RESUMO
DEAD- and DExH-box ATPases (DDX/DHXs) are abundant and highly conserved cellular enzymes ubiquitously involved in RNA processing. By remodeling RNA-RNA and RNA-protein interactions, they often function as gatekeepers that control the progression of diverse RNA maturation steps. Intriguingly, most DDX/DHXs localize to membraneless organelles (MLOs) such as nucleoli, nuclear speckles, stress granules, or processing bodies. Recent findings suggest not only that localization to MLOs can promote interaction between DDX/DHXs and their targets but also that DDX/DHXs are key regulators of MLO formation and turnover through their condensation and ATPase activity.In this review, we describe the molecular function of DDX/DHXs in ribosome biogenesis, messenger RNA splicing, export, translation, and storage or decay as well as their association with prominent MLOs. We discuss how the enzymatic function of DDX/DHXs in RNA processing is linked to DDX/DHX condensation, the accumulation of ribonucleoprotein particles and MLO dynamics. Future research will reveal how these processes orchestrate the RNA life cycle in MLO space and DDX/DHX time.
Assuntos
RNA Helicases DEAD-box , RNA Helicases DEAD-box/metabolismo , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/química , Humanos , Animais , RNA/metabolismo , RNA/genética , RNA/química , Splicing de RNA , Organelas/metabolismo , Organelas/genética , Ribossomos/metabolismo , Ribossomos/genética , Dobramento de RNA , Processamento Pós-Transcricional do RNA , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/genética , Nucléolo Celular/metabolismo , Nucléolo Celular/genética , RNA Mensageiro/metabolismo , RNA Mensageiro/genéticaRESUMO
Methylation of RNA nucleotides represents an important layer of gene expression regulation, and perturbation of the RNA methylome is associated with pathophysiology. In cells, RNA methylations are installed by RNA methyltransferases (RNMTs) that are specialized to catalyze particular types of methylation (ribose or different base positions). Furthermore, RNMTs must specifically recognize their appropriate target RNAs within the RNA-dense cellular environment. Some RNMTs are catalytically active alone and achieve target specificity via recognition of sequence motifs and/or RNA structures. Others function together with protein cofactors that can influence stability, S-adenosyl-L-methionine binding, and RNA affinity as well as aiding specific recruitment and catalytic activity. Association of RNMTs with guide RNAs represents an alternative mechanism to direct site-specific methylation by an RNMT that lacks intrinsic specificity. Recently, ribozyme-catalyzed methylation of RNA has been achieved in vitro, and here, we compare these different strategies for RNA methylation from structural and mechanistic perspectives.
Assuntos
Conformação de Ácido Nucleico , RNA Catalítico , RNA , RNA Catalítico/metabolismo , RNA Catalítico/química , RNA Catalítico/genética , Metilação , RNA/metabolismo , RNA/genética , RNA/química , Humanos , S-Adenosilmetionina/metabolismo , S-Adenosilmetionina/química , Nucleotídeos/metabolismo , Nucleotídeos/química , Nucleotídeos/genética , tRNA Metiltransferases/metabolismo , tRNA Metiltransferases/genética , tRNA Metiltransferases/química , Especificidade por Substrato , Animais , Modelos MolecularesRESUMO
RNAs localizing to the outer cell surface have been recently identified in mammalian cells, including RNAs with glycan modifications known as glycoRNAs. However, the functional significance of cell surface RNAs and their production are poorly known. We report that cell surface RNAs are critical for neutrophil recruitment and that the mammalian homologs of the sid-1 RNA transporter are required for glycoRNA expression. Cell surface RNAs can be readily detected in murine neutrophils, the elimination of which substantially impairs neutrophil recruitment to inflammatory sites in vivo and reduces neutrophils' adhesion to and migration through endothelial cells. Neutrophil glycoRNAs are predominantly on cell surface, important for neutrophil-endothelial interactions, and can be recognized by P-selectin (Selp). Knockdown of the murine Sidt genes abolishes neutrophil glycoRNAs and functionally mimics the loss of cell surface RNAs. Our data demonstrate the biological importance of cell surface glycoRNAs and highlight a noncanonical dimension of RNA-mediated cellular functions.
Assuntos
Células Endoteliais , Infiltração de Neutrófilos , Neutrófilos , RNA , Animais , Camundongos , Células Endoteliais/metabolismo , Neutrófilos/metabolismo , RNA/química , RNA/metabolismo , Proteínas de Transporte de Nucleotídeos/genética , Proteínas de Transporte de Nucleotídeos/metabolismoRESUMO
Cancer immunotherapy remains limited by poor antigenicity and a regulatory tumor microenvironment (TME). Here, we create "onion-like" multi-lamellar RNA lipid particle aggregates (LPAs) to substantially enhance the payload packaging and immunogenicity of tumor mRNA antigens. Unlike current mRNA vaccine designs that rely on payload packaging into nanoparticle cores for Toll-like receptor engagement in immune cells, systemically administered RNA-LPAs activate RIG-I in stromal cells, eliciting massive cytokine/chemokine response and dendritic cell/lymphocyte trafficking that provokes cancer immunogenicity and mediates rejection of both early- and late-stage murine tumor models. In client-owned canines with terminal gliomas, RNA-LPAs improved survivorship and reprogrammed the TME, which became "hot" within days of a single infusion. In a first-in-human trial, RNA-LPAs elicited rapid cytokine/chemokine release, immune activation/trafficking, tissue-confirmed pseudoprogression, and glioma-specific immune responses in glioblastoma patients. These data support RNA-LPAs as a new technology that simultaneously reprograms the TME while eliciting rapid and enduring cancer immunotherapy.
Assuntos
Imunoterapia , Lipídeos , RNA , Microambiente Tumoral , Animais , Cães , Feminino , Humanos , Camundongos , Antígenos de Neoplasias/imunologia , Neoplasias Encefálicas/terapia , Neoplasias Encefálicas/imunologia , Vacinas Anticâncer/imunologia , Vacinas Anticâncer/uso terapêutico , Linhagem Celular Tumoral , Citocinas/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Glioblastoma/terapia , Glioblastoma/imunologia , Glioma/terapia , Glioma/imunologia , Imunoterapia/métodos , Camundongos Endogâmicos C57BL , Neoplasias/terapia , Neoplasias/imunologia , RNA/química , RNA/uso terapêutico , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Lipídeos/químicaRESUMO
End resection in homologous recombination (HR) and HR-mediated repair of DNA double-strand breaks (DSBs) removes several kilobases from 5' strands of DSBs, but 3' strands are exempted from degradation. The mechanism by which the 3' overhangs are protected has not been determined. Here, we established that the protection of 3' overhangs is achieved through the transient formation of RNA-DNA hybrids. The DNA strand in the hybrids is the 3' ssDNA overhang, while the RNA strand is newly synthesized. RNA polymerase III (RNAPIII) is responsible for synthesizing the RNA strand. Furthermore, RNAPIII is actively recruited to DSBs by the MRN complex. CtIP and MRN nuclease activity is required for initiating the RNAPIII-mediated RNA synthesis at DSBs. A reduced level of RNAPIII suppressed HR, and genetic loss > 30 bp increased at DSBs. Thus, RNAPIII is an essential HR factor, and the RNA-DNA hybrid is an essential repair intermediate for protecting the 3' overhangs in DSB repair.
Assuntos
RNA Polimerase III/metabolismo , Reparo de DNA por Recombinação , Ciclo Celular , Linhagem Celular Tumoral , Quebras de DNA de Cadeia Dupla , Endodesoxirribonucleases/genética , Células HEK293 , Humanos , Proteína Homóloga a MRE11/metabolismo , Complexos Multiproteicos/química , Complexos Multiproteicos/metabolismo , Hibridização de Ácido Nucleico , RNA/químicaRESUMO
Glycans modify lipids and proteins to mediate inter- and intramolecular interactions across all domains of life. RNA is not thought to be a major target of glycosylation. Here, we challenge this view with evidence that mammals use RNA as a third scaffold for glycosylation. Using a battery of chemical and biochemical approaches, we found that conserved small noncoding RNAs bear sialylated glycans. These "glycoRNAs" were present in multiple cell types and mammalian species, in cultured cells, and in vivo. GlycoRNA assembly depends on canonical N-glycan biosynthetic machinery and results in structures enriched in sialic acid and fucose. Analysis of living cells revealed that the majority of glycoRNAs were present on the cell surface and can interact with anti-dsRNA antibodies and members of the Siglec receptor family. Collectively, these findings suggest the existence of a direct interface between RNA biology and glycobiology, and an expanded role for RNA in extracellular biology.
Assuntos
Membrana Celular/metabolismo , Polissacarídeos/metabolismo , RNA/metabolismo , Animais , Anticorpos/metabolismo , Sequência de Bases , Vias Biossintéticas , Linhagem Celular , Sobrevivência Celular , Humanos , Espectrometria de Massas , Ácido N-Acetilneuramínico/metabolismo , Poliadenilação , Polissacarídeos/química , RNA/química , RNA/genética , RNA não Traduzido/metabolismo , Lectinas Semelhantes a Imunoglobulina de Ligação ao Ácido Siálico/metabolismo , Coloração e RotulagemRESUMO
Rosalind Franklin provided the key data for deriving the double helix structure of DNA. The English chemist also pioneered structural studies of colloids, viruses, and RNA. To celebrate the 100th anniversary of Franklin's birth, I summarize her work, which shaped the emerging discipline of molecular biology.
Assuntos
Biologia Molecular/história , Biografias como Assunto , DNA/química , História do Século XX , RNA/química , Vírus/química , Difração de Raios XRESUMO
The ability to engineer natural proteins is pivotal to a future, pragmatic biology. CRISPR proteins have revolutionized genome modification, yet the CRISPR-Cas9 scaffold is not ideal for fusions or activation by cellular triggers. Here, we show that a topological rearrangement of Cas9 using circular permutation provides an advanced platform for RNA-guided genome modification and protection. Through systematic interrogation, we find that protein termini can be positioned adjacent to bound DNA, offering a straightforward mechanism for strategically fusing functional domains. Additionally, circular permutation enabled protease-sensing Cas9s (ProCas9s), a unique class of single-molecule effectors possessing programmable inputs and outputs. ProCas9s can sense a wide range of proteases, and we demonstrate that ProCas9 can orchestrate a cellular response to pathogen-associated protease activity. Together, these results provide a toolkit of safer and more efficient genome-modifying enzymes and molecular recorders for the advancement of precision genome engineering in research, agriculture, and biomedicine.
Assuntos
Sistemas CRISPR-Cas/fisiologia , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/fisiologia , Edição de Genes/métodos , Proteínas Associadas a CRISPR/química , DNA/química , Genoma , Modelos Moleculares , RNA/química , RNA Guia de Cinetoplastídeos/genéticaRESUMO
Group II introns are a class of retroelements that invade DNA through a copy-and-paste mechanism known as retrotransposition. Their coordinated activities occur within a complex that includes a maturase protein, which promotes splicing through an unknown mechanism. The mechanism of splice site exchange within the RNA active site during catalysis also remains unclear. We determined two cryo-EM structures at 3.6-Å resolution of a group II intron reverse splicing into DNA. These structures reveal that the branch-site domain VI helix swings 90°, enabling substrate exchange during DNA integration. The maturase assists catalysis through a transient RNA-protein contact with domain VI that positions the branch-site adenosine for lariat formation during forward splicing. These findings provide the first direct evidence of the role the maturase plays during group II intron catalysis. The domain VI dynamics closely parallel spliceosomal branch-site helix movement and provide strong evidence for a retroelement origin of the spliceosome.
Assuntos
Splicing de RNA , DNA Polimerase Dirigida por RNA/química , RNA/química , Domínio Catalítico , Microscopia Crioeletrônica , Escherichia coli/genética , Escherichia coli/metabolismo , Conformação de Ácido Nucleico , Estrutura Terciária de Proteína , RNA/metabolismo , DNA Polimerase Dirigida por RNA/metabolismo , Retroelementos , Spliceossomos/químicaRESUMO
DNA-RNA hybrids play a physiological role in cellular processes, but often, they represent non-scheduled co-transcriptional structures with a negative impact on transcription, replication and DNA repair. Accumulating evidence suggests that they constitute a source of replication stress, DNA breaks and genome instability. Reciprocally, DNA breaks facilitate DNA-RNA hybrid formation by releasing the double helix torsional conformation. Cells avoid DNA-RNA accumulation by either preventing or removing hybrids directly or by DNA repair-coupled mechanisms. Given the R-loop impact on chromatin and genome organization and its potential relation with genetic diseases, we review R-loop homeostasis as well as their physiological and pathological roles.
Assuntos
DNA/genética , Conformação de Ácido Nucleico , Estruturas R-Loop/genética , RNA/genética , Cromatina/química , Cromatina/genética , DNA/química , Quebras de DNA , Reparo do DNA/genética , Replicação do DNA/genética , Instabilidade Genômica/genética , Homeostase/genética , Humanos , RNA/química , Transcrição GênicaRESUMO
Csm, a type III-A CRISPR-Cas interference complex, is a CRISPR RNA (crRNA)-guided RNase that also possesses target RNA-dependent DNase and cyclic oligoadenylate (cOA) synthetase activities. However, the structural features allowing target RNA-binding-dependent activation of DNA cleavage and cOA generation remain unknown. Here, we report the structure of Csm in complex with crRNA together with structures of cognate or non-cognate target RNA bound Csm complexes. We show that depending on complementarity with the 5' tag of crRNA, the 3' anti-tag region of target RNA binds at two distinct sites of the Csm complex. Importantly, the interaction between the non-complementary anti-tag region of cognate target RNA and Csm1 induces a conformational change at the Csm1 subunit that allosterically activates DNA cleavage and cOA generation. Together, our structural studies provide crucial insights into the mechanistic processes required for crRNA-meditated sequence-specific RNA cleavage, RNA target-dependent non-specific DNA cleavage, and cOA generation.
Assuntos
Proteínas Associadas a CRISPR/ultraestrutura , Sistemas CRISPR-Cas/fisiologia , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/fisiologia , Proteínas de Bactérias , Proteínas Associadas a CRISPR/química , DNA/química , Desoxirribonucleases/metabolismo , Endorribonucleases/metabolismo , Modelos Moleculares , RNA/química , RNA Bacteriano/química , RNA Guia de Cinetoplastídeos/química , Ribonucleases/metabolismoRESUMO
We introduce APEX-seq, a method for RNA sequencing based on direct proximity labeling of RNA using the peroxidase enzyme APEX2. APEX-seq in nine distinct subcellular locales produced a nanometer-resolution spatial map of the human transcriptome as a resource, revealing extensive patterns of localization for diverse RNA classes and transcript isoforms. We uncover a radial organization of the nuclear transcriptome, which is gated at the inner surface of the nuclear pore for cytoplasmic export of processed transcripts. We identify two distinct pathways of messenger RNA localization to mitochondria, each associated with specific sets of transcripts for building complementary macromolecular machines within the organelle. APEX-seq should be widely applicable to many systems, enabling comprehensive investigations of the spatial transcriptome.
Assuntos
DNA Liase (Sítios Apurínicos ou Apirimidínicos)/metabolismo , Endonucleases/metabolismo , Enzimas Multifuncionais/metabolismo , RNA/metabolismo , Análise de Sequência de RNA/métodos , Corantes Fluorescentes/química , Células HEK293 , Humanos , Microscopia de Fluorescência , Mitocôndrias/genética , RNA/química , RNA Mensageiro/química , RNA Mensageiro/metabolismo , TranscriptomaRESUMO
Receptors of the innate immune system recognize conserved microbial features and provide key signals that initiate immune responses. Multiple transmembrane and cytosolic receptors have evolved to recognize RNA and DNA, including members of the Toll-like receptor and RIG-I-like receptor families and several DNA sensors. This strategy enables recognition of a broad range of pathogens; however, in some cases, this benefit is weighed against the cost of potential self recognition. Recognition of self nucleic acids by the innate immune system contributes to the pathology associated with several autoimmune or autoinflammatory diseases. In this review, we highlight our current understanding of nucleic acid sensing by innate immune receptors and discuss the regulatory mechanisms that normally prevent inappropriate responses to self.
Assuntos
DNA/química , Infecções/imunologia , RNA/química , Receptores Toll-Like/química , Receptores Toll-Like/metabolismo , Animais , Citosol/química , Retículo Endoplasmático/metabolismo , Humanos , Imunidade Inata , Lisossomos/metabolismo , Receptores Toll-Like/imunologiaRESUMO
The human genome contains over one million short tandem repeats. Expansion of a subset of these repeat tracts underlies over fifty human disorders, including common genetic causes of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (C9orf72), polyglutamine-associated ataxias and Huntington disease, myotonic dystrophy, and intellectual disability disorders such as Fragile X syndrome. In this Review, we discuss the four major mechanisms by which expansion of short tandem repeats causes disease: loss of function through transcription repression, RNA-mediated gain of function through gelation and sequestration of RNA-binding proteins, gain of function of canonically translated repeat-harbouring proteins, and repeat-associated non-AUG translation of toxic repeat peptides. Somatic repeat instability amplifies these mechanisms and influences both disease age of onset and tissue specificity of pathogenic features. We focus on the crosstalk between these disease mechanisms, and argue that they often synergize to drive pathogenesis. We also discuss the emerging native functions of repeat elements and how their dynamics might contribute to disease at a larger scale than currently appreciated. Lastly, we propose that lynchpins tying these disease mechanisms and native functions together offer promising therapeutic targets with potential shared applications across this class of human disorders.
Assuntos
Expansão das Repetições de DNA/genética , Doenças Neurodegenerativas/genética , Animais , Inativação Gênica , Instabilidade Genômica , Humanos , Mutação , Doenças Neurodegenerativas/patologia , Doenças Neurodegenerativas/fisiopatologia , Especificidade de Órgãos , Biossíntese de Proteínas , Estruturas R-Loop , RNA/química , RNA/metabolismo , Proteínas de Ligação a RNA/metabolismoRESUMO
RNAs fold into defined tertiary structures to function in critical biological processes. While quantitative models can predict RNA secondary structure stability, we are still unable to predict the thermodynamic stability of RNA tertiary structure. Here, we probe conformational preferences of diverse RNA two-way junctions to develop a predictive model for the formation of RNA tertiary structure. We quantitatively measured tertiary assembly energetics of >1,000 of RNA junctions inserted in multiple structural scaffolds to generate a "thermodynamic fingerprint" for each junction. Thermodynamic fingerprints enabled comparison of junction conformational preferences, revealing principles for how sequence influences 3-dimensional conformations. Utilizing fingerprints of junctions with known crystal structures, we generated ensembles for related junctions that predicted their thermodynamic effects on assembly formation. This work reveals sequence-structure-energetic relationships in RNA, demonstrates the capacity for diverse compensation strategies within tertiary structures, and provides a path to quantitative modeling of RNA folding energetics based on "ensemble modularity."
Assuntos
RNA/metabolismo , Pareamento Incorreto de Bases , Biblioteca Gênica , Conformação de Ácido Nucleico , Fotodegradação , RNA/química , Dobramento de RNA , Estabilidade de RNA , TermodinâmicaRESUMO
Eukaryotic cells contain large assemblies of RNA and protein, referred to as ribonucleoprotein (RNP) granules, which include cytoplasmic P-bodies, stress granules, and neuronal and germinal granules, as well as nuclear paraspeckles, Cajal bodies, and RNA foci formed from repeat expansion RNAs. Recent evidence argues that intermolecular RNA-RNA interactions play a role in forming and determining the composition of certain RNP granules. We hypothesize that intermolecular RNA-RNA interactions are favored in cells yet are limited by RNA-binding proteins, helicases, and ribosomes, thereby allowing normal RNA function. An over-abundance of intermolecular RNA-RNA interactions may be toxic since perturbations that increase RNA-RNA interactions such as long repeat expansion RNAs, arginine-containing dipeptide repeat polypeptides, and sequestration or loss of abundant RNA-binding proteins can contribute to degenerative diseases.
Assuntos
Grânulos Citoplasmáticos/metabolismo , Células Eucarióticas/metabolismo , Proteínas de Ligação a RNA/metabolismo , RNA/metabolismo , Animais , Humanos , RNA/química , Proteínas de Ligação a RNA/químicaRESUMO
Long mammalian introns make it challenging for the RNA processing machinery to identify exons accurately. We find that LINE-derived sequences (LINEs) contribute to this selection by recruiting dozens of RNA-binding proteins (RBPs) to introns. This includes MATR3, which promotes binding of PTBP1 to multivalent binding sites within LINEs. Both RBPs repress splicing and 3' end processing within and around LINEs. Notably, repressive RBPs preferentially bind to evolutionarily young LINEs, which are located far from exons. These RBPs insulate the LINEs and the surrounding intronic regions from RNA processing. Upon evolutionary divergence, changes in RNA motifs within LINEs lead to gradual loss of their insulation. Hence, older LINEs are located closer to exons, are a common source of tissue-specific exons, and increasingly bind to RBPs that enhance RNA processing. Thus, LINEs are hubs for the assembly of repressive RBPs and also contribute to the evolution of new, lineage-specific transcripts in mammals. VIDEO ABSTRACT.
Assuntos
Ribonucleoproteínas Nucleares Heterogêneas/química , Elementos Nucleotídeos Longos e Dispersos , Proteínas Associadas à Matriz Nuclear/química , Poliadenilação , Proteína de Ligação a Regiões Ricas em Polipirimidinas/química , Proteínas de Ligação a RNA/química , RNA/química , Processamento Alternativo , Animais , Sítios de Ligação , Éxons , Células HeLa , Humanos , Íntrons , Camundongos , Mutação , Motivos de Nucleotídeos , Filogenia , Ligação Proteica , Mapeamento de Interação de Proteínas , Splicing de RNARESUMO
Liquid-liquid phase separation (LLPS) is believed to underlie formation of biomolecular condensates, cellular compartments that concentrate macromolecules without surrounding membranes. Physical mechanisms that control condensate formation/dissolution are poorly understood. The RNA-binding protein fused in sarcoma (FUS) undergoes LLPS in vitro and associates with condensates in cells. We show that the importin karyopherin-ß2/transportin-1 inhibits LLPS of FUS. This activity depends on tight binding of karyopherin-ß2 to the C-terminal proline-tyrosine nuclear localization signal (PY-NLS) of FUS. Nuclear magnetic resonance (NMR) analyses reveal weak interactions of karyopherin-ß2 with sequence elements and structural domains distributed throughout the entirety of FUS. Biochemical analyses demonstrate that most of these same regions also contribute to LLPS of FUS. The data lead to a model where high-affinity binding of karyopherin-ß2 to the FUS PY-NLS tethers the proteins together, allowing multiple, distributed weak intermolecular contacts to disrupt FUS self-association, blocking LLPS. Karyopherin-ß2 may act analogously to control condensates in diverse cellular contexts.
Assuntos
Transporte Ativo do Núcleo Celular , Sinais de Localização Nuclear , Proteína FUS de Ligação a RNA/química , beta Carioferinas/química , Sítios de Ligação , Degeneração Lobar Frontotemporal/metabolismo , Humanos , Carioferinas/metabolismo , Luz , Extração Líquido-Líquido , Substâncias Macromoleculares , Espectroscopia de Ressonância Magnética , Mutação , Nefelometria e Turbidimetria , Ligação Proteica , Domínios Proteicos , RNA/química , Espalhamento de Radiação , TemperaturaRESUMO
Viruses that are typically benign sometimes invade the brainstem in otherwise healthy children. We report bi-allelic DBR1 mutations in unrelated patients from different ethnicities, each of whom had brainstem infection due to herpes simplex virus 1 (HSV1), influenza virus, or norovirus. DBR1 encodes the only known RNA lariat debranching enzyme. We show that DBR1 expression is ubiquitous, but strongest in the spinal cord and brainstem. We also show that all DBR1 mutant alleles are severely hypomorphic, in terms of expression and function. The fibroblasts of DBR1-mutated patients contain higher RNA lariat levels than control cells, this difference becoming even more marked during HSV1 infection. Finally, we show that the patients' fibroblasts are highly susceptible to HSV1. RNA lariat accumulation and viral susceptibility are rescued by wild-type DBR1. Autosomal recessive, partial DBR1 deficiency underlies viral infection of the brainstem in humans through the disruption of tissue-specific and cell-intrinsic immunity to viruses.
Assuntos
Encefalopatias Metabólicas Congênitas/genética , Tronco Encefálico/metabolismo , Tronco Encefálico/virologia , RNA/química , RNA/metabolismo , Alelos , Sequência de Aminoácidos , Animais , Encefalopatias Metabólicas Congênitas/patologia , Tronco Encefálico/patologia , Encefalite Viral/genética , Escherichia coli/metabolismo , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Fibroblastos/virologia , Herpesvirus Humano 1 , Humanos , Interferons/metabolismo , Íntrons/genética , Masculino , Camundongos , Proteínas Mutantes/metabolismo , Mutação/genética , Fases de Leitura Aberta/genética , Linhagem , RNA Nucleotidiltransferases/química , RNA Nucleotidiltransferases/deficiência , RNA Nucleotidiltransferases/genética , Receptor 3 Toll-Like/metabolismo , Replicação ViralRESUMO
Visceral adipose tissue (VAT) hosts a population of regulatory T (Treg) cells, with a unique phenotype, that controls local and systemic inflammation and metabolism. Generation of a T cell receptor transgenic mouse line, wherein VAT Tregs are highly enriched, facilitated study of their provenance, dependencies, and activities. We definitively established a role for T cell receptor specificity, uncovered an unexpected function for the primordial Treg transcription-factor, Foxp3, evidenced a cell-intrinsic role for interleukin-33 receptor, and ordered these dependencies within a coherent scenario. Genesis of the VAT-Treg phenotype entailed a priming step in the spleen, permitting them to exit the lymphoid organs and surveil nonlymphoid tissues, and a final diversification process within VAT, in response to microenvironmental cues. Understanding the principles of tissue-Treg biology is a prerequisite for precision-targeting strategies.