scholarly journals The nuclear DICER–circular RNA complex drives the deregulation of the glioblastoma cell microRNAome

2020 ◽  
Vol 6 (51) ◽  
pp. eabc0221 ◽  
Author(s):  
A. Bronisz ◽  
A. K. Rooj ◽  
K. Krawczyński ◽  
P. Peruzzi ◽  
E. Salińska ◽  
...  

The assortment of cellular microRNAs (“microRNAome”) is a vital readout of cellular homeostasis, but the mechanisms that regulate the microRNAome are poorly understood. The microRNAome of glioblastoma is substantially down-regulated in comparison to the normal brain. Here, we find malfunction of the posttranscriptional maturation of the glioblastoma microRNAome and link it to aberrant nuclear localization of DICER, the major enzymatic complex responsible for microRNA maturation. Analysis of DICER’s nuclear interactome reveals the presence of an RNA binding protein, RBM3, and of a circular RNA, circ2082, within the complex. Targeting of this complex by knockdown of circ2082 results in the restoration of cytosolic localization of DICER and widespread derepression of the microRNAome, leading to transcriptome-wide rearrangements that mitigate the tumorigenicity of glioblastoma cells in vitro and in vivo with correlation to favorable outcomes in patients with glioblastoma. These findings uncover the mechanistic foundation of microRNAome deregulation in malignant cells.

2009 ◽  
Vol 181 (4S) ◽  
pp. 153-153 ◽  
Author(s):  
Sabrina Danilin ◽  
Lionel Thomas ◽  
Thomas Charles ◽  
Carole Sourbier ◽  
Véronique Lindner ◽  
...  

1997 ◽  
Vol 17 (6) ◽  
pp. 3194-3201 ◽  
Author(s):  
R J Buckanovich ◽  
R B Darnell

Nova-1, an autoantigen in paraneoplastic opsoclonus myoclonus ataxia (POMA), a disorder associated with breast cancer and motor dysfunction, is a neuron-specific nuclear RNA binding protein. We have identified in vivo Nova-1 RNA ligands by combining affinity-elution-based RNA selection with protein-RNA immunoprecipitation. Starting with a pool of approximately 10(15) random 52-mer RNAs, we identified long stem-loop RNA ligands that bind to Nova-1 with high affinity (Kd of approximately 2 nM). The loop region of these RNAs harbors a approximately 15-bp pyrimidine-rich element [UCAU(N)(0-2)]3 which is essential for Nova-1 binding. Mutagenesis studies defined the third KH domain of Nova-1 and the [UCAU(N)(0-2)]3 element as necessary for in vitro binding. Consensus [UCAU (N)(0-2)], elements were identified in two neuronal pre-mRNAs, one encoding the inhibitory glycine receptor alpha2 (GlyR alpha2) and a second encoding Nova-1 itself. Nova-1 protein binds these RNAs with high affinity and specificity in vitro, and this binding can be blocked by POMA antisera. Moreover, both Nova-1 and GlyR alpha2 pre-mRNAs specifically coimmunoprecipitated with Nova-1 protein from brain extracts. Thus, Nova-1 functions as a sequence-specific nuclear RNA binding protein in vivo; disruption of the specific interaction between Nova-1 and GlyR alpha2 pre-mRNA may underlie the motor dysfunction seen in POMA.


2021 ◽  
Vol 12 (10) ◽  
Author(s):  
Jing Yang ◽  
Xing Zhang ◽  
Jiacheng Cao ◽  
Penghui Xu ◽  
Zetian Chen ◽  
...  

AbstractGastric cancer remains the third leading cause of cancer-related mortality worldwide. Emerging evidence has shown that circular RNAs (circRNAs) play a critical regulatory role in the occurrence and development of various cancers through sponging miRNAs or acting as RNA-binding protein (RBP) sponges. We found that circUBE2Q2 was significantly upregulated in GC tissues and cell lines. Knockdown of circUBE2Q2 inhibited proliferation, migration, invasion, and glycolysis, and increased autophagy in vitro. In addition, knockdown of circUBE2Q2 inhibited GC tumorigenicity and metastasis potential in vivo. A series of experiments were performed to confirm that circUBE2Q2 regulates GC progression via the circUBE2Q2-miR-370-3p-STAT3 axis and promotes tumor metastasis through exosomal communication. Further in vivo experiments confirmed that, combination treatment of circUBE2Q2 knocking down and STAT3 inhibitor has synergistic effects on the gastric cancer growth inhibition, which provides a possibility to enhance the sensitivity of targeted drugs to gastric cancer through targeting circUBE2Q2. Our findings revealed that circUBE2Q2 may serve as a new proliferation-promoting factor and prognostic marker in gastric cancer.


2020 ◽  
Author(s):  
Weijia Xie ◽  
Youhao Wang ◽  
Yao Zhang ◽  
Ying Xiang ◽  
Na Wu ◽  
...  

Abstract Background: Single nucleotide polymorphisms (SNPs) and long non-coding RNAs (lncRNAs) have been involved in the process of lung cancer. Following clues given by lung cancer risk-associated SNPs, we aimed to find novel functional lncRNAs as candidate targets in non-small cell lung cancer (NSCLC). Methods: Case-control analyses were performed in 626 cases and 736 controls matched up on sex and age. The lncRNA OSER1-AS1 was identified near a lung cancer risk-associated SNP rs4142441. Kaplan–Meier survival analysis was performed to investigate the association between OSER1-AS1 expression and overall survival. The influence of rs4142441 on the expression level of OSER1-AS1 was confirmed using Luciferase assays. Subsequently, the biological function of OSER1-AS1 was assessed in vitro by cell proliferation, migration, and invasion experiments through gain- and loss-of-function approaches, and in vivo by subcutaneous tumor model and tail vein injection lung metastasis model. ChIP and RIP experiments were carried out to investigate the interaction between transcription factors, RNA-binding proteins, and OSER1-AS1.Results: OSER1-AS1 was down-regulated in tumor tissue and its low expression was significantly associated with poor overall survival among non-smokers in NSCLC patients. Gain- and loss-of-function studies revealed that OSER1-AS1 acted as a tumor suppressor by inhibiting lung cancer cell growth, migration and invasion in vitro. Xenograft tumor assays and metastasis mouse model confirmed that OSER1-AS1 suppressed tumor growth and metastasis in vivo. The promoter of OSER1-AS1 was repressed by MYC, and the 3’-end of OSER1-AS1 was competitively targeted by microRNA hsa-miR-17-5p and RNA-binding protein ELAVL1. Conclusion: Our results indicated that OSER1-AS1 exerted tumor-suppressive functions by acting as an ELAVL1 decoy to keep it away from its target mRNAs. Our findings characterized OSER1-AS1 as a new tumor suppressive lncRNA in NSCLC, suggesting that OSER1-AS1 may be suitable as a potential biomarker for prognosis, and a potential target for treatment.


2021 ◽  
Author(s):  
Sarah E Cabral ◽  
Kimberly Mowry

RNA localization and biomolecular condensate formation are key biological strategies for organizing the cytoplasm and generating cellular and developmental polarity. While enrichment of RNAs and RNA-binding proteins (RBPs) is a hallmark of both processes, the functional and structural roles of RNA-RNA and RNA-protein interactions within condensates remain unclear. Recent work from our laboratory has shown that RNAs required for germ layer patterning in Xenopus oocytes localize in novel biomolecular condensates, termed Localization bodies (L-bodies). L-bodies are composed of a non-dynamic RNA phase enmeshed in a more dynamic protein-containing phase. However, the interactions that drive the biophysical characteristics of L-bodies are not known. Here, we test the role of RNA-protein interactions using an L-body RNA-binding protein, PTBP3, which contains four RNA-binding domains (RBDs). We find that binding of RNA to PTB is required for both RNA and PTBP3 to be enriched in L-bodies in vivo. Importantly, while RNA binding to a single RBD is sufficient to drive PTBP3 localization to L-bodies, interactions between multiple RRMs and RNA tunes the dynamics of PTBP3 within L-bodies. In vitro, recombinant PTBP3 phase separates into non-dynamic structures in an RNA-dependent manner, supporting a role for RNA-protein interactions as a driver of both recruitment of components to L-bodies and the dynamics of the components after enrichment. Our results point to a model where RNA serves as a concentration-dependent, non-dynamic substructure and multivalent interactions with RNA are a key driver of protein dynamics.


2020 ◽  
Vol 134 (14) ◽  
pp. 1973-1990
Author(s):  
Huaiming Wang ◽  
Rongkang Huang ◽  
Wentai Guo ◽  
Xiusen Qin ◽  
Zifeng Yang ◽  
...  

Abstract Colorectal cancer (CRC) is often diagnosed at later stages after it has metastasized to other organs. The development of chemoresistance also contributes to a poor prognosis. Therefore, an increased understanding of the metastatic properties of CRC and chemoresistance could improve patient survival. CUGBP elav-like family member 1 (CELF1) is an RNA-binding protein, which is overexpressed in many human malignant tumors. However, the influence of CELF1 in CRC is unclear. V-ets erythroblastosis virus E26 oncogene homologue 2 (ETS2) is an evolutionarily conserved proto-oncogene known to be overexpressed in a variety of human cancers including CRC. In thespresent tudy, we investigated the association between CELF1 and ETS2 in CRC tumorigenesis and oxaliplatin (L-OHP) resistance. We found a positive correlation between the elevated expression of CELF1 and ETS2 in human CRC tissues. Overexpression of CELF1 increased CRC cell proliferation, migration, and invasion in vitro and in a xenograft tumor growth model in vivo, and induced resistance to L-OHP. In contrast, CELF1 knockdown improved the response of CRC cells to L-OHP. Overexpression of ETS2 increased the malignant behavior of CRC cells (growth, migration, and invasion) and L-OHP resistance in vitro. Moreover, L-OHP resistance induced by CELF1 overexpression was reversed by ETS2 knockdown. The results of luciferase reporter and ribonucleoprotein immunoprecipitation assays indicated that CELF1 up-regulates ETS2 by binding to its 3′-UTR. Taken together, our findings have identified that CELF1 regulates ETS2 in a mechanism that results in CRC tumorigenesis and L-OHP resistance, and CELF1 may be a promising target for overcoming chemoresistance in CRC.


2001 ◽  
Vol 21 (12) ◽  
pp. 3888-3900 ◽  
Author(s):  
Takao Imai ◽  
Akinori Tokunaga ◽  
Tetsu Yoshida ◽  
Mitsuhiro Hashimoto ◽  
Katsuhiko Mikoshiba ◽  
...  

ABSTRACT Musashi1 (Msi1) is an RNA-binding protein that is highly expressed in neural progenitor cells, including neural stem cells. In this study, the RNA-binding sequences for Msi1 were determined by in vitro selection using a pool of degenerate 50-mer sequences. All of the selected RNA species contained repeats of (G/A)U n AGU (n = 1 to 3) sequences which were essential for Msi1 binding. These consensus elements were identified in some neural mRNAs. One of these, mammaliannumb (m-numb), which encodes a membrane-associated antagonist of Notch signaling, is a likely target of Msi1. Msi1 protein binds in vitro-transcribed m-numb RNA in its 3′-untranslated region (UTR) and binds endogenousm-numb mRNA in vivo, as shown by affinity precipitation followed by reverse transcription-PCR. Furthermore, adenovirus-induced Msi1 expression resulted in the down-regulation of endogenous m-Numb protein expression. Reporter assays using a chimeric mRNA that combined luciferase and the 3′-UTR of m-numb demonstrated that Msi1 decreased the reporter activity without altering the reporter mRNA level. Thus, our results suggested that Msi1 could regulate the expression of its target gene at the translational level. Furthermore, we found that Notch signaling activity was increased by Msi1 expression in connection with the posttranscriptional down-regulation of them-numb gene.


2001 ◽  
Vol 183 (20) ◽  
pp. 6017-6027 ◽  
Author(s):  
Seshagirirao Gudapaty ◽  
Kazushi Suzuki ◽  
Xin Wang ◽  
Paul Babitzke ◽  
Tony Romeo

ABSTRACT The global regulator CsrA (carbon storage regulator) ofEscherichia coli is a small RNA binding protein that represses various metabolic pathways and processes that are induced in the stationary phase of growth, while it activates certain exponential phase functions. Both repression and activation by CsrA involve posttranscriptional mechanisms, in which CsrA binding to mRNA leads to decreased or increased transcript stability, respectively. CsrA also binds to a small untranslated RNA, CsrB, forming a ribonucleoprotein complex, which antagonizes CsrA activity. We have further examined the regulatory interactions of CsrA and CsrB RNA. The 5′ end of the CsrB transcript was mapped, and acsrB::cam null mutant was constructed. CsrA protein and CsrB RNA levels were estimated throughout the growth curves of wild-type and isogenic csrA,csrB, rpoS, or csrA rpoSmutant strains. CsrA levels exhibited modest or negligible effects of these mutations. The intracellular concentration of CsrA exceeded the total CsrA-binding capacity of intracellular CsrB RNA. In contrast, CsrB levels were drastically decreased (∼10-fold) in thecsrA mutants. CsrB transcript stability was unaffected by csrA. The expression of a csrB-lacZtranscriptional fusion containing the region from −242 to +4 bp of thecsrB gene was decreased ∼20-fold by acsrA::kanR mutation in vivo but was unaffected by CsrA protein in vitro. These results reveal a significant, though most likely indirect, role for CsrA in regulatingcsrB transcription. Furthermore, our findings suggest that CsrA mediates an intriguing form of autoregulation, whereby its activity, but not its levels, is modulated through effects on an RNA antagonist, CsrB.


2020 ◽  
Author(s):  
Kristina Sakers ◽  
Yating Liu ◽  
Lorida Llaci ◽  
Michael J. Vasek ◽  
Michael A. Rieger ◽  
...  

AbstractQuaking RNA binding protein(QKI) is essential for oligodendrocyte development as myelination requires MBP mRNA regulation and localization by the cytoplasmic isoforms(e.g. QKI-6). QKI-6 is also highly expressed in astrocytes, which were recently demonstrated to have regulated mRNA localization. Here, we show via CLIPseq that QKI-6 binds 3’ UTRs of a subset of astrocytic mRNAs, including many enriched in peripheral processes. Binding is enriched near stop codons, which is mediated partially by QKI binding motifs(QBMs) yet spreads to adjacent sequences. We developed CRISPR TRAPseq: a viral approach for mosaic, cell-type specific gene mutation with simultaneous translational profiling. This enabled study of QKI-deleted astrocytes in an otherwise normal brain. Astrocyte-targeted QKI deletion altered translation and maturation, while also increasing synaptic density within the astrocyte’s territory. Overall, our data indicate QKI is required for astrocyte maturation and demonstrate an approach for a highly targeted translational assessment of gene knockout in specific cell-types in vivo.


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