RNA-Binding Protein Musashi-2 Inhibits Aldosterone Production

Abstract The adrenal cortex is the site of steroid hormone synthesis. These hormones control important physiological processes like metabolism, blood pressure and volume, and sexual characteristic development. While the signaling pathways, transcription factors, and steroidogenic enzymes are well-characterized, surprisingly little is known about the contribution RNA-binding proteins (RBPs). RBPs exert post-transcriptional control by interacting with specific elements within target mRNAs. Here we focus on the RBP, Mushashi-2 (MSI2), which binds to UAG sequences in the 3’UTR of its target transcripts. MSI2 is required for development of steroidogenic tissues which is consistent with its higher mRNA levels in human ovaries and testis. MSI2 also exhibits high expression levels in human adrenal tissue and the immortalized human adrenocortical cell line (H295R). Based on the compelling MSI2 expression pattern, we set out to determine the role of MSI2 on aldosterone production. Depletion of MSI2 using siRNA led to significantly lower aldosterone levels in H295R cells stimulated with AngII. We also employed an orthogonal loss-of-function approach by co-treating cells with AngII and increasing concentrations of Ro-08-2750 (Ro), a direct and selective inhibitor of MSI2-RNA interactions. Ro inhibited aldosterone production in a dose-dependent manner at 1 µM with almost complete inhibition at 5 µM. The molecular mechanism by which MSI2 regulates target RNA translation and/or decay is unknown. Moreover, whether MSI2 acts as a repressor or activator appears to be context dependent. Our goal is to determine the precise molecular mechanism by which MSI2 promotes aldosterone production. Specifically, we will identify MSI2 targets, temporally resolved consequences of MSI2 inhibition, and protein interaction partners. This work will impact our understanding of fundamental principles of RBP-mediated regulation, as well as novel regulatory mechanisms underlying human steroid hormone synthesis. Indeed, Ro (or further optimized compounds) may represent new therapeutic avenues for adrenal disease.

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C9orf72-associated arginine-rich dipeptide repeats induce RNA-dependent nuclear accumulation of Staufen in neurons

Human Molecular Genetics ◽

10.1093/hmg/ddab089 ◽

2021 ◽

Author(s):

Eun Seon Kim ◽

Chang Geon Chung ◽

Jeong Hyang Park ◽

Byung Su Ko ◽

Sung Soon Park ◽

...

Keyword(s):

Retinal Degeneration ◽

Rna Binding ◽

Rna Binding Proteins ◽

Nuclear Accumulation ◽

Heterozygous Mutation ◽

Pathological Feature ◽

Dependent Manner ◽

Cellular Processes ◽

Drosophila Model ◽

Post Transcriptional Regulation

Abstract RNA-binding proteins (RBPs) play essential roles in diverse cellular processes through post-transcriptional regulation of RNAs. The subcellular localization of RBPs is thus under tight control, the breakdown of which is associated with aberrant cytoplasmic accumulation of nuclear RBPs such as TDP-43 and FUS, well-known pathological markers for amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). Here, we report in Drosophila model for ALS/FTD that nuclear accumulation of a cytoplasmic RBP, Staufen, may be a new pathological feature. We found that in Drosophila C4da neurons expressing PR36, one of the arginine-rich dipeptide repeat proteins (DPRs), Staufen accumulated in the nucleus in Importin- and RNA-dependent manner. Notably, expressing Staufen with exogenous NLS—but not with mutated endogenous NLS—potentiated PR-induced dendritic defect, suggesting that nuclear-accumulated Staufen can enhance PR toxicity. PR36 expression increased Fibrillarin staining in the nucleolus, which was enhanced by heterozygous mutation of stau (stau+/−), a gene that codes Staufen. Furthermore, knockdown of fib, which codes Fibrillarin, exacerbated retinal degeneration mediated by PR toxicity, suggesting that increased amount of Fibrillarin by stau+/− is protective. Stau+/− also reduced the amount of PR-induced nuclear-accumulated Staufen and mitigated retinal degeneration and rescued viability of flies expressing PR36. Taken together, our data show that nuclear accumulation of Staufen in neurons may be an important pathological feature contributing to the pathogenesis of ALS/FTD.

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Function of Pumilio Genes in Human Embryonic Stem Cells and Their Effect in Stemness and Cardiomyogenesis

10.1101/751537 ◽

2019 ◽

Author(s):

Isabelle Leticia Zaboroski Silva ◽

Anny Waloski Robert ◽

Guillermo Cabrera Cabo ◽

Lucia Spangenberg ◽

Marco Augusto Stimamiglio ◽

...

Keyword(s):

Stem Cells ◽

Embryonic Stem Cells ◽

Rna Binding ◽

Rna Binding Proteins ◽

Embryonic Stem ◽

Mrna Levels ◽

Human Escs ◽

Mrna Targets ◽

Cardiomyogenic Differentiation

AbstractPosttranscriptional regulation plays a fundamental role in the biology of embryonic stem cells (ESCs). Many studies have demonstrated that multiple mRNAs are coregulated by one or more RNA binding proteins (RBPs) that orchestrate the expression of these molecules. A family of RBPs, known as PUF (Pumilio-FBF), is highly conserved among species and has been associated with the undifferentiated and differentiated states of different cell lines. In humans, two homologs of the PUF family have been found: Pumilio 1 (PUM1) and Pumilio 2 (PUM2). To understand the role of these proteins in human ESCs (hESCs), we first demonstrated the influence of the silencing of PUM1 and PUM2 on pluripotency genes. OCT4 and NANOG mRNA levels decreased significantly with the knockdown of Pumilio, suggesting that PUMILIO proteins play a role in the maintenance of pluripotency in hESCs. Furthermore, we observed that the hESCs silenced for PUM1 and 2 exhibited an improvement in efficiency of in vitro cardiomyogenic differentiation. Using in silico analysis, we identified mRNA targets of PUM1 and PUM2 expressed during cardiomyogenesis. With the reduction of PUM1 and 2, these target mRNAs would be active and could be involved in the progression of cardiomyogenesis.

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Multiple roles of heterogeneous nuclear ribonucleoprotein K during skeletal muscle cell differentiation

10.1101/2021.07.09.451593 ◽

2021 ◽

Author(s):

Keisuke Hitachi ◽

Yuri Kiyofuji ◽

Masashi Nakatani ◽

Kunihiro Tsuchida

Keyword(s):

Binding Proteins ◽

Rna Binding ◽

Rna Binding Proteins ◽

Protein Complexes ◽

Myogenic Differentiation ◽

Cell Physiology ◽

Transcriptional Level ◽

Loss Of Function ◽

Independent Manner ◽

Multiple Functions

RNA-binding proteins (RBPs) regulate cell physiology via the formation of ribonucleic-protein complexes with coding and non-coding RNAs. RBPs have multiple functions in the same cells; however, the precise mechanism through which their pleiotropic functions are determined remains unknown. In this study, we revealed the multiple inhibitory functions of hnRNPK for myogenic differentiation. We first identified hnRNPK as a lncRNA Myoparr binding protein. Gain- and loss-of-function experiments showed that hnRNPK repressed the expression of myogenin at the transcriptional level via binding to Myoparr. Moreover, hnRNPK repressed the expression of a set of genes coding for aminoacyl-tRNA synthetases in a Myoparr-independent manner. Mechanistically, hnRNPK regulated the eIF2α/Atf4 pathway, one branch of the intrinsic pathways of the endoplasmic reticulum sensors, in differentiating myoblasts. Thus, our findings demonstrate that hnRNPK plays multiple lncRNA-dependent and -independent roles in the inhibition of myogenic differentiation, indicating that the analysis of lncRNA-binding proteins will be useful for elucidating both the physiological functions of lncRNAs and the multiple functions of RBPs.

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RNA-binding proteins regulate aldosterone homeostasis in human steroidogenic cells

10.1101/2021.02.19.431050 ◽

2021 ◽

Author(s):

Rui Fu ◽

Kimberly Wellman ◽

Amber Baldwin ◽

Juilee Rege ◽

Kathryn Walters ◽

...

Keyword(s):

Gene Expression ◽

Time Course ◽

Binding Proteins ◽

Rna Binding ◽

Rna Binding Proteins ◽

Ex Vivo ◽

Human Cell Line ◽

Rna Decay ◽

Type I ◽

Aldosterone Production

ABSTRACTAngiotensin II (AngII) binds to the type I angiotensin receptor in the adrenal cortex to initiate a cascade of events leading to the production of aldosterone, a master regulator of blood pressure. Despite extensive characterization of the transcriptional and enzymatic control of adrenocortical steroidogenesis, there are still major gaps in our knowledge related to precise regulation of AII-induced gene expression kinetics. Specifically, we do not know the regulatory contribution of RNA-binding proteins (RBPs) and RNA decay, which can control the timing of stimulus-induced gene expression. To investigate this question, we performed a high-resolution RNA-seq time course of the AngII stimulation response and 4-thiouridine pulse labeling in a steroidogenic human cell line (H295R). We identified twelve temporally distinct gene expression responses that contained mRNA encoding proteins known to be important for various steps of aldosterone production, such as cAMP signaling components and steroidogenic enzymes. AngII response kinetics for many of these mRNAs revealed a coordinated increase in both synthesis and decay. These findings were validated in primary human adrenocortical cells stimulated ex vivo with AngII. Using a candidate siRNA screen, we identified a subset of RNA-binding protein and RNA decay factors that activate or repress AngII-stimulated aldosterone production. Among the repressors of aldosterone were BTG2, which promotes deadenylation and global RNA decay. BTG2 was induced in response to AngII stimulation and promoted the repression of mRNAs encoding pro-steroidogenic factors indicating the existence of an incoherent feedforward loop controlling aldosterone homeostasis. Together, these data support a model in which coordinated increases in transcription and regulated RNA decay facilitates the major transcriptomic changes required to implement a pro-steroidogenic gene expression program that is temporally restricted to prevent aldosterone overproduction.

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Triciribine Engages ZFP36L1 and HuR to Stabilize LDLR mRNA

Molecules ◽

10.3390/molecules25194505 ◽

2020 ◽

Vol 25 (19) ◽

pp. 4505

Author(s):

Hilde Sundvold

Keyword(s):

Rna Binding ◽

Rna Binding Proteins ◽

Low Density Lipoprotein ◽

Ring Finger ◽

Density Lipoprotein ◽

Dependent Manner ◽

Akt Inhibitor ◽

Human Hepatoma Cells ◽

Density Lipoprotein Receptor ◽

The Stability

An increased understanding of low-density lipoprotein receptor (LDLR) and its regulation may facilitate drug development for the treatment of hypercholesterolemia. Triciribine (TCN), which is a highly selective AKT inhibitor, increases the stability of LDLR mRNA downstream of extracellular signal-regulated kinase (ERK) in human hepatoma cells (HepG2). Here, a candidate approach was used in order to determine whether the RNA-binding proteins (RBPs) ZFP36 ring finger protein like 1 (ZFP36L1) and Hu antigen R (HuR) play a role in TCN-mediated stabilization of LDLR mRNA. The depletion of HuR led to a reduction of LDLR mRNA stability, an event that was more pronounced in TCN-treated cells. TCN was found to induce the translocation of nuclear HuR to cytoplasm in an ERK-dependent manner. ZFP36L1 depletion increased the stability of LDLR mRNA consistent with its destabilizing role. However, in contrast to HuR, TCN had no effect on LDLR mRNA turnover in ZFP36L1-depleted cells. TCN induced the phosphorylation of ZFP36L1 in an ERK/RSK-dependent manner and promoted its dissociation from the CCR4-NOT complex. In sum, these data suggest that TCN utilizes ERK signaling to increase the activity of HuR and inhibit ZFP36L1 to stabilize LDLR mRNA in HepG2 cells.

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RNA-Binding Proteins HuB, HuC, and HuD are Distinctly Regulated in Dorsal Root Ganglia Neurons from STZ-Sensitive Compared to STZ-Resistant Diabetic Mice

International Journal of Molecular Sciences ◽

10.3390/ijms20081965 ◽

2019 ◽

Vol 20 (8) ◽

pp. 1965 ◽

Cited By ~ 1

Author(s):

Cosmin Cătălin Mustăciosu ◽

Adela Banciu ◽

Călin Mircea Rusu ◽

Daniel Dumitru Banciu ◽

Diana Savu ◽

...

Keyword(s):

Gene Expression ◽

Body Weight ◽

Sensory Neurons ◽

Dorsal Root Ganglia ◽

Dorsal Root ◽

Transcriptional Control ◽

Binding Proteins ◽

Rna Binding ◽

Rna Binding Proteins ◽

Diabetic Mice

The neuron-specific Elav-like Hu RNA-binding proteins were described to play an important role in neuronal differentiation and plasticity by ensuring the post-transcriptional control of RNAs encoding for various proteins. Although Elav-like Hu proteins alterations were reported in diabetes or neuropathy, little is known about the regulation of neuron-specific Elav-like Hu RNA-binding proteins in sensory neurons of dorsal root ganglia (DRG) due to the diabetic condition. The goal of our study was to analyze the gene and protein expression of HuB, HuC, and HuD in DRG sensory neurons in diabetes. The diabetic condition was induced in CD-1 adult male mice with single-intraperitoneal injection of streptozotocin (STZ, 150 mg/kg), and 8-weeks (advanced diabetes) after induction was quantified the Elav-like proteins expression. Based on the glycemia values, we identified two types of responses to STZ, and mice were classified in STZ-resistant (diabetic resistant, glycemia < 260 mg/dL) and STZ-sensitive (diabetic, glycemia > 260 mg/dL). Body weight measurements indicated that 8-weeks after STZ-induction of diabetes, control mice have a higher increase in body weight compared to the diabetic and diabetic resistant mice. Moreover, after 8-weeks, diabetic mice (19.52 ± 3.52 s) have longer paw withdrawal latencies in the hot-plate test than diabetic resistant (11.36 ± 1.92 s) and control (11.03 ± 1.97 s) mice, that correlates with the installation of warm hypoalgesia due to the diabetic condition. Further on, we evidenced the decrease of Elav-like gene expression in DRG neurons of diabetic mice (Elavl2, 0.68 ± 0.05 fold; Elavl3, 0.65 ± 0.01 fold; Elavl4, 0.53 ± 0.07 fold) and diabetic resistant mice (Ealvl2, 0.56 ± 0.07 fold; Elavl3, 0.32 ± 0.09 fold) compared to control mice. Interestingly, Elav-like genes have a more accentuated downregulation in diabetic resistant than in diabetic mice, although hypoalgesia was evidenced only in diabetic mice. The Elav-like gene expression changes do not always correlate with the Hu protein expression changes. To detail, HuB is upregulated and HuD is downregulated in diabetic mice, while HuB, HuC, and HuD are downregulated in diabetic resistant mice compared to control mice. To resume, we demonstrated HuD downregulation and HuB upregulation in DRG sensory neurons induced by diabetes, which might be correlated with altered post-transcriptional control of RNAs involved in the regulation of thermal hypoalgesia condition caused by the advanced diabetic neuropathy.

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Effect of nutrition on plasma lipid profile and mRNA levels of ovarian genes involved in steroid hormone synthesis in Hu sheep during luteal phase1

Journal of Animal Science ◽

10.2527/jas.2013-6450 ◽

2013 ◽

Vol 91 (11) ◽

pp. 5229-5239 ◽

Cited By ~ 15

Author(s):

S. J. Ying ◽

S. H. Xiao ◽

C. L. Wang ◽

B. S. Zhong ◽

G. M. Zhang ◽

...

Keyword(s):

Lipid Profile ◽

Steroid Hormone ◽

Plasma Lipid ◽

Mrna Levels ◽

Plasma Lipid Profile ◽

Hormone Synthesis ◽

Hu Sheep

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SPLICING ABNORMALITIES IN MYOTONIC DYSTROPHIES

Istituto Lombardo - Accademia di Scienze e Lettere - Incontri di Studio ◽

10.4081/incontri.2012.58 ◽

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.

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PRMT7 regulates RNA-binding capacity and protein stability in Leishmania parasites

Nucleic Acids Research ◽

10.1093/nar/gkaa211 ◽

2020 ◽

Vol 48 (10) ◽

pp. 5511-5526

Author(s):

Tiago R Ferreira ◽

Adam A Dowle ◽

Ewan Parry ◽

Eliza V C Alves-Ferreira ◽

Karen Hogg ◽

...

Keyword(s):

Protein Modification ◽

Transcriptional Control ◽

Leishmania Major ◽

Rna Binding ◽

Rna Binding Proteins ◽

Binding Capacity ◽

Arginine Methylation ◽

Mrna Metabolism

Abstract RNA binding proteins (RBPs) are the primary gene regulators in kinetoplastids as transcriptional control is nearly absent, making Leishmania an exceptional model for investigating methylation of non-histone substrates. Arginine methylation is an evolutionarily conserved protein modification catalyzed by Protein aRginine Methyl Transferases (PRMTs). The chromatin modifier PRMT7 is the only Type III PRMT found in higher eukaryotes and a restricted number of unicellular eukaryotes. In Leishmania major, PRMT7 is a cytoplasmic protein implicit in pathogenesis with unknown substrates. Using comparative methyl-SILAC proteomics for the first time in protozoa, we identified 40 putative targets, including 17 RBPs hypomethylated upon PRMT7 knockout. PRMT7 can modify Alba3 and RBP16 trans-regulators (mammalian RPP25 and YBX2 homologs, respectively) as direct substrates in vitro. The absence of PRMT7 levels in vivo selectively reduces Alba3 mRNA-binding capacity to specific target transcripts and can impact the relative stability of RBP16 in the cytoplasm. RNA immunoprecipitation analyses demonstrate PRMT7-dependent methylation promotes Alba3 association with select target transcripts and thus indirectly stabilizes mRNA of a known virulence factor, δ-amastin surface antigen. These results highlight a novel role for PRMT7-mediated arginine methylation of RBP substrates, suggesting a regulatory pathway controlling gene expression and virulence in Leishmania. This work introduces Leishmania PRMTs as epigenetic regulators of mRNA metabolism with mechanistic insight into the functional manipulation of RBPs by methylation.

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

Eukaryotic Cell ◽

10.1128/ec.00018-14 ◽

2014 ◽

Vol 13 (5) ◽

pp. 664-674 ◽

Cited By ~ 19

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.

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