lncRNA Structure Research Articles

Analysis of Long‐noncoding RNA Structure‐Function Relationship in Prostate Cancer

The noncoding RNA (ncRNA) revolution has revealed myriad RNA species that play critical roles at all stages of life, including developmental biology and disease progression. For example, two long ncRNAs (lncRNA), Metastasis Associated Lung Adenocarcinoma Transcript‐1 (MALAT1; ~6.7 kb) and Second Chromosome Locus Associated with Prostate‐1 (SChLAP1; ~1.5 kb), are basally expressed in normal prostate tissue but are dysregulated in prostate cancer. MALAT1 acts in trans at nuclear speckles during mRNA post‐transcriptional processing while SChLAP1 acts in cis to influence oncogenic gene expression. There is compelling evidence that the 3′‐end of MALAT1 is a triple helix structure that acts as a molecular knot, driving transcript accumulation in cancer cells and furthering its metastatic potential, but we currently lack any biophysical data detailing the relationship between SChLAP1 structure and function. In general, the relationship among lncRNA structure, dynamics, and function is not well understood; for example, even with high‐resolution structures of the MALAT1 triple helix, questions remain regarding the role of intrinsic dynamics in transcript stability or protein binding. As lncRNA represent an underexplored therapeutic avenue, this work aims to investigate the role of lncRNA structure and dynamics in driving prostate cancer metastasis.Current work includes: 1) Understanding the role of the MALAT1 3′‐end triple helix structure and dynamics in global transcript stability and 2) Conducting the first biophysical analyses of SChLAP1 and identifying structural elements that are critical to metastasis. For the MALAT1 project, we have performed chemical probing experiments using both SHAPE‐ and DMS‐MaP chemical probing on the MALAT1 triple helix and 5′‐end extensions, revealing different conformations of the triple helix region. Additionally, we have performed exonuclease degradation assays on the triple helix and 5′‐end extensions in triplex de/stabilizing buffer conditions, showing that transcript stability is indeed tied to triple helix structural dynamic. For the SChLAP1 project, we have determined the first secondary structure model of full‐length SChLAP1 and have data supporting the formation of independent folding domains that when deleted from the full‐length transcript lower the invasive phenotype of prostate cells. We are currently working to investigate the tertiary structure of SChLAP1 and identify structure ensembles. Future work aims to design novel in‐cell mutational studies to identify regions of SChLAP1 that are critical for driving cell migration and invasion, two hallmarks of aggressive prostate cancer. This work will deepen our current understanding of the lncRNA MALAT1 triple helix dynamics in driving prostate cancer metastasis and provide the first biophysical and biochemical assessment of the lncRNA SChLAP1. Through this pursuit, we will provide the basis for assessing novel lncRNA structure‐function relationships and therapeutically targeting lncRNA in cancer.Support or Funding InformationEJM funded through grants award to AEH: Prostate Cancer Foundation YIA and NIH MIRA

Rs2262251 in lncRNA RP11-462G12.2 is associated with nonsyndromic cleft lip with/without cleft palate.

Nonsyndromic cleft lip with/without cleft palate (NSCL/P) is one of the most common human congenital defects. Rs2262251 (G>C) in long noncoding RNA (lncRNA) RP11-462G12.2 is in high linkage disequilibrium with rs8049367, which was identified in our previous genome-wide association study on NSCL/P, and is a potential causative single-nucleotide polymorphism (SNP) for NSCL/P. To test these hypotheses, rs2262251 was evaluated in another cohort of 1,314 cases and 1,259 controls. Rs2262251 was associated with NSCL/P risk (p = .003). However, no association was detected for cleft palate only. SNP rs2262251 affected the structure and expression of lncRNA RP11-462G12.2 in HEK293 and HEPM cells and in lip tissues from patients with NSCL/P. Overexpression of the rs2262251 G allele contributed to reducing the number of cells in the G0/G1 phase, inhibiting cell apoptosis, and promoting cell proliferation in vitro. The rs2262251 C allele regulated the expression of miR-744-5p and its target gene IQSEC2, both of which were expressed in human lip tissues, and showed reverse correlation during mouse lip development. Taken together, these findings suggest that rs2262251 is associated with the risk of NSCL/P and participates in a lncRNA-miRNA-mRNA regulatory axis in which miR-744-5p and IQSEC2 combine to control NSCL/P development.

Phylogenetic Analysis with Improved Parameters Reveals Conservation in lncRNA Structures

The existence of evolutionary conservation in base pairing is strong evidence for functional elements of RNA structure, although available tools for rigorous identification of structural conservation are limited. R-scape is a recently developed program for statistical prediction of pairwise covariation from sequence alignments, but it initially showed limited utility on long RNAs, especially those of eukaryotic origin. Here we show that R-scape can be adapted for a more powerful analysis of structure conservation in long RNA molecules, including mammalian lncRNAs.

Spatio-Temporal Transcriptional Dynamics of Maize Long Non-Coding RNAs Responsive to Drought Stress.

Long non-coding RNAs (lncRNAs) have emerged as important regulators in plant stress response. Here, we report a genome-wide lncRNA transcriptional analysis in response to drought stress using an expanded series of maize samples collected from three distinct tissues spanning four developmental stages. In total, 3488 high-confidence lncRNAs were identified, among which 1535 were characterized as drought responsive. By characterizing the genomic structure and expression pattern, we found that lncRNA structures were less complex than protein-coding genes, showing shorter transcripts and fewer exons. Moreover, drought-responsive lncRNAs exhibited higher tissue- and development-specificity than protein-coding genes. By exploring the temporal expression patterns of drought-responsive lncRNAs at different developmental stages, we discovered that the reproductive stage R1 was the most sensitive growth stage with more lncRNAs showing altered expression upon drought stress. Furthermore, lncRNA target prediction revealed 653 potential lncRNA-messenger RNA (mRNA) pairs, among which 124 pairs function in cis-acting mode and 529 in trans. Functional enrichment analysis showed that the targets were significantly enriched in molecular functions related to oxidoreductase activity, water binding, and electron carrier activity. Multiple promising targets of drought-responsive lncRNAs were discovered, including the V-ATPase encoding gene, vpp4. These findings extend our knowledge of lncRNAs as important regulators in maize drought response.

Landscape of SNPs-mediated lncRNA structural variations and their implication in human complex diseases.

An increasing number of functional studies shows that long noncoding RNAs (lncRNAs) are involved in many aspects of cellular physiology and fulfills a wide variety of regulatory roles at almost every stage of gene expression. A major feature of lncRNAs is the highly folded modular domains in transcripts. With improved modeling and definition, it is now feasible to explore and gain novel insights into the structural-functional relationship of lncRNAs and their association with complex human diseases. In this study, we utilized an automatic computational pipeline to scan lncRNA architecture at the genome-wide scale and to obtain a landscape of functional domains. An accurate alignment algorithm was performed to identify 40 triple pairs between single-nucleotide polymorphisms (SNPs), lncRNAs and diseases. In order to detect the potential contribution of a lncRNA's modular character, we estimated and evaluated structural rearrangements, which were derived from disease-associated SNPs. In addition, we focused on annotating and comparing the global and local heterogeneity of the wild-type and mutant lncRNAs. Assessing lncRNA architecture has yielded how variations in structured regions impact the molecular mechanisms of lncRNAs and how SNPs disturb binding and recruiting ability. These observations are the first glimpse of the 'lncRNA structurome' and make it possible to robustly explore and assemble intricate space conformation and their stress variation. This result also successfully demonstrates that lncRNA transcripts contain a complex structural landscape and highlights the proposed contribution of lncRNA structure in controlling RNA functions and disease mechanisms.

The Structure-To-Function Relationships of Gammaherpesvirus-Encoded Long Non-Coding RNAs and Their Contributions to Viral Pathogenesis.

Advances in next-generation sequencing have facilitated the discovery of a multitude of long non-coding RNAs (lncRNAs) with pleiotropic functions in cellular processes, disease, and viral pathogenesis. It came as no surprise when viruses were also revealed to transcribe their own lncRNAs. Among them, gammaherpesviruses, one of the three subfamilies of the Herpesviridae, code their largest number. These structurally and functionally intricate non-coding (nc) transcripts modulate cellular and viral gene expression to maintain viral latency or prompt lytic reactivation. These lncRNAs allow for the virus to escape cytosolic surveillance, sequester, and re-localize essential cellular factors and modulate the cell cycle and proliferation. Some viral lncRNAs act as “messenger molecules”, transferring information about viral infection to neighboring cells. This broad range of lncRNA functions is achieved through lncRNA structure-mediated interactions with effector molecules of viral and host origin, including other RNAs, proteins and DNAs. In this review, we discuss examples of gammaherpesvirus-encoded lncRNAs, emphasize their unique structural attributes, and link them to viral life cycle, pathogenesis, and disease progression. We will address their potential as novel targets for drug discovery and propose future directions to explore lncRNA structure and function relationship.

Long Non-coding RNA Structure and Function: Is There a Link?

RNA has emerged as the prime target for diagnostics, therapeutics and the development of personalized medicine. In particular, the non-coding RNAs (ncRNAs) that do not encode proteins, display remarkable biochemical versatility. They can fold into complex structures and interact with proteins, DNA and other RNAs, modulating the activity, DNA targets or partners of multiprotein complexes. Thus, ncRNAs confer regulatory plasticity and represent a new layer of epigenetic control that is dysregulated in disease. Intriguingly, for long non-coding RNAs (lncRNAs, >200 nucleotides length) structural conservation rather than nucleotide sequence conservation seems to be crucial for maintaining their function. LncRNAs tend to acquire complex secondary and tertiary structures and their functions only impose very subtle sequence constraints. In the present review we will discuss the biochemical assays that can be employed to determine the lncRNA structural configurations. The implications and challenges of linking function and lncRNA structure to design novel RNA therapeutic approaches will also be analyzed.

LncRNASNP2: an updated database of functional SNPs and mutations in human and mouse lncRNAs.

Long non-coding RNAs (lncRNAs) are emerging as important regulators in different biological processes through various ways. Because the related data, especially mutations in cancers, increased sharply, we updated the lncRNASNP to version 2 (http://bioinfo.life.hust.edu.cn/lncRNASNP2). lncRNASNP2 provides comprehensive information of SNPs and mutations in lncRNAs, as well as their impacts on lncRNA structure and function. lncRNASNP2 contains 7260238 SNPs on 141353 human lncRNA transcripts and 3921448 SNPs on 117405 mouse lncRNA transcripts. Besides the SNP information in the first version, the following new features were developed to improve the lncRNASNP2. (i) noncoding variants from COSMIC cancer data (859534) in lncRNAs and their effects on lncRNA structure and function; (ii) TCGA cancer mutations (315234) in lncRNAs and their impacts; (iii) lncRNA expression profiling of 20 cancer types in both tumor and its adjacent samples; (iv) expanded lncRNA-associated diseases; (v) optimized the results about lncRNAs structure change induced by variants; (vi) reduced false positives in miRNA and lncRNA interaction results. Furthermore, we developed online tools for users to analyze new variants in lncRNA. We aim to maintain the lncRNASNP as a useful resource for lncRNAs and their variants.

State of the art technologies to explore long non-coding RNAs in cancer.

Long non‐coding RNAs (lncRNAs) comprise a vast repertoire of RNAs playing a wide variety of crucial roles in tissue physiology in a cell‐specific manner. Despite being engaged in myriads of regulatory mechanisms, many lncRNAs have still remained to be assigned any functions. A constellation of experimental techniques including single‐molecule RNA in situ hybridization (sm‐RNA FISH), cross‐linking and immunoprecipitation (CLIP), RNA interference (RNAi), Clustered regularly interspaced short palindromic repeats (CRISPR) and so forth has been employed to shed light on lncRNA cellular localization, structure, interaction networks and functions. Here, we review these and other experimental approaches in common use for identification and characterization of lncRNAs, particularly those involved in different types of cancer, with focus on merits and demerits of each technique.

Insight into HOTAIR structural features and functions as landing pads for transcription regulation proteins

LncRNAs fulfill a wide range of regulatory functions at almost every process of gene expression. While derived from secondary structural features, lncRNAs may function as landing pads for transcription factors (TFs). In this paper, we detected the global structural landscape of 20,338 lncRNAs by utilizing a free energy minimization (MFE) algorithm, and identified the interactions between lncRNAs and TFs to analyze molecular association induced by the lncRNA structure. The accessibility analysis of full sequences as well as potential TF-binding fragments shows a large percentage of structural flanking sequence around the TF binding sites. This investigations paid great attention to the high-order architecture of HOTAIR lncRNA, and identified two coincident modular domains covering fragments 171-410bp and 811-1520bp via RNA-TF association predicting and in-silico computation mining. Then, the structural domains were implied potential landing pads to recruit regulatory proteins (13 TFs) and mediated coordinate regulation of transcription. Pathways and diseases enrichment analysis illustrated that the interacted TFs are significantly Pan-cancer relevant which is consistent with the known function of HOTAIR. Overall, the in-depth understanding of HOTAIR structure provides the first glimpse of coordinate regulation driven by modular features. The detailed architectural context could yield broad biological insights and provides a framework for comprehending lncRNA structure-function interrelationships.

LncRNA Structure: Message to the Heart

In this issue, Xue etal. (2016) describe the secondary structure of the heart-specific long non-coding RNA Braveheart, leading to the discovery of a short, asymmetric G-rich loop that controls cardiac lineage commitment by interacting with the transcription factor CNBP.

Understanding the Functions of Long Non-Coding RNAs through Their Higher-Order Structures.

Although thousands of long non-coding RNAs (lncRNAs) have been discovered in eukaryotes, very few molecular mechanisms have been characterized due to an insufficient understanding of lncRNA structure. Therefore, investigations of lncRNA structure and subsequent elucidation of the regulatory mechanisms are urgently needed. However, since lncRNA are high molecular weight molecules, which makes their crystallization difficult, obtaining information about their structure is extremely challenging, and the structures of only several lncRNAs have been determined so far. Here, we review the structure–function relationships of the widely studied lncRNAs found in the animal and plant kingdoms, focusing on the principles and applications of both in vitro and in vivo technologies for the study of RNA structures, including dimethyl sulfate-sequencing (DMS-seq), selective 2′-hydroxyl acylation analyzed by primer extension-sequencing (SHAPE-seq), parallel analysis of RNA structure (PARS), and fragmentation sequencing (FragSeq). The aim of this review is to provide a better understanding of lncRNA biological functions by studying them at the structural level.

Retrotransposon-associated long non-coding RNAs in mice and men.

Over a half of mammalian genomes is occupied by repetitive elements whose ability to provide functional sequences, move into new locations, and recombine underlies the so-called genome plasticity. At the same time, mobile elements exemplify selfish DNA, which is expanding in the genome at the expense of the host. The selfish generosity of mobile genetic elements is in the center of research interest as it offers insights into mechanisms underlying evolution and emergence of new genes. In terms of numbers, with over 20,000 in count, protein-coding genes make an outstanding >2% minority. This number is exceeded by an ever-growing list of genes producing long non-coding RNAs (lncRNAs), which do not encode for proteins. LncRNAs are a dynamically evolving population of genes. While it is not yet clear what fraction of lncRNAs represents functionally important ones, their features imply that many lncRNAs emerge at random as new non-functional elements whose functionality is acquired through natural selection. Here, we explore the intersection of worlds of mobile genetic elements (particularly retrotransposons) and lncRNAs. In addition to summarizing essential features of mobile elements and lncRNAs, we focus on how retrotransposons contribute to lncRNA evolution, structure, and function in mammals.

A comprehensive overview of lncRNA annotation resources.

Long noncoding RNAs (lncRNAs) are emerging as a class of important regulators participating in various biological functions and disease processes. With the widespread application of next-generation sequencing technologies, large numbers of lncRNAs have been identified, producing plenty of lncRNA annotation resources in different contexts. However, at present, we lack a comprehensive overview of these lncRNA annotation resources. In this study, we reviewed 24 currently available lncRNA annotation resources referring to > 205000 lncRNAs in over 50 tissues and cell lines. We characterized these annotation resources from different aspects, including exon structure, expression, histone modification and function. We found many distinct properties among these annotation resources. Especially, these resources showed diverse chromatin signatures, remarkable tissue and cell type dependence and functional specificity. Our results suggested the incompleteness and complementarity of current lncRNA annotations and the necessity of integration of multiple resources to comprehensively characterize lncRNAs. Finally, we developed 'LNCat' (lncRNA atlas, freely available at http://biocc.hrbmu.edu.cn/LNCat/), a user-friendly database that provides a genome browser of lncRNA structures, visualization of different resources from multiple angles and download of different combinations of lncRNA annotations, and supports rapid exploration, comparison and integration of lncRNA annotation resources. Overall, our study provides a comprehensive comparison of numerous lncRNA annotations, and can facilitate understanding of lncRNAs in human disease.

PRINS, a primate-specific long non-coding RNA, plays a role in the keratinocyte stress response and psoriasis pathogenesis.

In the last few years with the recent emergence of high-throughput technologies, thousands of long non-coding RNAs (lncRNAs) have been identified in the human genome. However, assigning functional annotation and determining cellular contexts for these RNAs are still in its infancy. As information gained about lncRNA structure, interacting partners, and roles in human diseases may be helpful in the characterization of novel lncRNAs, we review our knowledge on a selected group of lncRNAs that were identified serendipitously years ago by large-scale gene expression methods used to study human diseases. In particular, we focus on the Psoriasis-susceptibility-Related RNA Gene Induced by Stress (PRINS) lncRNA, first identified by our research group as a transcript highest expressed in psoriatic non-lesional epidermis. Results gathered for PRINS in the last 10 years indicate that it is conserved in primates and plays a role in keratinocyte stress response. Elevated levels of PRINS expression in psoriatic non-lesional keratinocytes alter the stress response of non-lesional epidermis and contribute to disease pathogenesis. Finally, we propose a categorization for the PRINS lncRNA based on a recently elaborated system for lncRNA classification.

Transcriptome sequencing reveals thousands of novel long non-coding RNAs in B cell lymphoma.

BackgroundGene profiling of diffuse large B cell lymphoma (DLBCL) has revealed broad gene expression deregulation compared to normal B cells. While many studies have interrogated well known and annotated genes in DLBCL, none have yet performed a systematic analysis to uncover novel unannotated long non-coding RNAs (lncRNA) in DLBCL. In this study we sought to uncover these lncRNAs by examining RNA-seq data from primary DLBCL tumors and performed supporting analysis to identify potential role of these lncRNAs in DLBCL.MethodsWe performed a systematic analysis of novel lncRNAs from the poly-adenylated transcriptome of 116 primary DLBCL samples. RNA-seq data were processed using de novo transcript assembly pipeline to discover novel lncRNAs in DLBCL. Systematic functional, mutational, cross-species, and co-expression analyses using numerous bioinformatics tools and statistical analysis were performed to characterize these novel lncRNAs.ResultsWe identified 2,632 novel, multi-exonic lncRNAs expressed in more than one tumor, two-thirds of which are not expressed in normal B cells. Long read single molecule sequencing supports the splicing structure of many of these lncRNAs. More than one-third of novel lncRNAs are differentially expressed between the two major DLBCL subtypes, ABC and GCB. Novel lncRNAs are enriched at DLBCL super-enhancers, with a fraction of them conserved between human and dog lymphomas. We see transposable elements (TE) overlap in the exonic regions; particularly significant in the last exon of the novel lncRNAs suggest potential usage of cryptic TE polyadenylation signals. We identified highly co-expressed protein coding genes for at least 88 % of the novel lncRNAs. Functional enrichment analysis of co-expressed genes predicts a potential function for about half of novel lncRNAs. Finally, systematic structural analysis of candidate point mutations (SNVs) suggests that such mutations frequently stabilize lncRNA structures instead of destabilizing them.ConclusionsDiscovery of these 2,632 novel lncRNAs in DLBCL significantly expands the lymphoma transcriptome and our analysis identifies potential roles of these lncRNAs in lymphomagenesis and/or tumor maintenance. For further studies, these novel lncRNAs also provide an abundant source of new targets for antisense oligonucleotide pharmacology, including shared targets between human and dog lymphomas.Electronic supplementary materialThe online version of this article (doi:10.1186/s13073-015-0230-7) contains supplementary material, which is available to authorized users.

N6-Methyladenosine Modification in a Long Noncoding RNA Hairpin Predisposes Its Conformation to Protein Binding

N6-Methyladenosine (m6A) is a reversible and abundant internal modification of messenger RNA (mRNA) and long noncoding RNA (lncRNA) with roles in RNA processing, transport, and stability. Although m6A does not preclude Watson–Crick base pairing, the N6-methyl group alters the stability of RNA secondary structure. Since changes in RNA structure can affect diverse cellular processes, the influence of m6A on mRNA and lncRNA structure has the potential to be an important mechanism for m6A function in the cell. Indeed, an m6A site in the lncRNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) was recently shown to induce a local change in structure that increases the accessibility of a U5-tract for recognition and binding by heterogeneous nuclear ribonucleoprotein C (HNRNPC). This m6A-dependent regulation of protein binding through a change in RNA structure, termed “m6A-switch”, affects transcriptome-wide mRNA abundance and alternative splicing. To further characterize this first example of an m6A-switch in a cellular RNA, we used nuclear magnetic resonance and Förster resonance energy transfer to demonstrate the effect of m6A on a 32-nucleotide RNA hairpin derived from the m6A-switch in MALAT1. The observed imino proton nuclear magnetic resonance resonances and Förster resonance energy transfer efficiencies suggest that m6A selectively destabilizes the portion of the hairpin stem where the U5-tract is located, increasing the solvent accessibility of the neighboring bases while maintaining the overall hairpin structure. The m6A-modified hairpin has a predisposed conformation that resembles the hairpin conformation in the RNA–HNRNPC complex more closely than the unmodified hairpin. The m6A-induced structural changes in the MALAT1 hairpin can serve as a model for a large family of m6A-switches that mediate the influence of m6A on cellular processes.

LncRNASNP: a database of SNPs in lncRNAs and their potential functions in human and mouse.

Long non-coding RNAs (lncRNAs) play key roles in various cellular contexts and diseases by diverse mechanisms. With the rapid growth of identified lncRNAs and disease-associated single nucleotide polymorphisms (SNPs), there is a great demand to study SNPs in lncRNAs. Aiming to provide a useful resource about lncRNA SNPs, we systematically identified SNPs in lncRNAs and analyzed their potential impacts on lncRNA structure and function. In total, we identified 495 729 and 777 095 SNPs in more than 30 000 lncRNA transcripts in human and mouse, respectively. A large number of SNPs were predicted with the potential to impact on the miRNA–lncRNA interaction. The experimental evidence and conservation of miRNA–lncRNA interaction, as well as miRNA expressions from TCGA were also integrated to prioritize the miRNA–lncRNA interactions and SNPs on the binding sites. Furthermore, by mapping SNPs to GWAS results, we found that 142 human lncRNA SNPs are GWAS tagSNPs and 197 827 lncRNA SNPs are in the GWAS linkage disequilibrium regions. All these data for human and mouse lncRNAs were imported into lncRNASNP database (http://bioinfo.life.hust.edu.cn/lncRNASNP/), which includes two sub-databases lncRNASNP-human and lncRNASNP-mouse. The lncRNASNP database has a user-friendly interface for searching and browsing through the SNP, lncRNA and miRNA sections.

LIPCAR

> Only one link of the chain of destiny can be handled at a time . > > — Winston Churchill All proteins are translated from RNA, but only a fraction of RNAs seem to be translated into proteins. Advanced genomics technologies have uncovered noncoding regulatory RNAs exhibiting extraordinary diversity in size, structure, and molecular function. We know a great deal about small (≈20 nucleotides) microRNAs that post-transcriptionally regulate translation of protein from target mRNAs having complementary 3′ sequences. These linear single-stranded nucleotides are transcribed either as independent gene products or as passengers within so-called miRtrons (microRNA-containing introns) of protein-coding genes and then processed and exported from the nucleus where they incorporate into RNA-induced silencing complexes.1 Because some microRNAs exhibit altered expression or differing circulating levels, they are being assessed as diagnostic biomarkers in cardiac disease. As yet, we know far less about the larger (>200 nucleotides) long noncoding RNAs (lncRNAs). lncRNAs are generated as antisense transcripts of protein-coding genes, as sense transcripts from within protein-coding gene introns, or as independent transcripts originating from intergenic regions.2 Unlike short microRNAs, lncRNAs are sufficiently long to develop multiple intramolecular RNA–RNA interactions conferring on them complex 3-dimensional structures. The unique physical configurations of different lncRNAs enable many of them to bind specific sets of proteins. Likewise, openly configured single-strand RNA sequences within lncRNA structures permit them to bind to complementary sequences in the genome. The combination of these 2 characteristics, protein binding and recognition of specific DNA sequences, evokes a characteristic lncRNA functionality: chaperoning transcriptional modulators or chromatin modifiers to specific genomic locations. In this manner, lncRNAs can epigenetically regulate gene expression.3 Article, see p 1569 Our nascent but growing understanding of lncRNA biology generally assumes that they are produced by, and act on, the nuclear genome. In this issue of Circulation Research …

Large-scale study of long non-coding RNA functions based on structure and expression features

Mammals and other complex organisms can transcribe an abundance of long non-coding RNAs (lncRNAs) that fulfill a wide variety of regulatory roles in many biological processes. These roles, including as scaffolds and as guides for protein-coding genes, mainly depend on the structure and expression level of lncRNAs. In this review, we focus on the current methods for analyzing lncRNA structure and expression, which is basic but necessary information for in-depth, large-scale analysis of lncRNA functions.