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1.
Life Sci Alliance ; 7(9)2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38955468

RESUMO

In addition to mitochondrial DNA, mitochondrial double-stranded RNA (mtdsRNA) is exported from mitochondria. However, specific channels for RNA transport have not been demonstrated. Here, we begin to characterize channel candidates for mtdsRNA export from the mitochondrial matrix to the cytosol. Down-regulation of SUV3 resulted in the accumulation of mtdsRNAs in the matrix, whereas down-regulation of PNPase resulted in the export of mtdsRNAs to the cytosol. Targeting experiments show that PNPase functions in both the intermembrane space and matrix. Strand-specific sequencing of the double-stranded RNA confirms the mitochondrial origin. Inhibiting or down-regulating outer membrane proteins VDAC1/2 and BAK/BAX or inner membrane proteins PHB1/2 strongly attenuated the export of mtdsRNAs to the cytosol. The cytosolic mtdsRNAs subsequently localized to large granules containing the stress protein TIA-1 and activated the type 1 interferon stress response pathway. Abundant mtdsRNAs were detected in a subset of non-small-cell lung cancer cell lines that were glycolytic, indicating relevance in cancer biology. Thus, we propose that mtdsRNA is a new damage-associated molecular pattern that is exported from mitochondria in a regulated manner.


Assuntos
Citosol , Mitocôndrias , Proibitinas , RNA de Cadeia Dupla , RNA Mitocondrial , Humanos , Citosol/metabolismo , Mitocôndrias/metabolismo , RNA de Cadeia Dupla/metabolismo , RNA Mitocondrial/metabolismo , RNA Mitocondrial/genética , Linhagem Celular Tumoral , Proteínas Repressoras/metabolismo , Proteínas Repressoras/genética , Transporte de RNA , Exorribonucleases/metabolismo , Exorribonucleases/genética , Canal de Ânion 1 Dependente de Voltagem/metabolismo , Canal de Ânion 1 Dependente de Voltagem/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Proteínas Mitocondriais
2.
Biol Lett ; 20(7): 20240147, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38982851

RESUMO

The nucleus interacts with the other organelles to perform essential functions of the eukaryotic cell. Mitochondria have their own genome and communicate back to the nucleus in what is known as mitochondrial retrograde response. Information is transferred to the nucleus in many ways, leading to wide-ranging changes in nuclear gene expression and culminating with changes in metabolic, regulatory or stress-related pathways. RNAs are emerging molecules involved in this signalling. RNAs encode precise information and are involved in highly target-specific signalling, through a wide range of processes known as RNA interference. RNA-mediated mitochondrial retrograde response requires these molecules to exit the mitochondrion, a process that is still mostly unknown. We suggest that the proteins/complexes translocases of the inner membrane, polynucleotide phosphorylase, mitochondrial permeability transition pore, and the subunits of oxidative phosphorylation complexes may be responsible for RNA export.


Assuntos
Núcleo Celular , Mitocôndrias , Mitocôndrias/metabolismo , Núcleo Celular/metabolismo , RNA/metabolismo , RNA/genética , Animais , Transporte de RNA , Células Eucarióticas/metabolismo , Eucariotos/metabolismo , Eucariotos/genética , Eucariotos/fisiologia , Transdução de Sinais
3.
Nature ; 631(8020): 432-438, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38898279

RESUMO

When mRNAs have been transcribed and processed in the nucleus, they are exported to the cytoplasm for translation. This export is mediated by the export receptor heterodimer Mex67-Mtr2 in the yeast Saccharomyces cerevisiae (TAP-p15 in humans)1,2. Interestingly, many long non-coding RNAs (lncRNAs) also leave the nucleus but it is currently unclear why they move to the cytoplasm3. Here we show that antisense RNAs (asRNAs) accelerate mRNA export by annealing with their sense counterparts through the helicase Dbp2. These double-stranded RNAs (dsRNAs) dominate export compared with single-stranded RNAs (ssRNAs) because they have a higher capacity and affinity for the export receptor Mex67. In this way, asRNAs boost gene expression, which is beneficial for cells. This is particularly important when the expression program changes. Consequently, the degradation of dsRNA, or the prevention of its formation, is toxic for cells. This mechanism illuminates the general cellular occurrence of asRNAs and explains their nuclear export.


Assuntos
Transporte Ativo do Núcleo Celular , Núcleo Celular , Proteínas de Transporte Nucleocitoplasmático , RNA Antissenso , RNA de Cadeia Dupla , RNA Mensageiro , Proteínas de Ligação a RNA , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , RNA de Cadeia Dupla/metabolismo , RNA de Cadeia Dupla/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Núcleo Celular/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Proteínas de Transporte Nucleocitoplasmático/genética , RNA Antissenso/metabolismo , RNA Antissenso/genética , RNA Helicases DEAD-box/metabolismo , RNA Helicases DEAD-box/genética , Regulação Fúngica da Expressão Gênica , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Transporte de RNA , Citoplasma/metabolismo
4.
Nucleus ; 15(1): 2360196, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38880976

RESUMO

The eukaryotic translation initiation factor eIF4E acts as a multifunctional factor that simultaneously influences mRNA processing, export, and translation in many organisms. Its multifactorial effects are derived from its capacity to bind to the methyl-7-guanosine cap on the 5'end of mRNAs and thus can act as a cap chaperone for transcripts in the nucleus and cytoplasm. In this review, we describe the multifactorial roles of eIF4E in major mRNA-processing events including capping, splicing, cleavage and polyadenylation, nuclear export and translation. We discuss the evidence that eIF4E acts at two levels to generate widescale changes to processing, export and ultimately the protein produced. First, eIF4E alters the production of components of the mRNA processing machinery, supporting a widescale reprogramming of multiple mRNA processing events. In this way, eIF4E can modulate mRNA processing without physically interacting with target transcripts. Second, eIF4E also physically interacts with both capped mRNAs and components of the RNA processing or translation machineries. Further, specific mRNAs are sensitive to eIF4E only in particular mRNA processing events. This selectivity is governed by the presence of cis-acting elements within mRNAs known as USER codes that recruit relevant co-factors engaging the appropriate machinery. In all, we describe the molecular bases for eIF4E's multifactorial function and relevant regulatory pathways, discuss the basis for selectivity, present a compendium of ~80 eIF4E-interacting factors which play roles in these activities and provide an overview of the relevance of its functions to its oncogenic potential. Finally, we summarize early-stage clinical studies targeting eIF4E in cancer.


Assuntos
Fator de Iniciação 4E em Eucariotos , Biossíntese de Proteínas , RNA Mensageiro , Humanos , Fator de Iniciação 4E em Eucariotos/metabolismo , Fator de Iniciação 4E em Eucariotos/genética , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Animais , Transporte de RNA , Processamento Pós-Transcricional do RNA
5.
Cell Res ; 34(7): 504-521, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38811766

RESUMO

Bidirectional transcription of mammalian mitochondrial DNA generates overlapping transcripts that are capable of forming double-stranded RNA (dsRNA) structures. Release of mitochondrial dsRNA into the cytosol activates the dsRNA-sensing immune signaling, which is a defense mechanism against microbial and viral attack and possibly cancer, but could cause autoimmune diseases when unchecked. A better understanding of the process is vital in therapeutic application of this defense mechanism and treatment of cognate human diseases. In addition to exporting dsRNAs, mitochondria also export and import a variety of non-coding RNAs. However, little is known about how these RNAs are transported across mitochondrial membranes. Here we provide direct evidence showing that adenine nucleotide translocase-2 (ANT2) functions as a mammalian RNA translocon in the mitochondrial inner membrane, independent of its ADP/ATP translocase activity. We also show that mitochondrial dsRNA efflux through ANT2 triggers innate immunity. Inhibiting this process alleviates inflammation in vivo, providing a potential therapeutic approach for treating autoimmune diseases.


Assuntos
Translocador 2 do Nucleotídeo Adenina , Mitocôndrias , Membranas Mitocondriais , RNA de Cadeia Dupla , Animais , Translocador 2 do Nucleotídeo Adenina/metabolismo , Translocador 2 do Nucleotídeo Adenina/genética , Humanos , RNA de Cadeia Dupla/metabolismo , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Camundongos , Imunidade Inata , Transporte de RNA , Células HEK293 , Camundongos Endogâmicos C57BL
6.
PLoS Pathog ; 20(5): e1012231, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38753876

RESUMO

Utilisation of RNA-binding proteins (RBPs) is an important aspect of post-transcriptional regulation of viral RNA. Viruses such as influenza A viruses (IAV) interact with RBPs to regulate processes including splicing, nuclear export and trafficking, while also encoding RBPs within their genomes, such as NP and NS1. But with almost 1000 RBPs encoded within the human genome it is still unclear what role, if any, many of these proteins play during viral replication. Using the RNA interactome capture (RIC) technique, we isolated RBPs from IAV infected cells to unravel the RBPome of mRNAs from IAV infected human cells. This led to the identification of one particular RBP, MKRN2, that associates with and positively regulates IAV mRNA. Through further validation, we determined that MKRN2 is involved in the nuclear-cytoplasmic trafficking of IAV mRNA potentially through an association with the RNA export mediator GLE1. In the absence of MKRN2, IAV mRNAs accumulate in the nucleus of infected cells, which may lead to their degradation by the nuclear RNA exosome complex. MKRN2, therefore, appears to be required for the efficient nuclear export of IAV mRNAs in human cells.


Assuntos
Vírus da Influenza A , Influenza Humana , RNA Mensageiro , RNA Viral , Proteínas de Ligação a RNA , Animais , Humanos , Transporte Ativo do Núcleo Celular , Núcleo Celular/metabolismo , Núcleo Celular/virologia , Vírus da Influenza A/genética , Influenza Humana/metabolismo , Influenza Humana/virologia , Influenza Humana/genética , Transporte de RNA , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , RNA Viral/metabolismo , RNA Viral/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Replicação Viral
7.
Curr Opin Plant Biol ; 79: 102541, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38663258

RESUMO

Messenger RNAs (mRNAs) are the templates for protein translation but can also act as non-cell-autonomous signaling molecules. Plants input endogenous and exogenous cues to mobile mRNAs and output them to local or systemic target cells and organs to support specific plant responses. Mobile mRNAs form ribonucleoprotein (RNP) complexes with proteins during transport. Components of these RNP complexes could interact with plasmodesmata (PDs), a major mediator of mRNA transport, to ensure mRNA mobility and transport selectivity. Based on advances in the last two to three years, this review summarizes mRNA transport mechanisms in local and systemic signaling from the perspective of RNP complex formation and PD transport. We also discuss the physiological roles of endogenous mRNA transport and the recently revealed roles of non-cell-autonomous mRNAs in inter-organism communication.


Assuntos
Plasmodesmos , RNA Mensageiro , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Plasmodesmos/metabolismo , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/genética , RNA de Plantas/metabolismo , RNA de Plantas/genética , Transporte de RNA , Plantas/metabolismo , Plantas/genética , Transdução de Sinais , Comunicação Celular
8.
New Phytol ; 243(1): 180-194, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38650347

RESUMO

Transcription and export (TREX) is a multi-subunit complex that links synthesis, processing and export of mRNAs. It interacts with the RNA helicase UAP56 and export factors such as MOS11 and ALYs to facilitate nucleocytosolic transport of mRNAs. Plant MOS11 is a conserved, but sparsely researched RNA-binding export factor, related to yeast Tho1 and mammalian CIP29/SARNP. Using biochemical approaches, the domains of Arabidopsis thaliana MOS11 required for interaction with UAP56 and RNA-binding were identified. Further analyses revealed marked genetic interactions between MOS11 and ALY genes. Cell fractionation in combination with transcript profiling demonstrated that MOS11 is required for export of a subset of mRNAs that are shorter and more GC-rich than MOS11-independent transcripts. The central α-helical domain of MOS11 proved essential for physical interaction with UAP56 and for RNA-binding. MOS11 is involved in the nucleocytosolic transport of mRNAs that are upregulated under stress conditions and accordingly mos11 mutant plants turned out to be sensitive to elevated NaCl concentrations and heat stress. Collectively, our analyses identify functional interaction domains of MOS11. In addition, the results establish that mRNA export is critically involved in the plant response to stress conditions and that MOS11 plays a prominent role at this.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Regulação da Expressão Gênica de Plantas , RNA Mensageiro , Proteínas de Ligação a RNA , Estresse Fisiológico , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/fisiologia , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Estresse Fisiológico/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Ligação Proteica , Mutação/genética , Transporte de RNA , Domínios Proteicos
9.
Nat Neurosci ; 27(6): 1087-1102, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38600167

RESUMO

In neurons, RNA granules are transported along the axon for local translation away from the soma. Recent studies indicate that some of this transport involves hitchhiking of RNA granules on lysosome-related vesicles. In the present study, we leveraged the ability to prevent transport of these vesicles into the axon by knockout of the lysosome-kinesin adaptor BLOC-one-related complex (BORC) to identify a subset of axonal mRNAs that depend on lysosome-related vesicles for transport. We found that BORC knockout causes depletion of a large group of axonal mRNAs mainly encoding ribosomal and mitochondrial/oxidative phosphorylation proteins. This depletion results in mitochondrial defects and eventually leads to axonal degeneration in human induced pluripotent stem cell (iPSC)-derived and mouse neurons. Pathway analyses of the depleted mRNAs revealed a mechanistic connection of BORC deficiency with common neurodegenerative disorders. These results demonstrate that mRNA transport on lysosome-related vesicles is critical for the maintenance of axonal homeostasis and that its failure causes axonal degeneration.


Assuntos
Axônios , Homeostase , Lisossomos , Mitocôndrias , RNA Mensageiro , Animais , Mitocôndrias/metabolismo , Lisossomos/metabolismo , Axônios/metabolismo , Camundongos , RNA Mensageiro/metabolismo , Homeostase/fisiologia , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Degeneração Neural/genética , Transporte Axonal/fisiologia , Camundongos Knockout , Neurônios/metabolismo , Transporte de RNA
10.
J Biol Chem ; 300(5): 107258, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38582448

RESUMO

Mitochondria are membrane-bound organelles of endosymbiotic origin with limited protein-coding capacity. The import of nuclear-encoded proteins and nucleic acids is required and essential for maintaining organelle mass, number, and activity. As plant mitochondria do not encode all the necessary tRNA types required, the import of cytosolic tRNA is vital for organelle maintenance. Recently, two mitochondrial outer membrane proteins, named Tric1 and Tric2, for tRNA import component, were shown to be involved in the import of cytosolic tRNA. Tric1/2 binds tRNAalavia conserved residues in the C-terminal Sterile Alpha Motif (SAM) domain. Here we report the X-ray crystal structure of the Tric1 SAM domain. We identified the ability of the SAM domain to form a helical superstructure with six monomers per helical turn and key amino acid residues responsible for its formation. We determined that the oligomerization of the Tric1 SAM domain may play a role in protein function whereby mutation of Gly241 introducing a larger side chain at this position disrupted the oligomer and resulted in the loss of RNA binding capability. Furthermore, complementation of Arabidopsis thaliana Tric1/2 knockout lines with a mutated Tric1 failed to restore the defective plant phenotype. AlphaFold2 structure prediction of both the SAM domain and Tric1 support a cyclic pentameric or hexameric structure. In the case of a hexameric structure, a pore of sufficient dimensions to transfer tRNA across the mitochondrial membrane is observed. Our results highlight the importance of oligomerization of Tric1 for protein function.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas Mitocondriais , Domínios Proteicos , RNA de Transferência , Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Cristalografia por Raios X , Mitocôndrias/metabolismo , Mitocôndrias/genética , Proteínas Mitocondriais/metabolismo , Proteínas Mitocondriais/química , Proteínas Mitocondriais/genética , Transporte de RNA , RNA de Transferência/metabolismo , RNA de Transferência/química , RNA de Transferência/genética
11.
RNA ; 30(6): 597-608, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38448244

RESUMO

The mammalian mitochondrial proteome comprises over 1000 proteins, with the majority translated from nuclear-encoded messenger RNAs (mRNAs). Mounting evidence suggests many of these mRNAs are localized to the outer mitochondrial membrane (OMM) in a pre- or cotranslational state. Upon reaching the mitochondrial surface, these mRNAs are locally translated to produce proteins that are cotranslationally imported into mitochondria. Here, we summarize various mechanisms cells use to localize RNAs, including transfer RNAs (tRNAs), to the OMM and recent technological advancements in the field to study these processes. While most early studies in the field were carried out in yeast, recent studies reveal RNA localization to the OMM and their regulation in higher organisms. Various factors regulate this localization process, including RNA sequence elements, RNA-binding proteins (RBPs), cytoskeletal motors, and translation machinery. In this review, we also highlight the role of RNA structures and modifications in mitochondrial RNA localization and discuss how these features can alter the binding properties of RNAs. Finally, in addition to RNAs related to mitochondrial function, RNAs involved in other cellular processes can also localize to the OMM, including those implicated in the innate immune response and piRNA biogenesis. As impairment of messenger RNA (mRNA) localization and regulation compromise mitochondrial function, future studies will undoubtedly expand our understanding of how RNAs localize to the OMM and investigate the consequences of their mislocalization in disorders, particularly neurodegenerative diseases, muscular dystrophies, and cancers.


Assuntos
Mitocôndrias , Membranas Mitocondriais , RNA Mitocondrial , Mitocôndrias/metabolismo , Mitocôndrias/genética , Humanos , Animais , Membranas Mitocondriais/metabolismo , RNA Mitocondrial/metabolismo , RNA Mitocondrial/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA/metabolismo , RNA/genética , Transporte de RNA , RNA de Transferência/genética , RNA de Transferência/metabolismo , Biossíntese de Proteínas , Proteínas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética
12.
J Biol Chem ; 300(4): 107170, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38492777

RESUMO

Intercellular miRNA exchange acts as a key mechanism to control gene expression post-transcriptionally in mammalian cells. Regulated export of repressive miRNAs allows the expression of inflammatory cytokines in activated macrophages. Intracellular trafficking of miRNAs from the endoplasmic reticulum to endosomes is a rate-determining step in the miRNA export process and plays an important role in controlling cellular miRNA levels and inflammatory processes in macrophages. We have identified the SNARE protein Syntaxin 5 (STX5) to show a synchronized expression pattern with miRNA activity loss in activated mammalian macrophage cells. STX5 is both necessary and sufficient for macrophage activation and clearance of the intracellular pathogen Leishmania donovani from infected macrophages. Exploring the mechanism of how STX5 acts as an immunostimulant, we have identified the de novo RNA-binding property of this SNARE protein that binds specific miRNAs and facilitates their accumulation in endosomes in a cooperative manner with human ELAVL1 protein, Human antigen R. This activity ensures the export of miRNAs and allows the expression of miRNA-repressed cytokines. Conversely, in its dual role in miRNA export, this SNARE protein prevents lysosomal targeting of endosomes by enhancing the fusion of miRNA-loaded endosomes with the plasma membrane to ensure accelerated release of extracellular vesicles and associated miRNAs.


Assuntos
Proteína Semelhante a ELAV 1 , Macrófagos , MicroRNAs , Proteínas Qa-SNARE , Animais , Humanos , Camundongos , Endossomos/metabolismo , Leishmania donovani/metabolismo , Leishmania donovani/genética , Ativação de Macrófagos , Macrófagos/metabolismo , MicroRNAs/metabolismo , MicroRNAs/genética , Proteínas Qa-SNARE/metabolismo , Proteínas Qa-SNARE/genética , Transporte de RNA , Proteína Semelhante a ELAV 1/metabolismo
13.
Nat Commun ; 15(1): 1640, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38388531

RESUMO

THOC6 variants are the genetic basis of autosomal recessive THOC6 Intellectual Disability Syndrome (TIDS). THOC6 is critical for mammalian Transcription Export complex (TREX) tetramer formation, which is composed of four six-subunit THO monomers. The TREX tetramer facilitates mammalian RNA processing, in addition to the nuclear mRNA export functions of the TREX dimer conserved through yeast. Human and mouse TIDS model systems revealed novel THOC6-dependent, species-specific TREX tetramer functions. Germline biallelic Thoc6 loss-of-function (LOF) variants result in mouse embryonic lethality. Biallelic THOC6 LOF variants reduce the binding affinity of ALYREF to THOC5 without affecting the protein expression of TREX members, implicating impaired TREX tetramer formation. Defects in RNA nuclear export functions were not detected in biallelic THOC6 LOF human neural cells. Instead, mis-splicing was detected in human and mouse neural tissue, revealing novel THOC6-mediated TREX coordination of mRNA processing. We demonstrate that THOC6 is required for key signaling pathways known to regulate the transition from proliferative to neurogenic divisions during human corticogenesis. Together, these findings implicate altered RNA processing in the developmental biology of TIDS neuropathology.


Assuntos
Deficiência Intelectual , RNA , Estilbenos , Ácidos Sulfônicos , Humanos , Animais , Camundongos , RNA/metabolismo , Deficiência Intelectual/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Processamento Pós-Transcricional do RNA , Transporte de RNA , Mamíferos/genética , Proteínas Nucleares/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo
14.
Nature ; 627(8002): 212-220, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38355801

RESUMO

Circular RNAs (circRNAs), which are increasingly being implicated in a variety of functions in normal and cancerous cells1-5, are formed by back-splicing of precursor mRNAs in the nucleus6-10. circRNAs are predominantly localized in the cytoplasm, indicating that they must be exported from the nucleus. Here we identify a pathway that is specific for the nuclear export of circular RNA. This pathway requires Ran-GTP, exportin-2 and IGF2BP1. Enhancing the nuclear Ran-GTP gradient by depletion or chemical inhibition of the major protein exporter CRM1 selectively increases the nuclear export of circRNAs, while reducing the nuclear Ran-GTP gradient selectively blocks circRNA export. Depletion or knockout of exportin-2 specifically inhibits nuclear export of circRNA. Analysis of nuclear circRNA-binding proteins reveals that interaction between IGF2BP1 and circRNA is enhanced by Ran-GTP. The formation of circRNA export complexes in the nucleus is promoted by Ran-GTP through its interactions with exportin-2, circRNA and IGF2BP1. Our findings demonstrate that adaptors such as IGF2BP1 that bind directly to circular RNAs recruit Ran-GTP and exportin-2 to export circRNAs in a mechanism that is analogous to protein export, rather than mRNA export.


Assuntos
Transporte Ativo do Núcleo Celular , Núcleo Celular , Transporte de RNA , RNA Circular , Transporte Ativo do Núcleo Celular/fisiologia , Núcleo Celular/metabolismo , Guanosina Trifosfato/metabolismo , Carioferinas/antagonistas & inibidores , Carioferinas/deficiência , Carioferinas/genética , Carioferinas/metabolismo , Proteínas Nucleares/metabolismo , Proteína ran de Ligação ao GTP/metabolismo , RNA Circular/metabolismo , Precursores de RNA/genética , Precursores de RNA/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteína Exportina 1/metabolismo , Transporte Proteico
15.
Nat Commun ; 15(1): 455, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38225262

RESUMO

mRNA export is an essential pathway for the regulation of gene expression. In humans, closely related RNA helicases, UAP56 and URH49, shape selective mRNA export pathways through the formation of distinct complexes, known as apo-TREX and apo-AREX complexes, and their subsequent remodeling into similar ATP-bound complexes. Therefore, defining the unidentified components of the apo-AREX complex and elucidating the molecular mechanisms underlying the formation of distinct apo-complexes is key to understanding their functional divergence. In this study, we identify additional apo-AREX components physically and functionally associated with URH49. Furthermore, by comparing the structures of UAP56 and URH49 and performing an integrated analysis of their chimeric mutants, we exhibit unique structural features that would contribute to the formation of their respective complexes. This study provides insights into the specific structural and functional diversification of these two helicases that diverged from the common ancestral gene Sub2.


Assuntos
RNA Helicases DEAD-box , RNA Helicases , Humanos , Transporte Ativo do Núcleo Celular , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , RNA Helicases/metabolismo , Transporte de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
16.
Trends Cell Biol ; 34(1): 48-57, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37380581

RESUMO

Messenger RNAs (mRNAs) in multicellular organisms can act as signals transported cell-to-cell and over long distances. In plants, mRNAs traffic cell-to-cell via plasmodesmata (PDs) and over long distances via the phloem vascular system to control diverse biological processes - such as cell fate and tissue patterning - in destination organs. Research on long-distance transport of mRNAs in plants has made remarkable progress, including the cataloguing of many mobile mRNAs, characterization of mRNA features important for transport, identification of mRNA-binding proteins involved in their transport, and understanding of the physiological roles of mRNA transport. However, information on short-range mRNA cell-to-cell transport is still limited. This review discusses the regulatory mechanisms and physiological functions of mRNA transport at the cellular and whole plant levels.


Assuntos
Plantas , Transporte de RNA , Humanos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Plantas/genética , Plantas/metabolismo , Comunicação Celular , Floema/genética , Floema/metabolismo
18.
RNA Biol ; 21(1): 1-12, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38091265

RESUMO

The division of the cellular space into nucleoplasm and cytoplasm promotes quality control mechanisms that prevent misprocessed mRNAs and junk RNAs from gaining access to the translational machinery. Here, we explore how properly processed mRNAs are distinguished from both misprocessed mRNAs and junk RNAs by the presence or absence of various 'identity features'.


Assuntos
Núcleo Celular , Splicing de RNA , Transporte Ativo do Núcleo Celular , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Núcleo Celular/genética , Núcleo Celular/metabolismo , Transporte de RNA , RNA não Traduzido/metabolismo
19.
Sci Rep ; 13(1): 14588, 2023 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-37666846

RESUMO

Alzheimer's disease (AD) is the most prevalent form of dementia, and it displays both clinical and molecular variability. RNA N6-methyladenosine (m6A) regulators are involved in a wide range of essential cellular processes. In this study, we aimed to identify molecular signatures associated with m6A in Alzheimer's disease and use those signatures to develop a predictive model. We examined the expression patterns of m6A regulators and immune features in Alzheimer's disease using the GSE33000 dataset. We examined the immune cell infiltration and molecular groups based on m6A-related genes in 310 Alzheimer's disease samples. The WGCNA algorithm was utilized to determine differently expressed genes within each cluster. After evaluating the strengths and weaknesses of the random forest model, the support vector machine model, the generalized linear model, and eXtreme Gradient Boosting, the best machine model was selected. Methods such as nomograms, calibration curves, judgment curve analysis, and the use of independent data sets were used to verify the accuracy of the predictions made. Alzheimer's disease and non-disease Alzheimer's groups were compared to identify dysregulated m6A-related genes and activated immune responses. In Alzheimer's disease, two molecular clusters linked to m6A were identified. Immune infiltration analysis indicated substantial variation in protection between groups. Cluster 1 included processes like the Toll-like receptor signaling cascade, positive regulation of chromatin binding, and numerous malignancies; cluster 2 included processes like the cell cycle, mRNA transport, and ubiquitin-mediated proteolysis. With a lower residual and root mean square error and a larger area under the curve (AUC = 0.951), the Random forest machine model showed the greatest discriminative performance. The resulting random forest model was based on five genes, and it performed well (AUC = 0.894) on external validation datasets. Accuracy in predicting Alzheimer's disease subgroups was also shown by analyses of nomograms, calibration curves, and decision curves. In this research, we methodically outlined the tangled web of connections between m6A and AD and created a promising prediction model for gauging the correlation between m6A subtype risk and AD pathology.


Assuntos
Doença de Alzheimer , RNA , Humanos , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/genética , Transporte de RNA , Adenosina/genética
20.
RNA ; 29(12): 1870-1880, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37699651

RESUMO

The conserved TREX complex has multiple functions in gene expression such as transcription elongation, 3' end processing, mRNP assembly and nuclear mRNA export as well as the maintenance of genomic stability. In Saccharomyces cerevisiae, TREX is composed of the pentameric THO complex, the DEAD-box RNA helicase Sub2, the nuclear mRNA export adaptor Yra1, and the SR-like proteins Gbp2 and Hrb1. Here, we present the structural analysis of the endogenous TREX complex of S. cerevisiae purified from its native environment. To this end, we used cross-linking mass spectrometry to gain structural information on regions of the complex that are not accessible to classical structural biology techniques. We also used negative-stain electron microscopy to investigate the organization of the cross-linked complex used for XL-MS by comparing our endogenous TREX complex with recently published structural models of recombinant THO-Sub2 complexes. According to our analysis, the endogenous yeast TREX complex preferentially assembles into a dimer.


Assuntos
Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , RNA Mensageiro/genética , Transporte de RNA , Transcrição Gênica , Proteínas de Transporte Nucleocitoplasmático/genética , Proteínas de Ligação a Poli(A)/genética
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