scholarly journals Discovering the Interactions between Circular RNAs and RNA-binding Proteins from CLIP-seq Data using circScan

2017 ◽  
Author(s):  
Bin Li ◽  
Xiao-Qin Zhang ◽  
Shu-Rong Liu ◽  
Shun Liu ◽  
Wen-Ju Sun ◽  
...  

AbstractAlthough tens of thousands of circular RNAs (circRNAs) have been identified in mammalian genomes, only few of them have been characterized with biological functions. Here, we report a new approach, circScan, to identify regulatory interactions between circRNAs and RNA-binding proteins (RBPs) by discovering back-splicing reads from Cross-Linking and Immunoprecipitation followed by high-throughput sequencing (CLIP-seq) data. By using our method, we have systematically scanned ~1500 CLIP-seq datasets, and identified ~12540 and ~1090 novel circRNA-RBP interactions in human and mouse genomes, respectively, which include all known interactions between circRNAs and Argonaute (AGO) proteins. More than twenty novel interactions were further experimentally confirmed by RNA Immunoprecipitation quantitative PCR (RIP-qPCR). Importantly, we uncovered that some natural circRNAs interacted with cap-independent translation factors eukaryotic initiation factor 3 (eIF3) and N6-Methyladenosine (m6A), indicating they can be translated into proteins. These findings demonstrate that circRNAs are regulated by various RBPs, suggesting they may play important roles in diverse biological processes.

2021 ◽  
Vol 22 (14) ◽  
pp. 7477
Author(s):  
Rok Razpotnik ◽  
Petra Nassib ◽  
Tanja Kunej ◽  
Damjana Rozman ◽  
Tadeja Režen

Circular RNAs (circRNAs) are increasingly recognized as having a role in cancer development. Their expression is modified in numerous cancers, including hepatocellular carcinoma (HCC); however, little is known about the mechanisms of their regulation. The aim of this study was to identify regulators of circRNAome expression in HCC. Using publicly available datasets, we identified RNA binding proteins (RBPs) with enriched motifs around the splice sites of differentially expressed circRNAs in HCC. We confirmed the binding of some of the candidate RBPs using ChIP-seq and eCLIP datasets in the ENCODE database. Several of the identified RBPs were found to be differentially expressed in HCC and/or correlated with the overall survival of HCC patients. According to our bioinformatics analyses and published evidence, we propose that NONO, PCPB2, PCPB1, ESRP2, and HNRNPK are candidate regulators of circRNA expression in HCC. We confirmed that the knocking down the epithelial splicing regulatory protein 2 (ESRP2), known to be involved in the maintenance of the adult liver phenotype, significantly changed the expression of candidate circRNAs in a model HCC cell line. By understanding the systemic changes in transcriptome splicing, we can identify new proteins involved in the molecular pathways leading to HCC development and progression.


2018 ◽  
Vol 48 (3) ◽  
pp. 1215-1229 ◽  
Author(s):  
Sihyung Wang ◽  
Youngmi Jung ◽  
Jeongeun Hyun ◽  
Matthew Friedersdorf ◽  
Seh-Hoon Oh ◽  
...  

Background/Aims: Myofibroblasts (MF) derived from quiescent nonfibrogenic hepatic stellate cells (HSC) are the major sources of fibrous matrix in cirrhosis. Because many factors interact to regulate expansion and regression of MF-HSC populations, efforts to prevent cirrhosis by targeting any one factor have had limited success, motivating research to identify mechanisms that integrate these diverse inputs. As key components of RNA regulons, RNA binding proteins (RBPs) may fulfill this function by orchestrating changes in the expression of multiple genes that must be coordinately regulated to affect the complex phenotypic modifications required for HSC transdifferentiation. Methods: We profiled the transcriptomes of quiescent and MF-HSC to identify RBPs that were differentially-expressed during HSC transdifferentiation, manipulated the expression of the most significantly induced RBP, insulin like growth factor 2 binding protein 3 (Igf2bp3), and evaluated transcriptomic and phenotypic effects. Results: Depleting Igf2bp3 changed the expression of thousands of HSC genes, including multiple targets of TGF-β signaling, and caused HSCs to reacquire a less proliferative, less myofibroblastic phenotype. RNA immunoprecipitation assays demonstrated that some of these effects were mediated by direct physical interactions between Igf2bp3 and mRNAs that control proliferative activity and mesenchymal traits. Inhibiting TGF-β receptor-1 signaling revealed a microRNA-dependent mechanism that induces Igf2bp3. Conclusions: The aggregate results indicate that HSC transdifferentiation is ultimately dictated by Igf2bp3-dependent RNA regulons and thus, can be controlled simply by manipulating Igf2bp3.


2019 ◽  
Author(s):  
Samudyata ◽  
Paulo P. Amaral ◽  
Pär G. Engström ◽  
Samuel C. Robson ◽  
Michael L. Nielsen ◽  
...  

AbstractSox2 is a master transcriptional regulator of embryonic development. In this study, we determined the protein interactome of Sox2 in the chromatin and nucleoplasm of mouse embryonic stem (mES) cells. Apart from canonical interactions with pluripotency-regulating transcription factors, we identified interactions with several chromatin modulators, including members of the heterochromatin protein 1 (HP1) family, suggesting a role of Sox2 in chromatin-mediated transcriptional repression. Sox2 was also found to interact with RNA binding proteins (RBPs), including proteins involved in RNA processing. RNA immunoprecipitation followed by sequencing revealed that Sox2 associates with different messenger RNAs, as well as small nucleolar RNA Snord34 and the non-coding RNA 7SK. 7SK has been shown to regulate transcription at regulatory regions, which could suggest a functional interaction with Sox2 for chromatin recruitment. Nevertheless, we found no evidence of Sox2 modulating recruitment of 7SK to chromatin when examining 7SK chromatin occupancy by Chromatin Isolation by RNA Purification (ChIRP) in Sox2 depleted mES cells. In addition, knockdown of 7SK in mES cells did not lead to any change in Sox2 occupancy at 7SK-regulated genes. Thus, our results show that Sox2 extensively interact with RBPs, and suggest that Sox2 and 7SK co-exist in a ribonucleoprotein complex whose function is not to regulate chromatin recruitment, but might rather regulate other processes in the nucleoplasm.Summary blurbSox2 interacts with RNA-binding proteins and diverse RNAs


2021 ◽  
Vol 12 (17) ◽  
pp. 5206-5219
Author(s):  
Meng-Ping Jiang ◽  
Wen-Xiu Xu ◽  
Jun-Chen Hou ◽  
Qi Xu ◽  
Dan-Dan Wang ◽  
...  

2019 ◽  
Vol 20 (16) ◽  
pp. 3926 ◽  
Author(s):  
Xing Zhao ◽  
Yujie Cai ◽  
Jianzhen Xu

CircRNAs are a class of noncoding RNA species with a circular configuration that is formed by either typical spliceosome-mediated or lariat-type splicing. The expression of circRNAs is usually abnormal in many cancers. Several circRNAs have been demonstrated to play important roles in carcinogenesis. In this review, we will first provide an introduction of circRNAs biogenesis, especially the regulation of circRNA by RNA-binding proteins, then we will focus on the recent findings of circRNA molecular mechanisms and functions in cancer development. Finally, some open questions are also discussed.


Reproduction ◽  
2010 ◽  
Vol 139 (2) ◽  
pp. 381-393 ◽  
Author(s):  
Masashi Yamaji ◽  
Takashi Tanaka ◽  
Mayo Shigeta ◽  
Shinichiro Chuma ◽  
Yumiko Saga ◽  
...  

Mutations of RNA-binding proteins such as NANOS3, TIAL1, and DND1 in mice have been known to result in the failure of survival and/or proliferation of primordial germ cells (PGCs) soon after their fate is specified (around embryonic day (E) 8.0), leading to the infertility of these animals. However, the mechanisms of actions of these RNA-binding proteins remain largely unresolved. As a foundation to explore the role of these RNA-binding proteins in germ cells, we established a novel transgenic reporter strain that expresses NANOS3 fused with EGFP under the control of Nanos3 regulatory elements. NANOS3–EGFP exhibited exclusive expression in PGCs as early as E7.25, and continued to be expressed in female germ cells until around E14.5 and in male germ cells throughout the fetal period with declining expression levels after E16.5. NANOS3–EGFP resumed strong expression in postnatal spermatogonia and continued to be expressed in undifferentiated spermatogonial cells in adults. Importantly, the Nanos3–EGFP transgene rescued the sterile phenotype of Nanos3 homozygous mutants, demonstrating the functional equivalency of NANOS3–EGFP with endogenous NANOS3. We found that throughout germ cell development, a predominant amount of  NANOS3–EGFP co-localized with TIAL1 (also known as TIAR) and phosphorylated eukaryotic initiation factor 2α, markers for the stress granules, whereas a fraction of it showed co-localization with DCP1A, a marker for the processing bodies. On the other hand, NANOS3–EGFP did not co-localize with Tudor domain-containing protein 1, a marker for the intermitochondrial cements, in spermatogenic cells. These findings unveil the presence of distinct posttranscriptional regulations in PGCs soon after their specification, for which RNA-binding proteins such as NANOS3 and TIAL1 would play critical functions.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Zhengfeng Wang ◽  
Xiujuan Lei

Abstract Background Circular RNAs (circRNAs) are widely expressed in cells and tissues and are involved in biological processes and human diseases. Recent studies have demonstrated that circRNAs can interact with RNA-binding proteins (RBPs), which is considered an important aspect for investigating the function of circRNAs. Results In this study, we design a slight variant of the capsule network, called circRB, to identify the sequence specificities of circRNAs binding to RBPs. In this model, the sequence features of circRNAs are extracted by convolution operations, and then, two dynamic routing algorithms in a capsule network are employed to discriminate between different binding sites by analysing the convolution features of binding sites. The experimental results show that the circRB method outperforms the existing computational methods. Afterwards, the trained models are applied to detect the sequence motifs on the seven circRNA-RBP bound sequence datasets and matched to known human RNA motifs. Some motifs on circular RNAs overlap with those on linear RNAs. Finally, we also predict binding sites on the reported full-length sequences of circRNAs interacting with RBPs, attempting to assist current studies. We hope that our model will contribute to better understanding the mechanisms of the interactions between RBPs and circRNAs. Conclusion In view of the poor studies about the sequence specificities of circRNA-binding proteins, we designed a classification framework called circRB based on the capsule network. The results show that the circRB method is an effective method, and it achieves higher prediction accuracy than other methods.


2019 ◽  
Vol 29 ◽  
pp. S720-S721 ◽  
Author(s):  
Jason Weick ◽  
Brian Rodriguez ◽  
Stephen Amoah ◽  
Michela DellOrco ◽  
Alexander Hafez ◽  
...  

Open Biology ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 190072 ◽  
Author(s):  
Christine Clayton

In trypanosomes, RNA polymerase II transcription is polycistronic and individual mRNAs are excised by trans -splicing and polyadenylation. The lack of individual gene transcription control is compensated by control of mRNA processing, translation and degradation. Although the basic mechanisms of mRNA decay and translation are evolutionarily conserved, there are also unique aspects, such as the existence of six cap-binding translation initiation factor homologues, a novel decapping enzyme and an mRNA stabilizing complex that is recruited by RNA-binding proteins. High-throughput analyses have identified nearly a hundred regulatory mRNA-binding proteins, making trypanosomes valuable as a model system to investigate post-transcriptional regulation.


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