scholarly journals Circular RNA: metabolism, functions and interactions with proteins

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Wei-Yi Zhou ◽  
Ze-Rong Cai ◽  
Jia Liu ◽  
De-Shen Wang ◽  
Huai-Qiang Ju ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Translational Medicine ◽  
Transcriptional Regulators ◽  
Circular Rna ◽  
Ternary Complexes ◽  
Circular Rnas ◽  
Biological Functions ◽  
Diagnostic Biomarkers ◽  
Rna Molecules ◽  
Made In

AbstractCircular RNAs (CircRNAs) are single-stranded, covalently closed RNA molecules that are ubiquitous across species ranging from viruses to mammals. Important advances have been made in the biogenesis, regulation, localization, degradation and modification of circRNAs. CircRNAs exert biological functions by acting as transcriptional regulators, microRNA (miR) sponges and protein templates. Moreover, emerging evidence has revealed that a group of circRNAs can serve as protein decoys, scaffolds and recruiters. However, the existing research on circRNA-protein interactions is quite limited. Hence, in this review, we briefly summarize recent progress in the metabolism and functions of circRNAs and elaborately discuss the patterns of circRNA-protein interactions, including altering interactions between proteins, tethering or sequestering proteins, recruiting proteins to chromatin, forming circRNA-protein-mRNA ternary complexes and translocating or redistributing proteins. Many discoveries have revealed that circRNAs have unique expression signatures and play crucial roles in a variety of diseases, enabling them to potentially act as diagnostic biomarkers and therapeutic targets. This review systematically evaluates the roles and mechanisms of circRNAs, with the hope of advancing translational medicine involving circRNAs.

scholarly journals N6-Methyladenosine Modification Opens a New Chapter in Circular RNA Biology

2021 ◽  
Vol 9 ◽  
Author(s):  
Jun Wu ◽  
Xin Guo ◽  
Yi Wen ◽  
Shangqing Huang ◽  
Xiaohui Yuan ◽  
...  
Keyword(s):  
Cellular Localization ◽  
Circular Rna ◽  
Regulatory Mechanisms ◽  
Circular Rnas ◽  
Biological Functions ◽  
Future Directions ◽  
Rna Molecules ◽  
Physiological Processes ◽  
Rna Biology ◽  
Insight Into

As the most abundant internal modification in eukaryotic cells, N6-methyladenosine (m6A) in mRNA has shown widespread regulatory roles in a variety of physiological processes and disease progressions. Circular RNAs (circRNAs) are a class of covalently closed circular RNA molecules and play an essential role in the pathogenesis of various diseases. Recently, accumulating evidence has shown that m6A modification is widely existed in circRNAs and found its key biological functions in regulating circRNA metabolism, including biogenesis, translation, degradation and cellular localization. Through regulating circRNAs, studies have shown the important roles of m6A modification in circRNAs during immunity and multiple diseases, which represents a new layer of control in physiological processes and disease progressions. In this review, we focused on the roles played by m6A in circRNA metabolism, summarized the regulatory mechanisms of m6A-modified circRNAs in immunity and diseases, and discussed the current challenges to study m6A modification in circRNAs and the possible future directions, providing a comprehensive insight into understanding m6A modification of circRNAs in RNA epigenetics.

scholarly journals Circular RNA in Diseased Heart

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1240 ◽  
Author(s):  
Ying Wang ◽  
Bin Liu
Keyword(s):  
Heart Disease ◽  
Protein Interactions ◽  
Regulatory Peptides ◽  
Circular Rna ◽  
Diagnostic Tools ◽  
Circular Rnas ◽  
Cardiovascular Research ◽  
Ample Evidence ◽  
Non Coding Rnas ◽  
Made In

Heart disease remains the leading cause of death globally and leads to tremendous socio-economic burden. Despite advances in the field of cardiovascular research, novel theranostics are still in urgent need. Remarkable progress has been made in understanding aberrant protein interactions and signaling pathways in the diseased heart, but less is known regarding epigenetic regulation. Non-coding RNAs have emerged as important regulators of cardiac function and have been implicated in disease. While significant progress has been made in understanding the roles of microRNAs and long non-coding RNAs, the functional roles of circular RNAs are less explored. Recent studies have provided ample evidence supporting their roles in multiple physiological processes including regulating the function of the heart. Compared with other RNAs, circular RNAs exhibit higher stability and more versatile functional modes: including sponging microRNAs, scaffolding proteins, regulating transcription, and even encoding small regulatory peptides. These characteristics make circular RNAs promising candidates for the development of diagnostic tools and therapies for heart disease. In this review, we will discuss the biogenesis of circular RNAs and provide an update of their functional implications in heart disease, with an emphasis on heart failure and arrhythmias.

scholarly journals The potential roles of circRNAs in osteoarthritis: a coming journey to find a treasure

2018 ◽  
Vol 38 (5) ◽  
Author(s):  
Hui-Zi Li ◽  
Zhong Lin ◽  
Xiang-He Xu ◽  
Nan Lin ◽  
Hua-Ding Lu
Keyword(s):  
Early Diagnosis ◽  
Therapeutic Targets ◽  
Differentially Expressed ◽  
Joint Disease ◽  
Circular Rnas ◽  
Biological Functions ◽  
Diagnostic Biomarkers

Osteoarthritis (OA), a common joint disease in elderly, causes serious social and economic burdens worldwide. Previous studies indicated that some differentially expressed circular RNAs (circRNAs) participated in the initiation and progression of OA. These findings suggested that circRNAs may act as promising diagnostic biomarkers and therapeutic targets for OA. In this review, we summarize the biogenesis and biological functions of circRNAs and explore the underlying roles of circRNAs in OA, which may enlighten further studies and contribute to the early diagnosis and intervention of OA.

scholarly journals The Regulatory Functions of Circular RNAs in Digestive System Cancers

Cancers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 770 ◽  
Author(s):  
Xiao Yuan ◽  
Ya Yuan ◽  
Zhi He ◽  
Diyan Li ◽  
Bo Zeng ◽  
...  
Keyword(s):  
Digestive System ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Circular Rna ◽  
Research Progress ◽  
Circular Rnas ◽  
Biological Functions ◽  
Ribonucleic Acids ◽  
Mirna Sponges ◽  
And Biological Markers

Circular ribonucleic acids (circRNAs), which are a type of covalently closed circular RNA, are receiving increasing attention. An increasing amount of evidence suggests that circRNAs are involved in the biogenesis and development of multiple diseases such as digestive system cancers. Dysregulated circRNAs have been found to act as oncogenes or tumour suppressors in digestive system cancers. Moreover, circRNAs are related to ageing and a wide variety of processes in tumour cells, such as cell apoptosis, invasion, migration, and proliferation. Moreover, circRNAs can perform a remarkable multitude of biological functions, such as regulating splicing or transcription, binding RNA-binding proteins to enable function, acting as microRNA (miRNA) sponges, and undergoing translated into proteins. However, in digestive system cancers, circRNAs function mainly as miRNA sponges. Herein, we summarise the latest research progress on biological functions of circRNAs in digestive system cancers. This review serves as a synopsis of potential therapeutic targets and biological markers for digestive system cancer.

Circular RNA as a potential diagnostic and/or therapeutic target for endometriosis

2020 ◽  
Vol 14 (13) ◽  
pp. 1277-1287
Author(s):  
Parisa M Dana ◽  
Mona Taghavipour ◽  
Hamed Mirzaei ◽  
Bahman Yousefi ◽  
Bahram Moazzami ◽  
...  
Keyword(s):  
Gene Expression ◽  
Signaling Pathways ◽  
Therapeutic Target ◽  
Noncoding Rnas ◽  
Circular Rna ◽  
Circular Rnas ◽  
Biological Functions ◽  
Parental Gene

Endometriosis is a pathology form of endometrium that behaves in a similar way to malignancies, such as invasion and resistance to apoptosis. Circular RNAs (CircRNAs) are a class of noncoding RNAs that have several biological functions including, miRNA sponging, sequestering of proteins, enhancing parental gene expression and translation resulting in polypeptides. In this review, we highlighted the roles of circRNAs as potential diagnostic and therapeutic biomarkers in endometriosis. Moreover, we summarized the roles of circRNAs in the pathogenesis of endometriosis via different signaling pathways, such as the miRNA network and apoptosis.

scholarly journals Transcriptome-wide profiles of circular RNA and RNA binding protein interactions reveal effects on circular RNA biogenesis and cancer pathway expression

2020 ◽  
Author(s):  
Trine Line Hauge Okholm ◽  
Shashank Sathe ◽  
Samuel S. Park ◽  
Andreas Bjerregaard Kamstrup ◽  
Asta Mannstaedt Rasmussen ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Protein Interactions ◽  
Binding Sites ◽  
Target Genes ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Circular Rna ◽  
Circular Rnas ◽  
Cancer Genes

AbstractCircular RNAs (circRNAs) are stable, often highly expressed RNA transcripts with potential to modulate other regulatory RNAs. A few circRNAs have been shown to bind RNA binding proteins (RBPs), however, little is known about the prevalence and strength of these interactions in different biological contexts. Here, we comprehensively evaluate the interplay between circRNAs and RBPs in the ENCODE cell lines, HepG2 and K562, by profiling the expression of circRNAs in fractionated total RNA-sequencing samples and analyzing binding sites of 150 RBPs in large eCLIP data sets. We show that KHSRP binding sites are enriched in flanking introns of circRNAs in both HepG2 and K562 cells, and that KHSRP depletion affects circRNA biogenesis. Additionally, we show that exons forming circRNAs are generally enriched with RBP binding sites compared to non-circularizing exons. To detect individual circRNAs with regulatory potency, we computationally identify circRNAs that are highly covered by RBP binding sites and experimentally validate circRNA-RBP interactions by RNA immunoprecipitations. We characterize circCDYL, a highly expressed circRNA with clinical and functional implications in bladder cancer, which is covered with GRWD1 binding sites. We confirm that circCDYL binds GRWD1 in vivo and functionally characterizes the effect of circCDYL-GRWD1 interactions on target genes in HepG2. Furthermore, we confirm interactions between circCDYL and RBPs in bladder cancer cells and demonstrate that circCDYL depletion affects hallmarks of cancer and perturbs the expression of key cancer genes, e.g. TP53 and MYC. Finally, we show that elevated levels of highly RBP-covered circRNAs, including circCDYL, are associated with overall survival of bladder cancer patients. Our study demonstrates transcriptome-wide and cell-type-specific circRNA-RBP interactions that could play important regulatory roles in tumorigenesis.

scholarly journals Parsimonious scenario for the emergence of viroid-like repliconsde novo

2019 ◽  
Author(s):  
Pablo Catalán ◽  
Santiago F. Elena ◽  
José A. Cuesta ◽  
Susanna Manrubia
Keyword(s):  
De Novo ◽  
Rna World ◽  
Circular Rna ◽  
Biochemical Properties ◽  
Circular Rnas ◽  
Sequence Motifs ◽  
Rna Sequences ◽  
Specific Sequence ◽  
Evolutionary Pathway ◽  
Rna Molecules

AbstractViroids are small, non-coding, circular RNA molecules that infect plants. Different hypotheses for their evolutionary origin have been put forward, such as an early emergence in a precellular RNA World or severalde novoindependent evolutionary origins in plants. Here we discuss the plausibility ofde novoemergence of viroid-like replicons by giving theoretical support to the likelihood of different steps along a parsimonious evolutionary pathway. While Avsunviroidae-like structures are relatively easy to obtain through evolution of a population of random RNA sequences of fixed length, rod-like structures typical of Pospiviroidae are difficult to fix. Using different quantitative approaches, we evaluate the likelihood that RNA sequences fold into a rod-like structure and bear specific sequence motifs facilitating interactions with other molecules,e.g.RNA polymerases, RNases and ligases. By means of numerical simulations, we show that circular RNA replicons analogous to Pospiviroidae emerge if evolution is seeded with minimal circular RNAs that grow through the gradual addition of nucleotides. Further, these rod-like replicons often maintain their structure if independent functional modules are acquired that impose selective constraints. The evolutionary scenario we propose here is consistent with the structural and biochemical properties of viroids described to date.

scholarly journals Closing the circle: current state and perspectives of circular RNA databases

2020 ◽  
Author(s):  
Marieke Vromman ◽  
Jo Vandesompele ◽  
Pieter-Jan Volders
Keyword(s):  
Splice Junction ◽  
Circular Rna ◽  
Circular Rnas ◽  
Working Mechanism ◽  
Comprehensive Overview ◽  
Specific Expression ◽  
Protein Coding ◽  
Rna Molecules ◽  
Current State ◽  
Coding Potential

Abstract Circular RNAs (circRNAs) are covalently closed RNA molecules that have been linked to various diseases, including cancer. However, a precise function and working mechanism are lacking for the larger majority. Following many different experimental and computational approaches to identify circRNAs, multiple circRNA databases were developed as well. Unfortunately, there are several major issues with the current circRNA databases, which substantially hamper progression in the field. First, as the overlap in content is limited, a true reference set of circRNAs is lacking. This results from the low abundance and highly specific expression of circRNAs, and varying sequencing methods, data-analysis pipelines, and circRNA detection tools. A second major issue is the use of ambiguous nomenclature. Thus, redundant or even conflicting names for circRNAs across different databases contribute to the reproducibility crisis. Third, circRNA databases, in essence, rely on the position of the circRNA back-splice junction, whereas alternative splicing could result in circRNAs with different length and sequence. To uniquely identify a circRNA molecule, the full circular sequence is required. Fourth, circRNA databases annotate circRNAs’ microRNA binding and protein-coding potential, but these annotations are generally based on presumed circRNA sequences. Finally, several databases are not regularly updated, contain incomplete data or suffer from connectivity issues. In this review, we present a comprehensive overview of the current circRNA databases and their content, features, and usability. In addition to discussing the current issues regarding circRNA databases, we come with important suggestions to streamline further research in this growing field.

scholarly journals Protein-Related Circular RNAs in Human Pathologies

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1841 ◽  
Author(s):  
Olga Wawrzyniak ◽  
Żaneta Zarębska ◽  
Konrad Kuczyński ◽  
Anna Gotz-Więckowska ◽  
Katarzyna Rolle
Keyword(s):  
Protein Interactions ◽  
Rna Binding ◽  
Current Knowledge ◽  
Close Association ◽  
Development Stage ◽  
Circular Rnas ◽  
Biological Functions ◽  
Bodily Fluids ◽  
Specific Manner ◽  
Regulate Protein

Circular RNAs (circRNAs) are a distinct family of RNAs derived from alternative splicing which play a crucial role in regulating gene expression by acting as microRNA (miRNA) and RNA binding protein (RBP) sponges. However, recent studies have also reported the multifunctional potential of these particles. Under different conditions, circRNAs not only regulate protein synthesis, destination, and degradation but can serve as protein scaffolds or recruiters and are also able to produce short peptides with active biological functions. circRNAs are under ongoing investigation because of their close association with the development of diseases. Some circRNAs are reportedly expressed in a tissue- and development stage-specific manner. Furthermore, due to other features of circRNAs, including their stability, conservation, and high abundance in bodily fluids, they are believed to be potential biomarkers for various diseases, including cancers. In this review, we focus on providing a summary of the current knowledge on circRNA–protein interactions. We present the properties and functions of circRNAs, the possible mechanisms of their translation abilities, and the emerging functions of circRNA-derived peptides in human pathologies.

scholarly journals Circular and long non-coding RNAs and their role in ophthalmologic diseases

2018 ◽  
Author(s):  
Olga Wawrzyniak ◽  
Żaneta Zarębska ◽  
Katarzyna Rolle ◽  
Anna Gotz-Więckowska
Keyword(s):  
Current Knowledge ◽  
Critical Role ◽  
Circular Rna ◽  
Age Related Macular Degeneration ◽  
Circular Rnas ◽  
Protein Coding ◽  
Rna Molecules ◽  
Age Related ◽  
Non Coding Rnas ◽  
Transcriptional Gene Regulation

Long non-coding RNAs are >200-nucleotide-long RNA molecules which lack or have limited protein-coding potential. They can regulate protein formation through several different mechanisms. Similarly, circular RNAs are reported to play a critical role in post-transcriptional gene regulation. Changes in the expression pattern of these molecules are known to underlie various diseases, including cancer, cardiovascular, neurological and immunological disorders (Rinn & Chang, 2012; Sun & Kraus, 2015). Recent studies suggest that they are differentially expressed both in healthy ocular tissues as well as in eye pathologies, such as neovascularization, proliferative vitreoretinopathy, glaucoma, cataract, ocular malignancy or even strabismus (Li et al., 2016). Aetiology of ocular diseases is multifactorial and combines genetic and environmental factors, including epigenetic and non-coding RNAs. In addition, disorders like diabetic retinopathy or age-related macular degeneration lack biomarkers for early detection as well as effective treatment methods that would allow controlling the disease progression at its early stages. The newly discovered non-coding RNAs seem to be the ideal candidates for novel molecular markers and therapeutic strategies. In this review, we summarized the current knowledge about gene expression regulators – long non-coding and circular RNA molecules in eye diseases.

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