scholarly journals Exploring chromatin structural roles of non-coding RNAs at imprinted domains

Author(s):  
David Llères ◽  
Yui Imaizumi ◽  
Robert Feil

Different classes of non-coding RNA (ncRNA) influence the organization of chromatin. Imprinted gene domains constitute a paradigm for exploring functional long ncRNAs (lncRNAs). Almost all express an lncRNA in a parent-of-origin dependent manner. The mono-allelic expression of these lncRNAs represses close by and distant protein-coding genes, through diverse mechanisms. Some control genes on other chromosomes as well. Interestingly, several imprinted chromosomal domains show a developmentally regulated, chromatin-based mechanism of imprinting with apparent similarities to X-chromosome inactivation. At these domains, the mono-allelic lncRNAs show a relatively stable, focal accumulation in cis. This facilitates the recruitment of Polycomb repressive complexes, lysine methyltranferases and other nuclear proteins — in part through direct RNA–protein interactions. Recent chromosome conformation capture and microscopy studies indicate that the focal aggregation of lncRNA and interacting proteins could play an architectural role as well, and correlates with close positioning of target genes. Higher-order chromatin structure is strongly influenced by CTCF/cohesin complexes, whose allelic association patterns and actions may be influenced by lncRNAs as well. Here, we review the gene-repressive roles of imprinted non-coding RNAs, particularly of lncRNAs, and discuss emerging links with chromatin architecture.

2021 ◽  
Vol 12 ◽  
Author(s):  
Ousman Tamgue ◽  
Julius Ebua Chia ◽  
Frank Brombacher

Triptolide is a diterpene triepoxide, which performs its biological activities via mechanisms including induction of apoptosis, targeting of pro-inflammatory cytokines, and reshaping of the epigenetic landscape of target cells. However, the targeting of long non-coding RNAs (lncRNAs) by triptolide has not yet been investigated, despite their emerging roles as key epigenetic regulators of inflammation and immune cell function during Mycobacterium tuberculosis (Mtb) infection. Hence, we investigated whether triptolide targets inflammation-associated lncRNA-PACER and lincRNA-p21 and how this targeting associates with Mtb killing within monocyte-derived macrophages (MDMs).Using RT-qPCR, we found that triptolide induced the expression of lincRNA-p21 but inhibited the expression of lncRNA-PACER in resting MDMs in a dose- and time-dependent manner. Moreover, Mtb infection induced the expression of lincRNA-p21 and lncRNA-PACER, and exposure to triptolide before or after Mtb infection led to further increase of Mtb-induced expression of these lncRNAs in MDMs. We further found that contrary to lncRNA-PACER, triptolide time- and dose-dependently upregulated Ptgs-2, which is a proximal gene regulated by lncRNA-PACER. Also, low-concentration triptolide inhibited the expression of cytokine IL-6, a known target of lincRNA-p21. Mtb infection induced the expression of IL-6 and Ptgs-2, and triptolide treatment further increased IL-6 but decreased Ptgs-2 expression in Mtb-infected MDMs. The inverse relation between the expression of these lncRNAs and their target genes is concordant with the conception that these lncRNAs mediate, at least partially, the cytotoxic and/or anti-inflammatory activities of triptolide in both resting and activated MDMs. Using the CFU count method, we found that triptolide decreased the intracellular growth of Mtb HN878. The alamarBlue assay showed that this decreased Mtb HN878 growth was not as a result of direct targeting of Mtb HN878 by triptolide, but rather evoking MDMs’ intracellular killing mechanisms which we speculate could include triptolide-induced enhancement of MDMs’ effector killing functions mediated by lncRNA-PACER and lincRNA-p21. Altogether, these results provide proof of the modulation of lncRNA-PACER and lincRNA-p21 expression by triptolide, and a possible link between these lncRNAs, the enhancement of MDMs’ effector killing functions and the intracellular Mtb-killing activities of triptolide. These findings prompt for further investigation of the precise contribution of these lncRNAs to triptolide-induced activities in MDMs.


2021 ◽  
Vol 22 ◽  
Author(s):  
Vandana Golhani ◽  
Suman Kumar Ray ◽  
Sukhes Mukherjee

: MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are proficient in regulating gene expression post-transcriptionally. Considering the recent trend in exploiting non-coding RNAs (ncRNAs) as cancer therapeutics, the potential use of miRNAs and lncRNAs as biomarkers and novel therapeutic agents against angiogenesis is an important scientific aspect. An estimated 70% of the genome is actively transcribed, only 2% of which codes for known protein-coding genes. Long noncoding RNAs (lncRNAs) are a large and diverse class of RNAs > 200 nucleotides in length, and not translated into protein, and are of utmost importance and it governs the expression of genes in a temporal, spatial, and cell context-dependent manner. Angiogenesis is an essential process for organ morphogenesis and growth during development, and it is relevant during the repair of wounded tissue in adults. It is coordinated by an equilibrium of pro-and anti-angiogenic factors; nevertheless, when affected, it promotes several diseases, including breast cancer. Signaling pathways involved here are tightly controlled systems that regulate the appropriate timing of gene expression required for the differentiation of cells down a particular lineage essential for proper tissue development. Lately, scientific reports are indicating that ncRNAs, such as miRNAs, and lncRNAs, play critical roles in angiogenesis related to breast cancer. The specific roles of various miRNAs and lncRNAs in regulating angiogenesis in breast cancer, with particular focus on the downstream targets and signaling pathways regulated by these ncRNAs with molecular medicine perspective, are highlighted in this write-up.


2014 ◽  
Author(s):  
Yongsheng Li ◽  
Yunpeng Zhang ◽  
Shengli Li ◽  
Jianping Lu ◽  
Juan Chen ◽  
...  

The development of human breast cancer is driven by changes in the genetic and epigenetic landscape of the cell. Despite growing appreciation of the importance of epigenetics in breast cancers, our knowledge of epigenetic alterations of non-coding RNAs (ncRNAs) in breast cancers remains limited. Here, we explored the epigenetic patterns of ncRNAs in breast cancers via a sequencing-based comparative methylome analysis, mainly focusing on two most popular ncRNA biotypes, long non-coding RNAs (lncRNAs) and miRNAs. Besides global hypomethylation and extensive CpG islands (CGIs) hypermethylation, we observed widely aberrant methylation in the promoters of ncRNAs, which was higher than that of protein-coding genes. Specifically, intergenic ncRNAs were observed to contribute a large slice of the aberrantly methylated ncRNA promoters. Moreover, we summarized five patterns of ncRNA promoter aberrant methylation in the context of genomic CGIs, where aberrant methylation occurred not only on the CGIs, but also flanking regions and CGI sparse promoters. Integration with transcriptional datasets, we found that the ncRNA promoter methylation events were associated with transcriptional changes. Furthermore, a panel of ncRNAs were identified as biomarkers that were able to discriminate between disease phenotypes (AUCs>0.90). Finally, the potential functions for aberrantly methylated ncRNAs were predicted based on similar patterns, adjacency and/or target genes, highlighting that ncRNAs and coding genes coordinately mediated pathways dysregulation in the development and progression of breast cancers. This study presents the aberrant methylation patterns of ncRNAs, which will be a highly valuable resource for investigations at understanding epigenetic regulation of breast cancers.


2021 ◽  
Author(s):  
Xiaonan Xu ◽  
Kaizhen Wang ◽  
Olga Vera ◽  
Akanksha Verma ◽  
Olivier Elemento ◽  
...  

Deregulated gene expression through epigenetic, transcriptional, and copy number alterations is a major driver of melanoma progression and metastasis. In addition to serving as blueprints for translation, some mRNAs post-transcriptionally regulate gene expression by competitively sequestering miRNAs they share with other targets. Here we report that such mRNAs, termed competitive endogenous RNAs (ceRNAs), contribute to melanoma progression and metastasis. ceRNA predictions identified multiple candidate genes on chromosome 1q, which is recurrently amplified in melanoma. Genetic studies reveal that three of these mRNAs, CEP170, NUCKS1, and ZC3H11A, promote melanoma migration, invasion, and metastasis in a protein coding-independent and miRNA binding site-dependent manner. Interestingly, CEP170, NUCKS1, and ZC3H11A cooperate to elicit oncogenic effects by collectively impairing the tumor suppressor activity of 8 miRNAs on several pro-metastatic target genes. Finally, this complex chromosome 1q ceRNA network is evident in other cancer types, suggesting ceRNA network deregulation is a common driver of cancer progression.


2021 ◽  
Vol 21 ◽  
Author(s):  
Han Yu ◽  
Zi-Ang Shen ◽  
Yuan-Ke Zhou ◽  
Pu-Feng Du

: Long non-coding RNAs (LncRNAs) are a type of RNA with little or no protein-coding ability. Their length is more than 200 nucleotides. A large number of studies have indicated that lncRNAs play a significant role in various biological processes, including chromatin organizations, epigenetic programmings, transcriptional regulations, post-transcriptional processing, and circadian mechanism at the cellular level. Since lncRNAs perform vast functions through their interactions with proteins, identifying lncRNA-protein interaction is crucial to the understandings of the lncRNA molecular functions. However, due to the high cost and time-consuming disadvantage of experimental methods, a variety of computational methods have emerged. Recently, many effective and novel machine learning methods have been developed. In general, these methods fall into two categories: semi-supervised learning methods and supervised learning methods. The latter category can be further classified into the deep learning-based method, the ensemble learning-based method, and the hybrid method. In this paper, we focused on supervised learning methods. We summarized the state-of-the-art methods in predicting lncRNA-protein interactions. Furthermore, the performance and the characteristics of different methods have also been compared in this work. Considering the limits of the existing models, we analyzed the problems and discussed future research potentials.


2005 ◽  
Vol 25 (14) ◽  
pp. 5965-5972 ◽  
Author(s):  
Yong-Heng Chen ◽  
Jeong Hoon Kim ◽  
Michael R. Stallcup

ABSTRACT Nuclear receptors (NRs) regulate target gene transcription through the recruitment of multiple coactivator complexes to the promoter regions of target genes. One important coactivator complex includes a p160 coactivator (GRIP1, SRC-1, or ACTR) and its downstream coactivators (e.g., p300, CARM1, CoCoA, and Fli-I), which contribute to transcriptional activation by protein acetylation, protein methylation, and protein-protein interactions. In this study, we identified a novel NR coactivator, GAC63, which binds to the N-terminal region of p160 coactivators as well as the ligand binding domains of some NRs. GAC63 enhanced transcriptional activation by NRs in a hormone-dependent and GRIP1-dependent manner in transient transfection assays and cooperated synergistically and selectively with other NR coactivators, including GRIP1 and CARM1, to enhance estrogen receptor function. Endogenous GAC63 was recruited to the estrogen-responsive pS2 gene promoter of MCF-7 cells in response to the hormone. Reduction of the endogenous GAC63 level by small interfering RNA inhibited transcriptional activation by the hormone-activated estrogen receptor. Thus, GAC63 is a physiologically relevant part of the p160 coactivator signaling pathway that mediates transcriptional activation by NRs.


Author(s):  
Zheguang Lin ◽  
Yibing Liu ◽  
Xiaomei Chen ◽  
Cong Han ◽  
Wei Wang ◽  
...  

AbstractLong non-coding RNAs (lncRNAs) emerge as critical regulators with various biological functions in living organisms. However, to date, no systematic characterization of lncRNAs has been investigated in the ectoparasitic mite Varroa destructor, the most severe biotic threat to honey bees worldwide. Here, we performed an initial genome-wide identification of lncRNAs in V. destructor via high-throughput sequencing technology and reported, for the first time, the transcriptomic landscape of lncRNAs in the devastating parasite. By means of a lncRNA identification pipeline, 6,645 novel lncRNA transcripts, encoded by 3,897 gene loci, were identified, including 2,066 sense lncRNAs, 2,772 lincRNAs, and 1,807 lncNATs. Compared with protein-coding mRNAs, V. destructor lncRNAs are shorter in terms of full length, as well as of the ORF length, contain less exons, and express at lower level. GO term and KEGG pathway enrichment analyses of the lncRNA target genes demonstrated that these predicted lncRNAs are likely to play key roles in cellular processes, genetic information processing and environmental responses. To our knowledge, this is the first catalog of lncRNA profile in the parasitiformes species, providing a valuable resource for genetic and genomic studies. Understanding the characteristics and features of lncRNAs in V. destructor would promote sustainable pest control.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wenjuan Zhao ◽  
Zijing Li ◽  
Quan Liu ◽  
Su Xie ◽  
Mengxun Li ◽  
...  

AbstractSkeletal muscle growth plays a critical role during porcine muscle development stages. Genome-wide transcriptome analysis reveals that long intergenic non-coding RNAs (lincRNAs) are implicated as crucial regulator involving in epigenetic regulation. However, comprehensive analysis of lincRNAs in embryonic muscle development stages remain still elusive. Here, we investigated the transcriptome profiles of Duroc embryonic muscle tissues from days 33, 65, and 90 of gestation using RNA-seq, and 228 putative lincRNAs were identified. Moreover, these lincRNAs exhibit the characteristics of shorter transcripts length, longer exons, less exon numbers and lower expression level compared with protein-coding transcripts. Expression profile analysis showed that a total of 120 lincRNAs and 2638 mRNAs were differentially expressed. In addition, we also performed quantitative trait locus (QTL) mapping analysis for differentially expressed lincRNAs (DE lincRNAs), 113 of 120 DE lincRNAs were localized on 2200 QTLs, we observed many QTLs involved in growth and meat quality traits. Furthermore, we predicted potential target genes of DE lincRNAs in cis or trans regulation. Gene ontology and pathway analysis reveals that potential targets of DE lincRNAs mostly were enriched in the processes and pathways related to tissue development, MAPK signaling pathway, Wnt signaling pathway, TGF-beta signaling pathway and insulin signaling pathway, which involved in skeletal muscle physiological functions. Based on cluster analysis, co-expression network analysis of DE lincRNAs and their potential target genes indicated that DE lincRNAs highly regulated protein-coding genes associated with skeletal muscle development. In this study, many of the DE lincRNAs may play essential roles in pig muscle growth and muscle mass. Our study provides crucial information for further exploring the molecular mechanisms of lincRNAs during skeletal muscle development.


2021 ◽  
Author(s):  
Wenjuan Zhao ◽  
Zijing Li ◽  
Quan Liu ◽  
Su Xie ◽  
Mengxun Li ◽  
...  

Abstract Skeletal muscle growth plays a critical role during porcine muscle development stages. Genome-wide transcriptome analysis reveals that thousands of long intergenic non-coding RNAs (lincRNAs) have been identified in various species and implicated as crucial regulator involving in epigenetic regulation. However, comprehensive analysis of lincRNAs in embryonic muscle development stages remain still elusive. Here, we investigated the transcriptome profiles of duroc embryonic muscle tissues from days 33, 65, and 90 of gestation using RNA-seq, there were 228 putative lincRNAs identified. Moreover, these lincRNAs exhibit the characteristics of shorter transcripts length, longer exons, less exon numbers and lower expression level compared with protein-coding transcripts. Differential expression analysis showed that a total of 91 lincRNAs and 2638 mRNAs were differentially expressed. In addition, we also performed quantitative trait locus (QTL) mapping analysis for DE lincRNAs, 113 of 120 DE lincRNAs were localized on 2200 QTLs, we observed many QTLs involved in growth and meat quality traits. Furthermore, we predicted potential target genes of DE lincRNAs in cis or trans regulation. Gene ontology and pathway analysis reveals that potential targets of DE lincRNAs mostly were enriched in the processes and pathways related to tissue development, MAPK signaling pathway, Wnt signaling pathway, TGF-beta signaling pathway and insulin signaling pathway, which involved in skeletal muscle physiological functions. Based on cluster analysis, a co-expression network analysis of DE lincRNAs and their potential target genes indicated that DE lincRNAs highly regulated protein-coding genes associated with skeletal muscle development. In this study, many of the DE lincRNAs identified may play essential roles in pig muscle growth and muscle mass. Our study provides crucial information for exploring further the molecular mechanisms of lincRNAs during skeletal muscle development.


2021 ◽  
Author(s):  
Cristina Zamora-Ballesteros ◽  
Jorge Martin-Garcia ◽  
Aroa Suarez-Vega ◽  
Julio Diez

One of the most promising strategies of Pine Pitch Canker (PPC) management is the use of reproductive plant material resistant to the disease. Understanding the complexity of plant transcriptome that underlies the defence to the causal agent Fusarium circinatum, would greatly facilitate the development of an accurate breeding program. Long non-coding RNAs (lncRNAs) are emerging as important transcriptional regulators under biotic stresses in plants. However, to date, characterization of lncRNAs in conifer trees has not been reported. In this study, transcriptomic identification of lncRNAs was carried out using strand-specific paired-end RNA sequencing, from Pinus radiata samples inoculated with F. circinatum at an early stage of infection. Overall, 13,312 lncRNAs were predicted through a bioinformatics approach, including long intergenic non-coding RNAs (92.3%), antisense lncRNAs (3.3%) and intronic lncRNAs (2.9%). Compared with protein-coding RNAs, pine lncRNAs are shorter, have lower expression, lower GC content and harbour fewer and shorter exons. A total of 164 differentially expressed (DE) lncRNAs were identified in response to F. circinatum infection in the inoculated versus mock-inoculated P. radiata seedlings. The predicted cis-regulated target genes of these pathogen-responsive lncRNAs were related to defence mechanisms such as kinase activity, phytohormone regulation, and cell wall reinforcement. Co-expression network analysis of DE lncRNAs, DE protein-coding RNAs and lncRNA target genes also indicated a potential network regulating pectinesterase activity and cell wall remodelling. This study presents the first analysis of conifer lncRNAs involved in the regulation of defence network and provides the basis for future functional characterizations of lncRNAs in relation to pine defence responses against F. circinatum.


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