Dataset Information

Formation of triple-helical structures by the 3'-end sequences of MALAT1 and MEN? noncoding RNAs.

ABSTRACT: Stability of the long noncoding-polyadenylated nuclear (PAN) RNA from Kaposi's sarcoma-associated herpesvirus is conferred by an expression and nuclear retention element (ENE). The ENE protects PAN RNA from a rapid deadenylation-dependent decay pathway via formation of a triple helix between the U-rich internal loop of the ENE and the 3'-poly(A) tail. Because viruses borrow molecular mechanisms from their hosts, we searched highly abundant human long-noncoding RNAs and identified putative ENE-like structures in metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and multiple endocrine neoplasia-? (MEN?) RNAs. Unlike the PAN ENE, the U-rich internal loops of both predicted cellular ENEs are interrupted by G and C nucleotides and reside upstream of genomically encoded A-rich tracts. We confirmed the ability of MALAT1 and MEN? sequences containing the predicted ENE and A-rich tract to increase the levels of an intronless ?-globin reporter RNA. UV thermal denaturation profiles at different pH values support formation of a triple-helical structure composed of multiple U•A-U base triples and a single C•G-C base triple. Additional analyses of the MALAT1 ENE revealed that robust stabilization activity requires an intact triple helix, strong stems at the duplex-triplex junctions, a G-C base pair flanking the triplex to mediate potential A-minor interactions, and the 3'-terminal A of the A-rich tract to form a blunt-ended triplex lacking unpaired nucleotides at the duplex-triplex junction. These examples of triple-helical, ENE-like structures in cellular noncoding RNAs, are unique.

SUBMITTER: Brown JA

PROVIDER: S-EPMC3511071 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature

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Publications

Formation of triple-helical structures by the 3'-end sequences of MALAT1 and MENβ noncoding RNAs.

Brown Jessica A JA Valenstein Max L ML Yario Therese A TA Tycowski Kazimierz T KT Steitz Joan A JA

Proceedings of the National Academy of Sciences of the United States of America 20121105 47

Stability of the long noncoding-polyadenylated nuclear (PAN) RNA from Kaposi's sarcoma-associated herpesvirus is conferred by an expression and nuclear retention element (ENE). The ENE protects PAN RNA from a rapid deadenylation-dependent decay pathway via formation of a triple helix between the U-rich internal loop of the ENE and the 3'-poly(A) tail. Because viruses borrow molecular mechanisms from their hosts, we searched highly abundant human long-noncoding RNAs and identified putative ENE-li ...[more]

PMID: 23129630

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Project description:BackgroundComputational prediction of noncoding RNAs (ncRNAs) is an important task in the post-genomic era. One common approach is to utilize the profile information contained in alignment data rather than single sequences. However, this strategy involves the possibility that the quality of input alignments can influence the performance of prediction methods. Therefore, the evaluation of the robustness against alignment errors is necessary as well as the development of accurate prediction methods.ResultsWe describe a new method, called Profile BPLA kernel, which predicts ncRNAs from alignment data in combination with support vector machines (SVMs). Profile BPLA kernel is an extension of base-pairing profile local alignment (BPLA) kernel which we previously developed for the prediction from single sequences. By utilizing the profile information of alignment data, the proposed kernel can achieve better accuracy than the original BPLA kernel. We show that Profile BPLA kernel outperforms the existing prediction methods which also utilize the profile information using the high-quality structural alignment dataset. In addition to these standard benchmark tests, we extensively evaluate the robustness of Profile BPLA kernel against errors in input alignments. We consider two different types of error: first, that all sequences in an alignment are actually ncRNAs but are aligned ignoring their secondary structures; second, that an alignment contains unrelated sequences which are not ncRNAs but still aligned. In both cases, the effects on the performance of Profile BPLA kernel are surprisingly small. Especially for the latter case, we demonstrate that Profile BPLA kernel is more robust compared to the existing prediction methods.ConclusionsProfile BPLA kernel provides a promising way for identifying ncRNAs from alignment data. It is more accurate than the existing prediction methods, and can keep its performance under the practical situations in which the quality of input alignments is not necessarily high.

Project description:Long noncoding RNAs (lncRNAs) are important regulators of chromatin; however, the mechanistic roles for many lncRNAs are poorly understood in part because their direct interactions with genomic loci and proteins are difficult to assess. We used CHART-seq to map the genomic binding sites for two highly expressed human lncRNAs, NEAT1 and MALAT1, which localize within the nucleus to paraspeckles and nuclear speckles, respectively. We show that NEAT1 and MALAT1 localize to hundreds of genomic sites in human cells, primarily over active genes. NEAT1 and MALAT1 exhibit colocalization to many of these loci, but display distinct gene body binding patterns at these sites, suggesting independent but complementary functions for these RNAs. Protein mass spectrometry analysis of CHART-enriched material (CHART-MS) identified numerous proteins enriched by both lncRNAs, supporting complementary binding and function, in addition to unique associated proteins. Transcriptional inhibition or stimulation affects the localization of NEAT1 to active chromatin sites, implying that DNA sequence itself does not target NEAT1 to chromatin and that localization responds to cues involved in the transcription process. Paired-end CHART-seq was performed for a single replicate of each capture oligonucleotide in untreated MCF-7 cells to establish binding sites of these RNAs, for a total of 6 samples. To investigate the effects of transcriptional inhibition and E2 stimulation on the localization of these RNAs, we performed paired-end CHART-seq with each capture oligonucleotide for two biological replicates of flavopiridol- and vehicle (DMSO)-treated MCF-7 cells and for two biological replicates of E2- and vehicle (ethanol)-treated MCF-7 cells. To establish the overlap of NEAT1 and MALAT1 binding sites with a known component of paraspeckles (NEAT1-containing subnuclear body), we performed paired-end ChIP-seq for the paraspeckle component PSF in MCF-7 cells, as well as a single-end biological replicate.

Dataset Information

Formation of triple-helical structures by the 3'-end sequences of MALAT1 and MEN? noncoding RNAs.

Publications

Formation of triple-helical structures by the 3'-end sequences of MALAT1 and MENβ noncoding RNAs.

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