scholarly journals Ras Suppresses TXNIP Expression by Restricting Ribosome Translocation

2018 ◽  
Author(s):  
Zhizhou Ye ◽  
Donald E. Ayer
Keyword(s):  
Protein Synthesis ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Aerobic Glycolysis ◽  
Protein Translation ◽  
Underlying Mechanism ◽  
Metabolic Reprogramming ◽  
Coding Region ◽  
Interacting Protein ◽  
Thioredoxin Interacting Protein

ABSTRACTOncogenic Ras upregulates aerobic glycolysis to meet the bioenergetic and biosynthetic demands of rapidly growing cells. In contrast, Thioredoxin interacting protein (TXNIP) is a potent inhibitor of glucose uptake and is frequently downregulated in human cancers. Our lab previously discovered that Ras activation suppresses TXNIP transcription and translation. In this report, we developed a system to study how Ras affects TXNIP translation in the absence of transcriptional affects. We show that whereas Ras drives a global increase in protein translation, it suppresses TXNIP protein synthesis by reducing the rate at which ribosomes transit the coding region of TXNIP mRNA. To investigate the underlying mechanism(s), we randomized or optimized the codons in the TXNIP message without altering the TXNIP primary amino acid sequence. Translation from these mRNA variants is still repressed by Ras, intimating that mRNA secondary structure, miRNAs, RNA binding proteins, or codon usage do not contribute to the blockade of TXNIP synthesis. Rather, we show that the N-terminus of the growing TXNIP polypeptide is the target for Ras-dependent translational repression. Our work demonstrates how Ras suppresses TXNIP translation elongation in the face of a global upregulation of protein synthesis and provides new insight into Ras-dependent metabolic reprogramming.

scholarly journals Ras Suppresses TXNIP Expression by Restricting Ribosome Translocation

2018 ◽  
Vol 38 (20) ◽  
Author(s):  
Zhizhou Ye ◽  
Donald E. Ayer
Keyword(s):  
Protein Synthesis ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Aerobic Glycolysis ◽  
Protein Translation ◽  
Underlying Mechanism ◽  
Metabolic Reprogramming ◽  
Coding Region ◽  
Interacting Protein ◽  
Thioredoxin Interacting Protein

ABSTRACT Oncogenic Ras upregulates aerobic glycolysis to meet the bioenergetic and biosynthetic demands of rapidly growing cells. In contrast, thioredoxin-interacting protein (TXNIP) is a potent inhibitor of glucose uptake and is frequently downregulated in human cancers. Our laboratory previously discovered that Ras activation suppresses TXNIP transcription and translation. In this study, we developed a system to study how Ras affects TXNIP translation in the absence of transcriptional effects. We show that whereas Ras drives a global increase in protein translation, it suppresses TXNIP protein synthesis by reducing the rate at which ribosomes transit the coding region of TXNIP mRNA. To investigate the underlying mechanism(s), we randomized or optimized the codons in the TXNIP message without altering the TXNIP primary amino acid sequence. Translation from these mRNA variants was still repressed by Ras, implying that mRNA secondary structure, microRNAs (miRNAs), RNA binding proteins, or codon usage does not contribute to the blockade of TXNIP synthesis. Rather, we show that the N terminus of the growing TXNIP polypeptide is the target for Ras-dependent translational repression. Our work demonstrates how Ras suppresses TXNIP translation elongation in the face of a global upregulation of protein synthesis and provides new insight into Ras-dependent metabolic reprogramming.

The Therapeutic Potential and Role of miRNA, lncRNA, and circRNA in Osteoarthritis

2019 ◽  
Vol 19 (4) ◽  
pp. 255-263 ◽  
Author(s):  
Yuangang Wu ◽  
Xiaoxi Lu ◽  
Bin Shen ◽  
Yi Zeng
Keyword(s):  
Gene Expression ◽  
Gene Therapy ◽  
Extracellular Matrix ◽  
Inflammatory Reaction ◽  
Noncoding Rna ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Translation ◽  
Cochrane Library

Background: Osteoarthritis (OA) is a disease characterized by progressive degeneration, joint hyperplasia, narrowing of joint spaces, and extracellular matrix metabolism. Recent studies have shown that the pathogenesis of OA may be related to non-coding RNA, and its pathological mechanism may be an effective way to reduce OA. Objective: The purpose of this review was to investigate the recent progress of miRNA, long noncoding RNA (lncRNA) and circular RNA (circRNA) in gene therapy of OA, discussing the effects of this RNA on gene expression, inflammatory reaction, apoptosis and extracellular matrix in OA. Methods: The following electronic databases were searched, including PubMed, EMBASE, Web of Science, and the Cochrane Library, for published studies involving the miRNA, lncRNA, and circRNA in OA. The outcomes included the gene expression, inflammatory reaction, apoptosis, and extracellular matrix. Results and Discussion: With the development of technology, miRNA, lncRNA, and circRNA have been found in many diseases. More importantly, recent studies have found that RNA interacts with RNA-binding proteins to regulate gene transcription and protein translation, and is involved in various pathological processes of OA, thus becoming a potential therapy for OA. Conclusion: In this paper, we briefly introduced the role of miRNA, lncRNA, and circRNA in the occurrence and development of OA and as a new target for gene therapy.

scholarly journals Long noncoding RNAs as tumorigenic factors and therapeutic targets for renal cell carcinoma

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Haiyan Shen ◽  
Guomin Luo ◽  
Qingjuan Chen
Keyword(s):  
Renal Cell Carcinoma ◽  
Cell Carcinoma ◽  
Renal Cell ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Noncoding Rnas ◽  
Protein Translation ◽  
Long Noncoding Rnas ◽  
In Vivo Studies

AbstractApproximately 338,000 patients are diagnosed with kidney cancer worldwide each year, and renal cell carcinoma (RCC), which is derived from renal epithelium, accounts for more than ninety percent of the malignancy. Next generation RNA sequencing has enabled the identification of novel long noncoding RNAs (lncRNAs) in the past 10 years. Recent studies have provided extensive evidence that lncRNAs bind to chromatin modification proteins, transcription factors, RNA-binding proteins and microRNAs, and thereby modulate gene expression through regulating chromatin status, gene transcription, pre-mRNA splicing, mRNA decay and stability, protein translation and stability. In vitro and in vivo studies have demonstrated that over-expression of oncogenic lncRNAs and silencing of tumor suppressive lncRNAs are a common feature of human RCC, and that aberrant lncRNA expression is a marker for poor patient prognosis, and is essential for the initiation and progression of RCC. Because lncRNAs, compared with mRNAs, are expressed in a tissue-specific manner, aberrantly expressed lncRNAs can be better targeted for the treatment of RCC through screening small molecule compounds which block the interaction between lncRNAs and their binding proteins or microRNAs.

scholarly journals MondoA-Mlx Transcriptional Activity Is Limited by mTOR-MondoA Interaction

2014 ◽  
Vol 35 (1) ◽  
pp. 101-110 ◽  
Author(s):  
Mohan R. Kaadige ◽  
Jingye Yang ◽  
Blake R. Wilde ◽  
Donald E. Ayer
Keyword(s):  
Glucose Uptake ◽  
Leucine Zipper ◽  
Aerobic Glycolysis ◽  
Mammalian Target Of Rapamycin ◽  
Mtor Inhibitors ◽  
Nutrient Status ◽  
Regulatory Relationship ◽  
Interacting Protein ◽  
Thioredoxin Interacting Protein ◽  
Helix Loop Helix

Mammalian target of rapamycin (mTOR) integrates multiple signals, including nutrient status, growth factor availability, and stress, to regulate cellular and organismal growth. How mTOR regulates transcriptional programs in response to these diverse stimuli is poorly understood. MondoA and its obligate transcription partner Mlx are basic helix-loop-helix leucine zipper (bHLHZip) transcription factors that sense and execute a glucose-responsive transcriptional program. MondoA-Mlx complexes activate expression of thioredoxin-interacting protein (TXNIP), which is a potent inhibitor of cellular glucose uptake and aerobic glycolysis. Both mTOR and MondoA are central regulators of glucose metabolism, yet whether they interact physically or functionally is unknown. We show that inhibition of mTOR induces MondoA-dependent expression of TXNIP, coinciding with reduced glucose uptake. Mechanistically, mTOR binds to MondoA in the cytoplasm and prevents MondoA-Mlx complex formation, restricting MondoA's nuclear entry and reducing TXNIP expression. Further, we show that mTOR inhibitors and reactive oxygen species (ROS) regulate interaction between MondoA and mTOR in an opposing manner. Like mTOR's suppression of the MondoA-TXNIP axis, MondoA can also suppress mTOR complex 1 (mTORC1) activity via its direct transcriptional regulation of TXNIP. Collectively, these studies reveal a regulatory relationship between mTOR and the MondoA-TXNIP axis that we propose contributes to glucose homeostasis.

scholarly journals Distinct expression of select and transcriptome-wide isolated 3’UTRs suggests critical roles in development and transition states

2020 ◽  
Author(s):  
Shaoyi Ji ◽  
Ze Yang ◽  
Leonardi Gozali ◽  
Thomas Kenney ◽  
Arif Kocabas ◽  
...  
Keyword(s):  
Gene Ontology ◽  
Gene Regulation ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Specific Gene ◽  
Coding Region ◽  
Proliferating Cells ◽  
Coding Regions ◽  
Micro Rnas

AbstractMature mRNA molecules are typically considered to be comprised of a 5’UTR, a 3’UTR and a coding region (CDS), all attached until degradation. Unexpectedly, however, there have been multiple recent reports of widespread differential expression of mRNA 3’UTRs and their cognate coding regions, resulting in the expression of isolated 3’UTRs (i3’UTRs); these i3’UTRs can be highly expressed, often in reciprocal patterns to their cognate CDS. Similar to the role of other lncRNAs, isolated 3’UTRs are likely to play an important role in gene regulation but little is known about the contexts in which they are deployed. To begin to parse the functions of i3’UTRs, here we carry out in vitro, in vivo and in silico analyses of differential 3’UTR/CDS mRNA ratio usage across tissues, development and cell state changes both for a select list of developmentally important genes as well as through unbiased transcriptome-wide analyses. Across two developmental paradigms we find a distinct switch from high i3’UTR expression of stem cell related genes in proliferating cells compared to newly differentiated cells. Our unbiased transcriptome analysis across multiple gene sets shows that regardless of tissue, genes with high 3’UTR to CDS ratios belong predominantly to gene ontology categories related to cell-type specific functions while in contrast, the gene ontology categories of genes with low 3’UTR to CDS ratios are similar and relate to common cellular functions. In addition to these specific findings our data provide critical information from which detailed hypotheses for individual i3’UTRs can be tested-with a common theme that i3’UTRs appear poised to regulate cell-specific gene expression and state.Significance StatementThe widespread existence and expression of mRNA 3’ untranslated sequences in the absence of their cognate coding regions (called isolated 3’UTRs or i3’UTRs) opens up considerable avenues for gene regulation not previously envisioned. Each isolated 3’UTR may still bind and interact with micro RNAs, RNA binding proteins as well as other nucleic acid sequences, all in the absence or low levels of cognate protein production. Here we document the expression, localization and regulation of i3’UTRs both within particular biological systems as well as across the transcriptome. As this is an entirely new area of experimental investigation these early studies are seminal to this burgeoning field.

scholarly journals The structural basis for RNA selectivity by the IMP family of RNA-binding proteins

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jeetayu Biswas ◽  
Vivek L. Patel ◽  
Varun Bhaskar ◽  
Jeffrey A. Chao ◽  
Robert H. Singer ◽  
...  
Keyword(s):  
Neural Development ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Stability ◽  
Underlying Mechanism ◽  
Structural Basis ◽  
General Mechanism ◽  
Binding Domains ◽  
Variable Loops

Abstract The IGF2 mRNA-binding proteins (ZBP1/IMP1, IMP2, IMP3) are highly conserved post-transcriptional regulators of RNA stability, localization and translation. They play important roles in cell migration, neural development, metabolism and cancer cell survival. The knockout phenotypes of individual IMP proteins suggest that each family member regulates a unique pool of RNAs, yet evidence and an underlying mechanism for this is lacking. Here, we combine systematic evolution of ligands by exponential enrichment (SELEX) and NMR spectroscopy to demonstrate that the major RNA-binding domains of the two most distantly related IMPs (ZBP1 and IMP2) bind to different consensus sequences and regulate targets consistent with their knockout phenotypes and roles in disease. We find that the targeting specificity of each IMP is determined by few amino acids in their variable loops. As variable loops often differ amongst KH domain paralogs, we hypothesize that this is a general mechanism for evolving specificity and regulation of the transcriptome.

scholarly journals SPLICING ABNORMALITIES IN MYOTONIC DYSTROPHIES

2014 ◽  
pp. 9-23
Author(s):  
Denis Furling
Keyword(s):  
Clinical Features ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Cardiac Conduction ◽  
Nuclear Accumulation ◽  
Common Mechanism ◽  
Inherited Disease ◽  
Loss Of Function ◽  
Coding Region ◽  
Membrane Structures

Myotonic dystrophy of type 1 (DM1) is one of the most common muscular dystrophy in adults characterized by progressive muscle wasting and weakness, myotonia, cardiac conduction defects, alteration in cognitive functions as well as several other multisystemic symptoms. DM1 is an autosomal dominant inherited disease caused by an unstable CTG expansion ranging from ~50 to more than 1,000 repeats in the 3’ non-coding region of the DMPK gene. Expression of DMPK RNAs with expanded CUG repeats supports a toxic RNA gain-of-function as a pathologic mechanism for DM1. A similar or common mechanism may also be involved in DM type 2 that is caused by CCTG expansion in the first intron of the CNP (ZNF9) gene and shares similar clinical features with DM1 disease. In both myotonic dystrophies, nuclear accumulation of pathogenic CUG/CCUGexp-RNAs alters the activities of the RNA binding proteins such as MBNL1 and CUG-BP1 that leads to alternative splicing mis-regulation of a numerous of transcripts in DM tissues and ultimately, to clinical features of the disease. An overview of the DM splicing mis-regulation will be presented, with focus on mis- regulation of the BIN1 mRNA. In muscle, BIN1 plays an important role in tubular invaginations of the plasma membrane and is required for biogenesis of T-tubules, which are specialized membrane structures essential for excitation-contraction coupling. BIN1 splicing mis-regulation in DM patients due to MBNL1 loss-of-function results in the expression of an inactive form of BIN1 deprived of phosphoinositide-binding and membrane-tubulating activities. Reproducing similar BIN1 mis-splicing defect in the muscles of wild type mice is sufficient to promote T-tubule alterations and muscle strength decrease, suggesting that alteration of BIN1 splicing may contributes to muscle weakness, a prominent feature in DM.

scholarly journals Depletion of the Trypanosome Pumilio Domain Protein PUF2 or of Some Other Essential Proteins Causes Transcriptome Changes Related to Coding Region Length

2014 ◽  
Vol 13 (5) ◽  
pp. 664-674 ◽  
Author(s):  
Bhaskar Anand Jha ◽  
Abeer Fadda ◽  
Clementine Merce ◽  
Elisha Mugo ◽  
Dorothea Droll ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mrna Translation ◽  
Open Reading Frames ◽  
Mrna Levels ◽  
Coding Region ◽  
Content Type ◽  
Puf Proteins ◽  
Reading Frames

ABSTRACT Pumilio domain RNA-binding proteins are known mainly as posttranscriptional repressors of gene expression that reduce mRNA translation and stability. Trypanosoma brucei has 11 PUF proteins. We show here that PUF2 is in the cytosol, with roughly the same number of molecules per cell as there are mRNAs. Although PUF2 exhibits a low level of in vivo RNA binding, it is not associated with polysomes. PUF2 also decreased reporter mRNA levels in a tethering assay, consistent with a repressive role. Depletion of PUF2 inhibited growth of bloodstream-form trypanosomes, causing selective loss of mRNAs with long open reading frames and increases in mRNAs with shorter open reading frames. Reexamination of published RNASeq data revealed the same trend in cells depleted of some other proteins. We speculate that these length effects could be caused by inhibition of the elongation phase of transcription or by an influence of translation status or polysomal conformation on mRNA decay.

scholarly journals miR-503 represses CUG-binding protein 1 translation by recruiting CUGBP1 mRNA to processing bodies

2012 ◽  
Vol 23 (1) ◽  
pp. 151-162 ◽  
Author(s):  
Yu-Hong Cui ◽  
Lan Xiao ◽  
Jaladanki N. Rao ◽  
Tongtong Zou ◽  
Lan Liu ◽  
...  
Keyword(s):  
Rna Binding ◽  
De Novo ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Mrna Levels ◽  
Intestinal Epithelial ◽  
Coding Region ◽  
Processing Bodies ◽  
Target Mrnas ◽  
Repressive Effect

microRNAs (miRNAs) and RNA-binding proteins (RBPs) jointly regulate gene expression at the posttranscriptional level and are involved in many aspects of cellular functions. The RBP CUG-binding protein 1 (CUGBP1) destabilizes and represses the translation of several target mRNAs, but the exact mechanism that regulates CUGBP1 abundance remains elusive. In this paper, we show that miR-503, computationally predicted to associate with three sites of the CUGBP1 mRNA, represses CUGBP1 expression. Overexpression of an miR-503 precursor (pre-miR-503) reduced the de novo synthesis of CUGBP1 protein, whereas inhibiting miR-503 by using an antisense RNA (antagomir) enhanced CUGBP1 biosynthesis and elevated its abundance; neither intervention changed total CUGBP1 mRNA levels. Studies using heterologous reporter constructs revealed a greater repressive effect of miR-503 through the CUGBP1 coding region sites than through the single CUGBP1 3′-untranslated region target site. CUGBP1 mRNA levels in processing bodies (P-bodies) increased in cells transfected with pre-miR-503, while silencing P-body resident proteins Ago2, RCK, or LSm4 decreased miR-503–mediated repression of CUGBP1 expression. Decreasing the levels of cellular polyamines reduced endogenous miR-503 levels and promoted CUGBP1 expression, an effect that was prevented by ectopic miR-503 overexpression. Repression of CUGBP1 by miR-503 in turn altered the expression of CUGBP1 target mRNAs and thus increased the sensitivity of intestinal epithelial cells to apoptosis. These findings identify miR-503 as both a novel regulator of CUGBP1 expression and a modulator of intestinal epithelial homoeostasis.

scholarly journals Translational Control of Cytochrome c by RNA-Binding Proteins TIA-1 and HuR

2006 ◽  
Vol 26 (8) ◽  
pp. 3295-3307 ◽  
Author(s):  
Tomoko Kawai ◽  
Ashish Lal ◽  
Xiaoling Yang ◽  
Stefanie Galban ◽  
Krystyna Mazan-Mamczarz ◽  
...  
Keyword(s):  
Er Stress ◽  
Translational Control ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Expression Patterns ◽  
Mrna Levels ◽  
Coding Region ◽  
Translation Rate ◽  
Translational Repressor

ABSTRACT Stresses affecting the endoplasmic reticulum (ER) globally modulate gene expression patterns by altering posttranscriptional processes such as translation. Here, we use tunicamycin (Tn) to investigate ER stress-triggered changes in the translation of cytochrome c, a pivotal regulator of apoptosis. We identified two RNA-binding proteins that associate with its ∼900-bp-long, adenine- and uridine-rich 3′ untranslated region (UTR): HuR, which displayed affinity for several regions of the cytochrome c 3′UTR, and T-cell-restricted intracellular antigen 1 (TIA-1), which preferentially bound the segment proximal to the coding region. HuR did not appear to influence the cytochrome c mRNA levels but instead promoted cytochrome c translation, as HuR silencing greatly diminished the levels of nascent cytochrome c protein. By contrast, TIA-1 functioned as a translational repressor of cytochrome c, with interventions to silence TIA-1 dramatically increasing cytochrome c translation. Following treatment with Tn, HuR binding to cytochrome c mRNA decreased, and both the presence of cytochrome c mRNA within actively translating polysomes and the rate of cytochrome c translation declined. Taken together, our data suggest that the translation rate of cytochrome c is determined by the opposing influences of HuR and TIA-1 upon the cytochrome c mRNA. Under unstressed conditions, cytochrome c mRNA is actively translated, but in response to ER stress agents, both HuR and TIA-1 contribute to lowering its biosynthesis rate. We propose that HuR and TIA-1 function coordinately to maintain precise levels of cytochrome c production under unstimulated conditions and to modify cytochrome c translation when damaged cells are faced with molecular decisions to follow a prosurvival or a prodeath path.

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