locate the correct target sequence efficiently while interrogating numerous nontarget sequences associated with correct PAMs.

Sequence-based design of bioactive small molecules that target precursor microRNAs.

PubMed

Velagapudi, Sai Pradeep; Gallo, Steven M; Disney, Matthew D

2014-04-01

Oligonucleotides are designed to target RNA using base pairing rules, but they can be hampered by poor cellular delivery and nonspecific stimulation of the immune system. Small molecules are preferred as lead drugs or probes but cannot be designed from sequence. Herein, we describe an approach termed Inforna that designs lead small molecules for RNA from solely sequence. Inforna was applied to all human microRNA hairpin precursors, and it identified bioactive small molecules that inhibit biogenesis by binding nuclease-processing sites (44% hit rate). Among 27 lead interactions, the most avid interaction is between a benzimidazole (1) and precursor microRNA-96. Compound 1 selectively inhibits biogenesis of microRNA-96, upregulating a protein target (FOXO1) and inducing apoptosis in cancer cells. Apoptosis is ablated when FOXO1 mRNA expression is knocked down by an siRNA, validating compound selectivity. Markedly, microRNA profiling shows that 1 only affects microRNA-96 biogenesis and is at least as selective as an oligonucleotide.

Sequence-based design of bioactive small molecules that target precursor microRNAs

PubMed Central

Velagapudi, Sai Pradeep; Gallo, Steven M.; Disney, Matthew D.

2014-01-01

Oligonucleotides are designed to target RNA using base pairing rules, however, they are hampered by poor cellular delivery and non-specific stimulation of the immune system. Small molecules are preferred as lead drugs or probes, but cannot be designed from sequence. Herein, we describe an approach termed Inforna that designs lead small molecules for RNA from solely sequence. Inforna was applied to all human microRNA precursors and identified bioactive small molecules that inhibit biogenesis by binding to nuclease processing sites (41% hit rate). Amongst 29 lead interactions, the most avid interaction is between a benzimidazole (1) and precursor microRNA-96. Compound 1 selectively inhibits biogenesis of microRNA-96, upregulating a protein target (FOXO1) and inducing apoptosis in cancer cells. Apoptosis is ablated when FOXO1 mRNA expression is knocked down by an siRNA, validating compound selectivity. Importantly, microRNA profiling shows that 1 only significantly effects microRNA-96 biogenesis and is more selective than an oligonucleotide. PMID:24509821

New support vector machine-based method for microRNA target prediction.

PubMed

Li, L; Gao, Q; Mao, X; Cao, Y

2014-06-09

MicroRNA (miRNA) plays important roles in cell differentiation, proliferation, growth, mobility, and apoptosis. An accurate list of precise target genes is necessary in order to fully understand the importance of miRNAs in animal development and disease. Several computational methods have been proposed for miRNA target-gene identification. However, these methods still have limitations with respect to their sensitivity and accuracy. Thus, we developed a new miRNA target-prediction method based on the support vector machine (SVM) model. The model supplies information of two binding sites (primary and secondary) for a radial basis function kernel as a similarity measure for SVM features. The information is categorized based on structural, thermodynamic, and sequence conservation. Using high-confidence datasets selected from public miRNA target databases, we obtained a human miRNA target SVM classifier model with high performance and provided an efficient tool for human miRNA target gene identification. Experiments have shown that our method is a reliable tool for miRNA target-gene prediction, and a successful application of an SVM classifier. Compared with other methods, the method proposed here improves the sensitivity and accuracy of miRNA prediction. Its performance can be further improved by providing more training examples.

microRNA-122 target sites in the hepatitis C virus RNA NS5B coding region and 3' untranslated region: function in replication and influence of RNA secondary structure.

PubMed

Gerresheim, Gesche K; Dünnes, Nadia; Nieder-Röhrmann, Anika; Shalamova, Lyudmila A; Fricke, Markus; Hofacker, Ivo; Höner Zu Siederdissen, Christian; Marz, Manja; Niepmann, Michael

2017-02-01

We have analyzed the binding of the liver-specific microRNA-122 (miR-122) to three conserved target sites of hepatitis C virus (HCV) RNA, two in the non-structural protein 5B (NS5B) coding region and one in the 3' untranslated region (3'UTR). miR-122 binding efficiency strongly depends on target site accessibility under conditions when the range of flanking sequences available for the formation of local RNA secondary structures changes. Our results indicate that the particular sequence feature that contributes most to the correlation between target site accessibility and binding strength varies between different target sites. This suggests that the dynamics of miRNA/Ago2 binding not only depends on the target site itself but also on flanking sequence context to a considerable extent, in particular in a small viral genome in which strong selection constraints act on coding sequence and overlapping cis-signals and model the accessibility of cis-signals. In full-length genomes, single and combination mutations in the miR-122 target sites reveal that site 5B.2 is positively involved in regulating overall genome replication efficiency, whereas mutation of site 5B.3 showed a weaker effect. Mutation of the 3'UTR site and double or triple mutants showed no significant overall effect on genome replication, whereas in a translation reporter RNA, the 3'UTR target site inhibits translation directed by the HCV 5'UTR. Thus, the miR-122 target sites in the 3'-region of the HCV genome are involved in a complex interplay in regulating different steps of the HCV replication cycle.

Mapping the miRNA interactome by crosslinking ligation and sequencing of hybrids (CLASH)

PubMed Central

Helwak, Aleksandra; Tollervey, David

2014-01-01

RNA-RNA interactions play critical roles in many cellular processes but studying them is difficult and laborious. Here, we describe an experimental procedure, termed crosslinking ligation and sequencing of hybrids (CLASH), which allows high-throughput identification of sites of RNA-RNA interaction. During CLASH, a tagged bait protein is UV crosslinked in vivo to stabilise RNA interactions and purified under denaturing conditions. RNAs associated with the bait protein are partially truncated, and the ends of RNA-duplexes are ligated together. Following linker addition, cDNA library preparation and high-throughput sequencing, the ligated duplexes give rise to chimeric cDNAs, which unambiguously identify RNA-RNA interaction sites independent of bioinformatic predictions. This protocol is optimized for studying miRNA targets bound by Argonaute proteins, but should be easily adapted for other RNA-binding proteins and classes of RNA. The protocol requires around 5 days to complete, excluding the time required for high-throughput sequencing and bioinformatic analyses. PMID:24577361

MicroRNA-200c Modulates the Expression of MUC4 and MUC16 by Directly Targeting Their Coding Sequences in Human Pancreatic Cancer

PubMed Central

Radhakrishnan, Prakash; Mohr, Ashley M.; Grandgenett, Paul M.; Steele, Maria M.; Batra, Surinder K.; Hollingsworth, Michael A.

2013-01-01

Transmembrane mucins, MUC4 and MUC16 are associated with tumor progression and metastatic potential in human pancreatic adenocarcinoma. We discovered that miR-200c interacts with specific sequences within the coding sequence of MUC4 and MUC16 mRNAs, and evaluated the regulatory nature of this association. Pancreatic cancer cell lines S2.028 and T3M-4 transfected with miR-200c showed a 4.18 and 8.50 fold down regulation of MUC4 mRNA, and 4.68 and 4.82 fold down regulation of MUC16 mRNA compared to mock-transfected cells, respectively. A significant reduction of glycoprotein expression was also observed. These results indicate that miR-200c overexpression regulates MUC4 and MUC16 mucins in pancreatic cancer cells by directly targeting the mRNA coding sequence of each, resulting in reduced levels of MUC4 and MUC16 mRNA and protein. These data suggest that, in addition to regulating proteins that modulate EMT, miR-200c influences expression of cell surface mucins in pancreatic cancer. PMID:24204560

MicroRNA-200c modulates the expression of MUC4 and MUC16 by directly targeting their coding sequences in human pancreatic cancer.

PubMed

Radhakrishnan, Prakash; Mohr, Ashley M; Grandgenett, Paul M; Steele, Maria M; Batra, Surinder K; Hollingsworth, Michael A

2013-01-01

Transmembrane mucins, MUC4 and MUC16 are associated with tumor progression and metastatic potential in human pancreatic adenocarcinoma. We discovered that miR-200c interacts with specific sequences within the coding sequence of MUC4 and MUC16 mRNAs, and evaluated the regulatory nature of this association. Pancreatic cancer cell lines S2.028 and T3M-4 transfected with miR-200c showed a 4.18 and 8.50 fold down regulation of MUC4 mRNA, and 4.68 and 4.82 fold down regulation of MUC16 mRNA compared to mock-transfected cells, respectively. A significant reduction of glycoprotein expression was also observed. These results indicate that miR-200c overexpression regulates MUC4 and MUC16 mucins in pancreatic cancer cells by directly targeting the mRNA coding sequence of each, resulting in reduced levels of MUC4 and MUC16 mRNA and protein. These data suggest that, in addition to regulating proteins that modulate EMT, miR-200c influences expression of cell surface mucins in pancreatic cancer.

Hydrophobization and bioconjugation for enhanced siRNA delivery and targeting

PubMed Central

De Paula, Daniel; Bentley, M. Vitória L.B.; Mahato, Ram I.

2007-01-01

RNA interference (RNAi) is an evolutionarily conserved process by which double-stranded small interfering RNA (siRNA) induces sequence-specific, post-transcriptional gene silencing. Unlike other mRNA targeting strategies, RNAi takes advantage of the physiological gene silencing machinery. The potential use of siRNA as therapeutic agents has attracted great attention as a novel approach for treating severe and chronic diseases. RNAi can be achieved by either delivery of chemically synthesized siRNAs or endogenous expression of small hairpin RNA, siRNA, and microRNA (miRNA). However, the relatively high dose of siRNA required for gene silencing limits its therapeutic applications. This review discusses several strategies to improve therapeutic efficacy as well as to abrogate off-target effects and immunostimulation caused by siRNAs. There is an in-depth discussion on various issues related to the (1) mechanisms of RNAi, (2) methods of siRNA production, (3) barriers to RNAi-based therapies, (4) biodistribution, (5) design of siRNA molecules, (6) chemical modification and bioconjugation, (7) complex formation with lipids and polymers, (8) encapsulation into lipid particles, and (9) target specificity for enhanced therapeutic effectiveness. PMID:17329355

TargetLink, a new method for identifying the endogenous target set of a specific microRNA in intact living cells.

PubMed

Xu, Yan; Chen, Yan; Li, Daliang; Liu, Qing; Xuan, Zhenyu; Li, Wen-Hong

2017-02-01

MicroRNAs are small non-coding RNAs acting as posttranscriptional repressors of gene expression. Identifying mRNA targets of a given miRNA remains an outstanding challenge in the field. We have developed a new experimental approach, TargetLink, that applied locked nucleic acid (LNA) as the affinity probe to enrich target genes of a specific microRNA in intact cells. TargetLink also consists a rigorous and systematic data analysis pipeline to identify target genes by comparing LNA-enriched sequences between experimental and control samples. Using miR-21 as a test microRNA, we identified 12 target genes of miR-21 in a human colorectal cancer cell by this approach. The majority of the identified targets interacted with miR-21 via imperfect seed pairing. Target validation confirmed that miR-21 repressed the expression of the identified targets. The cellular abundance of the identified miR-21 target transcripts varied over a wide range, with some targets expressed at a rather low level, confirming that both abundant and rare transcripts are susceptible to regulation by microRNAs, and that TargetLink is an efficient approach for identifying the target set of a specific microRNA in intact cells. C20orf111, one of the novel targets identified by TargetLink, was found to reside in the nuclear speckle and to be reliably repressed by miR-21 through the interaction at its coding sequence.

eRNA: a graphic user interface-based tool optimized for large data analysis from high-throughput RNA sequencing

PubMed Central

2014-01-01

Background RNA sequencing (RNA-seq) is emerging as a critical approach in biological research. However, its high-throughput advantage is significantly limited by the capacity of bioinformatics tools. The research community urgently needs user-friendly tools to efficiently analyze the complicated data generated by high throughput sequencers. Results We developed a standalone tool with graphic user interface (GUI)-based analytic modules, known as eRNA. The capacity of performing parallel processing and sample management facilitates large data analyses by maximizing hardware usage and freeing users from tediously handling sequencing data. The module miRNA identification” includes GUIs for raw data reading, adapter removal, sequence alignment, and read counting. The module “mRNA identification” includes GUIs for reference sequences, genome mapping, transcript assembling, and differential expression. The module “Target screening” provides expression profiling analyses and graphic visualization. The module “Self-testing” offers the directory setups, sample management, and a check for third-party package dependency. Integration of other GUIs including Bowtie, miRDeep2, and miRspring extend the program’s functionality. Conclusions eRNA focuses on the common tools required for the mapping and quantification analysis of miRNA-seq and mRNA-seq data. The software package provides an additional choice for scientists who require a user-friendly computing environment and high-throughput capacity for large data analysis. eRNA is available for free download at https://sourceforge.net/projects/erna/?source=directory. PMID:24593312

A screen of chemical modifications identifies position-specific modification by UNA to most potently reduce siRNA off-target effects

PubMed Central

Bramsen, Jesper B.; Pakula, Malgorzata M.; Hansen, Thomas B.; Bus, Claus; Langkjær, Niels; Odadzic, Dalibor; Smicius, Romualdas; Wengel, Suzy L.; Chattopadhyaya, Jyoti; Engels, Joachim W.; Herdewijn, Piet; Wengel, Jesper; Kjems, Jørgen

2010-01-01

Small interfering RNAs (siRNAs) are now established as the preferred tool to inhibit gene function in mammalian cells yet trigger unintended gene silencing due to their inherent miRNA-like behavior. Such off-target effects are primarily mediated by the sequence-specific interaction between the siRNA seed regions (position 2–8 of either siRNA strand counting from the 5′-end) and complementary sequences in the 3′UTR of (off-) targets. It was previously shown that chemical modification of siRNAs can reduce off-targeting but only very few modifications have been tested leaving more to be identified. Here we developed a luciferase reporter-based assay suitable to monitor siRNA off-targeting in a high throughput manner using stable cell lines. We investigated the impact of chemically modifying single nucleotide positions within the siRNA seed on siRNA function and off-targeting using 10 different types of chemical modifications, three different target sequences and three siRNA concentrations. We found several differently modified siRNAs to exercise reduced off-targeting yet incorporation of the strongly destabilizing unlocked nucleic acid (UNA) modification into position 7 of the siRNA most potently reduced off-targeting for all tested sequences. Notably, such position-specific destabilization of siRNA–target interactions did not significantly reduce siRNA potency and is therefore well suited for future siRNA designs especially for applications in vivo where siRNA concentrations, expectedly, will be low. PMID:20453030

Engineering RNA for Targeted siRNA Delivery and Medical Application

PubMed Central

Guo, Peixuan; Coban, Oana; Snead, Nick; Trebley, Joe; Hoeprich, Steve; Guo, Songchuan; Shu, Yi

2010-01-01

RNA engineering for nanotechnology and medical applications is an exciting emerging research field. RNA has intrinsically defined features on the nanometer scale and is a particularly interesting candidate for such applications due to its amazing diversity, flexibility and versatility in structure and function. Specifically, the current use of siRNA to silence target genes involved in disease has generated much excitement in the scientific community. The intrinsic ability to sequence-specifically down-regulate gene expression in a temporally- and spatially-controlled fashion has led to heightened interest and rapid development of siRNA-based therapeutics. Though methods for gene silencing with high efficacy and specificity have been achieved in vitro, the effective delivery of nucleic acids to specific cells in vivo has been a hurdle for RNA therapeutics. This review covers different RNA-based approaches for diagnosis, prevention and treatment of human disease, with a focus on the latest developments of nonviral carriers of siRNA for delivery in vivo. The applications and challenges of siRNA therapy, as well as potential solutions to these problems, the approaches for using phi29 pRNA-based vectors as polyvalent vehicles for specific delivery of siRNA, ribozymes, drugs or other therapeutic agents to specific cells for therapy will also be addressed. PMID:20230868

Mechanism of duplex DNA destabilization by RNA-guided Cas9 nuclease during target interrogation

PubMed Central

Mekler, Vladimir; Minakhin, Leonid; Severinov, Konstantin

2017-01-01

The prokaryotic clustered regularly interspaced short palindromic repeats (CRISPR)-associated 9 (Cas9) endonuclease cleaves double-stranded DNA sequences specified by guide RNA molecules and flanked by a protospacer adjacent motif (PAM) and is widely used for genome editing in various organisms. The RNA-programmed Cas9 locates the target site by scanning genomic DNA. We sought to elucidate the mechanism of initial DNA interrogation steps that precede the pairing of target DNA with guide RNA. Using fluorometric and biochemical assays, we studied Cas9/guide RNA complexes with model DNA substrates that mimicked early intermediates on the pathway to the final Cas9/guide RNA–DNA complex. The results show that Cas9/guide RNA binding to PAM favors separation of a few PAM-proximal protospacer base pairs allowing initial target interrogation by guide RNA. The duplex destabilization is mediated, in part, by Cas9/guide RNA affinity for unpaired segments of nontarget strand DNA close to PAM. Furthermore, our data indicate that the entry of double-stranded DNA beyond a short threshold distance from PAM into the Cas9/single-guide RNA (sgRNA) interior is hindered. We suggest that the interactions unfavorable for duplex DNA binding promote DNA bending in the PAM-proximal region during early steps of Cas9/guide RNA–DNA complex formation, thus additionally destabilizing the protospacer duplex. The mechanism that emerges from our analysis explains how the Cas9/sgRNA complex is able to locate the correct target sequence efficiently while interrogating numerous nontarget sequences associated with correct PAMs. PMID:28484024

AMPLIFICATION OF RIBOSOMAL RNA SEQUENCES

EPA Science Inventory

This book chapter offers an overview of the use of ribosomal RNA sequences. A history of the technology traces the evolution of techniques to measure bacterial phylogenetic relationships and recent advances in obtaining rRNA sequence information. The manual also describes procedu...

Accurate multiple sequence-structure alignment of RNA sequences using combinatorial optimization.

PubMed

Bauer, Markus; Klau, Gunnar W; Reinert, Knut

2007-07-27

The discovery of functional non-coding RNA sequences has led to an increasing interest in algorithms related to RNA analysis. Traditional sequence alignment algorithms, however, fail at computing reliable alignments of low-homology RNA sequences. The spatial conformation of RNA sequences largely determines their function, and therefore RNA alignment algorithms have to take structural information into account. We present a graph-based representation for sequence-structure alignments, which we model as an integer linear program (ILP). We sketch how we compute an optimal or near-optimal solution to the ILP using methods from combinatorial optimization, and present results on a recently published benchmark set for RNA alignments. The implementation of our algorithm yields better alignments in terms of two published scores than the other programs that we tested: This is especially the case with an increasing number of input sequences. Our program LARA is freely available for academic purposes from http://www.planet-lisa.net.

CasA mediates Cas3-catalyzed target degradation during CRISPR RNA-guided interference.

PubMed

Hochstrasser, Megan L; Taylor, David W; Bhat, Prashant; Guegler, Chantal K; Sternberg, Samuel H; Nogales, Eva; Doudna, Jennifer A

2014-05-06

In bacteria, the clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) DNA-targeting complex Cascade (CRISPR-associated complex for antiviral defense) uses CRISPR RNA (crRNA) guides to bind complementary DNA targets at sites adjacent to a trinucleotide signature sequence called the protospacer adjacent motif (PAM). The Cascade complex then recruits Cas3, a nuclease-helicase that catalyzes unwinding and cleavage of foreign double-stranded DNA (dsDNA) bearing a sequence matching that of the crRNA. Cascade comprises the CasA-E proteins and one crRNA, forming a structure that binds and unwinds dsDNA to form an R loop in which the target strand of the DNA base pairs with the 32-nt RNA guide sequence. Single-particle electron microscopy reconstructions of dsDNA-bound Cascade with and without Cas3 reveal that Cascade positions the PAM-proximal end of the DNA duplex at the CasA subunit and near the site of Cas3 association. The finding that the DNA target and Cas3 colocalize with CasA implicates this subunit in a key target-validation step during DNA interference. We show biochemically that base pairing of the PAM region is unnecessary for target binding but critical for Cas3-mediated degradation. In addition, the L1 loop of CasA, previously implicated in PAM recognition, is essential for Cas3 activation following target binding by Cascade. Together, these data show that the CasA subunit of Cascade functions as an essential partner of Cas3 by recognizing DNA target sites and positioning Cas3 adjacent to the PAM to ensure cleavage.

mCAL: A New Approach for Versatile Multiplex Action of Cas9 Using One sgRNA and Loci Flanked by a Programmed Target Sequence.

PubMed

Finnigan, Gregory C; Thorner, Jeremy

2016-07-07

Genome editing exploiting CRISPR/Cas9 has been adopted widely in academia and in the biotechnology industry to manipulate DNA sequences in diverse organisms. Molecular engineering of Cas9 itself and its guide RNA, and the strategies for using them, have increased efficiency, optimized specificity, reduced inappropriate off-target effects, and introduced modifications for performing other functions (transcriptional regulation, high-resolution imaging, protein recruitment, and high-throughput screening). Moreover, Cas9 has the ability to multiplex, i.e., to act at different genomic targets within the same nucleus. Currently, however, introducing concurrent changes at multiple loci involves: (i) identification of appropriate genomic sites, especially the availability of suitable PAM sequences; (ii) the design, construction, and expression of multiple sgRNA directed against those sites; (iii) potential difficulties in altering essential genes; and (iv) lingering concerns about "off-target" effects. We have devised a new approach that circumvents these drawbacks, as we demonstrate here using the yeast Saccharomyces cerevisiae First, any gene(s) of interest are flanked upstream and downstream with a single unique target sequence that does not normally exist in the genome. Thereafter, expression of one sgRNA and cotransformation with appropriate PCR fragments permits concomitant Cas9-mediated alteration of multiple genes (both essential and nonessential). The system we developed also allows for maintenance of the integrated, inducible Cas9-expression cassette or its simultaneous scarless excision. Our scheme-dubbed mCAL for " M: ultiplexing of C: as9 at A: rtificial L: oci"-can be applied to any organism in which the CRISPR/Cas9 methodology is currently being utilized. In principle, it can be applied to install synthetic sequences into the genome, to generate genomic libraries, and to program strains or cell lines so that they can be conveniently (and repeatedly

TarPmiR: a new approach for microRNA target site prediction.

PubMed

Ding, Jun; Li, Xiaoman; Hu, Haiyan

2016-09-15

The identification of microRNA (miRNA) target sites is fundamentally important for studying gene regulation. There are dozens of computational methods available for miRNA target site prediction. Despite their existence, we still cannot reliably identify miRNA target sites, partially due to our limited understanding of the characteristics of miRNA target sites. The recently published CLASH (crosslinking ligation and sequencing of hybrids) data provide an unprecedented opportunity to study the characteristics of miRNA target sites and improve miRNA target site prediction methods. Applying four different machine learning approaches to the CLASH data, we identified seven new features of miRNA target sites. Combining these new features with those commonly used by existing miRNA target prediction algorithms, we developed an approach called TarPmiR for miRNA target site prediction. Testing on two human and one mouse non-CLASH datasets, we showed that TarPmiR predicted more than 74.2% of true miRNA target sites in each dataset. Compared with three existing approaches, we demonstrated that TarPmiR is superior to these existing approaches in terms of better recall and better precision. The TarPmiR software is freely available at http://hulab.ucf.edu/research/projects/miRNA/TarPmiR/ CONTACTS: haihu@cs.ucf.edu or xiaoman@mail.ucf.edu Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press.

Uncovering novel landscape of cardiovascular diseases and therapeutic targets for cardioprotection via long noncoding RNA-miRNA-mRNA axes.

PubMed

He, Liang; Chen, Yan; Hao, Shuqing; Qian, Jinqiao

2018-05-01

Protein coding sequences account for around 3% of the human genome, the rest are noncoding RNA (ncRNA) including long ncRNA (lncRNA) and miRNA. Accumulating evidence indicates that lncRNAs and miRNAs are candidate biomarkers for diagnosis, prognosis and therapy of cardiovascular diseases. The lncRNAs act as sponge-like effects on numerous miRNAs, subsequently regulating miRNAs and their targets, mRNA functions. The role of lncRNA-miRNA-mRNA axis in pathogenesis of cardiovascular diseases has been recently reported and highlighted. Herein, this review discusses emerging roles of lncRNA-miRNA-mRNA axis in cardiovascular pathophysiology and regulation, with a novel focus on cardioprotective network activities of the two subgroup ncRNAs.

Next-generation sequencing identifies the natural killer cell microRNA transcriptome

PubMed Central

Fehniger, Todd A.; Wylie, Todd; Germino, Elizabeth; Leong, Jeffrey W.; Magrini, Vincent J.; Koul, Sunita; Keppel, Catherine R.; Schneider, Stephanie E.; Koboldt, Daniel C.; Sullivan, Ryan P.; Heinz, Michael E.; Crosby, Seth D.; Nagarajan, Rakesh; Ramsingh, Giridharan; Link, Daniel C.; Ley, Timothy J.; Mardis, Elaine R.

2010-01-01

Natural killer (NK) cells are innate lymphocytes important for early host defense against infectious pathogens and surveillance against malignant transformation. Resting murine NK cells regulate the translation of effector molecule mRNAs (e.g., granzyme B, GzmB) through unclear molecular mechanisms. MicroRNAs (miRNAs) are small noncoding RNAs that post-transcriptionally regulate the translation of their mRNA targets, and are therefore candidates for mediating this control process. While the expression and importance of miRNAs in T and B lymphocytes have been established, little is known about miRNAs in NK cells. Here, we used two next-generation sequencing (NGS) platforms to define the miRNA transcriptomes of resting and cytokine-activated primary murine NK cells, with confirmation by quantitative real-time PCR (qRT-PCR) and microarrays. We delineate a bioinformatics analysis pipeline that identified 302 known and 21 novel mature miRNAs from sequences obtained from NK cell small RNA libraries. These miRNAs are expressed over a broad range and exhibit isomiR complexity, and a subset is differentially expressed following cytokine activation. Using these miRNA NGS data, miR-223 was identified as a mature miRNA present in resting NK cells with decreased expression following cytokine activation. Furthermore, we demonstrate that miR-223 specifically targets the 3′ untranslated region of murine GzmB in vitro, indicating that this miRNA may contribute to control of GzmB translation in resting NK cells. Thus, the sequenced NK cell miRNA transcriptome provides a valuable framework for further elucidation of miRNA expression and function in NK cell biology. PMID:20935160

psRNATarget: a plant small RNA target analysis server (2017 release).

PubMed

Dai, Xinbin; Zhuang, Zhaohong; Zhao, Patrick Xuechun

2018-04-30

Plant regulatory small RNAs (sRNAs), which include most microRNAs (miRNAs) and a subset of small interfering RNAs (siRNAs), such as the phased siRNAs (phasiRNAs), play important roles in regulating gene expression. Although generated from genetically distinct biogenesis pathways, these regulatory sRNAs share the same mechanisms for post-translational gene silencing and translational inhibition. psRNATarget was developed to identify plant sRNA targets by (i) analyzing complementary matching between the sRNA sequence and target mRNA sequence using a predefined scoring schema and (ii) by evaluating target site accessibility. This update enhances its analytical performance by developing a new scoring schema that is capable of discovering miRNA-mRNA interactions at higher 'recall rates' without significantly increasing total prediction output. The scoring procedure is customizable for the users to search both canonical and non-canonical targets. This update also enables transmitting and analyzing 'big' data empowered by (a) the implementation of multi-threading chunked file uploading, which can be paused and resumed, using HTML5 APIs and (b) the allocation of significantly more computing nodes to its back-end Linux cluster. The updated psRNATarget server has clear, compelling and user-friendly interfaces that enhance user experiences and present data clearly and concisely. The psRNATarget is freely available at http://plantgrn.noble.org/psRNATarget/.

Genome-wide identification of microRNA targets in the neglected disease pathogens of the genus Echinococcus.

PubMed

Macchiaroli, Natalia; Maldonado, Lucas L; Zarowiecki, Magdalena; Cucher, Marcela; Gismondi, María Inés; Kamenetzky, Laura; Rosenzvit, Mara Cecilia

2017-06-01

MicroRNAs (miRNAs), a class of small non-coding RNAs, are key regulators of gene expression at post-transcriptional level and play essential roles in biological processes such as development. MiRNAs silence target mRNAs by binding to complementary sequences in the 3'untranslated regions (3'UTRs). The parasitic helminths of the genus Echinococcus are the causative agents of echinococcosis, a zoonotic neglected disease. In previous work, we performed a comprehensive identification and characterization of Echinococcus miRNAs. However, current knowledge about their targets is limited. Since target prediction algorithms rely on complementarity between 3'UTRs and miRNA sequences, a major limitation is the lack of accurate sequence information of 3'UTR for most species including parasitic helminths. We performed RNA-seq and developed a pipeline that integrates the transcriptomic data with available genomic data of this parasite in order to identify 3'UTRs of Echinococcus canadensis. The high confidence set of 3'UTRs obtained allowed the prediction of miRNA targets in Echinococcus through a bioinformatic approach. We performed for the first time a comparative analysis of miRNA targets in Echinococcus and Taenia. We found that many evolutionarily conserved target sites in Echinococcus and Taenia may be functional and under selective pressure. Signaling pathways such as MAPK and Wnt were among the most represented pathways indicating miRNA roles in parasite growth and development. Genome-wide identification and characterization of miRNA target genes in Echinococcus provide valuable information to guide experimental studies in order to understand miRNA functions in the parasites biology. miRNAs involved in essential functions, especially those being absent in the host or showing sequence divergence with respect to host orthologs, might be considered as novel therapeutic targets for echinococcosis control. Copyright © 2017 Elsevier B.V. All rights reserved.

Small molecule alteration of RNA sequence in cells and animals.

PubMed

Guan, Lirui; Luo, Yiling; Ja, William W; Disney, Matthew D

2017-10-18

RNA regulation and maintenance are critical for proper cell function. Small molecules that specifically alter RNA sequence would be exceptionally useful as probes of RNA structure and function or as potential therapeutics. Here, we demonstrate a photochemical approach for altering the trinucleotide expanded repeat causative of myotonic muscular dystrophy type 1 (DM1), r(CUG) exp . The small molecule, 2H-4-Ru, binds to r(CUG) exp and converts guanosine residues to 8-oxo-7,8-dihydroguanosine upon photochemical irradiation. We demonstrate targeted modification upon irradiation in cell culture and in Drosophila larvae provided a diet containing 2H-4-Ru. Our results highlight a general chemical biology approach for altering RNA sequence in vivo by using small molecules and photochemistry. Furthermore, these studies show that addition of 8-oxo-G lesions into RNA 3' untranslated regions does not affect its steady state levels. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phage-mediated Delivery of Targeted sRNA Constructs to Knock Down Gene Expression in E. coli.

PubMed

Bernheim, Aude G; Libis, Vincent K; Lindner, Ariel B; Wintermute, Edwin H

2016-03-20

RNA-mediated knockdowns are widely used to control gene expression. This versatile family of techniques makes use of short RNA (sRNA) that can be synthesized with any sequence and designed to complement any gene targeted for silencing. Because sRNA constructs can be introduced to many cell types directly or using a variety of vectors, gene expression can be repressed in living cells without laborious genetic modification. The most common RNA knockdown technology, RNA interference (RNAi), makes use of the endogenous RNA-induced silencing complex (RISC) to mediate sequence recognition and cleavage of the target mRNA. Applications of this technique are therefore limited to RISC-expressing organisms, primarily eukaryotes. Recently, a new generation of RNA biotechnologists have developed alternative mechanisms for controlling gene expression through RNA, and so made possible RNA-mediated gene knockdowns in bacteria. Here we describe a method for silencing gene expression in E. coli that functionally resembles RNAi. In this system a synthetic phagemid is designed to express sRNA, which may designed to target any sequence. The expression construct is delivered to a population of E. coli cells with non-lytic M13 phage, after which it is able to stably replicate as a plasmid. Antisense recognition and silencing of the target mRNA is mediated by the Hfq protein, endogenous to E. coli. This protocol includes methods for designing the antisense sRNA, constructing the phagemid vector, packaging the phagemid into M13 bacteriophage, preparing a live cell population for infection, and performing the infection itself. The fluorescent protein mKate2 and the antibiotic resistance gene chloramphenicol acetyltransferase (CAT) are targeted to generate representative data and to quantify knockdown effectiveness.

GRIL-seq provides a method for identifying direct targets of bacterial small regulatory RNA by in vivo proximity ligation.

PubMed

Han, Kook; Tjaden, Brian; Lory, Stephen

2016-12-22

The first step in the post-transcriptional regulatory function of most bacterial small non-coding RNAs (sRNAs) is base pairing with partially complementary sequences of targeted transcripts. We present a simple method for identifying sRNA targets in vivo and defining processing sites of the regulated transcripts. The technique, referred to as global small non-coding RNA target identification by ligation and sequencing (GRIL-seq), is based on preferential ligation of sRNAs to the ends of base-paired targets in bacteria co-expressing T4 RNA ligase, followed by sequencing to identify the chimaeras. In addition to the RNA chaperone Hfq, the GRIL-seq method depends on the activity of the pyrophosphorylase RppH. Using PrrF1, an iron-regulated sRNA in Pseudomonas aeruginosa, we demonstrated that direct regulatory targets of this sRNA can readily be identified. Therefore, GRIL-seq represents a powerful tool not only for identifying direct targets of sRNAs in a variety of environments, but also for uncovering novel roles for sRNAs and their targets in complex regulatory networks.

RNA sequencing analysis of human podocytes reveals glucocorticoid regulated gene networks targeting non-immune pathways

PubMed Central

Jiang, Lulu; Hindmarch, Charles C. T.; Rogers, Mark; Campbell, Colin; Waterfall, Christy; Coghill, Jane; Mathieson, Peter W.; Welsh, Gavin I.

2016-01-01

Glucocorticoids are steroids that reduce inflammation and are used as immunosuppressive drugs for many diseases. They are also the mainstay for the treatment of minimal change nephropathy (MCN), which is characterised by an absence of inflammation. Their mechanisms of action remain elusive. Evidence suggests that immunomodulatory drugs can directly act on glomerular epithelial cells or ‘podocytes’, the cell type which is the main target of injury in MCN. To understand the nature of glucocorticoid effects on non-immune cell functions, we generated RNA sequencing data from human podocyte cell lines and identified the genes that are significantly regulated in dexamethasone-treated podocytes compared to vehicle-treated cells. The upregulated genes are of functional relevance to cytoskeleton-related processes, whereas the downregulated genes mostly encode pro-inflammatory cytokines and growth factors. We observed a tendency for dexamethasone-upregulated genes to be downregulated in MCN patients. Integrative analysis revealed gene networks composed of critical signaling pathways that are likely targeted by dexamethasone in podocytes. PMID:27774996

Uncultivated Microbial Eukaryotic Diversity: A Method to Link ssu rRNA Gene Sequences with Morphology

PubMed Central

Hirst, Marissa B.; Kita, Kelley N.; Dawson, Scott C.

2011-01-01

Protists have traditionally been identified by cultivation and classified taxonomically based on their cellular morphologies and behavior. In the past decade, however, many novel protist taxa have been identified using cultivation independent ssu rRNA sequence surveys. New rRNA “phylotypes” from uncultivated eukaryotes have no connection to the wealth of prior morphological descriptions of protists. To link phylogenetically informative sequences with taxonomically informative morphological descriptions, we demonstrate several methods for combining whole cell rRNA-targeted fluorescent in situ hybridization (FISH) with cytoskeletal or organellar immunostaining. Either eukaryote or ciliate-specific ssu rRNA probes were combined with an anti-α-tubulin antibody or phalloidin, a common actin stain, to define cytoskeletal features of uncultivated protists in several environmental samples. The eukaryote ssu rRNA probe was also combined with Mitotracker® or a hydrogenosomal-specific anti-Hsp70 antibody to localize mitochondria and hydrogenosomes, respectively, in uncultivated protists from different environments. Using rRNA probes in combination with immunostaining, we linked ssu rRNA phylotypes with microtubule structure to describe flagellate and ciliate morphology in three diverse environments, and linked Naegleria spp. to their amoeboid morphology using actin staining in hay infusion samples. We also linked uncultivated ciliates to morphologically similar Colpoda-like ciliates using tubulin immunostaining with a ciliate-specific rRNA probe. Combining rRNA-targeted FISH with cytoskeletal immunostaining or stains targeting specific organelles provides a fast, efficient, high throughput method for linking genetic sequences with morphological features in uncultivated protists. When linked to phylotype, morphological descriptions of protists can both complement and vet the increasing number of sequences from uncultivated protists, including those of novel lineages

miRTar2GO: a novel rule-based model learning method for cell line specific microRNA target prediction that integrates Ago2 CLIP-Seq and validated microRNA-target interaction data.

PubMed

Ahadi, Alireza; Sablok, Gaurav; Hutvagner, Gyorgy

2017-04-07

MicroRNAs (miRNAs) are ∼19-22 nucleotides (nt) long regulatory RNAs that regulate gene expression by recognizing and binding to complementary sequences on mRNAs. The key step in revealing the function of a miRNA, is the identification of miRNA target genes. Recent biochemical advances including PAR-CLIP and HITS-CLIP allow for improved miRNA target predictions and are widely used to validate miRNA targets. Here, we present miRTar2GO, which is a model, trained on the common rules of miRNA-target interactions, Argonaute (Ago) CLIP-Seq data and experimentally validated miRNA target interactions. miRTar2GO is designed to predict miRNA target sites using more relaxed miRNA-target binding characteristics. More importantly, miRTar2GO allows for the prediction of cell-type specific miRNA targets. We have evaluated miRTar2GO against other widely used miRNA target prediction algorithms and demonstrated that miRTar2GO produced significantly higher F1 and G scores. Target predictions, binding specifications, results of the pathway analysis and gene ontology enrichment of miRNA targets are freely available at http://www.mirtar2go.org. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

[Screening specific recognition motif of RNA-binding proteins by SELEX in combination with next-generation sequencing technique].

PubMed

Zhang, Lu; Xu, Jinhao; Ma, Jinbiao

2016-07-25

RNA-binding protein exerts important biological function by specifically recognizing RNA motif. SELEX (Systematic evolution of ligands by exponential enrichment), an in vitro selection method, can obtain consensus motif with high-affinity and specificity for many target molecules from DNA or RNA libraries. Here, we combined SELEX with next-generation sequencing to study the protein-RNA interaction in vitro. A pool of RNAs with 20 bp random sequences were transcribed by T7 promoter, and target protein was inserted into plasmid containing SBP-tag, which can be captured by streptavidin beads. Through only one cycle, the specific RNA motif can be obtained, which dramatically improved the selection efficiency. Using this method, we found that human hnRNP A1 RRMs domain (UP1 domain) bound RNA motifs containing AGG and AG sequences. The EMSA experiment indicated that hnRNP A1 RRMs could bind the obtained RNA motif. Taken together, this method provides a rapid and effective method to study the RNA binding specificity of proteins.

Finding the target sites of RNA-binding proteins

PubMed Central

Li, Xiao; Kazan, Hilal; Lipshitz, Howard D; Morris, Quaid D

2014-01-01

RNA–protein interactions differ from DNA–protein interactions because of the central role of RNA secondary structure. Some RNA-binding domains (RBDs) recognize their target sites mainly by their shape and geometry and others are sequence-specific but are sensitive to secondary structure context. A number of small- and large-scale experimental approaches have been developed to measure RNAs associated in vitro and in vivo with RNA-binding proteins (RBPs). Generalizing outside of the experimental conditions tested by these assays requires computational motif finding. Often RBP motif finding is done by adapting DNA motif finding methods; but modeling secondary structure context leads to better recovery of RBP-binding preferences. Genome-wide assessment of mRNA secondary structure has recently become possible, but these data must be combined with computational predictions of secondary structure before they add value in predicting in vivo binding. There are two main approaches to incorporating structural information into motif models: supplementing primary sequence motif models with preferred secondary structure contexts (e.g., MEMERIS and RNAcontext) and directly modeling secondary structure recognized by the RBP using stochastic context-free grammars (e.g., CMfinder and RNApromo). The former better reconstruct known binding preferences for sequence-specific RBPs but are not suitable for modeling RBPs that recognize shape and geometry of RNAs. Future work in RBP motif finding should incorporate interactions between multiple RBDs and multiple RBPs in binding to RNA. WIREs RNA 2014, 5:111–130. doi: 10.1002/wrna.1201 PMID:24217996

Transcriptome Engineering with RNA-Targeting Type VI-D CRISPR Effectors.

PubMed

Konermann, Silvana; Lotfy, Peter; Brideau, Nicholas J; Oki, Jennifer; Shokhirev, Maxim N; Hsu, Patrick D

2018-04-19

Class 2 CRISPR-Cas systems endow microbes with diverse mechanisms for adaptive immunity. Here, we analyzed prokaryotic genome and metagenome sequences to identify an uncharacterized family of RNA-guided, RNA-targeting CRISPR systems that we classify as type VI-D. Biochemical characterization and protein engineering of seven distinct orthologs generated a ribonuclease effector derived from Ruminococcus flavefaciens XPD3002 (CasRx) with robust activity in human cells. CasRx-mediated knockdown exhibits high efficiency and specificity relative to RNA interference across diverse endogenous transcripts. As one of the most compact single-effector Cas enzymes, CasRx can also be flexibly packaged into adeno-associated virus. We target virally encoded, catalytically inactive CasRx to cis elements of pre-mRNA to manipulate alternative splicing, alleviating dysregulated tau isoform ratios in a neuronal model of frontotemporal dementia. Our results present CasRx as a programmable RNA-binding module for efficient targeting of cellular RNA, enabling a general platform for transcriptome engineering and future therapeutic development. Copyright © 2018 Elsevier Inc. All rights reserved.

Advances in single-cell RNA sequencing and its applications in cancer research.

PubMed

Zhu, Sibo; Qing, Tao; Zheng, Yuanting; Jin, Li; Shi, Leming

2017-08-08

Unlike population-level approaches, single-cell RNA sequencing enables transcriptomic analysis of an individual cell. Through the combination of high-throughput sequencing and bioinformatic tools, single-cell RNA-seq can detect more than 10,000 transcripts in one cell to distinguish cell subsets and dynamic cellular changes. After several years' development, single-cell RNA-seq can now achieve massively parallel, full-length mRNA sequencing as well as in situ sequencing and even has potential for multi-omic detection. One appealing area of single-cell RNA-seq is cancer research, and it is regarded as a promising way to enhance prognosis and provide more precise target therapy by identifying druggable subclones. Indeed, progresses have been made regarding solid tumor analysis to reveal intratumoral heterogeneity, correlations between signaling pathways, stemness, drug resistance, and tumor architecture shaping the microenvironment. Furthermore, through investigation into circulating tumor cells, many genes have been shown to promote a propensity toward stemness and the epithelial-mesenchymal transition, to enhance anchoring and adhesion, and to be involved in mechanisms of anoikis resistance and drug resistance. This review focuses on advances and progresses of single-cell RNA-seq with regard to the following aspects: 1. Methodologies of single-cell RNA-seq 2. Single-cell isolation techniques 3. Single-cell RNA-seq in solid tumor research 4. Single-cell RNA-seq in circulating tumor cell research 5.

Advances in single-cell RNA sequencing and its applications in cancer research

PubMed Central

Zhu, Sibo; Qing, Tao; Zheng, Yuanting; Jin, Li; Shi, Leming

2017-01-01

Unlike population-level approaches, single-cell RNA sequencing enables transcriptomic analysis of an individual cell. Through the combination of high-throughput sequencing and bioinformatic tools, single-cell RNA-seq can detect more than 10,000 transcripts in one cell to distinguish cell subsets and dynamic cellular changes. After several years’ development, single-cell RNA-seq can now achieve massively parallel, full-length mRNA sequencing as well as in situ sequencing and even has potential for multi-omic detection. One appealing area of single-cell RNA-seq is cancer research, and it is regarded as a promising way to enhance prognosis and provide more precise target therapy by identifying druggable subclones. Indeed, progresses have been made regarding solid tumor analysis to reveal intratumoral heterogeneity, correlations between signaling pathways, stemness, drug resistance, and tumor architecture shaping the microenvironment. Furthermore, through investigation into circulating tumor cells, many genes have been shown to promote a propensity toward stemness and the epithelial-mesenchymal transition, to enhance anchoring and adhesion, and to be involved in mechanisms of anoikis resistance and drug resistance. This review focuses on advances and progresses of single-cell RNA-seq with regard to the following aspects: 1. Methodologies of single-cell RNA-seq 2. Single-cell isolation techniques 3. Single-cell RNA-seq in solid tumor research 4. Single-cell RNA-seq in circulating tumor cell research 5. Perspectives PMID:28881849

Small molecules targeting viral RNA.

PubMed

Hermann, Thomas

2016-11-01

Highly conserved noncoding RNA (ncRNA) elements in viral genomes and transcripts offer new opportunities to expand the repertoire of drug targets for the development of antiinfective therapy. Ligands binding to ncRNA architectures are able to affect interactions, structural stability or conformational changes and thereby block processes essential for viral replication. Proof of concept for targeting functional RNA by small molecule inhibitors has been demonstrated for multiple viruses with RNA genomes. Strategies to identify antiviral compounds as inhibitors of ncRNA are increasingly emphasizing consideration of drug-like properties of candidate molecules emerging from screening and ligand design. Recent efforts of antiviral lead discovery for RNA targets have provided drug-like small molecules that inhibit viral replication and include inhibitors of human immunodeficiency virus (HIV), hepatitis C virus (HCV), severe respiratory syndrome coronavirus (SARS CoV), and influenza A virus. While target selectivity remains a challenge for the discovery of useful RNA-binding compounds, a better understanding is emerging of properties that define RNA targets amenable for inhibition by small molecule ligands. Insight from successful approaches of targeting viral ncRNA in HIV, HCV, SARS CoV, and influenza A will provide a basis for the future exploration of RNA targets for therapeutic intervention in other viral pathogens which create urgent, unmet medical needs. Viruses for which targeting ncRNA components in the genome or transcripts may be promising include insect-borne flaviviruses (Dengue, Zika, and West Nile) and filoviruses (Ebola and Marburg). WIREs RNA 2016, 7:726-743. doi: 10.1002/wrna.1373 For further resources related to this article, please visit the WIREs website. © 2016 Wiley Periodicals, Inc.

Structator: fast index-based search for RNA sequence-structure patterns

PubMed Central

2011-01-01

Background The secondary structure of RNA molecules is intimately related to their function and often more conserved than the sequence. Hence, the important task of searching databases for RNAs requires to match sequence-structure patterns. Unfortunately, current tools for this task have, in the best case, a running time that is only linear in the size of sequence databases. Furthermore, established index data structures for fast sequence matching, like suffix trees or arrays, cannot benefit from the complementarity constraints introduced by the secondary structure of RNAs. Results We present a novel method and readily applicable software for time efficient matching of RNA sequence-structure patterns in sequence databases. Our approach is based on affix arrays, a recently introduced index data structure, preprocessed from the target database. Affix arrays support bidirectional pattern search, which is required for efficiently handling the structural constraints of the pattern. Structural patterns like stem-loops can be matched inside out, such that the loop region is matched first and then the pairing bases on the boundaries are matched consecutively. This allows to exploit base pairing information for search space reduction and leads to an expected running time that is sublinear in the size of the sequence database. The incorporation of a new chaining approach in the search of RNA sequence-structure patterns enables the description of molecules folding into complex secondary structures with multiple ordered patterns. The chaining approach removes spurious matches from the set of intermediate results, in particular of patterns with little specificity. In benchmark experiments on the Rfam database, our method runs up to two orders of magnitude faster than previous methods. Conclusions The presented method's sublinear expected running time makes it well suited for RNA sequence-structure pattern matching in large sequence databases. RNA molecules containing several

Detection of siRNA Mediated Target mRNA Cleavage Activities in Human Cells by a Novel Stem-Loop Array RT-PCR Analysis

DTIC Science & Technology

2016-09-07

sequences of the target mRNA, and a double stranded stem at the 5′ end that forms a stem -loop to function as a forceps to stabilize the secondary...E-mjournal homepage: www.elsevier.com/locate/bbrepDetection of siRNA-mediated target mRNA cleavage activities in human cells by a novel stem -loop...challenges for the accurate and efficient detection and verification of cleavage sites on target mRNAs. Here we used a sensitive stem -loop array reverse

INFO-RNA--a server for fast inverse RNA folding satisfying sequence constraints.

PubMed

Busch, Anke; Backofen, Rolf

2007-07-01

INFO-RNA is a new web server for designing RNA sequences that fold into a user given secondary structure. Furthermore, constraints on the sequence can be specified, e.g. one can restrict sequence positions to a fixed nucleotide or to a set of nucleotides. Moreover, the user can allow violations of the constraints at some positions, which can be advantageous in complicated cases. The INFO-RNA web server allows biologists to design RNA sequences in an automatic manner. It is clearly and intuitively arranged and easy to use. The procedure is fast, as most applications are completed within seconds and it proceeds better and faster than other existing tools. The INFO-RNA web server is freely available at http://www.bioinf.uni-freiburg.de/Software/INFO-RNA/

Structure and specificity of the RNA-guided endonuclease Cas9 during DNA interrogation, target binding and cleavage

PubMed Central

Josephs, Eric A.; Kocak, D. Dewran; Fitzgibbon, Christopher J.; McMenemy, Joshua; Gersbach, Charles A.; Marszalek, Piotr E.

2015-01-01

CRISPR-associated endonuclease Cas9 cuts DNA at variable target sites designated by a Cas9-bound RNA molecule. Cas9's ability to be directed by single ‘guide RNA’ molecules to target nearly any sequence has been recently exploited for a number of emerging biological and medical applications. Therefore, understanding the nature of Cas9's off-target activity is of paramount importance for its practical use. Using atomic force microscopy (AFM), we directly resolve individual Cas9 and nuclease-inactive dCas9 proteins as they bind along engineered DNA substrates. High-resolution imaging allows us to determine their relative propensities to bind with different guide RNA variants to targeted or off-target sequences. Mapping the structural properties of Cas9 and dCas9 to their respective binding sites reveals a progressive conformational transformation at DNA sites with increasing sequence similarity to its target. With kinetic Monte Carlo (KMC) simulations, these results provide evidence of a ‘conformational gating’ mechanism driven by the interactions between the guide RNA and the 14th–17th nucleotide region of the targeted DNA, the stabilities of which we find correlate significantly with reported off-target cleavage rates. KMC simulations also reveal potential methodologies to engineer guide RNA sequences with improved specificity by considering the invasion of guide RNAs into targeted DNA duplex. PMID:26384421

Terminator oligo blocking efficiently eliminates rRNA from Drosophila small RNA sequencing libraries.

PubMed

Wickersheim, Michelle L; Blumenstiel, Justin P

2013-11-01

A large number of methods are available to deplete ribosomal RNA reads from high-throughput RNA sequencing experiments. Such methods are critical for sequencing Drosophila small RNAs between 20 and 30 nucleotides because size selection is not typically sufficient to exclude the highly abundant class of 30 nucleotide 2S rRNA. Here we demonstrate that pre-annealing terminator oligos complimentary to Drosophila 2S rRNA prior to 5' adapter ligation and reverse transcription efficiently depletes 2S rRNA sequences from the sequencing reaction in a simple and inexpensive way. This depletion is highly specific and is achieved with minimal perturbation of miRNA and piRNA profiles.

High-Throughput Mapping of Single-Neuron Projections by Sequencing of Barcoded RNA.

PubMed

Kebschull, Justus M; Garcia da Silva, Pedro; Reid, Ashlan P; Peikon, Ian D; Albeanu, Dinu F; Zador, Anthony M

2016-09-07

Neurons transmit information to distant brain regions via long-range axonal projections. In the mouse, area-to-area connections have only been systematically mapped using bulk labeling techniques, which obscure the diverse projections of intermingled single neurons. Here we describe MAPseq (Multiplexed Analysis of Projections by Sequencing), a technique that can map the projections of thousands or even millions of single neurons by labeling large sets of neurons with random RNA sequences ("barcodes"). Axons are filled with barcode mRNA, each putative projection area is dissected, and the barcode mRNA is extracted and sequenced. Applying MAPseq to the locus coeruleus (LC), we find that individual LC neurons have preferred cortical targets. By recasting neuroanatomy, which is traditionally viewed as a problem of microscopy, as a problem of sequencing, MAPseq harnesses advances in sequencing technology to permit high-throughput interrogation of brain circuits. Copyright © 2016 Elsevier Inc. All rights reserved.

C-mii: a tool for plant miRNA and target identification.

PubMed

Numnark, Somrak; Mhuantong, Wuttichai; Ingsriswang, Supawadee; Wichadakul, Duangdao

2012-01-01

MicroRNAs (miRNAs) have been known to play an important role in several biological processes in both animals and plants. Although several tools for miRNA and target identification are available, the number of tools tailored towards plants is limited, and those that are available have specific functionality, lack graphical user interfaces, and restrict the number of input sequences. Large-scale computational identifications of miRNAs and/or targets of several plants have been also reported. Their methods, however, are only described as flow diagrams, which require programming skills and the understanding of input and output of the connected programs to reproduce. To overcome these limitations and programming complexities, we proposed C-mii as a ready-made software package for both plant miRNA and target identification. C-mii was designed and implemented based on established computational steps and criteria derived from previous literature with the following distinguishing features. First, software is easy to install with all-in-one programs and packaged databases. Second, it comes with graphical user interfaces (GUIs) for ease of use. Users can identify plant miRNAs and targets via step-by-step execution, explore the detailed results from each step, filter the results according to proposed constraints in plant miRNA and target biogenesis, and export sequences and structures of interest. Third, it supplies bird's eye views of the identification results with infographics and grouping information. Fourth, in terms of functionality, it extends the standard computational steps of miRNA target identification with miRNA-target folding and GO annotation. Fifth, it provides helper functions for the update of pre-installed databases and automatic recovery. Finally, it supports multi-project and multi-thread management. C-mii constitutes the first complete software package with graphical user interfaces enabling computational identification of both plant miRNA genes and miRNA

C-mii: a tool for plant miRNA and target identification

PubMed Central

2012-01-01

Background MicroRNAs (miRNAs) have been known to play an important role in several biological processes in both animals and plants. Although several tools for miRNA and target identification are available, the number of tools tailored towards plants is limited, and those that are available have specific functionality, lack graphical user interfaces, and restrict the number of input sequences. Large-scale computational identifications of miRNAs and/or targets of several plants have been also reported. Their methods, however, are only described as flow diagrams, which require programming skills and the understanding of input and output of the connected programs to reproduce. Results To overcome these limitations and programming complexities, we proposed C-mii as a ready-made software package for both plant miRNA and target identification. C-mii was designed and implemented based on established computational steps and criteria derived from previous literature with the following distinguishing features. First, software is easy to install with all-in-one programs and packaged databases. Second, it comes with graphical user interfaces (GUIs) for ease of use. Users can identify plant miRNAs and targets via step-by-step execution, explore the detailed results from each step, filter the results according to proposed constraints in plant miRNA and target biogenesis, and export sequences and structures of interest. Third, it supplies bird's eye views of the identification results with infographics and grouping information. Fourth, in terms of functionality, it extends the standard computational steps of miRNA target identification with miRNA-target folding and GO annotation. Fifth, it provides helper functions for the update of pre-installed databases and automatic recovery. Finally, it supports multi-project and multi-thread management. Conclusions C-mii constitutes the first complete software package with graphical user interfaces enabling computational identification of

Targeting of cytosolic mRNA to mitochondria: naked RNA can bind to the mitochondrial surface.

PubMed

Michaud, Morgane; Maréchal-Drouard, Laurence; Duchêne, Anne-Marie

2014-05-01

Mitochondria contain hundreds of proteins but only a few are encoded by the mitochondrial genome. The other proteins are nuclear-encoded and imported into mitochondria. These proteins can be translated on free cytosolic polysomes, then targeted and imported into mitochondria. Nonetheless, numerous cytosolic mRNAs encoding mitochondrial proteins are detected at the surface of mitochondria in yeast, plants and animals. The localization of mRNAs to the vicinity of mitochondria would be a way for mitochondrial protein sorting. The mechanisms responsible for mRNA targeting to mitochondria are not clearly identified. Sequences within the mRNA molecules (cis-elements), as well as a few trans-acting factors, have been shown to be essential for targeting of some mRNAs. In order to identify receptors involved in mRNA docking to the mitochondrial surface, we have developed an in vitro mRNA binding assay with isolated plant mitochondria. We show that naked mRNAs are able to bind to isolated mitochondria, and our results strongly suggest that mRNA docking to the plant mitochondrial outer membrane requires at least one component of TOM complex. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

ssHMM: extracting intuitive sequence-structure motifs from high-throughput RNA-binding protein data

PubMed Central

Krestel, Ralf; Ohler, Uwe; Vingron, Martin; Marsico, Annalisa

2017-01-01

Abstract RNA-binding proteins (RBPs) play an important role in RNA post-transcriptional regulation and recognize target RNAs via sequence-structure motifs. The extent to which RNA structure influences protein binding in the presence or absence of a sequence motif is still poorly understood. Existing RNA motif finders either take the structure of the RNA only partially into account, or employ models which are not directly interpretable as sequence-structure motifs. We developed ssHMM, an RNA motif finder based on a hidden Markov model (HMM) and Gibbs sampling which fully captures the relationship between RNA sequence and secondary structure preference of a given RBP. Compared to previous methods which output separate logos for sequence and structure, it directly produces a combined sequence-structure motif when trained on a large set of sequences. ssHMM’s model is visualized intuitively as a graph and facilitates biological interpretation. ssHMM can be used to find novel bona fide sequence-structure motifs of uncharacterized RBPs, such as the one presented here for the YY1 protein. ssHMM reaches a high motif recovery rate on synthetic data, it recovers known RBP motifs from CLIP-Seq data, and scales linearly on the input size, being considerably faster than MEMERIS and RNAcontext on large datasets while being on par with GraphProt. It is freely available on Github and as a Docker image. PMID:28977546

The RDE-10/RDE-11 complex triggers RNAi-induced mRNA degradation by association with target mRNA in C. elegans

PubMed Central

Yang, Huan; Zhang, Ying; Vallandingham, Jim; Li, Hau; Florens, Laurence; Mak, Ho Yi

2012-01-01

The molecular mechanisms for target mRNA degradation in Caenorhabditis elegans undergoing RNAi are not fully understood. Using a combination of genetic, proteomic, and biochemical approaches, we report a divergent RDE-10/RDE-11 complex that is required for RNAi in C. elegans. Genetic analysis indicates that the RDE-10/RDE-11 complex acts in parallel to nuclear RNAi. Association of the complex with target mRNA is dependent on RDE-1 but not RRF-1, suggesting that target mRNA recognition depends on primary but not secondary siRNA. Furthermore, RDE-11 is required for mRNA degradation subsequent to target engagement. Deep sequencing reveals a fivefold decrease in secondary siRNA abundance in rde-10 and rde-11 mutant animals, while primary siRNA and microRNA biogenesis is normal. Therefore, the RDE-10/RDE-11 complex is critical for amplifying the exogenous RNAi response. Our work uncovers an essential output of the RNAi pathway in C. elegans. PMID:22508728

The RDE-10/RDE-11 complex triggers RNAi-induced mRNA degradation by association with target mRNA in C. elegans.

PubMed

Yang, Huan; Zhang, Ying; Vallandingham, Jim; Li, Hua; Li, Hau; Florens, Laurence; Mak, Ho Yi

2012-04-15

The molecular mechanisms for target mRNA degradation in Caenorhabditis elegans undergoing RNAi are not fully understood. Using a combination of genetic, proteomic, and biochemical approaches, we report a divergent RDE-10/RDE-11 complex that is required for RNAi in C. elegans. Genetic analysis indicates that the RDE-10/RDE-11 complex acts in parallel to nuclear RNAi. Association of the complex with target mRNA is dependent on RDE-1 but not RRF-1, suggesting that target mRNA recognition depends on primary but not secondary siRNA. Furthermore, RDE-11 is required for mRNA degradation subsequent to target engagement. Deep sequencing reveals a fivefold decrease in secondary siRNA abundance in rde-10 and rde-11 mutant animals, while primary siRNA and microRNA biogenesis is normal. Therefore, the RDE-10/RDE-11 complex is critical for amplifying the exogenous RNAi response. Our work uncovers an essential output of the RNAi pathway in C. elegans.

DSAP: deep-sequencing small RNA analysis pipeline.

PubMed

Huang, Po-Jung; Liu, Yi-Chung; Lee, Chi-Ching; Lin, Wei-Chen; Gan, Richie Ruei-Chi; Lyu, Ping-Chiang; Tang, Petrus

2010-07-01

DSAP is an automated multiple-task web service designed to provide a total solution to analyzing deep-sequencing small RNA datasets generated by next-generation sequencing technology. DSAP uses a tab-delimited file as an input format, which holds the unique sequence reads (tags) and their corresponding number of copies generated by the Solexa sequencing platform. The input data will go through four analysis steps in DSAP: (i) cleanup: removal of adaptors and poly-A/T/C/G/N nucleotides; (ii) clustering: grouping of cleaned sequence tags into unique sequence clusters; (iii) non-coding RNA (ncRNA) matching: sequence homology mapping against a transcribed sequence library from the ncRNA database Rfam (http://rfam.sanger.ac.uk/); and (iv) known miRNA matching: detection of known miRNAs in miRBase (http://www.mirbase.org/) based on sequence homology. The expression levels corresponding to matched ncRNAs and miRNAs are summarized in multi-color clickable bar charts linked to external databases. DSAP is also capable of displaying miRNA expression levels from different jobs using a log(2)-scaled color matrix. Furthermore, a cross-species comparative function is also provided to show the distribution of identified miRNAs in different species as deposited in miRBase. DSAP is available at http://dsap.cgu.edu.tw.

Linking maternal and somatic 5S rRNA types with different sequence-specific non-LTR retrotransposons

PubMed Central

Pagano, Johanna F.B.; Ensink, Wim A.; van Olst, Marina; van Leeuwen, Selina; Nehrdich, Ulrike; Zhu, Kongju; Spaink, Herman P.; Girard, Geneviève; Rauwerda, Han; Jonker, Martijs J.; Dekker, Rob J.

2017-01-01

5S rRNA is a ribosomal core component, transcribed from many gene copies organized in genomic repeats. Some eukaryotic species have two 5S rRNA types defined by their predominant expression in oogenesis or adult tissue. Our next-generation sequencing study on zebrafish egg, embryo, and adult tissue identified maternal-type 5S rRNA that is exclusively accumulated during oogenesis, replaced throughout the embryogenesis by a somatic-type, and thus virtually absent in adult somatic tissue. The maternal-type 5S rDNA contains several thousands of gene copies on chromosome 4 in tandem repeats with small intergenic regions, whereas the somatic-type is present in only 12 gene copies on chromosome 18 with large intergenic regions. The nine-nucleotide variation between the two 5S rRNA types likely affects TFIII binding and riboprotein L5 binding, probably leading to storage of maternal-type rRNA. Remarkably, these sequence differences are located exactly at the sequence-specific target site for genome integration by the 5S rRNA-specific Mutsu retrotransposon family. Thus, we could define maternal- and somatic-type MutsuDr subfamilies. Furthermore, we identified four additional maternal-type and two new somatic-type MutsuDr subfamilies, each with their own target sequence. This target-site specificity, frequently intact maternal-type retrotransposon elements, plus specific presence of Mutsu retrotransposon RNA and piRNA in egg and adult tissue, suggest an involvement of retrotransposons in achieving the differential copy number of the two types of 5S rDNA loci. PMID:28003516

Introduction to Single-Cell RNA Sequencing.

PubMed

Olsen, Thale Kristin; Baryawno, Ninib

2018-04-01

During the last decade, high-throughput sequencing methods have revolutionized the entire field of biology. The opportunity to study entire transcriptomes in great detail using RNA sequencing (RNA-seq) has fueled many important discoveries and is now a routine method in biomedical research. However, RNA-seq is typically performed in "bulk," and the data represent an average of gene expression patterns across thousands to millions of cells; this might obscure biologically relevant differences between cells. Single-cell RNA-seq (scRNA-seq) represents an approach to overcome this problem. By isolating single cells, capturing their transcripts, and generating sequencing libraries in which the transcripts are mapped to individual cells, scRNA-seq allows assessment of fundamental biological properties of cell populations and biological systems at unprecedented resolution. Here, we present the most common scRNA-seq protocols in use today and the basics of data analysis and discuss factors that are important to consider before planning and designing an scRNA-seq project. © 2018 by John Wiley & Sons, Inc. Copyright © 2018 John Wiley & Sons, Inc.

RBM24 stabilizes hepatitis B virus pregenomic RNA but inhibits core protein translation by targeting the terminal redundancy sequence.

PubMed

Yao, Yongxuan; Yang, Bo; Cao, Huang; Zhao, Kaitao; Yuan, Yifei; Chen, Yingshan; Zhang, Zhenhua; Wang, Yun; Pei, Rongjuan; Chen, Jizheng; Hu, Xue; Zhou, Yuan; Lu, Mengji; Wu, Chunchen; Chen, Xinwen

2018-05-14

The terminal redundancy (TR) sequence of the 3.5-kb hepatitis B virus (HBV) RNA contains sites that govern many crucial functions in the viral life cycle, including polyadenylation, translation, RNA packaging, and DNA synthesis. In the present study, RNA-binding motif protein 24 (RBM24) is shown to be involved in the modulation of HBV replication by targeting the TR of HBV RNA. In HBV-transfected hepatoma cell lines, both knockdown and overexpression of RBM24 led to decreased HBV replication and transcription. Ectopic expression of RBM24 inhibited HBV replication, which was partly restored by knockdown of RBM24, indicating that a proper level of RBM24 was required for HBV replication. The regulation of RBM24 of HBV replication and translation was achieved by the interaction between the RNA-binding domains of RBM24 and both the 5' and 3' TR of 3.5-kb RNA. RBM24 interacted with the 5' TR of HBV pregenomic RNA (pgRNA) to block 80S ribosome assembly on HBV pgRNA and thus inhibited core protein translation, whereas the interaction between RBM24 and the 3' TR enhanced the stability of HBV RNA. Finally, the regulatory function of RBM24 on HBV replication was further confirmed in a HBV infection model. In conclusion, the present study demonstrates the dual functions of RBM24 by interacting with different TRs of viral RNA and reveals that RBM24 is an important host gene for HBV replication.

Noncoding RNA Expression and Targeted Next-Generation Sequencing Distinguish Tubulocystic Renal Cell Carcinoma (TC-RCC) from Other Renal Neoplasms.

PubMed

Lawrie, Charles H; Armesto, María; Fernandez-Mercado, Marta; Arestín, María; Manterola, Lorea; Goicoechea, Ibai; Larrea, Erika; Caffarel, María M; Araujo, Angela M; Sole, Carla; Sperga, Maris; Alvarado-Cabrero, Isabel; Michal, Michal; Hes, Ondrej; López, José I

2018-01-01

Tubulocystic renal cell carcinoma (TC-RCC) is a rare recently described renal neoplasm characterized by gross, microscopic, and immunohistochemical differences from other renal tumor types and was recently classified as a distinct entity. However, this distinction remains controversial particularly because some genetic studies suggest a close relationship with papillary RCC (PRCC). The molecular basis of this disease remains largely unexplored. We therefore performed noncoding (nc) RNA/miRNA expression analysis and targeted next-generation sequencing mutational profiling on 13 TC-RCC cases (11 pure, two mixed TC-RCC/PRCC) and compared with other renal neoplasms. The expression profile of miRNAs and other ncRNAs in TC-RCC was distinct and validated 10 differentially expressed miRNAs by quantitative RT-PCR, including miR-155 and miR-34a, that were significantly down-regulated compared with PRCC cases (n = 22). With the use of targeted next-generation sequencing we identified mutations in 14 different genes, most frequently (>60% of TC-RCC cases) in ABL1 and PDFGRA genes. These mutations were present in <5% of clear cell RCC, PRCC, or chromophobe RCC cases (n > 600) of The Cancer Genome Atlas database. In summary, this study is by far the largest molecular study of TC-RCC cases and the first to investigate either ncRNA expression or their genomic profile. These results add molecular evidence that TC-RCC is indeed a distinct entity from PRCC and other renal neoplasms. Copyright © 2018 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

How to Tackle the Challenge of siRNA Delivery with Sequence-Defined Oligoamino Amides.

PubMed

Reinhard, Sören; Wagner, Ernst

2017-01-01

RNA interference (RNAi) as a mechanism of gene regulation provides exciting opportunities for medical applications. Synthetic small interfering RNA (siRNA) triggers the knockdown of complementary mRNA sequences in a catalytic fashion and has to be delivered into the cytosol of the targeted cells. The design of adequate carrier systems to overcome multiple extracellular and intracellular roadblocks within the delivery process has utmost importance. Cationic polymers form polyplexes through electrostatic interaction with negatively charged nucleic acids and present a promising class of carriers. Issues of polycations regarding toxicity, heterogeneity, and polydispersity can be overcome by solid-phase-assisted synthesis of sequence-defined cationic oligomers. These medium-sized highly versatile nucleic acid carriers display low cytotoxicity and can be modified and tailored in multiple ways to meet specific requirements of nucleic acid binding, polyplex size, shielding, targeting, and intracellular release of the cargo. In this way, sequence-defined cationic oligomers can mimic the dynamic and bioresponsive behavior of viruses. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Linking maternal and somatic 5S rRNA types with different sequence-specific non-LTR retrotransposons.

PubMed

Locati, Mauro D; Pagano, Johanna F B; Ensink, Wim A; van Olst, Marina; van Leeuwen, Selina; Nehrdich, Ulrike; Zhu, Kongju; Spaink, Herman P; Girard, Geneviève; Rauwerda, Han; Jonker, Martijs J; Dekker, Rob J; Breit, Timo M

2017-04-01

5S rRNA is a ribosomal core component, transcribed from many gene copies organized in genomic repeats. Some eukaryotic species have two 5S rRNA types defined by their predominant expression in oogenesis or adult tissue. Our next-generation sequencing study on zebrafish egg, embryo, and adult tissue identified maternal-type 5S rRNA that is exclusively accumulated during oogenesis, replaced throughout the embryogenesis by a somatic-type, and thus virtually absent in adult somatic tissue. The maternal-type 5S rDNA contains several thousands of gene copies on chromosome 4 in tandem repeats with small intergenic regions, whereas the somatic-type is present in only 12 gene copies on chromosome 18 with large intergenic regions. The nine-nucleotide variation between the two 5S rRNA types likely affects TFIII binding and riboprotein L5 binding, probably leading to storage of maternal-type rRNA. Remarkably, these sequence differences are located exactly at the sequence-specific target site for genome integration by the 5S rRNA-specific Mutsu retrotransposon family. Thus, we could define maternal- and somatic-type MutsuDr subfamilies. Furthermore, we identified four additional maternal-type and two new somatic-type MutsuDr subfamilies, each with their own target sequence. This target-site specificity, frequently intact maternal-type retrotransposon elements, plus specific presence of Mutsu retrotransposon RNA and piRNA in egg and adult tissue, suggest an involvement of retrotransposons in achieving the differential copy number of the two types of 5S rDNA loci. © 2017 Locati et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Direct Sequence Detection of Structured H5 Influenza Viral RNA

PubMed Central

Kerby, Matthew B.; Freeman, Sarah; Prachanronarong, Kristina; Artenstein, Andrew W.; Opal, Steven M.; Tripathi, Anubhav

2008-01-01

We describe the development of sequence-specific molecular beacons (dual-labeled DNA probes) for identification of the H5 influenza subtype, cleavage motif, and receptor specificity when hybridized directly with in vitro transcribed viral RNA (vRNA). The cloned hemagglutinin segment from a highly pathogenic H5N1 strain, A/Hanoi/30408/2005(H5N1), isolated from humans was used as template for in vitro transcription of sense-strand vRNA. The hybridization behavior of vRNA and a conserved subtype probe was characterized experimentally by varying conditions of time, temperature, and Mg2+ to optimize detection. Comparison of the hybridization rates of probe to DNA and RNA targets indicates that conformational switching of influenza RNA structure is a rate-limiting step and that the secondary structure of vRNA dominates the binding kinetics. The sensitivity and specificity of probe recognition of other H5 strains was calculated from sequence matches to the National Center for Biotechnology Information influenza database. The hybridization specificity of the subtype probes was experimentally verified with point mutations within the probe loop at five locations corresponding to the other human H5 strains. The abundance frequencies of the hemagglutinin cleavage motif and sialic acid recognition sequences were experimentally tested for H5 in all host viral species. Although the detection assay must be coupled with isothermal amplification on the chip, the new probes form the basis of a portable point-of-care diagnostic device for influenza subtyping. PMID:18403607

RNA processing in Neurospora crassa mitochondria: use of transfer RNA sequences as signals.

PubMed Central

Breitenberger, C A; Browning, K S; Alzner-DeWeerd, B; RajBhandary, U L

1985-01-01

We have used RNA gel transfer hybridization, S1 nuclease mapping and primer extension to analyze transcripts derived from several genes in Neurospora crassa mitochondria. The transcripts studied include those for cytochrome oxidase subunit III, 17S rRNA and an unidentified open reading frame. In all three cases, initial transcripts are long, include tRNA sequences, and are subsequently processed to generate the mature RNAs. We find that endpoints of the most abundant transcripts generally coincide with those of tRNA sequences. We therefore conclude that tRNA sequences in long transcripts act as primary signals for RNA processing in N. crassa mitochondria. The situation is somewhat analogous to that observed in mammalian mitochondrial systems. The difference, however, is that in mammalian mitochondria, noncoding spacers between tRNA, rRNA and protein genes are very short and in many cases non-existent, allowing no room for intergenic RNA processing signals whereas, in N. crassa mtDNA, intergenic non-coding sequences are usually several hundred nucleotides long and contain highly conserved GC-rich palindromic sequences. Since these GC-rich palindromic sequences are retained in the processed mature RNAs, we conclude that they do not serve as signals for RNA processing. Images Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. PMID:2990893

Parallel analysis of RNA ends enhances global investigation of microRNAs and target RNAs of Brachypodium distachyon

PubMed Central

2013-01-01

Background The wild grass Brachypodium distachyon has emerged as a model system for temperate grasses and biofuel plants. However, the global analysis of miRNAs, molecules known to be key for eukaryotic gene regulation, has been limited in B. distachyon to studies examining a few samples or that rely on computational predictions. Similarly an in-depth global analysis of miRNA-mediated target cleavage using parallel analysis of RNA ends (PARE) data is lacking in B. distachyon. Results B. distachyon small RNAs were cloned and deeply sequenced from 17 libraries that represent different tissues and stresses. Using a computational pipeline, we identified 116 miRNAs including not only conserved miRNAs that have not been reported in B. distachyon, but also non-conserved miRNAs that were not found in other plants. To investigate miRNA-mediated cleavage function, four PARE libraries were constructed from key tissues and sequenced to a total depth of approximately 70 million sequences. The roughly 5 million distinct genome-matched sequences that resulted represent an extensive dataset for analyzing small RNA-guided cleavage events. Analysis of the PARE and miRNA data provided experimental evidence for miRNA-mediated cleavage of 264 sites in predicted miRNA targets. In addition, PARE analysis revealed that differentially expressed miRNAs in the same family guide specific target RNA cleavage in a correspondingly tissue-preferential manner. Conclusions B. distachyon miRNAs and target RNAs were experimentally identified and analyzed. Knowledge gained from this study should provide insights into the roles of miRNAs and the regulation of their targets in B. distachyon and related plants. PMID:24367943

DIANA-microT web server: elucidating microRNA functions through target prediction.

PubMed

Maragkakis, M; Reczko, M; Simossis, V A; Alexiou, P; Papadopoulos, G L; Dalamagas, T; Giannopoulos, G; Goumas, G; Koukis, E; Kourtis, K; Vergoulis, T; Koziris, N; Sellis, T; Tsanakas, P; Hatzigeorgiou, A G

2009-07-01

Computational microRNA (miRNA) target prediction is one of the key means for deciphering the role of miRNAs in development and disease. Here, we present the DIANA-microT web server as the user interface to the DIANA-microT 3.0 miRNA target prediction algorithm. The web server provides extensive information for predicted miRNA:target gene interactions with a user-friendly interface, providing extensive connectivity to online biological resources. Target gene and miRNA functions may be elucidated through automated bibliographic searches and functional information is accessible through Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The web server offers links to nomenclature, sequence and protein databases, and users are facilitated by being able to search for targeted genes using different nomenclatures or functional features, such as the genes possible involvement in biological pathways. The target prediction algorithm supports parameters calculated individually for each miRNA:target gene interaction and provides a signal-to-noise ratio and a precision score that helps in the evaluation of the significance of the predicted results. Using a set of miRNA targets recently identified through the pSILAC method, the performance of several computational target prediction programs was assessed. DIANA-microT 3.0 achieved there with 66% the highest ratio of correctly predicted targets over all predicted targets. The DIANA-microT web server is freely available at www.microrna.gr/microT.

A comprehensive survey of 3' animal miRNA modification events and a possible role for 3' adenylation in modulating miRNA targeting effectiveness.

PubMed

Burroughs, A Maxwell; Ando, Yoshinari; de Hoon, Michiel J L; Tomaru, Yasuhiro; Nishibu, Takahiro; Ukekawa, Ryo; Funakoshi, Taku; Kurokawa, Tsutomu; Suzuki, Harukazu; Hayashizaki, Yoshihide; Daub, Carsten O

2010-10-01

Animal microRNA sequences are subject to 3' nucleotide addition. Through detailed analysis of deep-sequenced short RNA data sets, we show adenylation and uridylation of miRNA is globally present and conserved across Drosophila and vertebrates. To better understand 3' adenylation function, we deep-sequenced RNA after knockdown of nucleotidyltransferase enzymes. The PAPD4 nucleotidyltransferase adenylates a wide range of miRNA loci, but adenylation does not appear to affect miRNA stability on a genome-wide scale. Adenine addition appears to reduce effectiveness of miRNA targeting of mRNA transcripts while deep-sequencing of RNA bound to immunoprecipitated Argonaute (AGO) subfamily proteins EIF2C1-EIF2C3 revealed substantial reduction of adenine addition in miRNA associated with EIF2C2 and EIF2C3. Our findings show 3' addition events are widespread and conserved across animals, PAPD4 is a primary miRNA adenylating enzyme, and suggest a role for 3' adenine addition in modulating miRNA effectiveness, possibly through interfering with incorporation into the RNA-induced silencing complex (RISC), a regulatory role that would complement the role of miRNA uridylation in blocking DICER1 uptake.

MicroRNA-21 promotes proliferation of rat hepatocyte BRL-3A by targeting FASLG.

PubMed

Li, J J; Chan, W H; Leung, W Y; Wang, Y; Xu, C S

2015-04-27

Rat liver regeneration (RLR) induced by partial hepatectomy involves cell proliferation regulated by numerous factors, including microRNAs (miRNAs). miRNA high-throughput sequencing has been established and used to analyze miRNA expression profiles. This study showed that 39 miRNAs were related to RLR through the analysis of miRNA high-throughput sequencing. Their role toward rat normal hepatocyte line BRL-3A was studied by gain- and loss-of-function analyses, and one of them, microRNA-21 (miR-21), obviously upregulated and promoted BRL-3A cell proliferation. Using bioinformatics to search for miR-21 targets revealed that Fas ligand (FASLG) is one of miR-21's target genes. A dual-luciferase report assay and Western blot assay showed that miR-21 directly targeted the 3'-untranslated region of FASLG and inhibited the expression of FASLG, which suggests that miR-21 promoted BRL-3A cell proliferation by reducing FASLG expression.

RNA interference can target pre-mRNA: consequences for gene expression in a Caenorhabditis elegans operon.

PubMed Central

Bosher, J M; Dufourcq, P; Sookhareea, S; Labouesse, M

1999-01-01

In nematodes, flies, trypanosomes, and planarians, introduction of double-stranded RNA results in sequence-specific inactivation of gene function, a process termed RNA interference (RNAi). We demonstrate that RNAi against the Caenorhabditis elegans gene lir-1, which is part of the lir-1/lin-26 operon, induced phenotypes very different from a newly isolated lir-1 null mutation. Specifically, lir-1(RNAi) induced embryonic lethality reminiscent of moderately strong lin-26 alleles, whereas the lir-1 null mutant was viable. We show that the lir-1(RNAi) phenotypes resulted from a severe loss of lin-26 gene expression. In addition, we found that RNAi directed against lir-1 or lin-26 introns induced similar phenotypes, so we conclude that lir-1(RNAi) targets the lir-1/lin-26 pre-mRNA. This provides direct evidence that RNA interference can prevent gene expression by targeting nuclear transcripts. Our results highlight that caution may be necessary when interpreting RNA interference without the benefit of mutant alleles. PMID:10545456

Synchronous detection of ebolavirus conserved RNA sequences and ebolavirus-encoded miRNA-like fragment based on a zwitterionic copper (II) metal-organic framework.

PubMed

Qiu, Gui-Hua; Weng, Zi-Hua; Hu, Pei-Pei; Duan, Wen-Jun; Xie, Bao-Ping; Sun, Bin; Tang, Xiao-Yan; Chen, Jin-Xiang

2018-04-01

From a three-dimensional (3D) metal-organic framework (MOF) of {[Cu(Cmdcp)(phen)(H 2 O)] 2 ·9H 2 O} n (1, H 3 CmdcpBr = N-carboxymethyl-(3,5-dicarboxyl)pyridinium bromide, phen = phenanthroline), a sensitive and selective fluorescence sensor has been developed for the simultaneous detection of ebolavirus conserved RNA sequences and ebolavirus-encoded microRNA-like (miRNA-like) fragment. The results from molecular dynamics simulation confirmed that MOF 1 absorbs carboxyfluorescein (FAM)-tagged and 5(6)-carboxyrhodamine, triethylammonium salt (ROX)-tagged probe ss-DNA (probe DNA, P-DNA) by π … π stacking and hydrogen bonding, as well as additional electrostatic interactions to form a sensing platform of P-DNAs@1 with quenched FAM and ROX fluorescence. In the presence of targeted ebolavirus conserved RNA sequences or ebolavirus-encoded miRNA-like fragment, the fluorophore-labeled P-DNA hybridizes with the analyte to give a P-DNA@RNA duplex and released from MOF 1, triggering a fluorescence recovery. Simultaneous detection of two target RNAs has also been realized by single and synchronous fluorescence analysis. The formed sensing platform shows high sensitivity for ebolavirus conserved RNA sequences and ebolavirus-encoded miRNA-like fragment with detection limits at the picomolar level and high selectivity without cross-reaction between the two probes. MOF 1 thus shows the potential as an effective fluorescent sensing platform for the synchronous detection of two ebolavirus-related sequences, and offer improved diagnostic accuracy of Ebola virus disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Rational Design of Small Molecules Targeting Oncogenic Noncoding RNAs from Sequence.

PubMed

Disney, Matthew D; Angelbello, Alicia J

2016-12-20

The discovery of RNA catalysis in the 1980s and the dissemination of the human genome sequence at the start of this century inspired investigations of the regulatory roles of noncoding RNAs in biology. In fact, the Encyclopedia of DNA Elements (ENCODE) project has shown that only 1-2% of the human genome encodes protein, yet 75% is transcribed into RNA. Functional studies both preceding and following the ENCODE project have shown that these noncoding RNAs have important roles in regulating gene expression, developmental timing, and other critical functions. RNA's diverse roles are often a consequence of the various folds that it adopts. The single-stranded nature of the biopolymer enables it to adopt intramolecular folds with noncanonical pairings to lower its free energy. These folds can be scaffolds to bind proteins or to form frameworks to interact with other RNAs. Not surprisingly, dysregulation of certain noncoding RNAs has been shown to be causative of disease. Given this as the background, it is easy to see why it would be useful to develop methods that target RNA and manipulate its biology in rational and predictable ways. The antisense approach has afforded strategies to target RNAs via Watson-Crick base pairing and has typically focused on targeting partially unstructured regions of RNA. Small molecule strategies to target RNA would be desirable not only because compounds could be lead optimized via medicinal chemistry but also because structured regions within an RNA of interest could be targeted to directly interfere with RNA folds that contribute to disease. Additionally, small molecules have historically been the most successful drug candidates. Until recently, the ability to design small molecules that target non-ribosomal RNAs has been elusive, creating the perception that they are "undruggable". In this Account, approaches to demystify targeting RNA with small molecules are described. Rather than bulk screening for compounds that bind to singular

Sequencing and Characterisation of an Extensive Atlantic Salmon (Salmo salar L.) MicroRNA Repertoire

PubMed Central

Bekaert, Michaël; Lowe, Natalie R.; Bishop, Stephen C.; Bron, James E.; Taggart, John B.; Houston, Ross D.

2013-01-01

Atlantic salmon (Salmo salar L.), a member of the family Salmonidae, is a totemic species of ecological and cultural significance that is also economically important in terms of both sports fisheries and aquaculture. These factors have promoted the continuous development of genomic resources for this species, furthering both fundamental and applied research. MicroRNAs (miRNA) are small endogenous non-coding RNA molecules that control spatial and temporal expression of targeted genes through post-transcriptional regulation. While miRNA have been characterised in detail for many other species, this is not yet the case for Atlantic salmon. To identify miRNAs from Atlantic salmon, we constructed whole fish miRNA libraries for 18 individual juveniles (fry, four months post hatch) and characterised them by Illumina high-throughput sequencing (total of 354,505,167 paired-ended reads). We report an extensive and partly novel repertoire of miRNA sequences, comprising 888 miRNA genes (547 unique mature miRNA sequences), quantify their expression levels in basal conditions, examine their homology to miRNAs from other species and identify their predicted target genes. We also identify the location and putative copy number of the miRNA genes in the draft Atlantic salmon reference genome sequence. The Atlantic salmon miRNAs experimentally identified in this study provide a robust large-scale resource for functional genome research in salmonids. There is an opportunity to explore the evolution of salmonid miRNAs following the relatively recent whole genome duplication event in salmonid species and to investigate the role of miRNAs in the regulation of gene expression in particular their contribution to variation in economically and ecologically important traits. PMID:23922936

probeBase—an online resource for rRNA-targeted oligonucleotide probes and primers: new features 2016

PubMed Central

Greuter, Daniel; Loy, Alexander; Horn, Matthias; Rattei, Thomas

2016-01-01

probeBase http://www.probebase.net is a manually maintained and curated database of rRNA-targeted oligonucleotide probes and primers. Contextual information and multiple options for evaluating in silico hybridization performance against the most recent rRNA sequence databases are provided for each oligonucleotide entry, which makes probeBase an important and frequently used resource for microbiology research and diagnostics. Here we present a major update of probeBase, which was last featured in the NAR Database Issue 2007. This update describes a complete remodeling of the database architecture and environment to accommodate computationally efficient access. Improved search functions, sequence match tools and data output now extend the opportunities for finding suitable hierarchical probe sets that target an organism or taxon at different taxonomic levels. To facilitate the identification of complementary probe sets for organisms represented by short rRNA sequence reads generated by amplicon sequencing or metagenomic analysis with next generation sequencing technologies such as Illumina and IonTorrent, we introduce a novel tool that recovers surrogate near full-length rRNA sequences for short query sequences and finds matching oligonucleotides in probeBase. PMID:26586809

Small RNA Deep Sequencing and the Effects of microRNA408 on Root Gravitropic Bending in Arabidopsis

NASA Astrophysics Data System (ADS)

Li, Huasheng; Lu, Jinying; Sun, Qiao; Chen, Yu; He, Dacheng; Liu, Min

2015-11-01

MicroRNA (miRNA) is a non-coding small RNA composed of 20 to 24 nucleotides that influences plant root development. This study analyzed the miRNA expression in Arabidopsis root tip cells using Illumina sequencing and real-time PCR before (sample 0) and 15 min after (sample 15) a 3-D clinostat rotational treatment was administered. After stimulation was performed, the expression levels of seven miRNA genes, including Arabidopsis miR160, miR161, miR394, miR402, miR403, miR408, and miR823, were significantly upregulated. Illumina sequencing results also revealed two novel miRNAsthat have not been previously reported, The target genes of these miRNAs included pentatricopeptide repeat-containing protein and diadenosine tetraphosphate hydrolase. An overexpression vector of Arabidopsis miR408 was constructed and transferred to Arabidopsis plant. The roots of plants over expressing miR408 exhibited a slower reorientation upon gravistimulation in comparison with those of wild-type. This result indicate that miR408 could play a role in root gravitropic response.

Self-Assembly of Measles Virus Nucleocapsid-like Particles: Kinetics and RNA Sequence Dependence.

PubMed

Milles, Sigrid; Jensen, Malene Ringkjøbing; Communie, Guillaume; Maurin, Damien; Schoehn, Guy; Ruigrok, Rob W H; Blackledge, Martin

2016-08-01

Measles virus RNA genomes are packaged into helical nucleocapsids (NCs), comprising thousands of nucleo-proteins (N) that bind the entire genome. N-RNA provides the template for replication and transcription by the viral polymerase and is a promising target for viral inhibition. Elucidation of mechanisms regulating this process has been severely hampered by the inability to controllably assemble NCs. Here, we demonstrate self-organization of N into NC-like particles in vitro upon addition of RNA, providing a simple and versatile tool for investigating assembly. Real-time NMR and fluorescence spectroscopy reveals biphasic assembly kinetics. Remarkably, assembly depends strongly on the RNA-sequence, with the genomic 5' end and poly-Adenine sequences assembling efficiently, while sequences such as poly-Uracil are incompetent for NC formation. This observation has important consequences for understanding the assembly process. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Biotechnological applications of mobile group II introns and their reverse transcriptases: gene targeting, RNA-seq, and non-coding RNA analysis.

PubMed

Enyeart, Peter J; Mohr, Georg; Ellington, Andrew D; Lambowitz, Alan M

2014-01-13

Mobile group II introns are bacterial retrotransposons that combine the activities of an autocatalytic intron RNA (a ribozyme) and an intron-encoded reverse transcriptase to insert site-specifically into DNA. They recognize DNA target sites largely by base pairing of sequences within the intron RNA and achieve high DNA target specificity by using the ribozyme active site to couple correct base pairing to RNA-catalyzed intron integration. Algorithms have been developed to program the DNA target site specificity of several mobile group II introns, allowing them to be made into 'targetrons.' Targetrons function for gene targeting in a wide variety of bacteria and typically integrate at efficiencies high enough to be screened easily by colony PCR, without the need for selectable markers. Targetrons have found wide application in microbiological research, enabling gene targeting and genetic engineering of bacteria that had been intractable to other methods. Recently, a thermostable targetron has been developed for use in bacterial thermophiles, and new methods have been developed for using targetrons to position recombinase recognition sites, enabling large-scale genome-editing operations, such as deletions, inversions, insertions, and 'cut-and-pastes' (that is, translocation of large DNA segments), in a wide range of bacteria at high efficiency. Using targetrons in eukaryotes presents challenges due to the difficulties of nuclear localization and sub-optimal magnesium concentrations, although supplementation with magnesium can increase integration efficiency, and directed evolution is being employed to overcome these barriers. Finally, spurred by new methods for expressing group II intron reverse transcriptases that yield large amounts of highly active protein, thermostable group II intron reverse transcriptases from bacterial thermophiles are being used as research tools for a variety of applications, including qRT-PCR and next-generation RNA sequencing (RNA-seq). The

Statistical Use of Argonaute Expression and RISC Assembly in microRNA Target Identification

PubMed Central

Stanhope, Stephen A.; Sengupta, Srikumar; den Boon, Johan; Ahlquist, Paul; Newton, Michael A.

2009-01-01

MicroRNAs (miRNAs) posttranscriptionally regulate targeted messenger RNAs (mRNAs) by inducing cleavage or otherwise repressing their translation. We address the problem of detecting m/miRNA targeting relationships in homo sapiens from microarray data by developing statistical models that are motivated by the biological mechanisms used by miRNAs. The focus of our modeling is the construction, activity, and mediation of RNA-induced silencing complexes (RISCs) competent for targeted mRNA cleavage. We demonstrate that regression models accommodating RISC abundance and controlling for other mediating factors fit the expression profiles of known target pairs substantially better than models based on m/miRNA expressions alone, and lead to verifications of computational target pair predictions that are more sensitive than those based on marginal expression levels. Because our models are fully independent of exogenous results from sequence-based computational methods, they are appropriate for use as either a primary or secondary source of information regarding m/miRNA target pair relationships, especially in conjunction with high-throughput expression studies. PMID:19779550

Statistical use of argonaute expression and RISC assembly in microRNA target identification.

PubMed

Stanhope, Stephen A; Sengupta, Srikumar; den Boon, Johan; Ahlquist, Paul; Newton, Michael A

2009-09-01

MicroRNAs (miRNAs) posttranscriptionally regulate targeted messenger RNAs (mRNAs) by inducing cleavage or otherwise repressing their translation. We address the problem of detecting m/miRNA targeting relationships in homo sapiens from microarray data by developing statistical models that are motivated by the biological mechanisms used by miRNAs. The focus of our modeling is the construction, activity, and mediation of RNA-induced silencing complexes (RISCs) competent for targeted mRNA cleavage. We demonstrate that regression models accommodating RISC abundance and controlling for other mediating factors fit the expression profiles of known target pairs substantially better than models based on m/miRNA expressions alone, and lead to verifications of computational target pair predictions that are more sensitive than those based on marginal expression levels. Because our models are fully independent of exogenous results from sequence-based computational methods, they are appropriate for use as either a primary or secondary source of information regarding m/miRNA target pair relationships, especially in conjunction with high-throughput expression studies.

Targeting RNA in mammalian systems with small molecules.

PubMed

Donlic, Anita; Hargrove, Amanda E

2018-05-03

The recognition of RNA functions beyond canonical protein synthesis has challenged the central dogma of molecular biology. Indeed, RNA is now known to directly regulate many important cellular processes, including transcription, splicing, translation, and epigenetic modifications. The misregulation of these processes in disease has led to an appreciation of RNA as a therapeutic target. This potential was first recognized in bacteria and viruses, but discoveries of new RNA classes following the sequencing of the human genome have invigorated exploration of its disease-related functions in mammals. As stable structure formation is evolving as a hallmark of mammalian RNAs, the prospect of utilizing small molecules to specifically probe the function of RNA structural domains and their interactions is gaining increased recognition. To date, researchers have discovered bioactive small molecules that modulate phenotypes by binding to expanded repeats, microRNAs, G-quadruplex structures, and RNA splice sites in neurological disorders, cancers, and other diseases. The lessons learned from achieving these successes both call for additional studies and encourage exploration of the plethora of mammalian RNAs whose precise mechanisms of action remain to be elucidated. Efforts toward understanding fundamental principles of small molecule-RNA recognition combined with advances in methodology development should pave the way toward targeting emerging RNA classes such as long noncoding RNAs. Together, these endeavors can unlock the full potential of small molecule-based probing of RNA-regulated processes and enable us to discover new biology and underexplored avenues for therapeutic intervention in human disease. This article is categorized under: RNA Methods > RNA Analyses In Vitro and In Silico RNA Interactions with Proteins and Other Molecules > Small Molecule-RNA Interactions RNA in Disease and Development > RNA in Disease. © 2018 Wiley Periodicals, Inc.

Hairpin RNA Targeting Multiple Viral Genes Confers Strong Resistance to Rice Black-Streaked Dwarf Virus.

PubMed

Wang, Fangquan; Li, Wenqi; Zhu, Jinyan; Fan, Fangjun; Wang, Jun; Zhong, Weigong; Wang, Ming-Bo; Liu, Qing; Zhu, Qian-Hao; Zhou, Tong; Lan, Ying; Zhou, Yijun; Yang, Jie

2016-05-11

Rice black-streaked dwarf virus (RBSDV) belongs to the genus Fijivirus in the family of Reoviridae and causes severe yield loss in rice-producing areas in Asia. RNA silencing, as a natural defence mechanism against plant viruses, has been successfully exploited for engineering virus resistance in plants, including rice. In this study, we generated transgenic rice lines harbouring a hairpin RNA (hpRNA) construct targeting four RBSDV genes, S1, S2, S6 and S10, encoding the RNA-dependent RNA polymerase, the putative core protein, the RNA silencing suppressor and the outer capsid protein, respectively. Both field nursery and artificial inoculation assays of three generations of the transgenic lines showed that they had strong resistance to RBSDV infection. The RBSDV resistance in the segregating transgenic populations correlated perfectly with the presence of the hpRNA transgene. Furthermore, the hpRNA transgene was expressed in the highly resistant transgenic lines, giving rise to abundant levels of 21-24 nt small interfering RNA (siRNA). By small RNA deep sequencing, the RBSDV-resistant transgenic lines detected siRNAs from all four viral gene sequences in the hpRNA transgene, indicating that the whole chimeric fusion sequence can be efficiently processed by Dicer into siRNAs. Taken together, our results suggest that long hpRNA targeting multiple viral genes can be used to generate stable and durable virus resistance in rice, as well as other plant species.

High throughput deep degradome sequencing reveals microRNAs and their targets in response to drought stress in mulberry (Morus alba).

PubMed

Li, Ruixue; Chen, Dandan; Wang, Taichu; Wan, Yizhen; Li, Rongfang; Fang, Rongjun; Wang, Yuting; Hu, Fei; Zhou, Hong; Li, Long; Zhao, Weiguo

2017-01-01

MicroRNAs (miRNAs) play important regulatory roles by targeting mRNAs for cleavage or translational repression. Identification of miRNA targets is essential to better understanding the roles of miRNAs. miRNA targets have not been well characterized in mulberry (Morus alba). To anatomize miRNA guided gene regulation under drought stress, transcriptome-wide high throughput degradome sequencing was used in this study to directly detect drought stress responsive miRNA targets in mulberry. A drought library (DL) and a contrast library (CL) were constructed to capture the cleaved mRNAs for sequencing. In CL, 409 target genes of 30 conserved miRNA families and 990 target genes of 199 novel miRNAs were identified. In DL, 373 target genes of 30 conserved miRNA families and 950 target genes of 195 novel miRNAs were identified. Of the conserved miRNA families in DL, mno-miR156, mno-miR172, and mno-miR396 had the highest number of targets with 54, 52 and 41 transcripts, respectively, indicating that these three miRNA families and their target genes might play important functions in response to drought stress in mulberry. Additionally, we found that many of the target genes were transcription factors. By analyzing the miRNA-target molecular network, we found that the DL independent networks consisted of 838 miRNA-mRNA pairs (63.34%). The expression patterns of 11 target genes and 12 correspondent miRNAs were detected using qRT-PCR. Six miRNA targets were further verified by RNA ligase-mediated 5' rapid amplification of cDNA ends (RLM-5' RACE). Gene Ontology (GO) annotations and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that these target transcripts were implicated in a broad range of biological processes and various metabolic pathways. This is the first study to comprehensively characterize target genes and their associated miRNAs in response to drought stress by degradome sequencing in mulberry. This study provides a framework for understanding

RNA and DNA Targeting by a Reconstituted Thermus thermophilus Type III-A CRISPR-Cas System.

PubMed

Liu, Tina Y; Iavarone, Anthony T; Doudna, Jennifer A

2017-01-01

CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated) systems are RNA-guided adaptive immunity pathways used by bacteria and archaea to defend against phages and plasmids. Type III-A systems use a multisubunit interference complex called Csm, containing Cas proteins and a CRISPR RNA (crRNA) to target cognate nucleic acids. The Csm complex is intriguing in that it mediates RNA-guided targeting of both RNA and transcriptionally active DNA, but the mechanism is not well understood. Here, we overexpressed the five components of the Thermus thermophilus (T. thermophilus) Type III-A Csm complex (TthCsm) with a defined crRNA sequence, and purified intact TthCsm complexes from E. coli cells. The complexes were thermophilic, targeting complementary ssRNA more efficiently at 65°C than at 37°C. Sequence-independent, endonucleolytic cleavage of single-stranded DNA (ssDNA) by TthCsm was triggered by recognition of a complementary ssRNA, and required a lack of complementarity between the first 8 nucleotides (5' tag) of the crRNA and the 3' flanking region of the ssRNA. Mutation of the histidine-aspartate (HD) nuclease domain of the TthCsm subunit, Cas10/Csm1, abolished DNA cleavage. Activation of DNA cleavage was dependent on RNA binding but not cleavage. This leads to a model in which binding of an ssRNA target to the Csm complex would stimulate cleavage of exposed ssDNA in the cell, such as could occur when the RNA polymerase unwinds double-stranded DNA (dsDNA) during transcription. Our findings establish an amenable, thermostable system for more in-depth investigation of the targeting mechanism using structural biology methods, such as cryo-electron microscopy and x-ray crystallography.

Single-Cell RNA-Sequencing in Glioma.

PubMed

Johnson, Eli; Dickerson, Katherine L; Connolly, Ian D; Hayden Gephart, Melanie

2018-04-10

In this review, we seek to summarize the literature concerning the use of single-cell RNA-sequencing for CNS gliomas. Single-cell analysis has revealed complex tumor heterogeneity, subpopulations of proliferating stem-like cells and expanded our view of tumor microenvironment influence in the disease process. Although bulk RNA-sequencing has guided our initial understanding of glioma genetics, this method does not accurately define the heterogeneous subpopulations found within these tumors. Single-cell techniques have appealing applications in cancer research, as diverse cell types and the tumor microenvironment have important implications in therapy. High cost and difficult protocols prevent widespread use of single-cell RNA-sequencing; however, continued innovation will improve accessibility and expand our of knowledge gliomas.

Comprehensive modeling of microRNA targets predicts functional non-conserved and non-canonical sites.

PubMed

Betel, Doron; Koppal, Anjali; Agius, Phaedra; Sander, Chris; Leslie, Christina

2010-01-01

mirSVR is a new machine learning method for ranking microRNA target sites by a down-regulation score. The algorithm trains a regression model on sequence and contextual features extracted from miRanda-predicted target sites. In a large-scale evaluation, miRanda-mirSVR is competitive with other target prediction methods in identifying target genes and predicting the extent of their downregulation at the mRNA or protein levels. Importantly, the method identifies a significant number of experimentally determined non-canonical and non-conserved sites.

An RRM–ZnF RNA recognition module targets RBM10 to exonic sequences to promote exon exclusion

PubMed Central

Collins, Katherine M.; Kainov, Yaroslav A.; Christodolou, Evangelos; Ray, Debashish; Morris, Quaid; Hughes, Timothy; Taylor, Ian A.

2017-01-01

Abstract RBM10 is an RNA-binding protein that plays an essential role in development and is frequently mutated in the context of human disease. RBM10 recognizes a diverse set of RNA motifs in introns and exons and regulates alternative splicing. However, the molecular mechanisms underlying this seemingly relaxed sequence specificity are not understood and functional studies have focused on 3΄ intronic sites only. Here, we dissect the RNA code recognized by RBM10 and relate it to the splicing regulatory function of this protein. We show that a two-domain RRM1–ZnF unit recognizes a GGA-centered motif enriched in RBM10 exonic sites with high affinity and specificity and test that the interaction with these exonic sequences promotes exon skipping. Importantly, a second RRM domain (RRM2) of RBM10 recognizes a C-rich sequence, which explains its known interaction with the intronic 3΄ site of NUMB exon 9 contributing to regulation of the Notch pathway in cancer. Together, these findings explain RBM10's broad RNA specificity and suggest that RBM10 functions as a splicing regulator using two RNA-binding units with different specificities to promote exon skipping. PMID:28379442

An RRM-ZnF RNA recognition module targets RBM10 to exonic sequences to promote exon exclusion.

PubMed

Collins, Katherine M; Kainov, Yaroslav A; Christodolou, Evangelos; Ray, Debashish; Morris, Quaid; Hughes, Timothy; Taylor, Ian A; Makeyev, Eugene V; Ramos, Andres

2017-06-20

RBM10 is an RNA-binding protein that plays an essential role in development and is frequently mutated in the context of human disease. RBM10 recognizes a diverse set of RNA motifs in introns and exons and regulates alternative splicing. However, the molecular mechanisms underlying this seemingly relaxed sequence specificity are not understood and functional studies have focused on 3΄ intronic sites only. Here, we dissect the RNA code recognized by RBM10 and relate it to the splicing regulatory function of this protein. We show that a two-domain RRM1-ZnF unit recognizes a GGA-centered motif enriched in RBM10 exonic sites with high affinity and specificity and test that the interaction with these exonic sequences promotes exon skipping. Importantly, a second RRM domain (RRM2) of RBM10 recognizes a C-rich sequence, which explains its known interaction with the intronic 3΄ site of NUMB exon 9 contributing to regulation of the Notch pathway in cancer. Together, these findings explain RBM10's broad RNA specificity and suggest that RBM10 functions as a splicing regulator using two RNA-binding units with different specificities to promote exon skipping. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

YM500: a small RNA sequencing (smRNA-seq) database for microRNA research

PubMed Central

Cheng, Wei-Chung; Chung, I-Fang; Huang, Tse-Shun; Chang, Shih-Ting; Sun, Hsing-Jen; Tsai, Cheng-Fong; Liang, Muh-Lii; Wong, Tai-Tong; Wang, Hsei-Wei

2013-01-01

MicroRNAs (miRNAs) are small RNAs ∼22 nt in length that are involved in the regulation of a variety of physiological and pathological processes. Advances in high-throughput small RNA sequencing (smRNA-seq), one of the next-generation sequencing applications, have reshaped the miRNA research landscape. In this study, we established an integrative database, the YM500 (http://ngs.ym.edu.tw/ym500/), containing analysis pipelines and analysis results for 609 human and mice smRNA-seq results, including public data from the Gene Expression Omnibus (GEO) and some private sources. YM500 collects analysis results for miRNA quantification, for isomiR identification (incl. RNA editing), for arm switching discovery, and, more importantly, for novel miRNA predictions. Wetlab validation on >100 miRNAs confirmed high correlation between miRNA profiling and RT-qPCR results (R = 0.84). This database allows researchers to search these four different types of analysis results via our interactive web interface. YM500 allows researchers to define the criteria of isomiRs, and also integrates the information of dbSNP to help researchers distinguish isomiRs from SNPs. A user-friendly interface is provided to integrate miRNA-related information and existing evidence from hundreds of sequencing datasets. The identified novel miRNAs and isomiRs hold the potential for both basic research and biotech applications. PMID:23203880

A low molecular weight artificial RNA of unique size with multiple probe target regions

NASA Technical Reports Server (NTRS)

Pitulle, C.; Dsouza, L.; Fox, G. E.

1997-01-01

Artificial RNAs (aRNAs) containing novel sequence segments embedded in a deletion mutant of Vibrio proteolyticus 5S rRNA have previously been shown to be expressed from a plasmid borne growth rate regulated promoter in E. coli. These aRNAs accumulate to high levels and their detection is a promising tool for studies in molecular microbial ecology and in environmental monitoring. Herein a new construct is described which illustrates the versatility of detection that is possible with aRNAs. This 3xPen aRNA construct carries a 72 nucleotide insert with three copies of a unique 17 base probe target sequence. This aRNA is 160 nucleotides in length and again accumulates to high levels in the E. coli cytoplasm without incorporating into ribosomes. The 3xPen aRNA illustrates two improvements in detection. First, by appropriate selection of insert size, we obtained an aRNA which provides a unique and hence, easily quantifiable peak, on a high resolution gel profile of low molecular weight RNAs. Second, the existence of multiple probe targets results in a nearly commensurate increase in signal when detection is by hybridization. These aRNAs are naturally amplified and carry sequence segments that are not found in known rRNA sequences. It thus may be possible to detect them directly. An experimental step involving RT-PCR or PCR amplification of the gene could therefore be avoided.

repRNA: a web server for generating various feature vectors of RNA sequences.

PubMed

Liu, Bin; Liu, Fule; Fang, Longyun; Wang, Xiaolong; Chou, Kuo-Chen

2016-02-01

With the rapid growth of RNA sequences generated in the postgenomic age, it is highly desired to develop a flexible method that can generate various kinds of vectors to represent these sequences by focusing on their different features. This is because nearly all the existing machine-learning methods, such as SVM (support vector machine) and KNN (k-nearest neighbor), can only handle vectors but not sequences. To meet the increasing demands and speed up the genome analyses, we have developed a new web server, called "representations of RNA sequences" (repRNA). Compared with the existing methods, repRNA is much more comprehensive, flexible and powerful, as reflected by the following facts: (1) it can generate 11 different modes of feature vectors for users to choose according to their investigation purposes; (2) it allows users to select the features from 22 built-in physicochemical properties and even those defined by users' own; (3) the resultant feature vectors and the secondary structures of the corresponding RNA sequences can be visualized. The repRNA web server is freely accessible to the public at http://bioinformatics.hitsz.edu.cn/repRNA/ .

Endogenous miRNA and Target Concentrations Determine Susceptibility to Potential ceRNA Competition

PubMed Central

Bosson, Andrew D.; Zamudio, Jesse R.; Sharp, Phillip A.

2016-01-01

SUMMARY Target competition (ceRNA crosstalk) within miRNA-regulated gene networks has been proposed to influence biological systems. To assess target competition, we characterize and quantitate miRNA networks in two cell types. Argonaute iCLIP reveals that hierarchical binding of high- to low-affinity miRNA targets is a key characteristic of in vivo activity. Quantification of cellular miRNA and mRNA/ncRNA target pool levels indicates that miRNA:target pool ratios and an affinity partitioned target pool accurately predict in vivo Ago binding profiles and miRNA susceptibility to target competition. Using single-cell reporters, we directly test predictions and estimate that ~3,000 additional high-affinity target sites can affect active miRNA families with low endogenous miRNA:target ratios, such as miR-92/25. In contrast, the highly expressed miR-294 and let-7 families are not susceptible to increases of nearly 10,000 sites. These results show differential susceptibility based on endogenous miRNA:target pool ratios and provide a physiological context for ceRNA competition in vivo. PMID:25449132

The nonamer UUAUUUAUU is the key AU-rich sequence motif that mediates mRNA degradation.

PubMed Central

Zubiaga, A M; Belasco, J G; Greenberg, M E

1995-01-01

Labile mRNAs that encode cytokine and immediate-early gene products often contain AU-rich sequences within their 3' untranslated region (UTR). These AU-rich sequences appear to be key determinants of the short half-lives of these mRNAs, although the sequence features of these elements and the mechanism by which they target mRNAs for rapid decay have not been fully defined. We have examined the features of AU-rich elements (AREs) that are crucial for their function as determinants of mRNA instability in mammalian cells by testing the ability of various mutant c-fos AREs and synthetic AREs to direct rapid mRNA deadenylation and decay when inserted within the 3' UTR of the normally stable beta-globin mRNA. Evidence is presented that the pentamer AUUUA, which previously was suggested to be the minimal determinant of instability present in mammalian AREs, cannot direct rapid mRNA deadenylation and decay. Instead, the nonomer UUAUUUAUU is the elemental AU-rich sequence motif that destabilizes mRNA. Removal of one uridine residue from either end of the nonamer (UUAUUUAU or UAUUUAUU) results in a decrease of potency of the element, while removal of a uridine residue from both ends of the nonamer (UAUUUAU) eliminates detectable destabilizing activity. The inclusion of an additional uridine residue at both ends of the nonamer (UUUAUUUAUUU) does not further increase the efficacy of the element. Taken together, these findings suggest that the nonamer UUAUUUAUU is the minimal AU-rich motif that effectively destabilizes mRNA. Additional ARE potency is achieved by combining multiple copies of this nonamer in a single mRNA 3' UTR. Furthermore, analysis of poly(A) shortening rates for ARE-containing mRNAs reveals that the UUAUUUAUU sequence also accelerates mRNA deadenylation and suggests that the UUAUUUAUU motif targets mRNA for rapid deadenylation as an early step in the mRNA decay process. PMID:7891716

GRIL-Seq, a method for identifying direct targets of bacterial small regulatory RNA by in vivo proximity ligation

PubMed Central

Han, Kook; Tjaden, Brian; Lory, Stephen

2017-01-01

The first step in the post-transcriptional regulatory function of most bacterial small non-coding RNAs (sRNAs) is base-pairing with partially complementary sequences of targeted transcripts. We present a simple method for identifying sRNA targets in vivo and defining processing sites of the regulated transcripts. The technique (referred to as GRIL-Seq) is based on preferential ligation of sRNAs to ends of base-paired targets in bacteria co-expressing T4 RNA ligase, followed by sequencing to identify the chimeras. In addition to the RNA chaperone Hfq, the GRIL-Seq method depends on the activity of the pyrophosphorylase RppH. Using PrrF1, an iron-regulated sRNA in Pseudomonas aeruginosa, we demonstrate that direct regulatory targets of this sRNA can be readily identified. Therefore, GRIL-Seq represents a powerful tool not only for identifying direct targets of sRNAs in a variety of environments, but can also result in uncovering novel roles for sRNAs and their targets in complex regulatory networks. PMID:28005055

Analysis of Pteridium ribosomal RNA sequences by rapid direct sequencing.

PubMed

Tan, M K

1991-08-01

A total of 864 bases from 5 regions interspersed in the 18S and 26S rRNA molecules from various clones of Pteridium covering the general geographical distribution of the genus was analysed using a rapid rRNA sequencing technique. No base difference has been detected amongst the three major lineages, two of which apparently separated before the breakup of the ancient supercontinent, Pangaea. These regions of the rRNA sequences have thus been conserved for at least 160 million years and are here compared with other eukaryotic, especially plant rRNAs.

Development and Verification of an RNA Sequencing (RNA-Seq) Assay for the Detection of Gene Fusions in Tumors.

PubMed

Winters, Jennifer L; Davila, Jaime I; McDonald, Amber M; Nair, Asha A; Fadra, Numrah; Wehrs, Rebecca N; Thomas, Brittany C; Balcom, Jessica R; Jin, Long; Wu, Xianglin; Voss, Jesse S; Klee, Eric W; Oliver, Gavin R; Graham, Rondell P; Neff, Jadee L; Rumilla, Kandelaria M; Aypar, Umut; Kipp, Benjamin R; Jenkins, Robert B; Jen, Jin; Halling, Kevin C

2018-06-13

We assessed the performance characteristics of an RNA sequencing (RNA-Seq) assay designed to detect gene fusions in 571 genes to help manage patients with cancer. Polyadenylated RNA was converted to cDNA, which was then used to prepare next-generation sequencing libraries that were sequenced on an Illumina HiSeq 2500 instrument and analyzed with an in-house developed bioinformatic pipeline. The assay identified 38 of 41 gene fusions detected by another method, such as fluorescence in situ hybridization or RT-PCR, for a sensitivity of 93%. No false-positive gene fusions were identified in 15 normal tissue specimens and 10 tumor specimens that were negative for fusions by RNA sequencing or Mate Pair NGS (100% specificity). The assay also identified 22 fusions in 17 tumor specimens that had not been detected by other methods. Eighteen of the 22 fusions had not previously been described. Good intra-assay and interassay reproducibility was observed with complete concordance for the presence or absence of gene fusions in replicates. The analytical sensitivity of the assay was tested by diluting RNA isolated from gene fusion-positive cases with fusion-negative RNA. Gene fusions were generally detectable down to 12.5% dilutions for most fusions and as little as 3% for some fusions. This assay can help identify fusions in patients with cancer; these patients may in turn benefit from both US Food and Drug Administration-approved and investigational targeted therapies. Copyright © 2018 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

Computational sequence analysis of predicted long dsRNA transcriptomes of major crops reveals sequence complementarity with human genes.

PubMed

Jensen, Peter D; Zhang, Yuanji; Wiggins, B Elizabeth; Petrick, Jay S; Zhu, Jin; Kerstetter, Randall A; Heck, Gregory R; Ivashuta, Sergey I

2013-01-01

Long double-stranded RNAs (long dsRNAs) are precursors for the effector molecules of sequence-specific RNA-based gene silencing in eukaryotes. Plant cells can contain numerous endogenous long dsRNAs. This study demonstrates that such endogenous long dsRNAs in plants have sequence complementarity to human genes. Many of these complementary long dsRNAs have perfect sequence complementarity of at least 21 nucleotides to human genes; enough complementarity to potentially trigger gene silencing in targeted human cells if delivered in functional form. However, the number and diversity of long dsRNA molecules in plant tissue from crops such as lettuce, tomato, corn, soy and rice with complementarity to human genes that have a long history of safe consumption supports a conclusion that long dsRNAs do not present a significant dietary risk.

Fast online and index-based algorithms for approximate search of RNA sequence-structure patterns

PubMed Central

2013-01-01

Background It is well known that the search for homologous RNAs is more effective if both sequence and structure information is incorporated into the search. However, current tools for searching with RNA sequence-structure patterns cannot fully handle mutations occurring on both these levels or are simply not fast enough for searching large sequence databases because of the high computational costs of the underlying sequence-structure alignment problem. Results We present new fast index-based and online algorithms for approximate matching of RNA sequence-structure patterns supporting a full set of edit operations on single bases and base pairs. Our methods efficiently compute semi-global alignments of structural RNA patterns and substrings of the target sequence whose costs satisfy a user-defined sequence-structure edit distance threshold. For this purpose, we introduce a new computing scheme to optimally reuse the entries of the required dynamic programming matrices for all substrings and combine it with a technique for avoiding the alignment computation of non-matching substrings. Our new index-based methods exploit suffix arrays preprocessed from the target database and achieve running times that are sublinear in the size of the searched sequences. To support the description of RNA molecules that fold into complex secondary structures with multiple ordered sequence-structure patterns, we use fast algorithms for the local or global chaining of approximate sequence-structure pattern matches. The chaining step removes spurious matches from the set of intermediate results, in particular of patterns with little specificity. In benchmark experiments on the Rfam database, our improved online algorithm is faster than the best previous method by up to factor 45. Our best new index-based algorithm achieves a speedup of factor 560. Conclusions The presented methods achieve considerable speedups compared to the best previous method. This, together with the expected

Uncovering Small RNA-Mediated Responses to Cold Stress in a Wheat Thermosensitive Genic Male-Sterile Line by Deep Sequencing1[W][OA

PubMed Central

Tang, Zhonghui; Zhang, Liping; Xu, Chenguang; Yuan, Shaohua; Zhang, Fengting; Zheng, Yonglian; Zhao, Changping

2012-01-01

The male sterility of thermosensitive genic male sterile (TGMS) lines of wheat (Triticum aestivum) is strictly controlled by temperature. The early phase of anther development is especially susceptible to cold stress. MicroRNAs (miRNAs) play an important role in plant development and in responses to environmental stress. In this study, deep sequencing of small RNA (smRNA) libraries obtained from spike tissues of the TGMS line under cold and control conditions identified a total of 78 unique miRNA sequences from 30 families and trans-acting small interfering RNAs (tasiRNAs) derived from two TAS3 genes. To identify smRNA targets in the wheat TGMS line, we applied the degradome sequencing method, which globally and directly identifies the remnants of smRNA-directed target cleavage. We identified 26 targets of 16 miRNA families and three targets of tasiRNAs. Comparing smRNA sequencing data sets and TaqMan quantitative polymerase chain reaction results, we identified six miRNAs and one tasiRNA (tasiRNA-ARF [for Auxin-Responsive Factor]) as cold stress-responsive smRNAs in spike tissues of the TGMS line. We also determined the expression profiles of target genes that encode transcription factors in response to cold stress. Interestingly, the expression of cold stress-responsive smRNAs integrated in the auxin-signaling pathway and their target genes was largely noncorrelated. We investigated the tissue-specific expression of smRNAs using a tissue microarray approach. Our data indicated that miR167 and tasiRNA-ARF play roles in regulating the auxin-signaling pathway and possibly in the developmental response to cold stress. These data provide evidence that smRNA regulatory pathways are linked with male sterility in the TGMS line during cold stress. PMID:22508932

Targeting the kinesin Eg5 to monitor siRNA transfection in mammalian cells.

PubMed

Weil, D; Garçon, L; Harper, M; Duménil, D; Dautry, F; Kress, M

2002-12-01

RNA interference, the inhibition of gene expression by double-stranded RNA, provides a powerful tool for functional studies once the sequence of a gene is known. In most mammalian cells, only short molecules can be used because long ones induce the interferon pathway. With the identification of a proper target sequence, the penetration of the oligonucleotides constitutes the most serious limitation in the application of this technique. Here we show that a small interfering RNA (siRNA) targeting the mRNA of the kinesin Eg5 induces a rapid mitotic arrest and provides a convenient assay for the optimization of siRNA transfection. Thus, dose responses can be established for different transfection techniques, highlighting the great differences in response to transfection techniques of various cell types. We report that the calcium phosphate precipitation technique can be an efficient and cost-effective alternative to Oligofectamine in some adherent cells, while electroporation can be efficient for some cells growing in suspension such as hematopoietic cells and some adherent cells. Significantly, the optimal parameters for the electroporation of siRNA differ from those for plasmids, allowing the use of milder conditions that induce less cell toxicity. In summary, a single siRNA leading to an easily assayed phenotype can be used to monitor the transfection of siRNA into any type of proliferating cells of both human and murine origin.

Profiling of drought-responsive microRNA and mRNA in tomato using high-throughput sequencing.

PubMed

Liu, Minmin; Yu, Huiyang; Zhao, Gangjun; Huang, Qiufeng; Lu, Yongen; Ouyang, Bo

2017-06-26

Abiotic stresses cause severe loss of crop production. Among them, drought is one of the most frequent environmental stresses, which limits crop growth, development and productivity. Plant drought tolerance is fine-tuned by a complex gene regulatory network. Understanding the molecular regulation of this polygenic trait is crucial for the eventual success to improve plant yield and quality. Recent studies have demonstrated that microRNAs play critical roles in plant drought tolerance. However, little is known about the microRNA in drought response of the model plant tomato. Here, we described the profiling of drought-responsive microRNA and mRNA in tomato using high-throughput next-generation sequencing. Drought stress was applied on the seedlings of M82, a drought-sensitive cultivated tomato genotype, and IL9-1, a drought-tolerant introgression line derived from the stress-resistant wild species Solanum pennellii LA0716 and M82. Under drought, IL9-1 performed superior than M82 regarding survival rate, H 2 O 2 elimination and leaf turgor maintenance. A total of four small RNA and eight mRNA libraries were constructed and sequenced using Illumina sequencing technology. 105 conserved and 179 novel microRNAs were identified, among them, 54 and 98 were differentially expressed upon drought stress, respectively. The majority of the differentially-expressed conserved microRNAs was up-regulated in IL9-1 whereas down-regulated in M82. Under drought stress, 2714 and 1161 genes were found to be differentially expressed in M82 and IL9-1, respectively, and many of their homologues are involved in plant stress, such as genes encoding transcription factor and protein kinase. Various pathways involved in abiotic stress were revealed by Gene Ontology and pathway analysis. The mRNA sequencing results indicated that most of the target genes were regulated by their corresponding microRNAs, which suggested that microRNAs may play essential roles in the drought tolerance of tomato. In

Experimental investigation of an RNA sequence space

NASA Technical Reports Server (NTRS)

Lee, Youn-Hyung; Dsouza, Lisa; Fox, George E.

1993-01-01

Modern rRNAs are the historic consequence of an ongoing evolutionary exploration of a sequence space. These extant sequences belong to a special subset of the sequence space that is comprised only of those primary sequences that can validly perform the biological function(s) required of the particular RNA. If it were possible to readily identify all such valid sequences, stochastic predictions could be made about the relative likelihood of various evolutionary pathways available to an RNA. Herein an experimental system which can assess whether a particular sequence is likely to have validity as a eubacterial 5S rRNA is described. A total of ten naturally occurring, and hence known to be valid, sequences and two point mutants of unknown validity were used to test the usefulness of the approach. Nine of the ten valid sequences tested positive whereas both mutants tested as clearly defective. The tenth valid sequence gave results that would be interpreted as reflecting a borderline status were the answer not known. These results demonstrate that it is possible to experimentally determine which sequences in local regions of the sequence space are potentially valid 5S rRNAs.

Ribosomal RNA sequence suggest microsporidia are extremely ancient eukaryotes

NASA Technical Reports Server (NTRS)

Vossbrinck, C. R.; Maddox, J. V.; Friedman, S.; Debrunner-Vossbrinck, B. A.; Woese, C. R.

1987-01-01

A comparative sequence analysis of the 18S small subunit ribosomal RNA (rRNA) of the microsporidium Vairimorpha necatrix is presented. The results show that this rRNA sequence is more unlike those of other eukaryotes than any known eukaryote rRNA sequence. It is concluded that the lineage leading to microsporidia branched very early from that leading to other eukaryotes.

RNA sequencing reveals significant miRNAs in Atypical endometrial hyperplasia.

PubMed

Tang, Shiqian; Dai, Yinmei

2018-06-01

In this paper, we aimed to investigate the miRNAs that played a regulatory role in the development of atypical endometrial hyperplasia (AEH). RNA sequencing was performed for endometrial tissues from 3 AEH patients and 3 endometrial normal hyperplasia patients. RNA sequencing data were processed and differentially expressed (DE) miRNAs were identified between AEH and controls. The target genes for DE miRNAs were identified and mapped to the protein-protein interaction (PPI) network. The miRNA related functions were predicted and miRNA-disease gene network was constructed. Total 18 DE miRNAs were overlapped in three sample groups, among which hsa-miR-577, hsa-miR-182-5p and hsa-miR-183-5p were top three miRNAs that targeting largest number of genes. Function analysis showed that the 18 overlapped miRNAs mainly related with cancer and signaling transduction related pathways. PPI network showed that total 12 genes were among top 20 genes based on three network topological features including BCL2, UMPS, MAPK13, PRKCB, CREB1, IGF1, SP1, SMAD3, IGF1R, NOTCH2, WNT5A, TK2. Top 10 miRNAs in miRNA-disease gene network were identified such as hsa-miR-577 (degree = 17), hsa-miR-182-5p (degree = 16) and hsa-miR-3609 (degree = 13). hsa-miR-577 and hsa-miR-182-5p may play regulatory role in AEH through AMPK signal pathway and Wnt signaling pathway. Copyright © 2018 Elsevier B.V. All rights reserved.

RNA sequencing reveals target genes of temporomandibular joint osteoarthritis in rats after the treatment of low-intensity pulsed ultrasound.

PubMed

He, Dong; An, Yanxin; Li, Yanhua; Wang, Jing; Wu, Gaoyi; Chen, Lei; Zhu, Guoxiong

2018-06-06

To explore the potential molecular mechanism of low-intensity pulsed ultrasound (LIPUS) in the treatment of temporomandibular joint osteoarthritis (TMJ-OA), and identify the target genes for therapy of TMJ-OA. Rat TMJ-OA was induced by unilateral occlusal trauma (UOT). At 8 weeks, the experimental group rats were treated by LIPUS for 4 weeks (5 days every week). The cartilage was examined by histological techniques. Gene expression profile in control, placebo and LIPUS-treated group were measured by RNA sequencing (RNA-Seq). Gene oncology (GO) and kyoto encyclopedia of genes and genomes (KEGG) annotated were performed and ten differentially expressed genes (DEGs) were further validated in another individual by quantitative real-time polymerase chain reaction (qRT-PCR). Per-2, a circadian rhythm gene, was further confirmed by western blot. TMJ-OA model was successfully established in rats through UOT. LIPUS played a positive role in attenuating the retrogression of cartilage. The cartilage lesion was determined by HE and Safranin-O staining. A significant and bran-new gene profile of 58 mRNAs was obtained from the RNA-Seq (LIPUS-treated/placebo) and generated approximately 30GB data. Annotation, functional classification and pathway of the data were analyzed based on GO and KEGG database and ten candidate DEGs were identified. Some of these genes were proved to be related to OA, such as matrix-degrading enzyme (ADAMTS-8), complement (C1qa, C3, C5aR1). Some were reported for the first time in TMJ-OA, such as circadian gene (Per-2, Dbp, Npas2 and Arntl). According to the results of qRT-PCR validation, the sequencing data was with a high degree of credibility. The circadian gene Per-2 was up-regulated by LIPUS in TMJ-OA on the mRNA and protein level. This study reveals the potential therapeutic genes related to TMJ-OA. Especially the circadian Per-2 gene was detected up-regulated by the treatment of LIPUS. It provides us a precious, new target OA-related gene and

Improved design of hammerhead ribozyme for selective digestion of target RNA through recognition of site-specific adenosine-to-inosine RNA editing

PubMed Central

Fukuda, Masatora; Kurihara, Kei; Yamaguchi, Shota; Oyama, Yui; Deshimaru, Masanobu

2014-01-01

Adenosine-to-inosine (A-to-I) RNA editing is an endogenous regulatory mechanism involved in various biological processes. Site-specific, editing-state–dependent degradation of target RNA may be a powerful tool both for analyzing the mechanism of RNA editing and for regulating biological processes. Previously, we designed an artificial hammerhead ribozyme (HHR) for selective, site-specific RNA cleavage dependent on the A-to-I RNA editing state. In the present work, we developed an improved strategy for constructing a trans-acting HHR that specifically cleaves target editing sites in the adenosine but not the inosine state. Specificity for unedited sites was achieved by utilizing a sequence encoding the intrinsic cleavage specificity of a natural HHR. We used in vitro selection methods in an HHR library to select for an extended HHR containing a tertiary stabilization motif that facilitates HHR folding into an active conformation. By using this method, we successfully constructed highly active HHRs with unedited-specific cleavage. Moreover, using HHR cleavage followed by direct sequencing, we demonstrated that this ribozyme could cleave serotonin 2C receptor (HTR2C) mRNA extracted from mouse brain, depending on the site-specific editing state. This unedited-specific cleavage also enabled us to analyze the effect of editing state at the E and C sites on editing at other sites by using direct sequencing for the simultaneous quantification of the editing ratio at multiple sites. Our approach has the potential to elucidate the mechanism underlying the interdependencies of different editing states in substrate RNA with multiple editing sites. PMID:24448449

RNAcentral: A comprehensive database of non-coding RNA sequences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Kelly Porter; Lau, Britney Yan

RNAcentral is a database of non-coding RNA (ncRNA) sequences that aggregates data from specialised ncRNA resources and provides a single entry point for accessing ncRNA sequences of all ncRNA types from all organisms. Since its launch in 2014, RNAcentral has integrated twelve new resources, taking the total number of collaborating database to 22, and began importing new types of data, such as modified nucleotides from MODOMICS and PDB. We created new species-specific identifiers that refer to unique RNA sequences within a context of single species. Furthermore, the website has been subject to continuous improvements focusing on text and sequence similaritymore » searches as well as genome browsing functionality.« less

RNAcentral: A comprehensive database of non-coding RNA sequences

DOE PAGES

Williams, Kelly Porter; Lau, Britney Yan

2016-10-28

RNAcentral is a database of non-coding RNA (ncRNA) sequences that aggregates data from specialised ncRNA resources and provides a single entry point for accessing ncRNA sequences of all ncRNA types from all organisms. Since its launch in 2014, RNAcentral has integrated twelve new resources, taking the total number of collaborating database to 22, and began importing new types of data, such as modified nucleotides from MODOMICS and PDB. We created new species-specific identifiers that refer to unique RNA sequences within a context of single species. Furthermore, the website has been subject to continuous improvements focusing on text and sequence similaritymore » searches as well as genome browsing functionality.« less

Small RNA sequencing and functional characterization reveals microRNA-143 tumor suppressor activity in liposarcoma

PubMed Central

Ugras, Stacy; Brill, Elliott; Jacobsen, Anders; Hafner, Markus; Socci, Nicholas D.; DeCarolis, Penelope L.; Khanin, Raya; O'Connor, Rachael; Mihailovic, Aleksandra; Taylor, Barry S.; Sheridan, Robert; Gimble, Jeffrey M.; Viale, Agnes; Crago, Aimee; Antonescu, Cristina R.; Sander, Chris; Tuschl, Thomas; Singer, Samuel

2011-01-01

Liposarcoma remains the most common mesenchymal cancer, with a mortality rate of 60% among patients with this disease. To address the present lack of therapeutic options, we embarked upon a study of microRNA (miRNA) expression alterations associated with liposarcomagenesis with the goal of exploiting differentially expressed miRNAs and the gene products they regulate as potential therapeutic targets. MicroRNA expression was profiled in samples of normal adipose tissue, well-differentiated liposarcoma, and dedifferentiated liposarcoma by both deep sequencing of small RNA libraries and hybridization-based Agilent microarrays. The expression profiles discriminated liposarcoma from normal adipose tissue and well-differentiated from dedifferentiated disease. We defined over 40 miRNAs that were dysregulated in dedifferentiated liposarcomas in both the sequencing and the microarray analysis. The upregulated miRNAs included two cancer-associated species (miR-21, miR-26a), and the downregulated miRNAs included two species that were highly abundant in adipose tissue (miR-143, miR-145). Restoring miR-143 expression in dedifferentiated liposarcoma cells inhibited proliferation, induced apoptosis, and decreased expression of BCL2, TOP2A, PRC1, and PLK1. The downregulation of PRC1 and its docking partner PLK1 suggests that miR-143 inhibits cytokinesis in these cells. In support of this idea, treatment with a PLK1 inhibitor potently induced G2/M growth arrest and apoptosis in liposarcoma cells. Taken together, our findings suggest that miR-143 re-expression vectors or selective agents directed at miR-143 or its targets may have therapeutic value in dedifferentiated liposarcoma. PMID:21693658

Deep sequencing of small RNA libraries from human prostate epithelial and stromal cells reveal distinct pattern of microRNAs primarily predicted to target growth factors.

PubMed

Singh, Savita; Zheng, Yun; Jagadeeswaran, Guru; Ebron, Jey Sabith; Sikand, Kavleen; Gupta, Sanjay; Sunker, Ramanjulu; Shukla, Girish C

2016-02-28

Complex epithelial and stromal cell interactions are required during the development and progression of prostate cancer. Regulatory small non-coding microRNAs (miRNAs) participate in the spatiotemporal regulation of messenger RNA (mRNA) and regulation of translation affecting a large number of genes involved in prostate carcinogenesis. In this study, through deep-sequencing of size fractionated small RNA libraries we profiled the miRNAs of prostate epithelial (PrEC) and stromal (PrSC) cells. Over 50 million reads were obtained for PrEC in which 860,468 were unique sequences. Similarly, nearly 76 million reads for PrSC were obtained in which over 1 million were unique reads. Expression of many miRNAs of broadly conserved and poorly conserved miRNA families were identified. Sixteen highly expressed miRNAs with significant change in expression in PrSC than PrEC were further analyzed in silico. ConsensusPathDB showed the target genes of these miRNAs were significantly involved in adherence junction, cell adhesion, EGRF, TGF-β and androgen signaling. Let-7 family of tumor-suppressor miRNAs expression was highly pervasive in both, PrEC and PrSC cells. In addition, we have also identified several miRNAs that are unique to PrEC or PrSC cells and their predicted putative targets are a group of transcription factors. This study provides perspective on the miRNA expression in PrEC and PrSC, and reveals a global trend in miRNA interactome. We conclude that the most abundant miRNAs are potential regulators of development and differentiation of the prostate gland by targeting a set of growth factors. Additionally, high level expression of the most members of let-7 family miRNAs suggests their role in the fine tuning of the growth and proliferation of prostate epithelial and stromal cells. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Loop nucleotides control primary and mature miRNA function in target recognition and repression

PubMed Central

Yue, Si-Biao; Deis Trujillo, Robin; Tang, Yujie; O'Gorman, William E

2011-01-01

MicroRNA (miRNA) genes produce three major RNA products; primary (pri-), precursor (pre-), and mature miRNAs. Each product includes sequences complementary to cognate targets, thus they all can in principle interact with the targets. In a recent study we showed that pri-miRNAs play a direct role in target recognition and repression in the absence of functional mature miRNAs. Here we examined the functional contribution of pri-miRNAs in target regulation when full-length functional miRNAs are present. We found that pri-let-7 loop nucleotides control the production of the 5′ end of mature miRNAs and modulate the activity of the miRNA gene. This insight enabled us to modulate biogenesis of functional mature miRNAs and dissect the causal relationships between mature miRNA biogenesis and target repression. We demonstrate that both pri- and mature miRNAs can contribute to target repression and that their contributions can be distinguished by the differences between the pri- and mature miRNAs' sensitivity to bind to the first seed nucleotide. Our results demonstrate that the regulatory information encoded in the pri-/pre-miRNA loop nucleotides controls the activities of pri-miRNAs and mature let-7 by influencing pri-miRNA and target complex formation and the fidelity of mature miRNA seed generation. PMID:22142974

Genome-Wide Analysis of miRNA targets in Brachypodium and Biomass Energy Crops

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, Pamela J.

2015-08-11

MicroRNAs (miRNAs) contribute to the control of numerous biological processes through the regulation of specific target mRNAs. Although the identities of these targets are essential to elucidate miRNA function, the targets are much more difficult to identify than the small RNAs themselves. Before this work, we pioneered the genome-wide identification of the targets of Arabidopsis miRNAs using an approach called PARE (German et al., Nature Biotech. 2008; Nature Protocols, 2009). Under this project, we applied PARE to Brachypodium distachyon (Brachypodium), a model plant in the Poaceae family, which includes the major food grain and bioenergy crops. Through in-depth global analysismore » and examination of specific examples, this research greatly expanded our knowledge of miRNAs and target RNAs of Brachypodium. New regulation in response to environmental stress or tissue type was found, and many new miRNAs were discovered. More than 260 targets of new and known miRNAs with PARE sequences at the precise sites of miRNA-guided cleavage were identified and characterized. Combining PARE data with the small RNA data also identified the miRNAs responsible for initiating approximately 500 phased loci, including one of the novel miRNAs. PARE analysis also revealed that differentially expressed miRNAs in the same family guide specific target RNA cleavage in a correspondingly tissue-preferential manner. The project included generation of small RNA and PARE resources for bioenergy crops, to facilitate ongoing discovery of conserved miRNA-target RNA regulation. By associating specific miRNA-target RNA pairs with known physiological functions, the research provides insights about gene regulation in different tissues and in response to environmental stress. This, and release of new PARE and small RNA data sets should contribute basic knowledge to enhance breeding and may suggest new strategies for improvement of biomass energy crops.« less

SPAR: small RNA-seq portal for analysis of sequencing experiments.

PubMed

Kuksa, Pavel P; Amlie-Wolf, Alexandre; Katanic, Živadin; Valladares, Otto; Wang, Li-San; Leung, Yuk Yee

2018-05-04

The introduction of new high-throughput small RNA sequencing protocols that generate large-scale genomics datasets along with increasing evidence of the significant regulatory roles of small non-coding RNAs (sncRNAs) have highlighted the urgent need for tools to analyze and interpret large amounts of small RNA sequencing data. However, it remains challenging to systematically and comprehensively discover and characterize sncRNA genes and specifically-processed sncRNA products from these datasets. To fill this gap, we present Small RNA-seq Portal for Analysis of sequencing expeRiments (SPAR), a user-friendly web server for interactive processing, analysis, annotation and visualization of small RNA sequencing data. SPAR supports sequencing data generated from various experimental protocols, including smRNA-seq, short total RNA sequencing, microRNA-seq, and single-cell small RNA-seq. Additionally, SPAR includes publicly available reference sncRNA datasets from our DASHR database and from ENCODE across 185 human tissues and cell types to produce highly informative small RNA annotations across all major small RNA types and other features such as co-localization with various genomic features, precursor transcript cleavage patterns, and conservation. SPAR allows the user to compare the input experiment against reference ENCODE/DASHR datasets. SPAR currently supports analyses of human (hg19, hg38) and mouse (mm10) sequencing data. SPAR is freely available at https://www.lisanwanglab.org/SPAR.

High-throughput sequencing of human plasma RNA by using thermostable group II intron reverse transcriptases

PubMed Central

Qin, Yidan; Yao, Jun; Wu, Douglas C.; Nottingham, Ryan M.; Mohr, Sabine; Hunicke-Smith, Scott; Lambowitz, Alan M.

2016-01-01

Next-generation RNA-sequencing (RNA-seq) has revolutionized transcriptome profiling, gene expression analysis, and RNA-based diagnostics. Here, we developed a new RNA-seq method that exploits thermostable group II intron reverse transcriptases (TGIRTs) and used it to profile human plasma RNAs. TGIRTs have higher thermostability, processivity, and fidelity than conventional reverse transcriptases, plus a novel template-switching activity that can efficiently attach RNA-seq adapters to target RNA sequences without RNA ligation. The new TGIRT-seq method enabled construction of RNA-seq libraries from <1 ng of plasma RNA in <5 h. TGIRT-seq of RNA in 1-mL plasma samples from a healthy individual revealed RNA fragments mapping to a diverse population of protein-coding gene and long ncRNAs, which are enriched in intron and antisense sequences, as well as nearly all known classes of small ncRNAs, some of which have never before been seen in plasma. Surprisingly, many of the small ncRNA species were present as full-length transcripts, suggesting that they are protected from plasma RNases in ribonucleoprotein (RNP) complexes and/or exosomes. This TGIRT-seq method is readily adaptable for profiling of whole-cell, exosomal, and miRNAs, and for related procedures, such as HITS-CLIP and ribosome profiling. PMID:26554030

RNA interference targets arbovirus replication in Culicoides cells.

PubMed

Schnettler, Esther; Ratinier, Maxime; Watson, Mick; Shaw, Andrew E; McFarlane, Melanie; Varela, Mariana; Elliott, Richard M; Palmarini, Massimo; Kohl, Alain

2013-03-01

Arboviruses are transmitted to vertebrate hosts by biting arthropod vectors such as mosquitoes, ticks, and midges. These viruses replicate in both arthropods and vertebrates and are thus exposed to different antiviral responses in these organisms. RNA interference (RNAi) is a sequence-specific RNA degradation mechanism that has been shown to play a major role in the antiviral response against arboviruses in mosquitoes. Culicoides midges are important vectors of arboviruses, known to transmit pathogens of humans and livestock such as bluetongue virus (BTV) (Reoviridae), Oropouche virus (Bunyaviridae), and likely the recently discovered Schmallenberg virus (Bunyaviridae). In this study, we investigated whether Culicoides cells possess an antiviral RNAi response and whether this is effective against arboviruses, including those with double-stranded RNA (dsRNA) genomes, such as BTV. Using reporter gene-based assays, we established the presence of a functional RNAi response in Culicoides sonorensis-derived KC cells which is effective in inhibiting BTV infection. Sequencing of small RNAs from KC and Aedes aegypti-derived Aag2 cells infected with BTV or the unrelated Schmallenberg virus resulted in the production of virus-derived small interfering RNAs (viRNAs) of 21 nucleotides, similar to the viRNAs produced during arbovirus infections of mosquitoes. In addition, viRNA profiles strongly suggest that the BTV dsRNA genome is accessible to a Dicer-type nuclease. Thus, we show for the first time that midge cells target arbovirus replication by mounting an antiviral RNAi response mainly resembling that of other insect vectors of arboviruses.

Guide-bound structures of an RNA-targeting A-cleaving CRISPR-Cas13a enzyme

PubMed Central

Knott, Gavin J.; East-Seletsky, Alexandra; Cofsky, Joshua C.; Holton, James M.; Charles, Emeric; O’Connell, Mitchell R.; Doudna, Jennifer A.

2018-01-01

CRISPR adaptive immune systems protect bacteria from infections by deploying CRISPR RNA (crRNA)-guided enzymes to recognize and cut foreign nucleic acids. Type VI-A CRISPR-Cas systems include the Cas13a enzyme, an RNA-activated ribonuclease (RNase) capable of crRNA processing and single-stranded RNA degradation upon target transcript binding. Here we present the 2.0 Å resolution crystal structure of a crRNA-bound L. bacterium Cas13a (LbaCas13a), representing a recently discovered Cas13a enzyme subtype. This structure and accompanying biochemical experiments define for the first time the Cas13a catalytic residues that are directly responsible for crRNA maturation. In addition, the orientation of the foreign-derived target RNA-specifying sequence in the protein interior explains the conformational gating of Cas13a nuclease activation. These results describe how Cas13a enzymes generate functional crRNAs and how catalytic activity is blocked prior to target RNA recognition, with implications for both bacterial immunity and diagnostic applications. PMID:28892041

Guide-bound structures of an RNA-targeting A-cleaving CRISPR–Cas13a enzyme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knott, Gavin J.; East-Seletsky, Alexandra; Cofsky, Joshua C.

CRISPR adaptive immune systems protect bacteria from infections by deploying CRISPR RNA (crRNA)-guided enzymes to recognize and cut foreign nucleic acids. Type VI-A CRISPR–Cas systems include the Cas13a enzyme, an RNA-activated RNase capable of crRNA processing and single-stranded RNA degradation upon target-transcript binding. Here we present the 2.0-Å resolution crystal structure of a crRNA-bound Lachnospiraceae bacterium Cas13a (LbaCas13a), representing a recently discovered Cas13a enzyme subtype. This structure and accompanying biochemical experiments define the Cas13a catalytic residues that are directly responsible for crRNA maturation. In addition, the orientation of the foreign-derived target-RNA-specifying sequence in the protein interior explains the conformational gatingmore » of Cas13a nuclease activation. These results describe how Cas13a enzymes generate functional crRNAs and how catalytic activity is blocked before target-RNA recognition, with implications for both bacterial immunity and diagnostic applications.« less

Guide-bound structures of an RNA-targeting A-cleaving CRISPR–Cas13a enzyme

DOE PAGES

Knott, Gavin J.; East-Seletsky, Alexandra; Cofsky, Joshua C.; ...

2017-09-11

CRISPR adaptive immune systems protect bacteria from infections by deploying CRISPR RNA (crRNA)-guided enzymes to recognize and cut foreign nucleic acids. Type VI-A CRISPR–Cas systems include the Cas13a enzyme, an RNA-activated RNase capable of crRNA processing and single-stranded RNA degradation upon target-transcript binding. Here we present the 2.0-Å resolution crystal structure of a crRNA-bound Lachnospiraceae bacterium Cas13a (LbaCas13a), representing a recently discovered Cas13a enzyme subtype. This structure and accompanying biochemical experiments define the Cas13a catalytic residues that are directly responsible for crRNA maturation. In addition, the orientation of the foreign-derived target-RNA-specifying sequence in the protein interior explains the conformational gatingmore » of Cas13a nuclease activation. These results describe how Cas13a enzymes generate functional crRNAs and how catalytic activity is blocked before target-RNA recognition, with implications for both bacterial immunity and diagnostic applications.« less

Digital RNA sequencing minimizes sequence-dependent bias and amplification noise with optimized single-molecule barcodes

PubMed Central

Shiroguchi, Katsuyuki; Jia, Tony Z.; Sims, Peter A.; Xie, X. Sunney

2012-01-01

RNA sequencing (RNA-Seq) is a powerful tool for transcriptome profiling, but is hampered by sequence-dependent bias and inaccuracy at low copy numbers intrinsic to exponential PCR amplification. We developed a simple strategy for mitigating these complications, allowing truly digital RNA-Seq. Following reverse transcription, a large set of barcode sequences is added in excess, and nearly every cDNA molecule is uniquely labeled by random attachment of barcode sequences to both ends. After PCR, we applied paired-end deep sequencing to read the two barcodes and cDNA sequences. Rather than counting the number of reads, RNA abundance is measured based on the number of unique barcode sequences observed for a given cDNA sequence. We optimized the barcodes to be unambiguously identifiable, even in the presence of multiple sequencing errors. This method allows counting with single-copy resolution despite sequence-dependent bias and PCR-amplification noise, and is analogous to digital PCR but amendable to quantifying a whole transcriptome. We demonstrated transcriptome profiling of Escherichia coli with more accurate and reproducible quantification than conventional RNA-Seq. PMID:22232676

Identification and profiling of novel microRNAs in the Brassica rapa genome based on small RNA deep sequencing

PubMed Central

2012-01-01

Background MicroRNAs (miRNAs) are one of the functional non-coding small RNAs involved in the epigenetic control of the plant genome. Although plants contain both evolutionary conserved miRNAs and species-specific miRNAs within their genomes, computational methods often only identify evolutionary conserved miRNAs. The recent sequencing of the Brassica rapa genome enables us to identify miRNAs and their putative target genes. In this study, we sought to provide a more comprehensive prediction of B. rapa miRNAs based on high throughput small RNA deep sequencing. Results We sequenced small RNAs from five types of tissue: seedlings, roots, petioles, leaves, and flowers. By analyzing 2.75 million unique reads that mapped to the B. rapa genome, we identified 216 novel and 196 conserved miRNAs that were predicted to target approximately 20% of the genome’s protein coding genes. Quantitative analysis of miRNAs from the five types of tissue revealed that novel miRNAs were expressed in diverse tissues but their expression levels were lower than those of the conserved miRNAs. Comparative analysis of the miRNAs between the B. rapa and Arabidopsis thaliana genomes demonstrated that redundant copies of conserved miRNAs in the B. rapa genome may have been deleted after whole genome triplication. Novel miRNA members seemed to have spontaneously arisen from the B. rapa and A. thaliana genomes, suggesting the species-specific expansion of miRNAs. We have made this data publicly available in a miRNA database of B. rapa called BraMRs. The database allows the user to retrieve miRNA sequences, their expression profiles, and a description of their target genes from the five tissue types investigated here. Conclusions This is the first report to identify novel miRNAs from Brassica crops using genome-wide high throughput techniques. The combination of computational methods and small RNA deep sequencing provides robust predictions of miRNAs in the genome. The finding of numerous novel mi

Deep Sequencing Reveals Direct Targets of Gammaherpesvirus-Induced mRNA Decay and Suggests That Multiple Mechanisms Govern Cellular Transcript Escape

PubMed Central

Clyde, Karen; Glaunsinger, Britt A.

2011-01-01

One characteristic of lytic infection with gammaherpesviruses, including Kaposi's sarcoma-associated herpesvirus (KSHV), Epstein-Barr virus (EBV) and murine herpesvirus 68 (MHV68), is the dramatic suppression of cellular gene expression in a process known as host shutoff. The alkaline exonuclease proteins (KSHV SOX, MHV-68 muSOX and EBV BGLF5) have been shown to induce shutoff by destabilizing cellular mRNAs. Here we extend previous analyses of cellular mRNA abundance during lytic infection to characterize the effects of SOX and muSOX, in the absence of other viral genes, utilizing deep sequencing technology (RNA-seq). Consistent with previous observations during lytic infection, the majority of transcripts are downregulated in cells expressing either SOX or muSOX, with muSOX acting as a more potent shutoff factor than SOX. Moreover, most cellular messages fall into the same expression class in both SOX- and muSOX-expressing cells, indicating that both factors target similar pools of mRNAs. More abundant mRNAs are more efficiently downregulated, suggesting a concentration effect in transcript targeting. However, even among highly expressed genes there are mRNAs that escape host shutoff. Further characterization of select escapees reveals multiple mechanisms by which cellular genes can evade downregulation. While some mRNAs are directly refractory to SOX, the steady state levels of others remain unchanged, presumably as a consequence of downstream effects on mRNA biogenesis. Collectively, these studies lay the framework for dissecting the mechanisms underlying the susceptibility of mRNA to destruction during lytic gammaherpesvirus infection. PMID:21573023

Probe-Directed Degradation (PDD) for Flexible Removal of Unwanted cDNA Sequences from RNA-Seq Libraries.

PubMed

Archer, Stuart K; Shirokikh, Nikolay E; Preiss, Thomas

2015-04-01

Most applications for RNA-seq require the depletion of abundant transcripts to gain greater coverage of the underlying transcriptome. The sequences to be targeted for depletion depend on application and species and in many cases may not be supported by commercial depletion kits. This unit describes a method for generating RNA-seq libraries that incorporates probe-directed degradation (PDD), which can deplete any unwanted sequence set, with the low-bias split-adapter method of library generation (although many other library generation methods are in principle compatible). The overall strategy is suitable for applications requiring customized sequence depletion or where faithful representation of fragment ends and lack of sequence bias is paramount. We provide guidelines to rapidly design specific probes against the target sequence, and a detailed protocol for library generation using the split-adapter method including several strategies for streamlining the technique and reducing adapter dimer content. Copyright © 2015 John Wiley & Sons, Inc.

Soft computing model for optimized siRNA design by identifying off target possibilities using artificial neural network model.

PubMed

Murali, Reena; John, Philips George; Peter S, David

2015-05-15

The ability of small interfering RNA (siRNA) to do posttranscriptional gene regulation by knocking down targeted genes is an important research topic in functional genomics, biomedical research and in cancer therapeutics. Many tools had been developed to design exogenous siRNA with high experimental inhibition. Even though considerable amount of work has been done in designing exogenous siRNA, design of effective siRNA sequences is still a challenging work because the target mRNAs must be selected such that their corresponding siRNAs are likely to be efficient against that target and unlikely to accidentally silence other transcripts due to sequence similarity. In some cases, siRNAs may tolerate mismatches with the target mRNA, but knockdown of genes other than the intended target could make serious consequences. Hence to design siRNAs, two important concepts must be considered: the ability in knocking down target genes and the off target possibility on any nontarget genes. So before doing gene silencing by siRNAs, it is essential to analyze their off target effects in addition to their inhibition efficacy against a particular target. Only a few methods have been developed by considering both efficacy and off target possibility of siRNA against a gene. In this paper we present a new design of neural network model with whole stacking energy (ΔG) that enables to identify the efficacy and off target effect of siRNAs against target genes. The tool lists all siRNAs against a particular target with their inhibition efficacy and number of matches or sequence similarity with other genes in the database. We could achieve an excellent performance of Pearson Correlation Coefficient (R=0. 74) and Area Under Curve (AUC=0.906) when the threshold of whole stacking energy is ≥-34.6 kcal/mol. To the best of the author's knowledge, this is one of the best score while considering the "combined efficacy and off target possibility" of siRNA for silencing a gene. The proposed model

miRNA and Degradome Sequencing Reveal miRNA and Their Target Genes That May Mediate Shoot Growth in Spur Type Mutant “Yanfu 6”

PubMed Central

Song, Chunhui; Zhang, Dong; Zheng, Liwei; Zhang, Jie; Zhang, Baojuan; Luo, Wenwen; Li, Youmei; Li, Guangfang; Ma, Juanjuan; Han, Mingyu

2017-01-01

The spur-type growth habit in apple trees is characterized by short internodes, increased number of fruiting spurs, and compact growth that promotes flowering and facilitates management practices, such as pruning. The molecular mechanisms responsible for regulating spur-type growth have not been elucidated. In the present study, miRNAs and the expression of their potential target genes were evaluated in shoot tips of “Nagafu 2” (CF) and spur-type bud mutation “Yanfu 6” (YF). A total of 700 mature miRNAs were identified, including 202 known apple miRNAs and 498 potential novel miRNA candidates. A comparison of miRNA expression in CF and YF revealed 135 differentially expressed genes, most of which were downregulated in YF. YF also had lower levels of GA, ZR, IAA, and ABA hormones, relative to CF. Exogenous applications of GA promoted YF shoot growth. Based on the obtained results, a regulatory network involving plant hormones, miRNA, and their potential target genes is proposed for the molecular mechanism regulating the growth of YF. miRNA164, miRNA166, miRNA171, and their potential targets, and associated plant hormones, appear to regulate shoot apical meristem (SAM) growth. miRNA159, miRNA167, miRNA396, and their potential targets, and associated plant hormones appear to regulate cell division and internode length. This study provides a foundation for further studies designed to elucidate the mechanism underlying spur-type apple architecture. PMID:28424721

Evaluation of two main RNA-seq approaches for gene quantification in clinical RNA sequencing: polyA+ selection versus rRNA depletion.

PubMed

Zhao, Shanrong; Zhang, Ying; Gamini, Ramya; Zhang, Baohong; von Schack, David

2018-03-19

To allow efficient transcript/gene detection, highly abundant ribosomal RNAs (rRNA) are generally removed from total RNA either by positive polyA+ selection or by rRNA depletion (negative selection) before sequencing. Comparisons between the two methods have been carried out by various groups, but the assessments have relied largely on non-clinical samples. In this study, we evaluated these two RNA sequencing approaches using human blood and colon tissue samples. Our analyses showed that rRNA depletion captured more unique transcriptome features, whereas polyA+ selection outperformed rRNA depletion with higher exonic coverage and better accuracy of gene quantification. For blood- and colon-derived RNAs, we found that 220% and 50% more reads, respectively, would have to be sequenced to achieve the same level of exonic coverage in the rRNA depletion method compared with the polyA+ selection method. Therefore, in most cases we strongly recommend polyA+ selection over rRNA depletion for gene quantification in clinical RNA sequencing. Our evaluation revealed that a small number of lncRNAs and small RNAs made up a large fraction of the reads in the rRNA depletion RNA sequencing data. Thus, we recommend that these RNAs are specifically depleted to improve the sequencing depth of the remaining RNAs.

RNA-Targeted Therapeutics.

PubMed

Crooke, Stanley T; Witztum, Joseph L; Bennett, C Frank; Baker, Brenda F

2018-04-03

RNA-targeted therapies represent a platform for drug discovery involving chemically modified oligonucleotides, a wide range of cellular RNAs, and a novel target-binding motif, Watson-Crick base pairing. Numerous hurdles considered by many to be impassable have been overcome. Today, four RNA-targeted therapies are approved for commercial use for indications as diverse as Spinal Muscular Atrophy (SMA) and reduction of low-density lipoprotein cholesterol (LDL-C) and by routes of administration including subcutaneous, intravitreal, and intrathecal delivery. The technology is efficient and supports approaching "undruggable" targets. Three additional agents are progressing through registration, and more are in clinical development, representing several chemical and structural classes. Moreover, progress in understanding the molecular mechanisms by which these drugs work has led to steadily better clinical performance and a wide range of mechanisms that may be exploited for therapeutic purposes. Here we summarize the progress, future challenges, and opportunities for this drug discovery platform. Copyright © 2018 Elsevier Inc. All rights reserved.

Protospacer Adjacent Motif (PAM)-Distal Sequences Engage CRISPR Cas9 DNA Target Cleavage

PubMed Central

Ethier, Sylvain; Schmeing, T. Martin; Dostie, Josée; Pelletier, Jerry

2014-01-01

The clustered regularly interspaced short palindromic repeat (CRISPR)-associated enzyme Cas9 is an RNA-guided nuclease that has been widely adapted for genome editing in eukaryotic cells. However, the in vivo target specificity of Cas9 is poorly understood and most studies rely on in silico predictions to define the potential off-target editing spectrum. Using chromatin immunoprecipitation followed by sequencing (ChIP-seq), we delineate the genome-wide binding panorama of catalytically inactive Cas9 directed by two different single guide (sg) RNAs targeting the Trp53 locus. Cas9:sgRNA complexes are able to load onto multiple sites with short seed regions adjacent to 5′NGG3′ protospacer adjacent motifs (PAM). Yet among 43 ChIP-seq sites harboring seed regions analyzed for mutational status, we find editing only at the intended on-target locus and one off-target site. In vitro analysis of target site recognition revealed that interactions between the 5′ end of the guide and PAM-distal target sequences are necessary to efficiently engage Cas9 nucleolytic activity, providing an explanation for why off-target editing is significantly lower than expected from ChIP-seq data. PMID:25275497

GAMUT: GPU accelerated microRNA analysis to uncover target genes through CUDA-miRanda

PubMed Central

2014-01-01

Background Non-coding sequences such as microRNAs have important roles in disease processes. Computational microRNA target identification (CMTI) is becoming increasingly important since traditional experimental methods for target identification pose many difficulties. These methods are time-consuming, costly, and often need guidance from computational methods to narrow down candidate genes anyway. However, most CMTI methods are computationally demanding, since they need to handle not only several million query microRNA and reference RNA pairs, but also several million nucleotide comparisons within each given pair. Thus, the need to perform microRNA identification at such large scale has increased the demand for parallel computing. Methods Although most CMTI programs (e.g., the miRanda algorithm) are based on a modified Smith-Waterman (SW) algorithm, the existing parallel SW implementations (e.g., CUDASW++ 2.0/3.0, SWIPE) are unable to meet this demand in CMTI tasks. We present CUDA-miRanda, a fast microRNA target identification algorithm that takes advantage of massively parallel computing on Graphics Processing Units (GPU) using NVIDIA's Compute Unified Device Architecture (CUDA). CUDA-miRanda specifically focuses on the local alignment of short (i.e., ≤ 32 nucleotides) sequences against longer reference sequences (e.g., 20K nucleotides). Moreover, the proposed algorithm is able to report multiple alignments (up to 191 top scores) and the corresponding traceback sequences for any given (query sequence, reference sequence) pair. Results Speeds over 5.36 Giga Cell Updates Per Second (GCUPs) are achieved on a server with 4 NVIDIA Tesla M2090 GPUs. Compared to the original miRanda algorithm, which is evaluated on an Intel Xeon E5620@2.4 GHz CPU, the experimental results show up to 166 times performance gains in terms of execution time. In addition, we have verified that the exact same targets were predicted in both CUDA-miRanda and the original mi

Computational Analysis of Mouse piRNA Sequence and Biogenesis

PubMed Central

Betel, Doron; Sheridan, Robert; Marks, Debora S; Sander, Chris

2007-01-01

The recent discovery of a new class of 30-nucleotide long RNAs in mammalian testes, called PIWI-interacting RNA (piRNA), with similarities to microRNAs and repeat-associated small interfering RNAs (rasiRNAs), has raised puzzling questions regarding their biogenesis and function. We report a comparative analysis of currently available piRNA sequence data from the pachytene stage of mouse spermatogenesis that sheds light on their sequence diversity and mechanism of biogenesis. We conclude that (i) there are at least four times as many piRNAs in mouse testes than currently known; (ii) piRNAs, which originate from long precursor transcripts, are generated by quasi-random enzymatic processing that is guided by a weak sequence signature at the piRNA 5′ends resulting in a large number of distinct sequences; and (iii) many of the piRNA clusters contain inverted repeats segments capable of forming double-strand RNA fold-back segments that may initiate piRNA processing analogous to transposon silencing. PMID:17997596

A Bioinformatic Pipeline for Monitoring of the Mutational Stability of Viral Drug Targets with Deep-Sequencing Technology.

PubMed

Kravatsky, Yuri; Chechetkin, Vladimir; Fedoseeva, Daria; Gorbacheva, Maria; Kravatskaya, Galina; Kretova, Olga; Tchurikov, Nickolai

2017-11-23

The efficient development of antiviral drugs, including efficient antiviral small interfering RNAs (siRNAs), requires continuous monitoring of the strict correspondence between a drug and the related highly variable viral DNA/RNA target(s). Deep sequencing is able to provide an assessment of both the general target conservation and the frequency of particular mutations in the different target sites. The aim of this study was to develop a reliable bioinformatic pipeline for the analysis of millions of short, deep sequencing reads corresponding to selected highly variable viral sequences that are drug target(s). The suggested bioinformatic pipeline combines the available programs and the ad hoc scripts based on an original algorithm of the search for the conserved targets in the deep sequencing data. We also present the statistical criteria for the threshold of reliable mutation detection and for the assessment of variations between corresponding data sets. These criteria are robust against the possible sequencing errors in the reads. As an example, the bioinformatic pipeline is applied to the study of the conservation of RNA interference (RNAi) targets in human immunodeficiency virus 1 (HIV-1) subtype A. The developed pipeline is freely available to download at the website http://virmut.eimb.ru/. Brief comments and comparisons between VirMut and other pipelines are also presented.

RNA targeting with CRISPR-Cas13.

PubMed

Abudayyeh, Omar O; Gootenberg, Jonathan S; Essletzbichler, Patrick; Han, Shuo; Joung, Julia; Belanto, Joseph J; Verdine, Vanessa; Cox, David B T; Kellner, Max J; Regev, Aviv; Lander, Eric S; Voytas, Daniel F; Ting, Alice Y; Zhang, Feng

2017-10-12

RNA has important and diverse roles in biology, but molecular tools to manipulate and measure it are limited. For example, RNA interference can efficiently knockdown RNAs, but it is prone to off-target effects, and visualizing RNAs typically relies on the introduction of exogenous tags. Here we demonstrate that the class 2 type VI RNA-guided RNA-targeting CRISPR-Cas effector Cas13a (previously known as C2c2) can be engineered for mammalian cell RNA knockdown and binding. After initial screening of 15 orthologues, we identified Cas13a from Leptotrichia wadei (LwaCas13a) as the most effective in an interference assay in Escherichia coli. LwaCas13a can be heterologously expressed in mammalian and plant cells for targeted knockdown of either reporter or endogenous transcripts with comparable levels of knockdown as RNA interference and improved specificity. Catalytically inactive LwaCas13a maintains targeted RNA binding activity, which we leveraged for programmable tracking of transcripts in live cells. Our results establish CRISPR-Cas13a as a flexible platform for studying RNA in mammalian cells and therapeutic development.

Construction of armored RNA containing long-size chimeric RNA by increasing the number and affinity of the pac site in exogenous rna and sequence coding coat protein of the MS2 bacteriophage.

PubMed

Wei, Baojun; Wei, Yuxiang; Zhang, Kuo; Yang, Changmei; Wang, Jing; Xu, Ruihuan; Zhan, Sien; Lin, Guigao; Wang, Wei; Liu, Min; Wang, Lunan; Zhang, Rui; Li, Jinming

2008-01-01

To construct a one-plasmid expression system of the armored RNA containing long chimeric RNA by increasing the number and affinity of the pac site. The plasmid pET-MS2-pac was constructed with one C-variant pac site, and then the plasmid pM-CR-2C containing 1,891-bp chimeric sequences and two C-variant pac sites was produced. Meanwhile, three plasmids (pM-CR-C, pM-CR-2W and pM-CR-W) were obtained as parallel controls with a different number and affinity of the pac site. Finally, the armored RNA was expressed and purified. The armored RNA with 1,891 bases target RNA was expressed successfully by the one-plasmid expression system with two C-variant pac sites, while for one pac site, no matter whether the affinity was changed or not, only the 1,200 bases target RNA was packaged. It was also found that the C-variant pac site could increase the expression efficiency of the armored RNA. The armored RNA with 1,891-bp exogenous RNA in our study showed the characterization of ribonuclease resistance and stability at different time points and temperature conditions. The armored RNA with 1,891 bases exogenous RNA was constructed and the expression system can be used as a platform for preparation of the armored RNA containing long RNA sequences. Copyright 2008 S. Karger AG, Basel.

miRBase: integrating microRNA annotation and deep-sequencing data.

PubMed

Kozomara, Ana; Griffiths-Jones, Sam

2011-01-01

miRBase is the primary online repository for all microRNA sequences and annotation. The current release (miRBase 16) contains over 15,000 microRNA gene loci in over 140 species, and over 17,000 distinct mature microRNA sequences. Deep-sequencing technologies have delivered a sharp rise in the rate of novel microRNA discovery. We have mapped reads from short RNA deep-sequencing experiments to microRNAs in miRBase and developed web interfaces to view these mappings. The user can view all read data associated with a given microRNA annotation, filter reads by experiment and count, and search for microRNAs by tissue- and stage-specific expression. These data can be used as a proxy for relative expression levels of microRNA sequences, provide detailed evidence for microRNA annotations and alternative isoforms of mature microRNAs, and allow us to revisit previous annotations. miRBase is available online at: http://www.mirbase.org/.

Capturing microRNA targets using an RNA-induced silencing complex (RISC)-trap approach.

PubMed

Cambronne, Xiaolu A; Shen, Rongkun; Auer, Paul L; Goodman, Richard H

2012-12-11

Identifying targets is critical for understanding the biological effects of microRNA (miRNA) expression. The challenge lies in characterizing the cohort of targets for a specific miRNA, especially when targets are being actively down-regulated in miRNA- RNA-induced silencing complex (RISC)-messengerRNA (mRNA) complexes. We have developed a robust and versatile strategy called RISCtrap to stabilize and purify targets from this transient interaction. Its utility was demonstrated by determining specific high-confidence target datasets for miR-124, miR-132, and miR-181 that contained known and previously unknown transcripts. Two previously unknown miR-132 targets identified with RISCtrap, adaptor protein CT10 regulator of kinase 1 (CRK1) and tight junction-associated protein 1 (TJAP1), were shown to be endogenously regulated by miR-132 in adult mouse forebrain. The datasets, moreover, differed in the number of targets and in the types and frequency of microRNA recognition element (MRE) motifs, thus revealing a previously underappreciated level of specificity in the target sets regulated by individual miRNAs.

Size, Shape, and Sequence-Dependent Immunogenicity of RNA Nanoparticles.

PubMed

Guo, Sijin; Li, Hui; Ma, Mengshi; Fu, Jian; Dong, Yizhou; Guo, Peixuan

2017-12-15

RNA molecules have emerged as promising therapeutics. Like all other drugs, the safety profile and immune response are important criteria for drug evaluation. However, the literature on RNA immunogenicity has been controversial. Here, we used the approach of RNA nanotechnology to demonstrate that the immune response of RNA nanoparticles is size, shape, and sequence dependent. RNA triangle, square, pentagon, and tetrahedron with same shape but different sizes, or same size but different shapes were used as models to investigate the immune response. The levels of pro-inflammatory cytokines induced by these RNA nanoarchitectures were assessed in macrophage-like cells and animals. It was found that RNA polygons without extension at the vertexes were immune inert. However, when single-stranded RNA with a specific sequence was extended from the vertexes of RNA polygons, strong immune responses were detected. These immunostimulations are sequence specific, because some other extended sequences induced little or no immune response. Additionally, larger-size RNA square induced stronger cytokine secretion. 3D RNA tetrahedron showed stronger immunostimulation than planar RNA triangle. These results suggest that the immunogenicity of RNA nanoparticles is tunable to produce either a minimal immune response that can serve as safe therapeutic vectors, or a strong immune response for cancer immunotherapy or vaccine adjuvants. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

HYBRIDIZATION PROPERTIES OF DNA SEQUENCES DIRECTING THE SYNTHESIS OF MESSENGER RNA AND HETEROGENEOUS NUCLEAR RNA

PubMed Central

Greenberg, Jay R.; Perry, Robert P.

1971-01-01

The relationship of the DNA sequences from which polyribosomal messenger RNA (mRNA) and heterogeneous nuclear RNA (NRNA) of mouse L cells are transcribed was investigated by means of hybridization kinetics and thermal denaturation of the hybrids. Hybridization was performed in formamide solutions at DNA excess. Under these conditions most of the hybridizing mRNA and NRNA react at values of Dot (DNA concentration multiplied by time) expected for RNA transcribed from the nonrepeated or rarely repeated fraction of the genome. However, a fraction of both mRNA and NRNA hybridize at values of Dot about 10,000 times lower, and therefore must be transcribed from highly redundant DNA sequences. The fraction of NRNA hybridizing to highly repeated sequences is about 1.7 times greater than the corresponding fraction of mRNA. The hybrids formed by the rapidly reacting fractions of both NRNA and mRNA melt over a narrow temperature range with a midpoint about 11°C below that of native L cell DNA. This indicates that these hybrids consist of partially complementary sequences with approximately 11% mismatching of bases. Hybrids formed by the slowly reacting fraction of NRNA melt within 4°–6°C of native DNA, indicating very little, if any, mismatching of bases. Hybrids of the slowly reacting components of mRNA, formed under conditions of sufficiently low RNA input, have a high thermal stability, similar to that observed for hybrids of the slowly reacting NRNA component. However, when higher inputs of mRNA are used, hybrids are formed which have a strikingly lower thermal stability. This observation can be explained by assuming that there is sufficient similarity among the relatively rare DNA sequences coding for mRNA so that under hybridization conditions, in which these DNA sequences are not truly in excess, reversible hybrids exhibiting a considerable amount of mispairing are formed. The fact that a comparable phenomenon has not been observed for NRNA may mean that there is

RNAcentral: an international database of ncRNA sequences

DOE PAGES

Williams, Kelly Porter

2014-10-28

The field of non-coding RNA biology has been hampered by the lack of availability of a comprehensive, up-to-date collection of accessioned RNA sequences. Here we present the first release of RNAcentral, a database that collates and integrates information from an international consortium of established RNA sequence databases. The initial release contains over 8.1 million sequences, including representatives of all major functional classes. A web portal (http://rnacentral.org) provides free access to data, search functionality, cross-references, source code and an integrated genome browser for selected species.

Targeted CRISPR disruption reveals a role for RNase MRP RNA in human preribosomal RNA processing.

PubMed

Goldfarb, Katherine C; Cech, Thomas R

2017-01-01

MRP RNA is an abundant, essential noncoding RNA whose functions have been proposed in yeast but are incompletely understood in humans. Mutations in the genomic locus for MRP RNA cause pleiotropic human diseases, including cartilage hair hypoplasia (CHH). Here we applied CRISPR-Cas9 genome editing to disrupt the endogenous human MRP RNA locus, thereby attaining what has eluded RNAi and RNase H experiments: elimination of MRP RNA in the majority of cells. The resulting accumulation of ribosomal RNA (rRNA) precursor-analyzed by RNA fluorescent in situ hybridization (FISH), Northern blots, and RNA sequencing-implicates MRP RNA in pre-rRNA processing. Amelioration of pre-rRNA imbalance is achieved through rescue of MRP RNA levels by ectopic expression. Furthermore, affinity-purified MRP ribonucleoprotein (RNP) from HeLa cells cleaves the human pre-rRNA in vitro at at least one site used in cells, while RNP isolated from cells with CRISPR-edited MRP loci loses this activity, and ectopic MRP RNA expression restores cleavage activity. Thus, a role for RNase MRP in human pre-rRNA processing is established. As demonstrated here, targeted CRISPR disruption is a valuable tool for functional studies of essential noncoding RNAs that are resistant to RNAi and RNase H-based degradation. © 2017 Goldfarb and Cech; Published by Cold Spring Harbor Laboratory Press.

Deep sequencing of foot-and-mouth disease virus reveals RNA sequences involved in genome packaging.

PubMed

Logan, Grace; Newman, Joseph; Wright, Caroline F; Lasecka-Dykes, Lidia; Haydon, Daniel T; Cottam, Eleanor M; Tuthill, Tobias J

2017-10-18

Non-enveloped viruses protect their genomes by packaging them into an outer shell or capsid of virus-encoded proteins. Packaging and capsid assembly in RNA viruses can involve interactions between capsid proteins and secondary structures in the viral genome as exemplified by the RNA bacteriophage MS2 and as proposed for other RNA viruses of plants, animals and human. In the picornavirus family of non-enveloped RNA viruses, the requirements for genome packaging remain poorly understood. Here we show a novel and simple approach to identify predicted RNA secondary structures involved in genome packaging in the picornavirus foot-and-mouth disease virus (FMDV). By interrogating deep sequencing data generated from both packaged and unpackaged populations of RNA we have determined multiple regions of the genome with constrained variation in the packaged population. Predicted secondary structures of these regions revealed stem loops with conservation of structure and a common motif at the loop. Disruption of these features resulted in attenuation of virus growth in cell culture due to a reduction in assembly of mature virions. This study provides evidence for the involvement of predicted RNA structures in picornavirus packaging and offers a readily transferable methodology for identifying packaging requirements in many other viruses. Importance In order to transmit their genetic material to a new host, non-enveloped viruses must protect their genomes by packaging them into an outer shell or capsid of virus-encoded proteins. For many non-enveloped RNA viruses the requirements for this critical part of the viral life cycle remain poorly understood. We have identified RNA sequences involved in genome packaging of the picornavirus foot-and-mouth disease virus. This virus causes an economically devastating disease of livestock affecting both the developed and developing world. The experimental methods developed to carry out this work are novel, simple and transferable to the

RNA circularization reveals terminal sequence heterogeneity in a double-stranded RNA virus.

PubMed

Widmer, G

1993-03-01

Double-stranded RNA viruses (dsRNA), termed LRV1, have been found in several strains of the protozoan parasite Leishmania. With the aim of constructing a full-length cDNA copy of the viral genome, including its terminal sequences, a protocol based on PCR amplification across the 3'-5' junction of circularized RNA was developed. This method proved to be applicable to dsRNA. It provided a relatively simple alternative to one-sided PCR, without loss of specificity inherent in the use of generic primers. LRV1 terminal nucleotide sequences obtained by this method showed a considerable variation in length, particularly at the 5' end of the positive strand, as well as the potential for forming 3' overhangs. The opposite genomic end terminates in 0, 1, or 2 TCA trinucleotide repeats. These results are compared with terminal sequences derived from one-sided PCR experiments.

Evaluation of sequence alignments and oligonucleotide probes with respect to three-dimensional structure of ribosomal RNA using ARB software package

PubMed Central

Kumar, Yadhu; Westram, Ralf; Kipfer, Peter; Meier, Harald; Ludwig, Wolfgang

2006-01-01

Background Availability of high-resolution RNA crystal structures for the 30S and 50S ribosomal subunits and the subsequent validation of comparative secondary structure models have prompted the biologists to use three-dimensional structure of ribosomal RNA (rRNA) for evaluating sequence alignments of rRNA genes. Furthermore, the secondary and tertiary structural features of rRNA are highly useful and successfully employed in designing rRNA targeted oligonucleotide probes intended for in situ hybridization experiments. RNA3D, a program to combine sequence alignment information with three-dimensional structure of rRNA was developed. Integration into ARB software package, which is used extensively by the scientific community for phylogenetic analysis and molecular probe designing, has substantially extended the functionality of ARB software suite with 3D environment. Results Three-dimensional structure of rRNA is visualized in OpenGL 3D environment with the abilities to change the display and overlay information onto the molecule, dynamically. Phylogenetic information derived from the multiple sequence alignments can be overlaid onto the molecule structure in a real time. Superimposition of both statistical and non-statistical sequence associated information onto the rRNA 3D structure can be done using customizable color scheme, which is also applied to a textual sequence alignment for reference. Oligonucleotide probes designed by ARB probe design tools can be mapped onto the 3D structure along with the probe accessibility models for evaluation with respect to secondary and tertiary structural conformations of rRNA. Conclusion Visualization of three-dimensional structure of rRNA in an intuitive display provides the biologists with the greater possibilities to carry out structure based phylogenetic analysis. Coupled with secondary structure models of rRNA, RNA3D program aids in validating the sequence alignments of rRNA genes and evaluating probe target sites

The binding of TIA-1 to RNA C-rich sequences is driven by its C-terminal RRM domain.

PubMed

Cruz-Gallardo, Isabel; Aroca, Ángeles; Gunzburg, Menachem J; Sivakumaran, Andrew; Yoon, Je-Hyun; Angulo, Jesús; Persson, Cecilia; Gorospe, Myriam; Karlsson, B Göran; Wilce, Jacqueline A; Díaz-Moreno, Irene

2014-01-01

T-cell intracellular antigen-1 (TIA-1) is a key DNA/RNA binding protein that regulates translation by sequestering target mRNAs in stress granules (SG) in response to stress conditions. TIA-1 possesses three RNA recognition motifs (RRM) along with a glutamine-rich domain, with the central domains (RRM2 and RRM3) acting as RNA binding platforms. While the RRM2 domain, which displays high affinity for U-rich RNA sequences, is primarily responsible for interaction with RNA, the contribution of RRM3 to bind RNA as well as the target RNA sequences that it binds preferentially are still unknown. Here we combined nuclear magnetic resonance (NMR) and surface plasmon resonance (SPR) techniques to elucidate the sequence specificity of TIA-1 RRM3. With a novel approach using saturation transfer difference NMR (STD-NMR) to quantify protein-nucleic acids interactions, we demonstrate that isolated RRM3 binds to both C- and U-rich stretches with micromolar affinity. In combination with RRM2 and in the context of full-length TIA-1, RRM3 significantly enhanced the binding to RNA, particularly to cytosine-rich RNA oligos, as assessed by biotinylated RNA pull-down analysis. Our findings provide new insight into the role of RRM3 in regulating TIA-1 binding to C-rich stretches, that are abundant at the 5' TOPs (5' terminal oligopyrimidine tracts) of mRNAs whose translation is repressed under stress situations.

The binding of TIA-1 to RNA C-rich sequences is driven by its C-terminal RRM domain

PubMed Central

Cruz-Gallardo, Isabel; Aroca, Ángeles; Gunzburg, Menachem J; Sivakumaran, Andrew; Yoon, Je-Hyun; Angulo, Jesús; Persson, Cecilia; Gorospe, Myriam; Karlsson, B Göran; Wilce, Jacqueline A; Díaz-Moreno, Irene

2014-01-01

T-cell intracellular antigen-1 (TIA-1) is a key DNA/RNA binding protein that regulates translation by sequestering target mRNAs in stress granules (SG) in response to stress conditions. TIA-1 possesses three RNA recognition motifs (RRM) along with a glutamine-rich domain, with the central domains (RRM2 and RRM3) acting as RNA binding platforms. While the RRM2 domain, which displays high affinity for U-rich RNA sequences, is primarily responsible for interaction with RNA, the contribution of RRM3 to bind RNA as well as the target RNA sequences that it binds preferentially are still unknown. Here we combined nuclear magnetic resonance (NMR) and surface plasmon resonance (SPR) techniques to elucidate the sequence specificity of TIA-1 RRM3. With a novel approach using saturation transfer difference NMR (STD-NMR) to quantify protein–nucleic acids interactions, we demonstrate that isolated RRM3 binds to both C- and U-rich stretches with micromolar affinity. In combination with RRM2 and in the context of full-length TIA-1, RRM3 significantly enhanced the binding to RNA, particularly to cytosine-rich RNA oligos, as assessed by biotinylated RNA pull-down analysis. Our findings provide new insight into the role of RRM3 in regulating TIA-1 binding to C-rich stretches, that are abundant at the 5′ TOPs (5′ terminal oligopyrimidine tracts) of mRNAs whose translation is repressed under stress situations. PMID:24824036

Computational Prediction of the Immunomodulatory Potential of RNA Sequences.

PubMed

Nagpal, Gandharva; Chaudhary, Kumardeep; Dhanda, Sandeep Kumar; Raghava, Gajendra Pal Singh

2017-01-01

Advances in the knowledge of various roles played by non-coding RNAs have stimulated the application of RNA molecules as therapeutics. Among these molecules, miRNA, siRNA, and CRISPR-Cas9 associated gRNA have been identified as the most potent RNA molecule classes with diverse therapeutic applications. One of the major limitations of RNA-based therapeutics is immunotoxicity of RNA molecules as it may induce the innate immune system. In contrast, RNA molecules that are potent immunostimulators are strong candidates for use in vaccine adjuvants. Thus, it is important to understand the immunotoxic or immunostimulatory potential of these RNA molecules. The experimental techniques for determining immunostimulatory potential of siRNAs are time- and resource-consuming. To overcome this limitation, recently our group has developed a web-based server "imRNA" for predicting the immunomodulatory potential of RNA sequences. This server integrates a number of modules that allow users to perform various tasks including (1) generation of RNA analogs with reduced immunotoxicity, (2) identification of highly immunostimulatory regions in RNA sequence, and (3) virtual screening. This server may also assist users in the identification of minimum mutations required in a given RNA sequence to minimize its immunomodulatory potential that is required for designing RNA-based therapeutics. Besides, the server can be used for designing RNA-based vaccine adjuvants as it may assist users in the identification of mutations required for increasing immunomodulatory potential of a given RNA sequence. In summary, this chapter describes major applications of the "imRNA" server in designing RNA-based therapeutics and vaccine adjuvants (http://www.imtech.res.in/raghava/imrna/).

Non-coding RNA generated following lariat-debranching mediates targeting of AID to DNA

PubMed Central

Zheng, Simin; Vuong, Bao Q.; Vaidyanathan, Bharat; Lin, Jia-Yu; Huang, Feng-Ting; Chaudhuri, Jayanta

2015-01-01

SUMMARY Transcription through immunoglobulin switch (S) regions is essential for class switch recombination (CSR) but no molecular function of the transcripts has been described. Likewise, recruitment of activation-induced cytidine deaminase (AID) to S regions is critical for CSR; however, the underlying mechanism has not been fully elucidated. Here, we demonstrate that intronic switch RNA acts in trans to target AID to S region DNA. AID binds directly to switch RNA through G-quadruplexes formed by the RNA molecules. Disruption of this interaction by mutation of a key residue in the putative RNA-binding domain of AID impairs recruitment of AID to S region DNA, thereby abolishing CSR. Additionally, inhibition of RNA lariat processing leads to loss of AID localization to S regions and compromises CSR; both defects can be rescued by exogenous expression of switch transcripts in a sequence-specific manner. These studies uncover an RNA-mediated mechanism of targeting AID to DNA. PMID:25957684

Analysis of the siRNA-Mediated Gene Silencing Process Targeting Three Homologous Genes Controlling Soybean Seed Oil Quality.

PubMed

Lu, Sha; Yin, Xiaoyan; Spollen, William; Zhang, Ning; Xu, Dong; Schoelz, James; Bilyeu, Kristin; Zhang, Zhanyuan J

2015-01-01

In the past decade, RNA silencing has gained significant attention because of its success in genomic scale research and also in the genetic improvement of crop plants. However, little is known about the molecular basis of siRNA processing in association with its target transcript. To reveal this process for improving hpRNA-mediated gene silencing in crop plants, the soybean GmFAD3 gene family was chosen as a test model. We analyzed RNAi mutant soybean lines in which three members of the GmFAD3 gene family were silenced. The silencing levels of FAD3A, FAD3B and FAD3C were correlated with the degrees of sequence homology between the inverted repeat of hpRNA and the GmFAD3 transcripts in the RNAi lines. Strikingly, transgenes in two of the three RNAi lines were heavily methylated, leading to a dramatic reduction of hpRNA-derived siRNAs. Small RNAs corresponding to the loop portion of the hairpin transcript were detected while much lower levels of siRNAs were found outside of the target region. siRNAs generated from the 318-bp inverted repeat were found to be diced much more frequently at stem sequences close to the loop and associated with the inferred cleavage sites on the target transcripts, manifesting "hot spots". The top candidate hpRNA-derived siRNA share certain sequence features with mature miRNA. This is the first comprehensive and detailed study revealing the siRNA-mediated gene silencing mechanism in crop plants using gene family GmFAD3 as a test model.

MicroRNA-guided prioritization of genome-wide association signals reveals the importance of microRNA-target gene networks for complex traits in cattle.

PubMed

Fang, Lingzhao; Sørensen, Peter; Sahana, Goutam; Panitz, Frank; Su, Guosheng; Zhang, Shengli; Yu, Ying; Li, Bingjie; Ma, Li; Liu, George; Lund, Mogens Sandø; Thomsen, Bo

2018-06-19

MicroRNAs (miRNA) are key modulators of gene expression and so act as putative fine-tuners of complex phenotypes. Here, we hypothesized that causal variants of complex traits are enriched in miRNAs and miRNA-target networks. First, we conducted a genome-wide association study (GWAS) for seven functional and milk production traits using imputed sequence variants (13~15 million) and >10,000 animals from three dairy cattle breeds, i.e., Holstein (HOL), Nordic red cattle (RDC) and Jersey (JER). Second, we analyzed for enrichments of association signals in miRNAs and their miRNA-target networks. Our results demonstrated that genomic regions harboring miRNA genes were significantly (P < 0.05) enriched with GWAS signals for milk production traits and mastitis, and that enrichments within miRNA-target gene networks were significantly higher than in random gene-sets for the majority of traits. Furthermore, most between-trait and across-breed correlations of enrichments with miRNA-target networks were significantly greater than with random gene-sets, suggesting pleiotropic effects of miRNAs. Intriguingly, genes that were differentially expressed in response to mammary gland infections were significantly enriched in the miRNA-target networks associated with mastitis. All these findings were consistent across three breeds. Collectively, our observations demonstrate the importance of miRNAs and their targets for the expression of complex traits.

Common features of microRNA target prediction tools

PubMed Central

Peterson, Sarah M.; Thompson, Jeffrey A.; Ufkin, Melanie L.; Sathyanarayana, Pradeep; Liaw, Lucy; Congdon, Clare Bates

2014-01-01

The human genome encodes for over 1800 microRNAs (miRNAs), which are short non-coding RNA molecules that function to regulate gene expression post-transcriptionally. Due to the potential for one miRNA to target multiple gene transcripts, miRNAs are recognized as a major mechanism to regulate gene expression and mRNA translation. Computational prediction of miRNA targets is a critical initial step in identifying miRNA:mRNA target interactions for experimental validation. The available tools for miRNA target prediction encompass a range of different computational approaches, from the modeling of physical interactions to the incorporation of machine learning. This review provides an overview of the major computational approaches to miRNA target prediction. Our discussion highlights three tools for their ease of use, reliance on relatively updated versions of miRBase, and range of capabilities, and these are DIANA-microT-CDS, miRanda-mirSVR, and TargetScan. In comparison across all miRNA target prediction tools, four main aspects of the miRNA:mRNA target interaction emerge as common features on which most target prediction is based: seed match, conservation, free energy, and site accessibility. This review explains these features and identifies how they are incorporated into currently available target prediction tools. MiRNA target prediction is a dynamic field with increasing attention on development of new analysis tools. This review attempts to provide a comprehensive assessment of these tools in a manner that is accessible across disciplines. Understanding the basis of these prediction methodologies will aid in user selection of the appropriate tools and interpretation of the tool output. PMID:24600468

Common features of microRNA target prediction tools.

PubMed

Peterson, Sarah M; Thompson, Jeffrey A; Ufkin, Melanie L; Sathyanarayana, Pradeep; Liaw, Lucy; Congdon, Clare Bates

2014-01-01

The human genome encodes for over 1800 microRNAs (miRNAs), which are short non-coding RNA molecules that function to regulate gene expression post-transcriptionally. Due to the potential for one miRNA to target multiple gene transcripts, miRNAs are recognized as a major mechanism to regulate gene expression and mRNA translation. Computational prediction of miRNA targets is a critical initial step in identifying miRNA:mRNA target interactions for experimental validation. The available tools for miRNA target prediction encompass a range of different computational approaches, from the modeling of physical interactions to the incorporation of machine learning. This review provides an overview of the major computational approaches to miRNA target prediction. Our discussion highlights three tools for their ease of use, reliance on relatively updated versions of miRBase, and range of capabilities, and these are DIANA-microT-CDS, miRanda-mirSVR, and TargetScan. In comparison across all miRNA target prediction tools, four main aspects of the miRNA:mRNA target interaction emerge as common features on which most target prediction is based: seed match, conservation, free energy, and site accessibility. This review explains these features and identifies how they are incorporated into currently available target prediction tools. MiRNA target prediction is a dynamic field with increasing attention on development of new analysis tools. This review attempts to provide a comprehensive assessment of these tools in a manner that is accessible across disciplines. Understanding the basis of these prediction methodologies will aid in user selection of the appropriate tools and interpretation of the tool output.

Capturing microRNA targets using an RNA-induced silencing complex (RISC)-trap approach

PubMed Central

Cambronne, Xiaolu A.; Shen, Rongkun; Auer, Paul L.; Goodman, Richard H.

2012-01-01

Identifying targets is critical for understanding the biological effects of microRNA (miRNA) expression. The challenge lies in characterizing the cohort of targets for a specific miRNA, especially when targets are being actively down-regulated in miRNA– RNA-induced silencing complex (RISC)–messengerRNA (mRNA) complexes. We have developed a robust and versatile strategy called RISCtrap to stabilize and purify targets from this transient interaction. Its utility was demonstrated by determining specific high-confidence target datasets for miR-124, miR-132, and miR-181 that contained known and previously unknown transcripts. Two previously unknown miR-132 targets identified with RISCtrap, adaptor protein CT10 regulator of kinase 1 (CRK1) and tight junction-associated protein 1 (TJAP1), were shown to be endogenously regulated by miR-132 in adult mouse forebrain. The datasets, moreover, differed in the number of targets and in the types and frequency of microRNA recognition element (MRE) motifs, thus revealing a previously underappreciated level of specificity in the target sets regulated by individual miRNAs. PMID:23184980

Highly multiplexed subcellular RNA sequencing in situ

PubMed Central

Lee, Je Hyuk; Daugharthy, Evan R.; Scheiman, Jonathan; Kalhor, Reza; Ferrante, Thomas C.; Yang, Joyce L.; Terry, Richard; Jeanty, Sauveur S. F.; Li, Chao; Amamoto, Ryoji; Peters, Derek T.; Turczyk, Brian M.; Marblestone, Adam H.; Inverso, Samuel A.; Bernard, Amy; Mali, Prashant; Rios, Xavier; Aach, John; Church, George M.

2014-01-01

Understanding the spatial organization of gene expression with single nucleotide resolution requires localizing the sequences of expressed RNA transcripts within a cell in situ. Here we describe fluorescent in situ RNA sequencing (FISSEQ), in which stably cross-linked cDNA amplicons are sequenced within a biological sample. Using 30-base reads from 8,742 genes in situ, we examined RNA expression and localization in human primary fibroblasts using a simulated wound healing assay. FISSEQ is compatible with tissue sections and whole mount embryos, and reduces the limitations of optical resolution and noisy signals on single molecule detection. Our platform enables massively parallel detection of genetic elements, including gene transcripts and molecular barcodes, and can be used to investigate cellular phenotype, gene regulation, and environment in situ. PMID:24578530

Computational Prediction of miRNA Genes from Small RNA Sequencing Data

PubMed Central

Kang, Wenjing; Friedländer, Marc R.

2015-01-01

Next-generation sequencing now for the first time allows researchers to gage the depth and variation of entire transcriptomes. However, now as rare transcripts can be detected that are present in cells at single copies, more advanced computational tools are needed to accurately annotate and profile them. microRNAs (miRNAs) are 22 nucleotide small RNAs (sRNAs) that post-transcriptionally reduce the output of protein coding genes. They have established roles in numerous biological processes, including cancers and other diseases. During miRNA biogenesis, the sRNAs are sequentially cleaved from precursor molecules that have a characteristic hairpin RNA structure. The vast majority of new miRNA genes that are discovered are mined from small RNA sequencing (sRNA-seq), which can detect more than a billion RNAs in a single run. However, given that many of the detected RNAs are degradation products from all types of transcripts, the accurate identification of miRNAs remain a non-trivial computational problem. Here, we review the tools available to predict animal miRNAs from sRNA sequencing data. We present tools for generalist and specialist use cases, including prediction from massively pooled data or in species without reference genome. We also present wet-lab methods used to validate predicted miRNAs, and approaches to computationally benchmark prediction accuracy. For each tool, we reference validation experiments and benchmarking efforts. Last, we discuss the future of the field. PMID:25674563

Ancient Origin of the U2 Small Nuclear RNA Gene-Targeting Non-LTR Retrotransposons Utopia

PubMed Central

Kojima, Kenji K.

2015-01-01

Most non-long terminal repeat (non-LTR) retrotransposons encoding a restriction-like endonuclease show target-specific integration into repetitive sequences such as ribosomal RNA genes and microsatellites. However, only a few target-specific lineages of non-LTR retrotransposons are distributed widely and no lineage is found across the eukaryotic kingdoms. Here we report the most widely distributed lineage of target sequence-specific non-LTR retrotransposons, designated Utopia. Utopia is found in three supergroups of eukaryotes: Amoebozoa, SAR, and Opisthokonta. Utopia is inserted into a specific site of U2 small nuclear RNA genes with different strength of specificity for each family. Utopia families from oomycetes and wasps show strong target specificity while only a small number of Utopia copies from reptiles are flanked with U2 snRNA genes. Oomycete Utopia families contain an “archaeal” RNase H domain upstream of reverse transcriptase (RT), which likely originated from a plant RNase H gene. Analysis of Utopia from oomycetes indicates that multiple lineages of Utopia have been maintained inside of U2 genes with few copy numbers. Phylogenetic analysis of RT suggests the monophyly of Utopia, and it likely dates back to the early evolution of eukaryotes. PMID:26556480

Validated MicroRNA Target Databases: An Evaluation.

PubMed

Lee, Yun Ji Diana; Kim, Veronica; Muth, Dillon C; Witwer, Kenneth W

2015-11-01

Preclinical Research Positive findings from preclinical and clinical studies involving depletion or supplementation of microRNA (miRNA) engender optimism about miRNA-based therapeutics. However, off-target effects must be considered. Predicting these effects is complicated. Each miRNA may target many gene transcripts, and the rules governing imperfectly complementary miRNA: target interactions are incompletely understood. Several databases provide lists of the relatively small number of experimentally confirmed miRNA: target pairs. Although incomplete, this information might allow assessment of at least some of the off-target effects. We evaluated the performance of four databases of experimentally validated miRNA: target interactions (miRWalk 2.0, miRTarBase, miRecords, and TarBase 7.0) using a list of 50 alphabetically consecutive genes. We examined the provided citations to determine the degree to which each interaction was experimentally supported. To assess stability, we tested at the beginning and end of a five-month period. Results varied widely by database. Two of the databases changed significantly over the course of 5 months. Most reported evidence for miRNA: target interactions were indirect or otherwise weak, and relatively few interactions were supported by more than one publication. Some returned results appear to arise from simplistic text searches that offer no insight into the relationship of the search terms, may not even include the reported gene or miRNA, and may thus, be invalid. We conclude that validation databases provide important information, but not all information in all extant databases is up-to-date or accurate. Nevertheless, the more comprehensive validation databases may provide useful starting points for investigation of off-target effects of proposed small RNA therapies. © 2015 Wiley Periodicals, Inc.

miRTarBase update 2018: a resource for experimentally validated microRNA-target interactions.

PubMed

Chou, Chih-Hung; Shrestha, Sirjana; Yang, Chi-Dung; Chang, Nai-Wen; Lin, Yu-Ling; Liao, Kuang-Wen; Huang, Wei-Chi; Sun, Ting-Hsuan; Tu, Siang-Jyun; Lee, Wei-Hsiang; Chiew, Men-Yee; Tai, Chun-San; Wei, Ting-Yen; Tsai, Tzi-Ren; Huang, Hsin-Tzu; Wang, Chung-Yu; Wu, Hsin-Yi; Ho, Shu-Yi; Chen, Pin-Rong; Chuang, Cheng-Hsun; Hsieh, Pei-Jung; Wu, Yi-Shin; Chen, Wen-Liang; Li, Meng-Ju; Wu, Yu-Chun; Huang, Xin-Yi; Ng, Fung Ling; Buddhakosai, Waradee; Huang, Pei-Chun; Lan, Kuan-Chun; Huang, Chia-Yen; Weng, Shun-Long; Cheng, Yeong-Nan; Liang, Chao; Hsu, Wen-Lian; Huang, Hsien-Da

2018-01-04

MicroRNAs (miRNAs) are small non-coding RNAs of ∼ 22 nucleotides that are involved in negative regulation of mRNA at the post-transcriptional level. Previously, we developed miRTarBase which provides information about experimentally validated miRNA-target interactions (MTIs). Here, we describe an updated database containing 422 517 curated MTIs from 4076 miRNAs and 23 054 target genes collected from over 8500 articles. The number of MTIs curated by strong evidence has increased ∼1.4-fold since the last update in 2016. In this updated version, target sites validated by reporter assay that are available in the literature can be downloaded. The target site sequence can extract new features for analysis via a machine learning approach which can help to evaluate the performance of miRNA-target prediction tools. Furthermore, different ways of browsing enhance user browsing specific MTIs. With these improvements, miRTarBase serves as more comprehensively annotated, experimentally validated miRNA-target interactions databases in the field of miRNA related research. miRTarBase is available at http://miRTarBase.mbc.nctu.edu.tw/. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Double-stranded RNA targeting calmodulin reveals a potential target for pest management of Nilaparvata lugens.

PubMed

Wang, Weixia; Wan, Pinjun; Lai, Fengxiang; Zhu, Tingheng; Fu, Qiang

2018-07-01

Calmodulin (CaM) is an essential protein in cellular activity and plays important roles in many processes in insect development. RNA interference (RNAi) has been hypothesized to be a promising method for pest control. CaM is a good candidate for RNAi target. However, the sequence and function of CaM in Nilaparvata lugens are unknown. Furthermore, the double-stranded RNA (dsRNA) target to CaM gene in pest control is still unavailable. In the present study, two alternatively spliced variants of CaM transcripts, designated NlCaM1 and NlCaM2, were cloned from N. lugens. The two cDNA sequences exhibited 100% identity to each other in the open reading frame (ORF), and only differed in the 3' untranslated region (UTR). NlCaM including NlCaM1 and NlCaM2 mRNA was detectable in all developmental stages and tissues of N. lugens, with significantly increased expression in the salivary glands. Knockdown of NlCaM expression by RNAi with different dsRNAs led to an inability to molt properly, increased mortality, which ranged from 49.7 to 92.5%, impacted development of the ovaries and led to female infertility. There were no significant reductions in the transcript levels of vitellogenin and its receptor or in the total vitellogenin protein level relative to the control group. However, a significant reduction in vitellogenin protein was detected in ovaries injected with dsNlCaM. In addition, a specific dsRNA of NlCaM for control of N. lugens was designed and tested. NlCaM plays important roles mainly in nymph development and uptake of vitellogenin by ovaries in vitellogenesis in N. lugens. dsRNA derived from the less conserved 3'-UTR of NlCaM shows great potential for RNAi-based N. lugens management. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

RNA sequencing: current and prospective uses in metabolic research.

PubMed

Vikman, Petter; Fadista, Joao; Oskolkov, Nikolay

2014-10-01

Previous global RNA analysis was restricted to known transcripts in species with a defined transcriptome. Next generation sequencing has transformed transcriptomics by making it possible to analyse expressed genes with an exon level resolution from any tissue in any species without any a priori knowledge of which genes that are being expressed, splice patterns or their nucleotide sequence. In addition, RNA sequencing is a more sensitive technique compared with microarrays with a larger dynamic range, and it also allows for investigation of imprinting and allele-specific expression. This can be done for a cost that is able to compete with that of a microarray, making RNA sequencing a technique available to most researchers. Therefore RNA sequencing has recently become the state of the art with regards to large-scale RNA investigations and has to a large extent replaced microarrays. The only drawback is the large data amounts produced, which together with the complexity of the data can make a researcher spend far more time on analysis than performing the actual experiment. © 2014 Society for Endocrinology.

Simultaneous sequencing of coding and noncoding RNA reveals a human transcriptome dominated by a small number of highly expressed noncoding genes.

PubMed

Boivin, Vincent; Deschamps-Francoeur, Gabrielle; Couture, Sonia; Nottingham, Ryan M; Bouchard-Bourelle, Philia; Lambowitz, Alan M; Scott, Michelle S; Abou-Elela, Sherif

2018-07-01

Comparing the abundance of one RNA molecule to another is crucial for understanding cellular functions but most sequencing techniques can target only specific subsets of RNA. In this study, we used a new fragmented ribodepleted TGIRT sequencing method that uses a thermostable group II intron reverse transcriptase (TGIRT) to generate a portrait of the human transcriptome depicting the quantitative relationship of all classes of nonribosomal RNA longer than 60 nt. Comparison between different sequencing methods indicated that FRT is more accurate in ranking both mRNA and noncoding RNA than viral reverse transcriptase-based sequencing methods, even those that specifically target these species. Measurements of RNA abundance in different cell lines using this method correlate with biochemical estimates, confirming tRNA as the most abundant nonribosomal RNA biotype. However, the single most abundant transcript is 7SL RNA, a component of the signal recognition particle. S tructured n on c oding RNAs (sncRNAs) associated with the same biological process are expressed at similar levels, with the exception of RNAs with multiple functions like U1 snRNA. In general, sncRNAs forming RNPs are hundreds to thousands of times more abundant than their mRNA counterparts. Surprisingly, only 50 sncRNA genes produce half of the non-rRNA transcripts detected in two different cell lines. Together the results indicate that the human transcriptome is dominated by a small number of highly expressed sncRNAs specializing in functions related to translation and splicing. © 2018 Boivin et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Evaluating the Detection of Hydrocarbon-Degrading Bacteria in 16S rRNA Gene Sequencing Surveys

PubMed Central

Berry, David; Gutierrez, Tony

2017-01-01

Hydrocarbonoclastic bacteria (HCB) play a key role in the biodegradation of oil hydrocarbons in marine and other environments. A small number of taxa have been identified as obligate HCB, notably the Gammaproteobacterial genera Alcanivorax, Cycloclasticus, Marinobacter, Neptumonas, Oleiphilus, Oleispira, and Thalassolituus, as well as the Alphaproteobacterial genus Thalassospira. Detection of HCB in amplicon-based sequencing surveys relies on high coverage by PCR primers and accurate taxonomic classification. In this study, we performed a phylogenetic analysis to identify 16S rRNA gene sequence regions that represent the breadth of sequence diversity within these taxa. Using validated sequences, we evaluated 449 universal 16S rRNA gene-targeted bacterial PCR primer pairs for their coverage of these taxa. The results of this analysis provide a practical framework for selection of suitable primer sets for optimal detection of HCB in sequencing surveys. PMID:28567035

Evaluating the Detection of Hydrocarbon-Degrading Bacteria in 16S rRNA Gene Sequencing Surveys.

PubMed

Berry, David; Gutierrez, Tony

2017-01-01

Hydrocarbonoclastic bacteria (HCB) play a key role in the biodegradation of oil hydrocarbons in marine and other environments. A small number of taxa have been identified as obligate HCB, notably the Gammaproteobacterial genera Alcanivorax, Cycloclasticus, Marinobacter, Neptumonas, Oleiphilus, Oleispira , and Thalassolituus , as well as the Alphaproteobacterial genus Thalassospira . Detection of HCB in amplicon-based sequencing surveys relies on high coverage by PCR primers and accurate taxonomic classification. In this study, we performed a phylogenetic analysis to identify 16S rRNA gene sequence regions that represent the breadth of sequence diversity within these taxa. Using validated sequences, we evaluated 449 universal 16S rRNA gene-targeted bacterial PCR primer pairs for their coverage of these taxa. The results of this analysis provide a practical framework for selection of suitable primer sets for optimal detection of HCB in sequencing surveys.

How Messenger RNA and Nascent Chain Sequences Regulate Translation Elongation.

PubMed

Choi, Junhong; Grosely, Rosslyn; Prabhakar, Arjun; Lapointe, Christopher P; Wang, Jinfan; Puglisi, Joseph D

2018-06-20

Translation elongation is a highly coordinated, multistep, multifactor process that ensures accurate and efficient addition of amino acids to a growing nascent-peptide chain encoded in the sequence of translated messenger RNA (mRNA). Although translation elongation is heavily regulated by external factors, there is clear evidence that mRNA and nascent-peptide sequences control elongation dynamics, determining both the sequence and structure of synthesized proteins. Advances in methods have driven experiments that revealed the basic mechanisms of elongation as well as the mechanisms of regulation by mRNA and nascent-peptide sequences. In this review, we highlight how mRNA and nascent-peptide elements manipulate the translation machinery to alter the dynamics and pathway of elongation.

Defining RNA motif-aminoglycoside interactions via two-dimensional combinatorial screening and structure-activity relationships through sequencing.

PubMed

Velagapudi, Sai Pradeep; Disney, Matthew D

2013-10-15

RNA is an extremely important target for the development of chemical probes of function or small molecule therapeutics. Aminoglycosides are the most well studied class of small molecules to target RNA. However, the RNA motifs outside of the bacterial rRNA A-site that are likely to be bound by these compounds in biological systems is largely unknown. If such information were known, it could allow for aminoglycosides to be exploited to target other RNAs and, in addition, could provide invaluable insights into potential bystander targets of these clinically used drugs. We utilized two-dimensional combinatorial screening (2DCS), a library-versus-library screening approach, to select the motifs displayed in a 3×3 nucleotide internal loop library and in a 6-nucleotide hairpin library that bind with high affinity and selectivity to six aminoglycoside derivatives. The selected RNA motifs were then analyzed using structure-activity relationships through sequencing (StARTS), a statistical approach that defines the privileged RNA motif space that binds a small molecule. StARTS allowed for the facile annotation of the selected RNA motif-aminoglycoside interactions in terms of affinity and selectivity. The interactions selected by 2DCS generally have nanomolar affinities, which is higher affinity than the binding of aminoglycosides to a mimic of their therapeutic target, the bacterial rRNA A-site. Copyright © 2013 Elsevier Ltd. All rights reserved.

Defining RNA motif–aminoglycoside interactions via two-dimensional combinatorial screening and structure–activity relationships through sequencing

PubMed Central

Velagapudi, Sai Pradeep; Disney, Matthew D.

2013-01-01

RNA is an extremely important target for the development of chemical probes of function or small molecule therapeutics. Aminoglycosides are the most well studied class of small molecules to target RNA. However, the RNA motifs outside of the bacterial rRNA A-site that are likely to be bound by these compounds in biological systems is largely unknown. If such information were known, it could allow for aminoglycosides to be exploited to target other RNAs and, in addition, could provide invaluable insights into potential bystander targets of these clinically used drugs. We utilized two-dimensional combinatorial screening (2DCS), a library-versus-library screening approach, to select the motifs displayed in a 3 × 3 nucleotide internal loop library and in a 6-nucleotide hairpin library that bind with high affinity and selectivity to six aminoglycoside derivatives. The selected RNA motifs were then analyzed using structure–activity relationships through sequencing (StARTS), a statistical approach that defines the privileged RNA motif space that binds a small molecule. StARTS allowed for the facile annotation of the selected RNA motif–aminoglycoside interactions in terms of affinity and selectivity. The interactions selected by 2DCS generally have nanomolar affinities, which is higher affinity than the binding of aminoglycosides to a mimic of their therapeutic target, the bacterial rRNA A-site. PMID:23719281

Computational analysis of ribonomics datasets identifies long non-coding RNA targets of γ-herpesviral miRNAs.

PubMed

Sethuraman, Sunantha; Thomas, Merin; Gay, Lauren A; Renne, Rolf

2018-05-29

Ribonomics experiments involving crosslinking and immuno-precipitation (CLIP) of Ago proteins have expanded the understanding of the miRNA targetome of several organisms. These techniques, collectively referred to as CLIP-seq, have been applied to identifying the mRNA targets of miRNAs expressed by Kaposi's Sarcoma-associated herpes virus (KSHV) and Epstein-Barr virus (EBV). However, these studies focused on identifying only those RNA targets of KSHV and EBV miRNAs that are known to encode proteins. Recent studies have demonstrated that long non-coding RNAs (lncRNAs) are also targeted by miRNAs. In this study, we performed a systematic re-analysis of published datasets from KSHV- and EBV-driven cancers. We used CLIP-seq data from lymphoma cells or EBV-transformed B cells, and a crosslinking, ligation and sequencing of hybrids dataset from KSHV-infected endothelial cells, to identify novel lncRNA targets of viral miRNAs. Here, we catalog the lncRNA targetome of KSHV and EBV miRNAs, and provide a detailed in silico analysis of lncRNA-miRNA binding interactions. Viral miRNAs target several hundred lncRNAs, including a subset previously shown to be aberrantly expressed in human malignancies. In addition, we identified thousands of lncRNAs to be putative targets of human miRNAs, suggesting that miRNA-lncRNA interactions broadly contribute to the regulation of gene expression.

Transcriptome-Wide Identification of RNA Targets of Arabidopsis SERINE/ARGININE-RICH45 Uncovers the Unexpected Roles of This RNA Binding Protein in RNA Processing[OPEN

PubMed Central

Wang, Yajun; Hamilton, Michael; Ben-Hur, Asa; Reddy, Anireddy S.N.

2015-01-01

Plant SR45 and its metazoan ortholog RNPS1 are serine/arginine-rich (SR)-like RNA binding proteins that function in splicing/postsplicing events and regulate diverse processes in eukaryotes. Interactions of SR45 with both RNAs and proteins are crucial for regulating RNA processing. However, in vivo RNA targets of SR45 are currently unclear. Using RNA immunoprecipitation followed by high-throughput sequencing, we identified over 4000 Arabidopsis thaliana RNAs that directly or indirectly associate with SR45, designated as SR45-associated RNAs (SARs). Comprehensive analyses of these SARs revealed several roles for SR45. First, SR45 associates with and regulates the expression of 30% of abscisic acid (ABA) signaling genes at the postsplicing level. Second, although most SARs are derived from intron-containing genes, surprisingly, 340 SARs are derived from intronless genes. Expression analysis of the SARs suggests that SR45 differentially regulates intronless and intron-containing SARs. Finally, we identified four overrepresented RNA motifs in SARs that likely mediate SR45’s recognition of its targets. Therefore, SR45 plays an unexpected role in mRNA processing of intronless genes, and numerous ABA signaling genes are targeted for regulation at the posttranscriptional level. The diverse molecular functions of SR45 uncovered in this study are likely applicable to other species in view of its conservation across eukaryotes. PMID:26603559

MicroTrout: A comprehensive, genome-wide miRNA target prediction framework for rainbow trout, Oncorhynchus mykiss.

PubMed

Mennigen, Jan A; Zhang, Dapeng

2016-12-01

Rainbow trout represent an important teleost research model and aquaculture species. As such, rainbow trout are employed in diverse areas of biological research, including basic biological disciplines such as comparative physiology, toxicology, and, since rainbow trout have undergone both teleost- and salmonid-specific rounds of genome duplication, molecular evolution. In recent years, microRNAs (miRNAs, small non-protein coding RNAs) have emerged as important posttranscriptional regulators of gene expression in animals. Given the increasingly recognized importance of miRNAs as an additional layer in the regulation of gene expression and hence biological function, recent efforts using RNA- and genome sequencing approaches have resulted in the creation of several resources for the construction of a comprehensive repertoire of rainbow trout miRNAs and isomiRs (variant miRNA sequences that all appear to derive from the same gene but vary in sequence due to post-transcriptional processing). Importantly, through the recent publication of the rainbow trout genome (Berthelot et al., 2014), mRNA 3'UTR information has become available, allowing for the first time the genome-wide prediction of miRNA-target RNA relationships in this species. We here report the creation of the microtrout database, a comprehensive resource for rainbow trout miRNA and annotated 3'UTRs. The comprehensive database was used to implement an algorithm to predict genome-wide rainbow trout-specific miRNA-mRNA target relationships, generating an improved predictive framework over previously published approaches. This work will serve as a useful framework and sequence resource to experimentally address the role of miRNAs in several research areas using the rainbow trout model, examples of which are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Analysis of microRNA profile of Anopheles sinensis by deep sequencing and bioinformatic approaches.

PubMed

Feng, Xinyu; Zhou, Xiaojian; Zhou, Shuisen; Wang, Jingwen; Hu, Wei

2018-03-12

microRNAs (miRNAs) are small non-coding RNAs widely identified in many mosquitoes. They are reported to play important roles in development, differentiation and innate immunity. However, miRNAs in Anopheles sinensis, one of the Chinese malaria mosquitoes, remain largely unknown. We investigated the global miRNA expression profile of An. sinensis using Illumina Hiseq 2000 sequencing. Meanwhile, we applied a bioinformatic approach to identify potential miRNAs in An. sinensis. The identified miRNA profiles were compared and analyzed by two approaches. The selected miRNAs from the sequencing result and the bioinformatic approach were confirmed with qRT-PCR. Moreover, target prediction, GO annotation and pathway analysis were carried out to understand the role of miRNAs in An. sinensis. We identified 49 conserved miRNAs and 12 novel miRNAs by next-generation high-throughput sequencing technology. In contrast, 43 miRNAs were predicted by the bioinformatic approach, of which two were assigned as novel. Comparative analysis of miRNA profiles by two approaches showed that 21 miRNAs were shared between them. Twelve novel miRNAs did not match any known miRNAs of any organism, indicating that they are possibly species-specific. Forty miRNAs were found in many mosquito species, indicating that these miRNAs are evolutionally conserved and may have critical roles in the process of life. Both the selected known and novel miRNAs (asi-miR-281, asi-miR-184, asi-miR-14, asi-miR-nov5, asi-miR-nov4, asi-miR-9383, and asi-miR-2a) could be detected by quantitative real-time PCR (qRT-PCR) in the sequenced sample, and the expression patterns of these miRNAs measured by qRT-PCR were in concordance with the original miRNA sequencing data. The predicted targets for the known and the novel miRNAs covered many important biological roles and pathways indicating the diversity of miRNA functions. We also found 21 conserved miRNAs and eight counterparts of target immune pathway genes in An. sinensis

Novel Approach to Analyzing MFE of Noncoding RNA Sequences

PubMed Central

George, Tina P.; Thomas, Tessamma

2016-01-01

Genomic studies have become noncoding RNA (ncRNA) centric after the study of different genomes provided enormous information on ncRNA over the past decades. The function of ncRNA is decided by its secondary structure, and across organisms, the secondary structure is more conserved than the sequence itself. In this study, the optimal secondary structure or the minimum free energy (MFE) structure of ncRNA was found based on the thermodynamic nearest neighbor model. MFE of over 2600 ncRNA sequences was analyzed in view of its signal properties. Mathematical models linking MFE to the signal properties were found for each of the four classes of ncRNA analyzed. MFE values computed with the proposed models were in concordance with those obtained with the standard web servers. A total of 95% of the sequences analyzed had deviation of MFE values within ±15% relative to those obtained from standard web servers. PMID:27695341

Novel Approach to Analyzing MFE of Noncoding RNA Sequences.

PubMed

George, Tina P; Thomas, Tessamma

2016-01-01

Genomic studies have become noncoding RNA (ncRNA) centric after the study of different genomes provided enormous information on ncRNA over the past decades. The function of ncRNA is decided by its secondary structure, and across organisms, the secondary structure is more conserved than the sequence itself. In this study, the optimal secondary structure or the minimum free energy (MFE) structure of ncRNA was found based on the thermodynamic nearest neighbor model. MFE of over 2600 ncRNA sequences was analyzed in view of its signal properties. Mathematical models linking MFE to the signal properties were found for each of the four classes of ncRNA analyzed. MFE values computed with the proposed models were in concordance with those obtained with the standard web servers. A total of 95% of the sequences analyzed had deviation of MFE values within ±15% relative to those obtained from standard web servers.

Global preamplification simplifies targeted mRNA quantification

PubMed Central

Kroneis, Thomas; Jonasson, Emma; Andersson, Daniel; Dolatabadi, Soheila; Ståhlberg, Anders

2017-01-01

The need to perform gene expression profiling using next generation sequencing and quantitative real-time PCR (qPCR) on small sample sizes and single cells is rapidly expanding. However, to analyse few molecules, preamplification is required. Here, we studied global and target-specific preamplification using 96 optimised qPCR assays. To evaluate the preamplification strategies, we monitored the reactions in real-time using SYBR Green I detection chemistry followed by melting curve analysis. Next, we compared yield and reproducibility of global preamplification to that of target-specific preamplification by qPCR using the same amount of total RNA. Global preamplification generated 9.3-fold lower yield and 1.6-fold lower reproducibility than target-specific preamplification. However, the performance of global preamplification is sufficient for most downstream applications and offers several advantages over target-specific preamplification. To demonstrate the potential of global preamplification we analysed the expression of 15 genes in 60 single cells. In conclusion, we show that global preamplification simplifies targeted gene expression profiling of small sample sizes by a flexible workflow. We outline the pros and cons for global preamplification compared to target-specific preamplification. PMID:28332609

Plant microRNA-Target Interaction Identification Model Based on the Integration of Prediction Tools and Support Vector Machine

PubMed Central

Meng, Jun; Shi, Lin; Luan, Yushi

2014-01-01

Background Confident identification of microRNA-target interactions is significant for studying the function of microRNA (miRNA). Although some computational miRNA target prediction methods have been proposed for plants, results of various methods tend to be inconsistent and usually lead to more false positive. To address these issues, we developed an integrated model for identifying plant miRNA–target interactions. Results Three online miRNA target prediction toolkits and machine learning algorithms were integrated to identify and analyze Arabidopsis thaliana miRNA-target interactions. Principle component analysis (PCA) feature extraction and self-training technology were introduced to improve the performance. Results showed that the proposed model outperformed the previously existing methods. The results were validated by using degradome sequencing supported Arabidopsis thaliana miRNA-target interactions. The proposed model constructed on Arabidopsis thaliana was run over Oryza sativa and Vitis vinifera to demonstrate that our model is effective for other plant species. Conclusions The integrated model of online predictors and local PCA-SVM classifier gained credible and high quality miRNA-target interactions. The supervised learning algorithm of PCA-SVM classifier was employed in plant miRNA target identification for the first time. Its performance can be substantially improved if more experimentally proved training samples are provided. PMID:25051153

RNA editing in Drosophila melanogaster: new targets and functionalconsequences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stapleton, Mark; Carlson, Joseph W.; Celniker, Susan E.

2006-09-05

Adenosine deaminases that act on RNA (ADARs) catalyze the site-specific conversion of adenosine to inosine in primary mRNA transcripts. These re-coding events affect coding potential, splice-sites, and stability of mature mRNAs. ADAR is an essential gene and studies in mouse, C. elegans, and Drosophila suggest its primary function is to modify adult behavior by altering signaling components in the nervous system. By comparing the sequence of isogenic cDNAs to genomic DNA, we have identified and experimentally verified 27 new targets of Drosophila ADAR. Our analyses lead us to identify new classes of genes whose transcripts are targets of ADAR includingmore » components of the actin cytoskeleton, and genes involved in ion homeostasis and signal transduction. Our results indicate that editing in Drosophila increases the diversity of the proteome, and does so in a manner that has direct functional consequences on protein function.« less

Sequence analysis of RNase MRP RNA reveals its origination from eukaryotic RNase P RNA

PubMed Central

Zhu, Yanglong; Stribinskis, Vilius; Ramos, Kenneth S.; Li, Yong

2006-01-01

RNase MRP is a eukaryote-specific endoribonuclease that generates RNA primers for mitochondrial DNA replication and processes precursor rRNA. RNase P is a ubiquitous endoribonuclease that cleaves precursor tRNA transcripts to produce their mature 5′ termini. We found extensive sequence homology of catalytic domains and specificity domains between their RNA subunits in many organisms. In Candida glabrata, the internal loop of helix P3 is 100% conserved between MRP and P RNAs. The helix P8 of MRP RNA from microsporidia Encephalitozoon cuniculi is identical to that of P RNA. Sequence homology can be widely spread over the whole molecule of MRP RNA and P RNA, such as those from Dictyostelium discoideum. These conserved nucleotides between the MRP and P RNAs strongly support the hypothesis that the MRP RNA is derived from the P RNA molecule in early eukaryote evolution. PMID:16540690

RNAPattMatch: a web server for RNA sequence/structure motif detection based on pattern matching with flexible gaps

PubMed Central

Drory Retwitzer, Matan; Polishchuk, Maya; Churkin, Elena; Kifer, Ilona; Yakhini, Zohar; Barash, Danny

2015-01-01

Searching for RNA sequence-structure patterns is becoming an essential tool for RNA practitioners. Novel discoveries of regulatory non-coding RNAs in targeted organisms and the motivation to find them across a wide range of organisms have prompted the use of computational RNA pattern matching as an enhancement to sequence similarity. State-of-the-art programs differ by the flexibility of patterns allowed as queries and by their simplicity of use. In particular—no existing method is available as a user-friendly web server. A general program that searches for RNA sequence-structure patterns is RNA Structator. However, it is not available as a web server and does not provide the option to allow flexible gap pattern representation with an upper bound of the gap length being specified at any position in the sequence. Here, we introduce RNAPattMatch, a web-based application that is user friendly and makes sequence/structure RNA queries accessible to practitioners of various background and proficiency. It also extends RNA Structator and allows a more flexible variable gaps representation, in addition to analysis of results using energy minimization methods. RNAPattMatch service is available at http://www.cs.bgu.ac.il/rnapattmatch. A standalone version of the search tool is also available to download at the site. PMID:25940619

RNA from the 5' end of the R2 retrotransposon controls R2 protein binding to and cleavage of its DNA target site.

PubMed

Christensen, Shawn M; Ye, Junqiang; Eickbush, Thomas H

2006-11-21

Non-LTR retrotransposons insert into eukaryotic genomes by target-primed reverse transcription (TPRT), a process in which cleaved DNA targets are used to prime reverse transcription of the element's RNA transcript. Many of the steps in the integration pathway of these elements can be characterized in vitro for the R2 element because of the rigid sequence specificity of R2 for both its DNA target and its RNA template. R2 retrotransposition involves identical subunits of the R2 protein bound to different DNA sequences upstream and downstream of the insertion site. The key determinant regulating which DNA-binding conformation the protein adopts was found to be a 320-nt RNA sequence from near the 5' end of the R2 element. In the absence of this 5' RNA the R2 protein binds DNA sequences upstream of the insertion site, cleaves the first DNA strand, and conducts TPRT when RNA containing the 3' untranslated region of the R2 transcript is present. In the presence of the 320-nt 5' RNA, the R2 protein binds DNA sequences downstream of the insertion site. Cleavage of the second DNA strand by the downstream subunit does not appear to occur until after the 5' RNA is removed from this subunit. We postulate that the removal of the 5' RNA normally occurs during reverse transcription, and thus provides a critical temporal link to first- and second-strand DNA cleavage in the R2 retrotransposition reaction.

Analysis of sequencing data for probing RNA secondary structures and protein-RNA binding in studying posttranscriptional regulations.

PubMed

Hu, Xihao; Wu, Yang; Lu, Zhi John; Yip, Kevin Y

2016-11-01

High-throughput sequencing has been used to study posttranscriptional regulations, where the identification of protein-RNA binding is a major and fast-developing sub-area, which is in turn benefited by the sequencing methods for whole-transcriptome probing of RNA secondary structures. In the study of RNA secondary structures using high-throughput sequencing, bases are modified or cleaved according to their structural features, which alter the resulting composition of sequencing reads. In the study of protein-RNA binding, methods have been proposed to immuno-precipitate (IP) protein-bound RNA transcripts in vitro or in vivo By sequencing these transcripts, the protein-RNA interactions and the binding locations can be identified. For both types of data, read counts are affected by a combination of confounding factors, including expression levels of transcripts, sequence biases, mapping errors and the probing or IP efficiency of the experimental protocols. Careful processing of the sequencing data and proper extraction of important features are fundamentally important to a successful analysis. Here we review and compare different experimental methods for probing RNA secondary structures and binding sites of RNA-binding proteins (RBPs), and the computational methods proposed for analyzing the corresponding sequencing data. We suggest how these two types of data should be integrated to study the structural properties of RBP binding sites as a systematic way to better understand posttranscriptional regulations. © The Author 2015. Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Identifying novel sequence variants of RNA 3D motifs

PubMed Central

Zirbel, Craig L.; Roll, James; Sweeney, Blake A.; Petrov, Anton I.; Pirrung, Meg; Leontis, Neocles B.

2015-01-01

Predicting RNA 3D structure from sequence is a major challenge in biophysics. An important sub-goal is accurately identifying recurrent 3D motifs from RNA internal and hairpin loop sequences extracted from secondary structure (2D) diagrams. We have developed and validated new probabilistic models for 3D motif sequences based on hybrid Stochastic Context-Free Grammars and Markov Random Fields (SCFG/MRF). The SCFG/MRF models are constructed using atomic-resolution RNA 3D structures. To parameterize each model, we use all instances of each motif found in the RNA 3D Motif Atlas and annotations of pairwise nucleotide interactions generated by the FR3D software. Isostericity relations between non-Watson–Crick basepairs are used in scoring sequence variants. SCFG techniques model nested pairs and insertions, while MRF ideas handle crossing interactions and base triples. We use test sets of randomly-generated sequences to set acceptance and rejection thresholds for each motif group and thus control the false positive rate. Validation was carried out by comparing results for four motif groups to RMDetect. The software developed for sequence scoring (JAR3D) is structured to automatically incorporate new motifs as they accumulate in the RNA 3D Motif Atlas when new structures are solved and is available free for download. PMID:26130723

Structurally complex and highly active RNA ligases derived from random RNA sequences

NASA Technical Reports Server (NTRS)

Ekland, E. H.; Szostak, J. W.; Bartel, D. P.

1995-01-01

Seven families of RNA ligases, previously isolated from random RNA sequences, fall into three classes on the basis of secondary structure and regiospecificity of ligation. Two of the three classes of ribozymes have been engineered to act as true enzymes, catalyzing the multiple-turnover transformation of substrates into products. The most complex of these ribozymes has a minimal catalytic domain of 93 nucleotides. An optimized version of this ribozyme has a kcat exceeding one per second, a value far greater than that of most natural RNA catalysts and approaching that of comparable protein enzymes. The fact that such a large and complex ligase emerged from a very limited sampling of sequence space implies the existence of a large number of distinct RNA structures of equivalent complexity and activity.

Discovery and Annotation of Plant Endogenous Target Mimicry Sequences from Public Transcriptome Libraries: A Case Study of Prunus persica.

PubMed

Karakülah, Gökhan

2017-06-28

Novel transcript discovery through RNA sequencing has substantially improved our understanding of the transcriptome dynamics of biological systems. Endogenous target mimicry (eTM) transcripts, a novel class of regulatory molecules, bind to their target microRNAs (miRNAs) by base pairing and block their biological activity. The objective of this study was to provide a computational analysis framework for the prediction of putative eTM sequences in plants, and as an example, to discover previously un-annotated eTMs in Prunus persica (peach) transcriptome. Therefore, two public peach transcriptome libraries downloaded from Sequence Read Archive (SRA) and a previously published set of long non-coding RNAs (lncRNAs) were investigated with multi-step analysis pipeline, and 44 putative eTMs were found. Additionally, an eTM-miRNA-mRNA regulatory network module associated with peach fruit organ development was built via integration of the miRNA target information and predicted eTM-miRNA interactions. My findings suggest that one of the most widely expressed miRNA families among diverse plant species, miR156, might be potentially sponged by seven putative eTMs. Besides, the study indicates eTMs potentially play roles in the regulation of development processes in peach fruit via targeting specific miRNAs. In conclusion, by following the step-by step instructions provided in this study, novel eTMs can be identified and annotated effectively in public plant transcriptome libraries.

[Effects of small RNA interference targeting mammalian target of rapamycin on paraquat-induced pulmonary fibrosis in rats].

PubMed

Yang, Wenbin; Zhao, Xiaoqing; Liang, Ran; Chen, Da

2017-09-01

To investigate the effects of small RNA interference targeting mammalian target of rapamycin (mTOR) expression on paraquat-induced pulmonary fibrosis in rats. Human embryonic kidney cells HEK-293 were cultured in vitro. The mTOR small interfering RNA (mTOR-siRNA) expression plasmid transfection lentivirus was constructed, and non-specific sequence plasmid with no homology to mTOR gene was set as the control. Seventy-two healthy male Sprague-Dawley (SD) rats were randomly divided into normal saline (NS) control group, paraquat model group, mTOR unrelated sequence group, and mTOR-siRNA group, with 18 rats in each group. Paraquat poisoning animal model was reproduced by intraperitoneally injecting 20% paraquat solution 15 mg/kg, while the NS control group was intraperitoneally injected the same volumes of NS. Rats in the mTOR unrelated sequence group and mTOR-siRNA group were injected 1×10 9 TU/mL lentivirus solution 50 μL into the airway, respectively, while in the NS control group and paraquat model group were injected the same volumes of NS. At 7, 14 and 28 days after treatment, 6 rats in each group were sacrificed respectively for lung tissue, the pathological changes and fibrosis of lung tissues were observed under light microscope. The levels of hydroxyproline (HYP) in lung tissues were determined by alkaline hydrolysis. The mRNA and protein expressions of mTOR in lung tissues were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western Blot. Under light microscope, there was no obvious pathological changes in the lung tissues in the NS control group, while in the paraquat model group and mTOR unrelated sequence group, lung tissue in rats were damaged, there were a lot of inflammatory cell infiltration, a large number of matrix collagen and fibrous tissues hyperplasia, and gradually increased with time, and it was consistent with paraquat-induced lung tissue fibrosis process. The pathological and fibrotic changes in lung tissue of mTOR-siRNA

Group II intron inhibits conjugative relaxase expression in bacteria by mRNA targeting

PubMed Central

Piazza, Carol Lyn; Smith, Dorie

2018-01-01

Group II introns are mobile ribozymes that are rare in bacterial genomes, often cohabiting with various mobile elements, and seldom interrupting housekeeping genes. What accounts for this distribution has not been well understood. Here, we demonstrate that Ll.LtrB, the group II intron residing in a relaxase gene on a conjugative plasmid from Lactococcus lactis, inhibits its host gene expression and restrains the naturally cohabiting mobile element from conjugative horizontal transfer. We show that reduction in gene expression is mainly at the mRNA level, and results from the interaction between exon-binding sequences (EBSs) in the intron and intron-binding sequences (IBSs) in the mRNA. The spliced intron targets the relaxase mRNA and reopens ligated exons, causing major mRNA loss. Taken together, this study provides an explanation for the distribution and paucity of group II introns in bacteria, and suggests a potential force for those introns to evolve into spliceosomal introns. PMID:29905149

Group II intron inhibits conjugative relaxase expression in bacteria by mRNA targeting.

PubMed

Qu, Guosheng; Piazza, Carol Lyn; Smith, Dorie; Belfort, Marlene

2018-06-15

Group II introns are mobile ribozymes that are rare in bacterial genomes, often cohabiting with various mobile elements, and seldom interrupting housekeeping genes. What accounts for this distribution has not been well understood. Here, we demonstrate that Ll.LtrB, the group II intron residing in a relaxase gene on a conjugative plasmid from Lactococcus lactis , inhibits its host gene expression and restrains the naturally cohabiting mobile element from conjugative horizontal transfer. We show that reduction in gene expression is mainly at the mRNA level, and results from the interaction between exon-binding sequences (EBSs) in the intron and intron-binding sequences (IBSs) in the mRNA. The spliced intron targets the relaxase mRNA and reopens ligated exons, causing major mRNA loss. Taken together, this study provides an explanation for the distribution and paucity of group II introns in bacteria, and suggests a potential force for those introns to evolve into spliceosomal introns. © 2018, Qu et al.

MicroRNA-944 Affects Cell Growth by Targeting EPHA7 in Non-Small Cell Lung Cancer.

PubMed

Liu, Minxia; Zhou, Kecheng; Cao, Yi

2016-09-26

MicroRNAs (miRNAs) have critical roles in lung tumorigenesis and development. To determine aberrantly expressed miRNAs involved in non-small cell lung cancer (NSCLC) and investigate pathophysiological functions and mechanisms, we firstly carried out small RNA deep sequencing in NSCLC cell lines (EPLC-32M1, A549 and 801D) and a human immortalized cell line 16HBE, we then studied miRNA function by cell proliferation and apoptosis. cDNA microarray, luciferase reporter assay and miRNA transfection were used to investigate interaction between the miRNA and target gene. miR-944 was significantly down-regulated in NSCLC and had many putative targets. Moreover, the forced expression of miR-944 significantly inhibited the proliferation of NSCLC cells in vitro. By integrating mRNA expression data and miR-944-target prediction, we disclosed that EPHA7 was a potential target of miR-944, which was further verified by luciferase reporter assay and microRNA transfection. Our data indicated that miR-944 targets EPHA7 in NSCLC and regulates NSCLC cell proliferation, which may offer a new mechanism underlying the development and progression of NSCLC.

Species-specific identification of Dekkera/Brettanomyces yeasts by fluorescently labeled DNA probes targeting the 26S rRNA.

PubMed

Röder, Christoph; König, Helmut; Fröhlich, Jürgen

2007-09-01

Sequencing of the complete 26S rRNA genes of all Dekkera/Brettanomyces species colonizing different beverages revealed the potential for a specific primer and probe design to support diagnostic PCR approaches and FISH. By analysis of the complete 26S rRNA genes of all five currently known Dekkera/Brettanomyces species (Dekkera bruxellensis, D. anomala, Brettanomyces custersianus, B. nanus and B. naardenensis), several regions with high nucleotide sequence variability yet distinct from the D1/D2 domains were identified. FISH species-specific probes targeting the 26S rRNA gene's most variable regions were designed. Accessibility of probe targets for hybridization was facilitated by the construction of partially complementary 'side'-labeled probes, based on secondary structure models of the rRNA sequences. The specificity and routine applicability of the FISH-based method for yeast identification were tested by analyzing different wine isolates. Investigation of the prevalence of Dekkera/Brettanomyces yeasts in the German viticultural regions Wonnegau, Nierstein and Bingen (Rhinehesse, Rhineland-Palatinate) resulted in the isolation of 37 D. bruxellensis strains from 291 wine samples.

Identifying transposon insertions and their effects from RNA-sequencing data.

PubMed

de Ruiter, Julian R; Kas, Sjors M; Schut, Eva; Adams, David J; Koudijs, Marco J; Wessels, Lodewyk F A; Jonkers, Jos

2017-07-07

Insertional mutagenesis using engineered transposons is a potent forward genetic screening technique used to identify cancer genes in mouse model systems. In the analysis of these screens, transposon insertion sites are typically identified by targeted DNA-sequencing and subsequently assigned to predicted target genes using heuristics. As such, these approaches provide no direct evidence that insertions actually affect their predicted targets or how transcripts of these genes are affected. To address this, we developed IM-Fusion, an approach that identifies insertion sites from gene-transposon fusions in standard single- and paired-end RNA-sequencing data. We demonstrate IM-Fusion on two separate transposon screens of 123 mammary tumors and 20 B-cell acute lymphoblastic leukemias, respectively. We show that IM-Fusion accurately identifies transposon insertions and their true target genes. Furthermore, by combining the identified insertion sites with expression quantification, we show that we can determine the effect of a transposon insertion on its target gene(s) and prioritize insertions that have a significant effect on expression. We expect that IM-Fusion will significantly enhance the accuracy of cancer gene discovery in forward genetic screens and provide initial insight into the biological effects of insertions on candidate cancer genes. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Fluorescence turn-on detection of target sequence DNA based on silicon nanodot-mediated quenching.

PubMed

Zhang, Yanan; Ning, Xinping; Mao, Guobin; Ji, Xinghu; He, Zhike

2018-05-01

We have developed a new enzyme-free method for target sequence DNA detection based on the dynamic quenching of fluorescent silicon nanodots (SiNDs) toward Cy5-tagged DNA probe. Fascinatingly, the water-soluble SiNDs can quench the fluorescence of cyanine (Cy5) in Cy5-tagged DNA probe in homogeneous solution, and the fluorescence of Cy5-tagged DNA probe can be restored in the presence of target sequence DNA (the synthetic target miRNA-27a). Based on this phenomenon, a SiND-featured fluorescent sensor has been constructed for "turn-on" detection of the synthetic target miRNA-27a for the first time. This newly developed approach possesses the merits of low cost, simple design, and convenient operation since no enzymatic reaction, toxic reagents, or separation procedures are involved. The established method achieves a detection limit of 0.16 nM, and the relative standard deviation of this method is 9% (1 nM, n = 5). The linear range is 0.5-20 nM, and the recoveries in spiked human fluids are in the range of 90-122%. This protocol provides a new tactic in the development of the nonenzymic miRNA biosensors and opens a promising avenue for early diagnosis of miRNA-associated disease. Graphical abstract The SiND-based fluorescent sensor for detection of S-miR-27a.

ETS target genes: Identification of Egr1 as a target by RNA differential display and whole genome PCR techniques

PubMed Central

Robinson, Lois; Panayiotakis, Alexandra; Papas, Takis S.; Kola, Ismail; Seth, Arun

1997-01-01

ETS transcription factors play important roles in hematopoiesis, angiogenesis, and organogenesis during murine development. The ETS genes also have a role in neoplasia, for example in Ewing’s sarcomas and retrovirally induced cancers. The ETS genes encode transcription factors that bind to specific DNA sequences and activate transcription of various cellular and viral genes. To isolate novel ETS target genes, we used two approaches. In the first approach, we isolated genes by the RNA differential display technique. Previously, we have shown that the overexpression of ETS1 and ETS2 genes effects transformation of NIH 3T3 cells and specific transformants produce high levels of the ETS proteins. To isolate ETS1 and ETS2 responsive genes in these transformed cells, we prepared RNA from ETS1, ETS2 transformants, and normal NIH 3T3 cell lines and converted it into cDNA. This cDNA was amplified by PCR and displayed on sequencing gels. The differentially displayed bands were subcloned into plasmid vectors. By Northern blot analysis, several clones showed differential patterns of mRNA expression in the NIH 3T3-, ETS1-, and ETS2-expressing cell lines. Sixteen clones were analyzed by DNA sequence analysis, and 13 of them appeared to be unique because their DNA sequences did not match with any of the known genes present in the gene bank. Three known genes were found to be identical to the CArG box binding factor, phospholipase A2-activating protein, and early growth response 1 (Egr1) genes. In the second approach, to isolate ETS target promoters directly, we performed ETS1 binding with MboI-cleaved genomic DNA in the presence of a specific mAb followed by whole genome PCR. The immune complex-bound ETS binding sites containing DNA fragments were amplified and subcloned into pBluescript and subjected to DNA sequence and computer analysis. We found that, of a large number of clones isolated, 43 represented unique sequences not previously identified. Three clones turned out to

MicroRNA duplication accelerates the recruitment of new targets during vertebrate evolution

PubMed Central

Luo, Junjie; Wang, Yirong; Yuan, Jian

2018-01-01

The repertoire of miRNAs has considerably expanded during metazoan evolution, and duplication is an important mechanism for generating new functional miRNAs. However, relatively little is known about the functional divergence between paralogous miRNAs and the possible coevolution between duplicated miRNAs and the genomic contexts. By systematically examining small RNA expression profiles across various human tissues and interrogating the publicly available miRNA:mRNA pairing chimeras, we found that changes in expression patterns and targeting preferences are widespread for duplicated miRNAs in vertebrates. Both the empirical interactions and target predictions suggest that evolutionarily conserved homo-seed duplicated miRNAs pair with significantly higher numbers of target sites compared to the single-copy miRNAs. Our birth-and-death evolutionary analysis revealed that the new target sites of miRNAs experienced frequent gains and losses during function development. Our results suggest that a newly emerged target site has a higher probability to be functional and maintained by natural selection if it is paired to a seed shared by multiple paralogous miRNAs rather than being paired to a single-copy miRNA. We experimentally verified the divergence in target repression between two paralogous miRNAs by transfecting let-7a and let-7b mimics into kidney-derived cell lines of four mammalian species and measuring the resulting transcriptome alterations by extensive high-throughput sequencing. Our results also suggest that the gains and losses of let-7 target sites might be associated with the evolution of repressiveness of let-7 across mammalian species. PMID:29511046

Second generation sequencing of microRNA in Human Bone Cells treated with Parathyroid Hormone or Dexamethasone.

PubMed

Laxman, Navya; Rubin, Carl-Johan; Mallmin, Hans; Nilsson, Olle; Tellgren-Roth, Christian; Kindmark, Andreas

2016-03-01

We investigated the impact of treatment with parathyroid hormone (PTH) and dexamethasone (DEX) for 2 and 24h by RNA sequencing of miRNAs in primary human bone (HOB) cells. A total of 207 million reads were obtained, and normalized absolute expression retrieved for 373 most abundant miRNAs. In naïve control cells, 7 miRNAs were differentially expressed (FDR<0.05) between the two time points. Ten miRNAs exhibited differential expression (FDR <0.05) across two time points and treatments after adjusting for expression in controls and were selected for downstream analyses. Results show significant effects on miRNA expression when comparing PTH with DEX at 2h with even more pronounced effects at 24h. Interestingly, several miRNAs exhibiting differences in expression are predicted to target genes involved in bone metabolism e.g. miR-30c2, miR-203 and miR-205 targeting RUNX2, and miR-320 targeting β-catenin (CTNNB1) mRNA expression. CTNNB1and RUNX2 levels were decreased after DEX treatment and increased after PTH treatment. Our analysis also identified 2 putative novel miRNAs in PTH and DEX treated cells at 24h. RNA sequencing showed that PTH and DEX treatment affect miRNA expression in HOB cells and that regulated miRNAs in turn are correlated with expression levels of key genes involved in bone metabolism. Copyright © 2016 Elsevier Inc. All rights reserved.

Sequence-specific antimicrobials using efficiently delivered RNA-guided nucleases.

PubMed

Citorik, Robert J; Mimee, Mark; Lu, Timothy K

2014-11-01

Current antibiotics tend to be broad spectrum, leading to indiscriminate killing of commensal bacteria and accelerated evolution of drug resistance. Here, we use CRISPR-Cas technology to create antimicrobials whose spectrum of activity is chosen by design. RNA-guided nucleases (RGNs) targeting specific DNA sequences are delivered efficiently to microbial populations using bacteriophage or bacteria carrying plasmids transmissible by conjugation. The DNA targets of RGNs can be undesirable genes or polymorphisms, including antibiotic resistance and virulence determinants in carbapenem-resistant Enterobacteriaceae and enterohemorrhagic Escherichia coli. Delivery of RGNs significantly improves survival in a Galleria mellonella infection model. We also show that RGNs enable modulation of complex bacterial populations by selective knockdown of targeted strains based on genetic signatures. RGNs constitute a class of highly discriminatory, customizable antimicrobials that enact selective pressure at the DNA level to reduce the prevalence of undesired genes, minimize off-target effects and enable programmable remodeling of microbiota.

International interlaboratory study comparing single organism 16S rRNA gene sequencing data: Beyond consensus sequence comparisons

PubMed Central

Olson, Nathan D.; Lund, Steven P.; Zook, Justin M.; Rojas-Cornejo, Fabiola; Beck, Brian; Foy, Carole; Huggett, Jim; Whale, Alexandra S.; Sui, Zhiwei; Baoutina, Anna; Dobeson, Michael; Partis, Lina; Morrow, Jayne B.

2015-01-01

This study presents the results from an interlaboratory sequencing study for which we developed a novel high-resolution method for comparing data from different sequencing platforms for a multi-copy, paralogous gene. The combination of PCR amplification and 16S ribosomal RNA gene (16S rRNA) sequencing has revolutionized bacteriology by enabling rapid identification, frequently without the need for culture. To assess variability between laboratories in sequencing 16S rRNA, six laboratories sequenced the gene encoding the 16S rRNA from Escherichia coli O157:H7 strain EDL933 and Listeria monocytogenes serovar 4b strain NCTC11994. Participants performed sequencing methods and protocols available in their laboratories: Sanger sequencing, Roche 454 pyrosequencing®, or Ion Torrent PGM®. The sequencing data were evaluated on three levels: (1) identity of biologically conserved position, (2) ratio of 16S rRNA gene copies featuring identified variants, and (3) the collection of variant combinations in a set of 16S rRNA gene copies. The same set of biologically conserved positions was identified for each sequencing method. Analytical methods using Bayesian and maximum likelihood statistics were developed to estimate variant copy ratios, which describe the ratio of nucleotides at each identified biologically variable position, as well as the likely set of variant combinations present in 16S rRNA gene copies. Our results indicate that estimated variant copy ratios at biologically variable positions were only reproducible for high throughput sequencing methods. Furthermore, the likely variant combination set was only reproducible with increased sequencing depth and longer read lengths. We also demonstrate novel methods for evaluating variable positions when comparing multi-copy gene sequence data from multiple laboratories generated using multiple sequencing technologies. PMID:27077030

An Unsolved Mystery: The Target-Recognizing RNA Species of MicroRNA Genes

PubMed Central

Chen, Chang-Zheng

2013-01-01

MicroRNAs (miRNAs) are an abundant class of endogenous ~ 21-nucleotide (nt) RNAs. These small RNAs are produced from long primary miRNA transcripts — pri-miRNAs — through sequential endonucleolytic maturation steps that yield precursor miRNA (pre-miRNA) intermediates and then the mature miRNAs. The mature miRNAs are loaded into the RNA-induced silencing complexes (RISC), and guide RISC to target mRNAs for cleavage and/or translational repression. This paradigm, which represents one of major discoveries of modern molecular biology, is built on the assumption that mature miRNAs are the only species produced from miRNA genes that recognize targets. This assumption has guided the miRNA field for more than a decade and has led to our current understanding of the mechanisms of target recognition and repression by miRNAs. Although progress has been made, fundamental questions remain unanswered with regard to the principles of target recognition and mechanisms of repression. Here I raise questions about the assumption that mature miRNAs are the only target-recognizing species produced from miRNA genes and discuss the consequences of working under an incomplete or incorrect assumption. Moreover, I present evolution-based and experimental evidence that support the roles of pri-/pre-miRNAs in target recognition and repression. Finally, I propose a conceptual framework that integrates the functions of pri-/pre-miRNAs and mature miRNAs in target recognition and repression. The integrated framework opens experimental enquiry and permits interpretation of fundamental problems that have so far been precluded. PMID:23685275

Integrated sequencing of exome and mRNA of large-sized single cells.

PubMed

Wang, Lily Yan; Guo, Jiajie; Cao, Wei; Zhang, Meng; He, Jiankui; Li, Zhoufang

2018-01-10

Current approaches of single cell DNA-RNA integrated sequencing are difficult to call SNPs, because a large amount of DNA and RNA is lost during DNA-RNA separation. Here, we performed simultaneous single-cell exome and transcriptome sequencing on individual mouse oocytes. Using microinjection, we kept the nuclei intact to avoid DNA loss, while retaining the cytoplasm inside the cell membrane, to maximize the amount of DNA and RNA captured from the single cell. We then conducted exome-sequencing on the isolated nuclei and mRNA-sequencing on the enucleated cytoplasm. For single oocytes, exome-seq can cover up to 92% of exome region with an average sequencing depth of 10+, while mRNA-sequencing reveals more than 10,000 expressed genes in enucleated cytoplasm, with similar performance for intact oocytes. This approach provides unprecedented opportunities to study DNA-RNA regulation, such as RNA editing at single nucleotide level in oocytes. In future, this method can also be applied to other large cells, including neurons, large dendritic cells and large tumour cells for integrated exome and transcriptome sequencing.

A biochemical approach to identifying microRNA targets

PubMed Central

Karginov, Fedor V.; Conaco, Cecilia; Xuan, Zhenyu; Schmidt, Bryan H.; Parker, Joel S.; Mandel, Gail; Hannon, Gregory J.

2007-01-01

Identifying the downstream targets of microRNAs (miRNAs) is essential to understanding cellular regulatory networks. We devised a direct biochemical method for miRNA target discovery that combined RNA-induced silencing complex (RISC) purification with microarray analysis of bound mRNAs. Because targets of miR-124a have been analyzed, we chose it as our model. We honed our approach both by examining the determinants of stable binding between RISC and synthetic target RNAs in vitro and by determining the dependency of both repression and RISC coimmunoprecipitation on miR-124a seed sites in two of its well characterized targets in vivo. Examining the complete spectrum of miR-124 targets in 293 cells yielded both a set that were down-regulated at the mRNA level, as previously observed, and a set whose mRNA levels were unaffected by miR-124a. Reporter assays validated both classes, extending the spectrum of mRNA targets that can be experimentally linked to the miRNA pathway. PMID:18042700

Natural antisense transcript-targeted regulation of inducible nitric oxide synthase mRNA levels.

PubMed

Yoshigai, Emi; Hara, Takafumi; Araki, Yoshiro; Tanaka, Yoshito; Oishi, Masaharu; Tokuhara, Katsuji; Kaibori, Masaki; Okumura, Tadayoshi; Kwon, A-Hon; Nishizawa, Mikio

2013-04-01

Natural antisense transcripts (asRNAs) are frequently transcribed from mammalian genes. Recently, we found that non-coding asRNAs are transcribed from the 3' untranslated region (3'UTR) of the rat and mouse genes encoding inducible nitric oxide synthase (iNOS), which catalyzes the production of the inflammatory mediator nitric oxide. The iNOS asRNA stabilizes iNOS mRNA by interacting with the mRNA 3'UTR. Furthermore, single-stranded 'sense' oligonucleotides corresponding to the iNOS mRNA sequence were found to reduce iNOS mRNA levels by interfering with mRNA-asRNA interactions in rat hepatocytes. This method was named natural antisense transcript-targeted regulation (NATRE) technology. In this study, we detected human iNOS asRNA expressed in hepatocarcinoma and colon carcinoma tissues. The human iNOS asRNA harbored a sequence complementary to an evolutionarily conserved region of the iNOS mRNA 3'UTR. When introduced into hepatocytes, iNOS sense oligonucleotides that were modified by substitution with partial phosphorothioate bonds and locked nucleic acids or 2'-O-methyl nucleic acids greatly reduced levels of iNOS mRNA and iNOS protein. Moreover, sense oligonucleotides and short interfering RNAs decreased iNOS mRNA to comparable levels. These results suggest that NATRE technology using iNOS sense oligonucleotides could potentially be used to treat human inflammatory diseases and cancers by reducing iNOS mRNA levels. Copyright © 2013 Elsevier Inc. All rights reserved.

Sequence to Structure (S2S): display, manipulate and interconnect RNA data from sequence to structure.

PubMed

Jossinet, Fabrice; Westhof, Eric

2005-08-01

Efficient RNA sequence manipulations (such as multiple alignments) need to be constrained by rules of RNA structure folding. The structural knowledge has increased dramatically in the last years with the accumulation of several large RNA structures similar to those of the bacterial ribosome subunits. However, no tool in the RNA community provides an easy way to link and integrate progress made at the sequence level using the available three-dimensional information. Sequence to Structure (S2S) proposes a framework in which an user can easily display, manipulate and interconnect heterogeneous RNA data, such as multiple sequence alignments, secondary and tertiary structures. S2S has been implemented using the Java language and has been developed and tested under UNIX systems, such as Linux and MacOSX. S2S is available at http://bioinformatics.org/S2S/.

Screening for plant viruses by next generation sequencing using a modified double strand RNA extraction protocol with an internal amplification control.

PubMed

Kesanakurti, Prasad; Belton, Mark; Saeed, Hanaa; Rast, Heidi; Boyes, Ian; Rott, Michael

2016-10-01

The majority of plant viruses contain RNA genomes. Detection of viral RNA genomes in infected plant material by next generation sequencing (NGS) is possible through the extraction and sequencing of total RNA, total RNA devoid of ribosomal RNA, small RNA interference (RNAi) molecules, or double stranded RNA (dsRNA). Plants do not typically produce high molecular weight dsRNA, therefore the presence of dsRNA makes it an attractive target for plant virus diagnostics. The sensitivity of NGS as a diagnostic method demands an effective dsRNA protocol that is both representative of the sample and minimizes sample cross contamination. We have developed a modified dsRNA extraction protocol that is more efficient compared to traditional protocols, requiring reduced amounts of starting material, that is less prone to sample cross contamination. This was accomplished by using bead based homogenization of plant material in closed, disposable 50ml tubes. To assess the quality of extraction, we also developed an internal control by designing a real-time (quantitative) PCR (qPCR) assay that targets endornaviruses present in Phaseolus vulgaris cultivar Black Turtle Soup (BTS). Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Quantifying the relationship between sequence and three-dimensional structure conservation in RNA

PubMed Central

2010-01-01

Background In recent years, the number of available RNA structures has rapidly grown reflecting the increased interest on RNA biology. Similarly to the studies carried out two decades ago for proteins, which gave the fundamental grounds for developing comparative protein structure prediction methods, we are now able to quantify the relationship between sequence and structure conservation in RNA. Results Here we introduce an all-against-all sequence- and three-dimensional (3D) structure-based comparison of a representative set of RNA structures, which have allowed us to quantitatively confirm that: (i) there is a measurable relationship between sequence and structure conservation that weakens for alignments resulting in below 60% sequence identity, (ii) evolution tends to conserve more RNA structure than sequence, and (iii) there is a twilight zone for RNA homology detection. Discussion The computational analysis here presented quantitatively describes the relationship between sequence and structure for RNA molecules and defines a twilight zone region for detecting RNA homology. Our work could represent the theoretical basis and limitations for future developments in comparative RNA 3D structure prediction. PMID:20550657

Impact of sequencing depth and read length on single cell RNA sequencing data of T cells.

PubMed

Rizzetto, Simone; Eltahla, Auda A; Lin, Peijie; Bull, Rowena; Lloyd, Andrew R; Ho, Joshua W K; Venturi, Vanessa; Luciani, Fabio

2017-10-06

Single cell RNA sequencing (scRNA-seq) provides great potential in measuring the gene expression profiles of heterogeneous cell populations. In immunology, scRNA-seq allowed the characterisation of transcript sequence diversity of functionally relevant T cell subsets, and the identification of the full length T cell receptor (TCRαβ), which defines the specificity against cognate antigens. Several factors, e.g. RNA library capture, cell quality, and sequencing output affect the quality of scRNA-seq data. We studied the effects of read length and sequencing depth on the quality of gene expression profiles, cell type identification, and TCRαβ reconstruction, utilising 1,305 single cells from 8 publically available scRNA-seq datasets, and simulation-based analyses. Gene expression was characterised by an increased number of unique genes identified with short read lengths (<50 bp), but these featured higher technical variability compared to profiles from longer reads. Successful TCRαβ reconstruction was achieved for 6 datasets (81% - 100%) with at least 0.25 millions (PE) reads of length >50 bp, while it failed for datasets with <30 bp reads. Sufficient read length and sequencing depth can control technical noise to enable accurate identification of TCRαβ and gene expression profiles from scRNA-seq data of T cells.

LncRNA Expression Profile of Human Thoracic Aortic Dissection by High-Throughput Sequencing.

PubMed

Sun, Jie; Chen, Guojun; Jing, Yuanwen; He, Xiang; Dong, Jianting; Zheng, Junmeng; Zou, Meisheng; Li, Hairui; Wang, Shifei; Sun, Yili; Liao, Wangjun; Liao, Yulin; Feng, Li; Bin, Jianping

2018-01-01

In this study, the long non-coding RNA (lncRNA) expression profile in human thoracic aortic dissection (TAD), a highly lethal cardiovascular disease, was investigated. Human TAD (n=3) and normal aortic tissues (NA) (n=3) were examined by high-throughput sequencing. Bioinformatics analyses were performed to predict the roles of aberrantly expressed lncRNAs. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to validate the results. A total of 269 lncRNAs (159 up-regulated and 110 down-regulated) and 2, 255 mRNAs (1 294 up-regulated and 961 down-regulated) were aberrantly expressed in human TAD (fold-change> 1.5, P< 0.05). QRT-PCR results of five dysregulated genes were consistent with HTS data. A lncRNA-mRNA coexpression analysis showed positive correlations between the up-regulated lncRNA (ENSG00000269936) and its adjacent up-regulated mRNA (MAP2K6, R=0.940, P< 0.01), and between the down-regulated lncRNA_1421 and its down-regulated mRNAs (FBLN5, R=0.950, P< 0.01; ACTA2, R=0.96, P< 0.01; TIMP3, R=0.96, P< 0.05). The lncRNA-miRNA-mRNA network indicated that the up-regulated lncRNA XIST and p21 had similar sequences targeted by has-miR-17-5p. The results of luciferase assay and fluorescence immuno-cytochemistry were consistent with that. And qRT-PCR results showed that lncRNA XIST and p21 were expressed at a higher level and has-miR-17-5p was expressed at a lower level in TAD than in NA. The predicted binding motifs of three up-regulated lncRNAs (ENSG00000248508, ENSG00000226530, and EG00000259719) were correlated with up-regulated RUNX1 (R=0.982, P< 0.001; R=0.967, P< 0.01; R=0.960, P< 0.01, respectively). Our study revealed a set of dysregulated lncRNAs and predicted their multiple potential functions in human TAD. These findings suggest that lncRNAs are novel potential therapeutic targets for human TAD. © 2018 The Author(s). Published by S. Karger AG, Basel.

Mitochondrial tRNA cleavage by tRNA-targeting ribonuclease causes mitochondrial dysfunction observed in mitochondrial disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ogawa, Tetsuhiro, E-mail: atetsu@mail.ecc.u-tokyo.ac.jp; Shimizu, Ayano; Takahashi, Kazutoshi

2014-08-15

Highlights: • MTS-tagged ribonuclease was translocated successfully to the mitochondrial matrix. • MTS-tagged ribonuclease cleaved mt tRNA and reduced COX activity. • Easy and reproducible method of inducing mt tRNA dysfunction. - Abstract: Mitochondrial DNA (mtDNA) is a genome possessed by mitochondria. Since reactive oxygen species (ROS) are generated during aerobic respiration in mitochondria, mtDNA is commonly exposed to the risk of DNA damage. Mitochondrial disease is caused by mitochondrial dysfunction, and mutations or deletions on mitochondrial tRNA (mt tRNA) genes are often observed in mtDNA of patients with the disease. Hence, the correlation between mt tRNA activity and mitochondrialmore » dysfunction has been assessed. Then, cybrid cells, which are constructed by the fusion of an enucleated cell harboring altered mtDNA with a ρ{sup 0} cell, have long been used for the analysis due to difficulty in mtDNA manipulation. Here, we propose a new method that involves mt tRNA cleavage by a bacterial tRNA-specific ribonuclease. The ribonuclease tagged with a mitochondrial-targeting sequence (MTS) was successfully translocated to the mitochondrial matrix. Additionally, mt tRNA cleavage, which resulted in the decrease of cytochrome c oxidase (COX) activity, was observed.« less

Sequence determinants of improved CRISPR sgRNA design.

PubMed

Xu, Han; Xiao, Tengfei; Chen, Chen-Hao; Li, Wei; Meyer, Clifford A; Wu, Qiu; Wu, Di; Cong, Le; Zhang, Feng; Liu, Jun S; Brown, Myles; Liu, X Shirley

2015-08-01

The CRISPR/Cas9 system has revolutionized mammalian somatic cell genetics. Genome-wide functional screens using CRISPR/Cas9-mediated knockout or dCas9 fusion-mediated inhibition/activation (CRISPRi/a) are powerful techniques for discovering phenotype-associated gene function. We systematically assessed the DNA sequence features that contribute to single guide RNA (sgRNA) efficiency in CRISPR-based screens. Leveraging the information from multiple designs, we derived a new sequence model for predicting sgRNA efficiency in CRISPR/Cas9 knockout experiments. Our model confirmed known features and suggested new features including a preference for cytosine at the cleavage site. The model was experimentally validated for sgRNA-mediated mutation rate and protein knockout efficiency. Tested on independent data sets, the model achieved significant results in both positive and negative selection conditions and outperformed existing models. We also found that the sequence preference for CRISPRi/a is substantially different from that for CRISPR/Cas9 knockout and propose a new model for predicting sgRNA efficiency in CRISPRi/a experiments. These results facilitate the genome-wide design of improved sgRNA for both knockout and CRISPRi/a studies. © 2015 Xu et al.; Published by Cold Spring Harbor Laboratory Press.

VIRmiRNA: a comprehensive resource for experimentally validated viral miRNAs and their targets.

PubMed

Qureshi, Abid; Thakur, Nishant; Monga, Isha; Thakur, Anamika; Kumar, Manoj

2014-01-01