Structural analyses of the CRISPR protein Csc2 reveal the RNA-binding interface of the type I-D Cas7 family

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.

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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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Roles of Emerging RNA-Binding Activity of cGAS in Innate Antiviral Response

Frontiers in Immunology ◽

10.3389/fimmu.2021.741599 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yuying Ma ◽

Xiaohui Wang ◽

Weisheng Luo ◽

Ji Xiao ◽

Xiaowei Song ◽

...

Keyword(s):

Dna Binding ◽

Mammalian Cells ◽

Rna Binding ◽

Binding Protein ◽

Structural Similarity ◽

Antiviral Response ◽

Binding Activity ◽

Type I Interferons ◽

Type I ◽

Innate Antiviral Response

cGAS, a DNA sensor in mammalian cells, catalyzes the generation of 2’-3’-cyclic AMP-GMP (cGAMP) once activated by the binding of free DNA. cGAMP can bind to STING, activating downstream TBK1-IRF-3 signaling to initiate the expression of type I interferons. Although cGAS has been considered a traditional DNA-binding protein, several lines of evidence suggest that cGAS is a potential RNA-binding protein (RBP), which is mainly supported by its interactions with RNAs, RBP partners, RNA/cGAS-phase-separations as well as its structural similarity with the dsRNA recognition receptor 2’-5’ oligoadenylate synthase. Moreover, two influential studies reported that the cGAS-like receptors (cGLRs) of fly Drosophila melanogaster sense RNA and control 3′-2′-cGAMP signaling. In this review, we summarize and discuss in depth recent studies that identified or implied cGAS as an RBP. We also comprehensively summarized current experimental methods and computational tools that can identify or predict RNAs that bind to cGAS. Based on these discussions, we appeal that the RNA-binding activity of cGAS cannot be ignored in the cGAS-mediated innate antiviral response. It will be important to identify RNAs that can bind and regulate the activity of cGAS in cells with or without virus infection. Our review provides novel insight into the regulation of cGAS by its RNA-binding activity and extends beyond its DNA-binding activity. Our review would be significant for understanding the precise modulation of cGAS activity, providing the foundation for the future development of drugs against cGAS-triggering autoimmune diseases such as Aicardi-Gourtières syndrome.

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CryoEM structures of MDA5-dsRNA filaments at different stages of ATP hydrolysis

10.1101/376319 ◽

2018 ◽

Author(s):

Qin Yu ◽

Kun Qu ◽

Yorgo Modis

Keyword(s):

Rna Binding ◽

Atp Hydrolysis ◽

Type I ◽

List Type ◽

Base Pairs ◽

Nucleotide Analogs ◽

Double Stranded Rna ◽

Transition State Analogs ◽

Helical Twist ◽

Dsrna Binding

SummaryDouble-stranded RNA (dsRNA) is a potent proinflammatory signature of viral infection. Long cytosolic dsRNA is recognized by MDA5. The cooperative assembly of MDA5 into helical filaments on dsRNA nucleates the assembly of a multiprotein type-I-interferon signaling platform. Here, we determined cryoEM structures of MDA5-dsRNA filaments with different helical twists and bound nucleotide analogs, at resolutions sufficient to build and refine atomic models. The structures identify the filament forming interfaces, which encode the dsRNA binding cooperativity and length specificity of MDA5. The predominantly hydrophobic interface contacts confer flexibility, reflected in the variable helical twist within filaments. Mutation of filament-forming residues can result in loss or gain of signaling activity. Each MDA5 molecule spans 14 or 15 RNA base pairs, depending on the twist. Variations in twist also correlate with variations in the occupancy and type of nucleotide in the active site, providing insights on how ATP hydrolysis contributes to MDA5-dsRNA recognition.eTOCStructures of MDA5 bound to double-stranded RNA reveal a flexible, predominantly hydrophobic filament forming interface. The filaments have variable helical twist. Structures determined with ATP and transition state analogs show how the ATPase cycle is coupled to changes in helical twist, the mode of RNA binding and the length of the RNA footprint of MDA5.HighlightsCryoEM structures of MDA5-dsRNA filaments determined for three catalytic statesFilament forming interfaces are flexible and predominantly hydrophobicMutation of filament-forming residues can cause loss or gain of IFN-β signalingATPase cycle is coupled to changes in filament twist and size of the RNA footprint

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Safety and Transcriptome Analysis of Live Attenuated Brucella Vaccine Strain S2 on Non-pregnant Cynomolgus Monkeys Without Abortive Effect on Pregnant Cynomolgus Monkeys

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.641022 ◽

2021 ◽

Vol 8 ◽

Author(s):

Shijing Sun ◽

Hui Jiang ◽

Qiaoling Li ◽

Yufu Liu ◽

Qiang Gao ◽

...

Keyword(s):

Signaling Pathway ◽

Vaccine Strain ◽

Transcriptome Analysis ◽

Rna Binding ◽

Actin Binding ◽

Economic Losses ◽

Mammalian Host ◽

Type I ◽

Oligoadenylate Synthetase ◽

Cynomolgus Monkeys

Brucellosis, caused by Brucella spp., is an important zoonotic disease leading to enormous economic losses in livestock, posing a great threat to public health worldwide. The live attenuated Brucella suis (B. suis) strain S2, a safe and effective vaccine, is widely used in animals in China. However, S2 vaccination in animals may raise debates and concerns in terms of safety to primates, particularly humans. In this study, we used cynomolgus monkey as an animal model to evaluate the safety of the S2 vaccine strain on primates. In addition, we performed transcriptome analysis to determine gene expression profiling on cynomolgus monkeys immunized with the S2 vaccine. Our results suggested that the S2 vaccine was safe for cynomolgus monkeys. The transcriptome analysis identified 663 differentially expressed genes (DEGs), of which 348 were significantly upregulated and 315 were remarkably downregulated. The Gene Ontology (GO) classification and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that these DEGs were involved in various biological processes (BPs), including the chemokine signaling pathway, actin cytoskeleton regulation, the defense response, immune system processing, and the type-I interferon signaling pathway. The molecular functions of the DEGs were mainly comprised of 2'-5'-oligoadenylate synthetase activity, double-stranded RNA binding, and actin-binding. Moreover, the cellular components of these DEGs included integrin complex, myosin II complex, and blood microparticle. Our findings alleviate the concerns over the safety of the S2 vaccine on primates and provide a genetic basis for the response from a mammalian host following vaccination with the S2 vaccine.

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Hypogonadism associated withCyp19a1 (Aromatase) post-transcriptional upregulation inCelf1-KO mice

Molecular and Cellular Biology ◽

10.1128/mcb.00074-15 ◽

2015 ◽

pp. MCB.00074-15 ◽

Cited By ~ 2

Author(s):

Gaella Boulanger ◽

Marie Cibois ◽

Justine Viet ◽

Alexis Fostier ◽

Stéphane Deschamps ◽

...

Keyword(s):

Rna Binding ◽

Hypogonadotropic Hypogonadism ◽

Type I ◽

Male Gametes ◽

Low Concentrations ◽

Reporter Assays ◽

High Concentrations ◽

In Vitro Interaction

CELF1 is a multifunctional RNA-binding protein that controls several aspects of RNA fate. The targeted disruption of theCelf1gene in mice causes male infertility due to impaired spermiogenesis, the post-meiotic differentiation of male gametes. Here, we investigated the molecular reasons that underlie this testicular phenotype. By measuring sex hormone levels, we detected low concentrations of testosterone inCelf1-null mice. We investigated the effect ofCelf1disruption on the expression levels of steroidogenic enzyme genes, and we observed thatCyp19a1was upregulated.Cyp19a1encodes aromatase, which transforms testosterone into estradiol. Administration of testosterone or the aromatase inhibitor Letrozole partly rescued the spermiogenesis defects, indicating that a lack of testosterone associated with excessive aromatase contributes to the testicular phenotype. In vivo and in vitro interaction assays demonstrated that CELF1 binds toCyp19a1mRNA, and reporter assays supported the conclusion that CELF1 directly repressesCyp19a1translation. We conclude that CELF1 downregulatesCyp19a1/Aromatasepost-transcriptionally to achieve high concentrations of testosterone compatible with spermiogenesis completion. We discuss the implications of these findings with respect to reproductive defects in men, including patients suffering from isolated hypogonadotropic hypogonadism and myotonic dystrophy type I.

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Structural basis for recognition of human 7SK long noncoding RNA by the La-related protein Larp7

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1806276115 ◽

2018 ◽

Vol 115 (28) ◽

pp. E6457-E6466 ◽

Cited By ~ 20

Author(s):

Catherine D. Eichhorn ◽

Yuan Yang ◽

Lucas Repeta ◽

Juli Feigon

Keyword(s):

Noncoding Rna ◽

Rna Binding ◽

Rna Binding Proteins ◽

Transcription Elongation ◽

Structural Basis ◽

Titration Calorimetry ◽

Rna Recognition Motif ◽

Related Protein ◽

Binding Interface ◽

And Function

The La and the La-related protein (LARP) superfamily is a diverse class of RNA binding proteins involved in RNA processing, folding, and function. Larp7 binds to the abundant long noncoding 7SK RNA and is required for 7SK ribonucleoprotein (RNP) assembly and function. The 7SK RNP sequesters a pool of the positive transcription elongation factor b (P-TEFb) in an inactive state; on release, P-TEFb phosphorylates RNA Polymerase II to stimulate transcription elongation. Despite its essential role in transcription, limited structural information is available for the 7SK RNP, particularly for protein–RNA interactions. Larp7 contains an N-terminal La module that binds UUU-3′OH and a C-terminal atypical RNA recognition motif (xRRM) required for specific binding to 7SK and P-TEFb assembly. Deletion of the xRRM is linked to gastric cancer in humans. We report the 2.2-Å X-ray crystal structure of the human La-related protein group 7 (hLarp7) xRRM bound to the 7SK stem-loop 4, revealing a unique binding interface. Contributions of observed interactions to binding affinity were investigated by mutagenesis and isothermal titration calorimetry. NMR 13C spin relaxation data and comparison of free xRRM, RNA, and xRRM–RNA structures show that the xRRM is preordered to bind a flexible loop 4. Combining structures of the hLarp7 La module and the xRRM–7SK complex presented here, we propose a structural model for Larp7 binding to the 7SK 3′ end and mechanism for 7SK RNP assembly. This work provides insight into how this domain contributes to 7SK recognition and assembly of the core 7SK RNP.

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Further investigation of the characteristics and biological function of Eimeria tenella apical membrane antigen 1

Parasite ◽

10.1051/parasite/2020068 ◽

2020 ◽

Vol 27 ◽

pp. 70

Author(s):

Qingjie Wang ◽

Qiping Zhao ◽

Shunhai Zhu ◽

Bing Huang ◽

Shuilan Yu ◽

...

Keyword(s):

Rna Binding ◽

Apical Membrane ◽

Mapk Signaling ◽

Eimeria Tenella ◽

Host Cells ◽

Differentially Expressed ◽

Type I ◽

Dependent Manner ◽

Apical Membrane Antigen 1 ◽

Apical Membrane Antigen

Apical membrane antigen 1 (AMA1) is a type I integral membrane protein that is highly conserved in apicomplexan parasites. Previous studies have shown that Eimeria tenella AMA1 (EtAMA1) is critical for sporozoite invasion of host cells. Here, we show that EtAMA1 is a microneme protein secreted by sporozoites, confirming previous results. Individual and combined treatment with antibodies of EtAMA1 and its interacting proteins, E. tenella rhoptry neck protein 2 (EtRON2) and Eimeria-specific protein (EtESP), elicited significant anti-invasion effects on the parasite in a concentration-dependent manner. The overexpression of EtAMA1 in DF-1 cells showed a significant increase of sporozoite invasion. Isobaric tags for relative and absolute quantitation (iTRAQ) coupled with LC-MS/MS were used to screen differentially expressed proteins (DEPs) in DF-1 cells transiently transfected with EtAMA1. In total, 3953 distinct nonredundant proteins were identiﬁed and 163 of these were found to be differentially expressed, including 91 upregulated proteins and 72 downregulated proteins. The DEPs were mainly localized within the cytoplasm and were involved in protein binding and poly(A)-RNA binding. KEEG analyses suggested that the key pathways that the DEPs belonged to included melanogenesis, spliceosomes, tight junctions, and the FoxO and MAPK signaling pathways. The data in this study not only provide a comprehensive dataset for the overall protein changes caused by EtAMA1 expression, but also shed light on EtAMA1’s potential molecular mechanisms during Eimeria infections.

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