scholarly journals Protein Arginine Methylation in Candida albicans: Role in Nuclear Transport

2007 ◽  
Vol 6 (7) ◽  
pp. 1119-1129 ◽  
Author(s):  
Anne E. McBride ◽  
Cecilia Zurita-Lopez ◽  
Anthony Regis ◽  
Emily Blum ◽  
Ana Conboy ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Protein Transport ◽  
Rna Binding ◽  
Fluorescent Protein ◽  
Rna Binding Proteins ◽  
Nuclear Transport ◽  
Arginine Methylation ◽  
Type I ◽  
Sequencing Project ◽  
Protein Arginine Methylation

ABSTRACT Protein arginine methylation plays a key role in numerous eukaryotic processes, such as protein transport and signal transduction. In Candida albicans, two candidate protein arginine methyltransferases (PRMTs) have been identified from the genome sequencing project. Based on sequence comparison, C. albicans candidate PRMTs display similarity to Saccharomyces cerevisiae Hmt1 and Rmt2. Here we demonstrate functional homology of Hmt1 between C. albicans and S. cerevisiae: CaHmt1 supports growth of S. cerevisiae strains that require Hmt1, and CaHmt1 methylates Npl3, a major Hmt1 substrate, in S. cerevisiae. In C. albicans strains lacking CaHmt1, asymmetric dimethylarginine and ω-monomethylarginine levels are significantly decreased, indicating that Hmt1 is the major C. albicans type I PRMT1. Given the known effects of type I PRMTs on nuclear transport of RNA-binding proteins, we tested whether Hmt1 affects nuclear transport of a putative Npl3 ortholog in C. albicans. CaNpl3 allows partial growth of S. cerevisiae npl3Δ strains, but its arginine-glycine-rich C terminus can fully substitute for that of ScNpl3 and also directs methylation-sensitive association with ScNpl3. Expression of green fluorescent protein-tagged CaNpl3 proteins in C. albicans strains with and without CaHmt1 provides evidence for CaHmt1 facilitating export of CaNpl3 in this fungus. We have also identified the C. albicans Rmt2, a type IV fungus- and plant-specific PRMT, by amino acid analysis of an rmt2Δ/rmt2Δ strain, as well as biochemical evidence for additional cryptic PRMTs.

scholarly journals Characterization of the Drosophila protein arginine methyltransferases DART1 and DART4

2004 ◽  
Vol 379 (2) ◽  
pp. 283-289 ◽  
Author(s):  
Marie-Chloé BOULANGER ◽  
Tina Branscombe MIRANDA ◽  
Steven CLARKE ◽  
Marco di FRUSCIO ◽  
Beat SUTER ◽  
...  
Keyword(s):  
Rna Binding ◽  
Developmental Stages ◽  
Rna Binding Proteins ◽  
Genetic System ◽  
Arginine Methylation ◽  
Type I ◽  
Protein Arginine Methyltransferases ◽  
Arginine Residues ◽  
Drosophila Protein

The role of arginine methylation in Drosophila melanogaster is unknown. We identified a family of nine PRMTs (protein arginine methyltransferases) by sequence homology with mammalian arginine methyltransferases, which we have named DART1 to DART9 (Drosophilaarginine methyltransferases 1–9). In keeping with the mammalian PRMT nomenclature, DART1, DART4, DART5 and DART7 are the putative homologues of PRMT1, PRMT4, PRMT5 and PRMT7. Other DART family members have a closer resemblance to PRMT1, but do not have identifiable homologues. All nine genes are expressed in Drosophila at various developmental stages. DART1 and DART4 have arginine methyltransferase activity towards substrates, including histones and RNA-binding proteins. Amino acid analysis of the methylated arginine residues confirmed that both DART1 and DART4 catalyse the formation of asymmetrical dimethylated arginine residues and they are type I arginine methyltransferases. The presence of PRMTs in D. melanogaster suggest that flies are a suitable genetic system to study arginine methylation.

scholarly journals Altered RNA splicing initiates the viral mimicry response from inverted SINEs following type I PRMT inhibition in Triple-Negative Breast Cancer

2021 ◽  
Author(s):  
Cheryl Arrowsmith ◽  
Qin Wu ◽  
David Nie ◽  
Wail alawi ◽  
Jennifer Cruickshank ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Breast Cancer Subtype ◽  
Arginine Methylation ◽  
Interferon Response ◽  
Type I

Abstract Triple negative breast cancer (TNBC) is the most aggressive breast cancer subtype with the worst prognosis and few effective therapies. Here, we undertook a screen of epigenetic chemical probes to systematically uncover the epigenetic regulators critical for TNBC growth. We identified MS023, an inhibitor of type I protein arginine methyltransferases (PRMTs), as having anti-tumor growth activity in TNBC in vitro and in vivo. Pathway analysis of TNBC cell lines indicates that the activation of interferon responses pre- and post-MS023 treatment is a functional biomarker and determinant of response; and these observations extend to a panel of patient-derived organoids. Inhibition of type I PRMT triggers an interferon response through the antiviral defense pathway with the induction of double-stranded RNA (dsRNA). The observed dsRNA accumulation is derived, at least in part, from inverted-repeat Alus (IR-Alus), many of which are expressed from retained introns induced by MS023, which inhibits arginine methylation of RNA-binding proteins and alters mRNA splicing machinery. Together, our results represent a shift in understanding the anti-tumor mechanism of type I PRMT inhibitors and provide a novel rationale and biomarker approach for the clinical development of type I PRMT inhibitors.

scholarly journals RNA-binding proteins regulate aldosterone homeostasis in human steroidogenic cells

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.

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

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.

scholarly journals Automated High-Content Screening for Compounds That Disassemble the Perinucleolar Compartment

2009 ◽  
Vol 14 (9) ◽  
pp. 1045-1053 ◽  
Author(s):  
John T. Norton ◽  
Steven A. Titus ◽  
Dwayne Dexter ◽  
Christopher P. Austin ◽  
Wei Zheng ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Cellular Proliferation ◽  
Rna Binding ◽  
Fluorescent Protein ◽  
Rna Binding Proteins ◽  
High Content Screening ◽  
Screening Assay ◽  
Phenotypic Marker ◽  
Perinucleolar Compartment

All solid malignancies share characteristic traits, including unlimited cellular proliferation, evasion of immune regulation, and the propensity to metastasize. The authors have previously described that a subnuclear structure, the perinucleolar compartment (PNC), is associated with the metastatic phenotype in solid tumor cancer cells. The percentage of cancer cells that contain PNCs (PNC prevalence) is indicative of the malignancy of a tumor both in vitro and in vivo, and thus PNC prevalence is a marker that reflects metastatic capability in a population of tumor cells. Although the function of the PNC remains to be determined, the PNC is highly enriched with small RNAs and RNA binding proteins. The initial chemical biology studies using a set of anticancer drugs that disassemble PNCs revealed a direct association of the structure with DNA. Therefore, PNC prevalence reduction as a phenotypic marker can be used to identify compounds that target cellular processes required for PNC maintenance and hence used to elucidate the nature of the PNC function. Here the authors report the development of an automated high-content screening assay that is capable of detecting PNC prevalence in prostate cancer cells (PC-3M) stably expressing a green fluorescent protein (GFP)—fusion protein that localizes to the PNC. The assay was optimized using known PNC-reducing drugs and non-PNC-reducing cytotoxic drugs. After optimization, the fidelity of the assay was probed with a collection of 8284 compounds and was shown to be robust and capable of detecting known and novel PNC-reducing compounds, making it the first reported high-content phenotypic screen for small changes in nuclear structure. ( Journal of Biomolecular Screening 2009:1045-1053)

scholarly journals Ectopic expression ofDrosophilaELAV and human HuD inDrosophilawing disc cells reveals functional distinctions and similarities

2002 ◽  
Vol 115 (11) ◽  
pp. 2413-2421 ◽  
Author(s):  
Gakuta Toba ◽  
Jan Qui ◽  
Sandhya P. Koushika ◽  
Kalpana White
Keyword(s):  
Mammalian Cells ◽  
Rna Binding ◽  
Fluorescent Protein ◽  
Rna Binding Proteins ◽  
Mrna Level ◽  
Ectopic Expression ◽  
Wing Disc ◽  
Transcript Stability ◽  
Endogenous Expression ◽  
Disc Cells

Drosophila ELAV and human HuD are two neuronal RNA binding proteins that show remarkable sequence homology, yet differ in their respective documented roles in post-transcriptional regulation. ELAV regulates neural-specific alternative splicing of specific transcripts, and HuD stabilizes specific mRNAs that are otherwise unstable due to AU-rich elements(AREs) in their 3′ untranslated region (UTR). AREs are major determinants of transcript stability in mammalian cells. The role of each of these proteins was investigated and compared, by ectopically expressing them in Drosophila imaginal wing disc cells, which lack endogenous expression of either protein. The effect of the ectopic expression of ELAV and HuD was assessed on two sets of green fluorescent protein reporter transgenes,which were all driven with a broadly expressing promoter. Each set consisted of three reporter transgenes: (1) with an uninterrupted open reading frame(ORF); (2) with a constitutively spliced intron inserted into the ORF; and (3)with the intron nASI whose splicing is regulated in neurons by ELAV,inserted into the ORF. The two sets differed from each other only in their 3′UTR: Heat-shock-protein-70Ab (Hsp70Ab) trailer with ARE-like characteristics or Actin 5C (Act5C) trailer. Our results show that:(1) both ectopically expressed ELAV and HuD can enhance expression of transgenes with the Hsp70Ab 3′UTR, but not of transgenes with Act5C 3′UTR; (2) this enhancement is accompanied by an increase in mRNA level; (3) only ELAV can induce neural-specific splicing of nASI; and (4) although HuD is localized primarily to the cytoplasm,ELAV is localized to both the cytoplasm and the nucleus.

scholarly journals Pb103 Regulates Zygote/Ookinete Development in Plasmodium berghei via Double Zinc Finger Domains

Pathogens ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1536
Author(s):  
Makoto Hirai ◽  
Akimasa Maeta ◽  
Toshiyuki Mori ◽  
Toshihiro Mita
Keyword(s):  
Zinc Finger ◽  
Rna Binding ◽  
Fluorescent Protein ◽  
Rna Binding Proteins ◽  
Critical Role ◽  
Specific Protein ◽  
Translational Repression ◽  
Vitro Fertilization ◽  
Zinc Finger Domains

Sexual reproduction of Plasmodium parasites takes place in anopheline mosquitoes, where male and female gametes fuse to form zygotes and then ookinetes. These processes are orchestrated by stage-specific protein expression, which is mediated in part by translational repression. Accumulating evidence shows that RNA binding proteins (RBPs) play crucial roles in these processes. Here, we report the characterization of P. berghei 103 (Pb103), which encodes a protein possessing double zinc finger domains (ZFs), an RBP. Reporter parasites expressing azami green fluorescent protein (AGFP) under the endogenous Pb103 gene promoter (Pb103-AGFP reporter) showed that the AGFP fluorescent signal was detected from gametes to ookinetes, while AGFP mRNA was translationally repressed in female gametocytes. The Pb103-disrupted parasites (Pb103(−)) grew and produced gametocytes with similar efficiencies to those of wild-type parasites. However, no oocysts were formed in mosquitoes fed Pb103(−). An in vitro fertilization assay showed abortion at the zygote stage in Pb103(−), suggesting that Pb103 plays a critical role in zygote/ookinete development. Cross-fertilization assays with Pb103(−) and male- or female-sterile parasites revealed that Pb103 was essential exclusively for female gametes. To identify the domains critical for zygote/ookinete development, transgenic parasites expressing partially deleted Pb103 were generated and assayed for ookinete maturation. As a result, deleting either of two ZFs but not the C-terminal region abolished zygote/ookinete development, highlighting the indispensable roles of ZFs in parasite sexual development, most likely via translational repression.

scholarly journals Human DICER helicase domain recruits PKR and modulates its antiviral activity

2021 ◽  
Vol 17 (5) ◽  
pp. e1009549
Author(s):  
Thomas C. Montavon ◽  
Morgane Baldaccini ◽  
Mathieu Lefèvre ◽  
Erika Girardi ◽  
Béatrice Chane-Woon-Ming ◽  
...  
Keyword(s):  
Rna Silencing ◽  
Mammalian Cells ◽  
Sindbis Virus ◽  
Rna Binding ◽  
Semliki Forest Virus ◽  
Rna Binding Proteins ◽  
Helicase Domain ◽  
Type I ◽  
Dependent Manner ◽  
Rna Helicases

The antiviral innate immune response mainly involves type I interferon (IFN) in mammalian cells. The contribution of the RNA silencing machinery remains to be established, but several recent studies indicate that the ribonuclease DICER can generate viral siRNAs in specific conditions. It has also been proposed that type I IFN and RNA silencing could be mutually exclusive antiviral responses. In order to decipher the implication of DICER during infection of human cells with alphaviruses such as the Sindbis virus and Semliki forest virus, we determined its interactome by proteomics analysis. We show that DICER specifically interacts with several double-stranded RNA binding proteins and RNA helicases during viral infection. In particular, proteins such as DHX9, ADAR-1 and the protein kinase RNA-activated (PKR) are enriched with DICER in virus-infected cells. We demonstrate that the helicase domain of DICER is essential for this interaction and that its deletion confers antiviral properties to this protein in an RNAi-independent, PKR-dependent, manner.

scholarly journals Arginine Methylation Regulates SARS-CoV-2 Nucleocapsid Protein Function and Viral Replication

2021 ◽  
Author(s):  
Ting Cai ◽  
Zhenbao Yu ◽  
Zhen Wang ◽  
Chen Liang ◽  
Stephane Richard
Keyword(s):  
Protein Function ◽  
Rna Binding ◽  
Binding Capacity ◽  
Viral Proteins ◽  
Arginine Methylation ◽  
Host Protein ◽  
Hek293 Cells ◽  
Type I ◽  
Dependent Manner ◽  
N Protein

Viral proteins are known to be methylated by host protein arginine methyltransferases (PRMTs) playing critical roles during viral infections. Herein, we show that PRMT1 methylates SARS-CoV-2 nucleocapsid (N) protein at residues R95 and R177 within RGG/RG sequences. Arginine methylation of N protein was confirmed by immunoblotting viral proteins extracted from SARS-CoV-2 virions isolated by cell culture. We demonstrate that arginine methylation of N protein is required for its RNA binding capacity, since treatment with a type I PRMT inhibitor (MS023) or substitution of R95K or R177K inhibited interaction with the 5'-UTR of the SARS-CoV-2 genomic RNA. We defined the N interactome in HEK293 cells with or without MS023 treatment and identified PRMT1 and many of its RGG/RG substrates including the known interactor, G3BP1, and other components of stress granules (SG). Methylation of N protein at R95 regulates another function namely its property to suppress the formation of SGs. MS023 treatment or R95K substitution blocked N-mediated suppression of SGs. Also, the co-expression of methylarginine reader TDRD3 quenched N-mediated suppression of SGs in a dose-dependent manner. Finally, pre-treatment of VeroE6 cells with MS023 significantly reduced SARS-CoV-2 replication. With type I PRMT inhibitors being in clinical trials for cancer treatment, inhibiting arginine methylation to target the later stages of the viral life cycle such as viral genome packaging and assembly of virions may be an additional therapeutic application of these drugs.

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