scholarly journals A genome-wide map of circular RNAs in adult zebrafish

2017 ◽  
Vol 1 (Special Issue) ◽  
pp. 14-14
Author(s):  
Disha Sharma ◽  
Paras Sehgal ◽  
Angom Ramcharan Singh ◽  
Shamsudheen Karuthedath Vellarikkal ◽  
Samatha Mathew ◽  
...  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Disha Sharma ◽  
Paras Sehgal ◽  
Samatha Mathew ◽  
Shamsudheen Karuthedath Vellarikkal ◽  
Angom Ramcharan Singh ◽  
...  

2019 ◽  
Author(s):  
Xu-Kai Ma ◽  
Meng-Ran Wang ◽  
Chu-Xiao Liu ◽  
Rui Dong ◽  
Gordon G. Carmichael ◽  
...  

ABSTRACTSequences of circular RNAs (circRNAs) produced from back-splicing of exon(s) completely overlap with sequences from cognate linear RNAs transcribed from the same gene loci with the exception of their back-splicing junction (BSJ) sites. Examination of global circRNA expression from RNA-seq datasets generally relies on the detection of RNA-seq fragments spanning BSJ sites, but a direct comparison of circular and linear RNA expression from the same gene loci in a genome-wide manner has remained challenging. This is because quantification of BSJ fragments differs from that of linear RNA expression that uses normalized RNA-seq fragments mapped to the whole gene bodies. Here, we have developed a computational pipeline for circular and linear RNA expression analysis from ribosomal-RNA depleted RNA-seq (CLEAR, https://github.com/YangLab/CLEAR). A new quantitation parameter, FPB (fragments per billion mapped bases), is applied to evaluate circular and linear RNA expression individually by fragments mapped to circRNA-specific BSJ sites or to linear RNA-specific splicing junction (SJ) sites. Then, circular and linear RNA expression are directly compared by dividing FPBcirc by FPBlinear to generate a CIRCscore, which indicates the relative circRNA expression using linear RNA expression as the background. Highly-expressed circRNAs with low cognate linear RNA expression background can be identified for further investigation.


Cancers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1473 ◽  
Author(s):  
Franz ◽  
Ralla ◽  
Weickmann ◽  
Jung ◽  
Rochow ◽  
...  

Circular RNAs (circRNAs) may act as novel cancer biomarkers. However, a genome-wide evaluation of circRNAs in clear cell renal cell carcinoma (ccRCC) has yet to be conducted. Therefore, the objective of this study was to identify and validate circRNAs in ccRCC tissue with a focus to evaluate their potential as prognostic biomarkers. A genome-wide identification of circRNAs in total RNA extracted from ccRCC tissue samples was performed using microarray analysis. Three relevant differentially expressed circRNAs were selected (circEGLN3, circNOX4, and circRHOBTB3), their circular nature was experimentally confirmed, and their expression—along with that of their linear counterparts—was measured in 99 malignant and 85 adjacent normal tissue samples using specifically established RT-qPCR assays. The capacity of circRNAs to discriminate between malignant and adjacent normal tissue samples and their prognostic potential (with the endpoints cancer-specific, recurrence-free, and overall survival) after surgery were estimated by C-statistics, Kaplan-Meier method, univariate and multivariate Cox regression analysis, decision curve analysis, and Akaike and Bayesian information criteria. CircEGLN3 discriminated malignant from normal tissue with 97% accuracy. We generated a prognostic for the three endpoints by multivariate Cox regression analysis that included circEGLN3, circRHOBT3 and linRHOBTB3. The predictive outcome accuracy of the clinical models based on clinicopathological factors was improved in combination with this circRNA-based signature. Bootstrapping as well as Akaike and Bayesian information criteria confirmed the statistical significance and robustness of the combined models. Limitations of this study include its retrospective nature and the lack of external validation. The study demonstrated the promising potential of circRNAs as diagnostic and particularly prognostic biomarkers in ccRCC patients.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Junjie Shao ◽  
Liqiang Wang ◽  
Xinyue Liu ◽  
Meng Yang ◽  
Haimei Chen ◽  
...  

Abstract Circular RNAs (circRNAs) play important roles in animals, plants, and fungi. However, no circRNAs have been reported in Ganoderma lucidum. Here, we carried out a genome-wide identification of the circRNAs in G.lucidum using RNA-Seq data, and analyzed their features. In total, 250 and 2193 circRNAs were identified from strand-specific RNA-seq data generated from the polyA(−) and polyA(−)/RNase R-treated libraries, respectively. Six of 131 (4.58%) predicted circRNAs were experimentally confirmed. Across three developmental stages, 731 exonic circRNAs (back spliced read counts ≥ 5) and their parent genes were further analyzed. CircRNAs were preferred originating from exons with flanking introns, and the lengths of the flanking intron were longer than those of the control introns. A total of 200 circRNAs were differentially expressed across the three developmental stages of G. lucidum. The expression profiles of 119 (16.3%) exonic circRNAs and their parent genes showed significant positive correlations (r ≥ 0.9, q < 0.01), whereas 226 (30.9%) exonic circRNAs and their parent genes exhibited significant negative correlations (r ≤ −0.9, q < 0.01), in which 53 parent genes are potentially involved in the transcriptional regulation, polysaccharide biosynthesis etc. Our results indicated that circRNAs are present in G. lucidum, with potentially important regulatory roles.


2021 ◽  
Vol 12 ◽  
Author(s):  
Mei Jiang ◽  
Haimei Chen ◽  
Qing Du ◽  
Liqiang Wang ◽  
Xinyue Liu ◽  
...  

Circular RNAs (circRNAs) play various roles in cellular functions. However, no studies have been reported on the potential involvement of circRNAs in the biosynthesis of secondary metabolites in plants. Here, we performed a genome-wide discovery of circRNAs from root, stem and leaf samples of Salvia miltiorrhiza using RNA-Seq. We predicted a total of 2,476 circRNAs with at least two junction reads using circRNA_finder and CIRI, of which 2,096, 151 and 229 were exonic, intronic and intergenic circRNAs, respectively. Sequence similarity analysis showed that 294 out of 2,476 circRNAs were conserved amongst multiple plants. Of the 55 predicted circRNAs, 31 (56%) were validated successfully by PCR and Sanger sequencing using convergent and divergent primer pairs. Alternative circularisation analysis showed that most parental genes produced two circRNAs. Functional enrichment analyses of the parental genes showed that the primary metabolism pathways were significantly enriched, particularly the carbon metabolism. Differential expression analysis showed that the expression profiles of circRNAs were tissue-specific. Co-expression analysis showed 275 circRNAs, and their parental genes had significantly positive correlations. However, 14 had significantly negative correlations. Weighted gene co-expression network analysis showed that nine circRNAs were co-expressed with four modules of protein-coding genes. Next, we found 416 exonic circRNAs with miRNA-binding sites, suggesting possible interactions between circRNAs and miRNAs. Lastly, we found six validated circRNAs, namely, SMscf2473-46693-46978, SMscf3091-29256-29724, SMscf16-111773-112193, SMscf432-13232-13866, SMscf7007-10563-10888 and SMscf1730-1749-2013, which were originated from the genes involved in the biosynthesis of secondary metabolites. Their parental genes were acetyl-CoA C-acetyltransferase 1 (SmAACT1), 1-deoxy-d-xylulose-5-phosphate synthase 2 (SmDXS2), 4-hydroxy-3-methylbut-2-enyl diphosphate reductase 1 (SmHDR1), kaurene synthase-like 2 (SmKSL2), DWF4 and CYP88A3, respectively. In particular, the correlation coefficient of SMscf2473-46693-46978 and SmDXS2 gene was 0.86 (p = 0.003), indicating a potential interaction between this pair of circRNA and its parent gene. Our results provided the first comprehensive catalogue of circRNAs in S. miltiorrhiza and identified one circRNA that might play important roles in the biosynthesis of secondary metabolites.


2021 ◽  
Author(s):  
Taeyoung Hwang ◽  
Sojin Kim ◽  
Tamrin Chowdhury ◽  
Hyeon Jong Yu ◽  
Kyung-Min Kim ◽  
...  

Abstract BackgroundAlu is a primate-specific repeat element in the human genome and has been increasingly appreciated as a regulatory element in many biological processes. But the role of Alu has not been studied comprehensively in brain tumor because an evolutionary perspective has been the subject of little research in brain tumor. We aim to investigate the relevance of Alu to the gliomagenesis.MethodsUsing a total of 41 pairs of neurotypicial brain tissue samples and samples of diverse gliomas, we performed strand-specific RNA-seq and analyzed two Alu-associated post-transcriptional regulations, A-to-I editing and circular RNAs, and Alu expression in a genome-wide way. ResultsWe found that while both A-to-I editing and circular RNA are decreased overall in gliomas, grade 2 oligodendrogliomas do not show this same pattern of global changes. Instead, in comparison with other gliomas, oligodendrogliomas showed a higher proportion of perturbed Alu RNA. Adenosine deaminase acting on RNA 2 (ADAR2) was down-regulated in gliomas other than grade 2 oligodendrogliomas, contributing to the observed Alu-associated perturbation. ConclusionsOur results demonstrate that Alu is associated with glioma development and grade 2 oligodendroglioma exhibits a unique pattern of Alu-associated post-transcriptional regulations, which provides an insight to gliomagenesis from the perspective of an evolutionary genetic element.


2017 ◽  
Vol 49 (9) ◽  
pp. 484-490 ◽  
Author(s):  
Xi Cheng ◽  
Bina Joe

Circular RNAs (circRNAs) have emerged as an important new class of genomic regulatory molecules contributing to the development of various diseases, but their relevance to the development and progression of hypertension remains largely unknown. A major impediment to begin studying circRNAs in rat models of inherited hypertension is that the rat as a valuable model of human diseases lags far behind the mouse and human in providing knowledge on circRNAs. In this study, a genome-wide circRNA profiling was performed from four rat strains that are widely used in hypertension research: the Dahl salt-sensitive rat (S), the Dahl salt-resistant rat (R), the spontaneously hypertensive rat (SHR), and the Wistar Kyoto rat (WKY). Combined hybridization data obtained from these four strains allowed for the identification of 12,846 circRNAs as being expressed in the rat kidneys. Out of these, 318 and 110 circRNAs were differentially expressed with a fold change > 1.5 ( P < 0.05) in S vs. R and SHR vs. WKY, respectively. Among these circRNAs, circRNA/microRNA interaction was predicted since circRNAs are known as microRNA sponges to sequester microRNAs. Several circRNAs were further validated by quantitative real-time PCR. To our knowledge, our study is the primary report of profiling circRNAs in renal tissue and illustrates that circRNAs could be candidate genetic factors controlling blood pressure.


BMC Genomics ◽  
2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Xingwei Cao ◽  
Xingye Xu ◽  
Jie Dong ◽  
Ying Xue ◽  
Lilian Sun ◽  
...  

Abstract Background Circular RNAs (circRNAs) are a group of noncoding RNAs that participate in gene expression regulation in various pathways. The essential roles of circRNAs have been revealed in many species. However, knowledge of circRNAs in fungi is still not comprehensive. Results Trichophyton rubrum (T. rubrum) is considered a model organism of human pathogenic filamentous fungi and dermatophytes. In this study, we performed a genome-wide investigation of circRNAs in T. rubrum based on high-throughput sequencing and ultimately identified 4254 circRNAs. Most of these circRNAs were specific to the conidial or mycelial stage, revealing a developmental stage-specific expression pattern. In addition, 940 circRNAs were significantly differentially expressed between the conidial and mycelial stages. PCR experiments conducted on seven randomly selected differentially expressed (DE-) circRNAs confirmed the circularized structures and relative expression levels of these circRNAs. Based on their genome locations, most circRNAs originated from intergenic regions, unlike those in plants and animals. Furthermore, we constructed circRNA-miRNA-mRNA regulatory networks that included 661 DE-circRNAs targeting 140 miRNAs and further regulating 2753 mRNAs. The relative expression levels of two randomly selected circRNA-miRNA-mRNA axes were investigated by qRT-PCR, and the competing endogenous RNA (ceRNA) network theory was validated. Functional enrichment analysis of the target genes suggested that they were significantly involved in posttranscriptional processes and protein synthesis as well as some small-molecule metabolism processes. CircRNAs are relatively more conserved in closely related dermatophytes but rarely conserved in distantly related species. Tru_circ07138_001 is a highly conserved circRNA that was conserved in all ten dermatophytes analyzed in our study and three distantly related species. Its host gene TERG_07138 was also highly conserved in two of these distantly related species Gallus gallus and Caenorhabditis elegans. The specific role of this circRNA deserves further exploration. Conclusions Our study is the first to provide a global profile of circRNAs in T. rubrum as well as dermatophytes. These results could serve as valuable resources for research on circRNA regulatory mechanisms in fungi and reveal new insights for further investigation of the physical characteristics of these significant human fungal pathogens.


2014 ◽  
Vol 226 (03) ◽  
Author(s):  
F Ponthan ◽  
D Pal ◽  
J Vormoor ◽  
O Heidenreich
Keyword(s):  

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