RESUMO
Dorsal root ganglia (DRG) somatosensory neurons detect mechanical, thermal, and chemical stimuli acting on the body. Achieving a holistic view of how different DRG neuron subtypes relay neural signals from the periphery to the CNS has been challenging with existing tools. Here, we develop and curate a mouse genetic toolkit that allows for interrogating the properties and functions of distinct cutaneous targeting DRG neuron subtypes. These tools have enabled a broad morphological analysis, which revealed distinct cutaneous axon arborization areas and branching patterns of the transcriptionally distinct DRG neuron subtypes. Moreover, in vivo physiological analysis revealed that each subtype has a distinct threshold and range of responses to mechanical and/or thermal stimuli. These findings support a model in which morphologically and physiologically distinct cutaneous DRG sensory neuron subtypes tile mechanical and thermal stimulus space to collectively encode a wide range of natural stimuli.
Assuntos
Gânglios Espinais , Células Receptoras Sensoriais , Análise da Expressão Gênica de Célula Única , Animais , Camundongos , Gânglios Espinais/citologia , Células Receptoras Sensoriais/citologia , Pele/inervaçãoRESUMO
Plant roots encounter numerous pathogenic microbes that often cause devastating diseases. One such pathogen, Plasmodiophora brassicae (Pb), causes clubroot disease and severe yield losses on cruciferous crops worldwide. Here, we report the isolation and characterization of WeiTsing (WTS), a broad-spectrum clubroot resistance gene from Arabidopsis. WTS is transcriptionally activated in the pericycle upon Pb infection to prevent pathogen colonization in the stele. Brassica napus carrying the WTS transgene displayed strong resistance to Pb. WTS encodes a small protein localized in the endoplasmic reticulum (ER), and its expression in plants induces immune responses. The cryoelectron microscopy (cryo-EM) structure of WTS revealed a previously unknown pentameric architecture with a central pore. Electrophysiology analyses demonstrated that WTS is a calcium-permeable cation-selective channel. Structure-guided mutagenesis indicated that channel activity is strictly required for triggering defenses. The findings uncover an ion channel analogous to resistosomes that triggers immune signaling in the pericycle.
Assuntos
Brassica napus , Plasmodioforídeos , Microscopia Crioeletrônica , Chumbo , Brassica napus/genética , Plasmodioforídeos/fisiologia , Canais Iônicos , Doenças das PlantasRESUMO
The properties of dorsal root ganglia (DRG) neurons that innervate the distal colon are poorly defined, hindering our understanding of their roles in normal physiology and gastrointestinal (GI) disease. Here, we report genetically defined subsets of colon-innervating DRG neurons with diverse morphologic and physiologic properties. Four colon-innervating DRG neuron populations are mechanosensitive and exhibit distinct force thresholds to colon distension. The highest threshold population, selectively labeled using Bmpr1b genetic tools, is necessary and sufficient for behavioral responses to high colon distension, which is partly mediated by the mechanosensory ion channel Piezo2. This Aδ-HTMR population mediates behavioral over-reactivity to colon distension caused by inflammation in a model of inflammatory bowel disease. Thus, like cutaneous DRG mechanoreceptor populations, colon-innervating mechanoreceptors exhibit distinct anatomical and physiological properties and tile force threshold space, and genetically defined colon-innervating HTMRs mediate pathophysiological responses to colon distension, revealing a target population for therapeutic intervention.
Assuntos
Gânglios Espinais , Mecanorreceptores , Mecanorreceptores/fisiologia , Colo , Neurônios , Pele/inervaçãoRESUMO
The gastrointestinal tract is in a state of constant motion. These movements are tightly regulated by the presence of food and help digestion by mechanically breaking down and propelling gut content. Mechanical sensing in the gut is thought to be essential for regulating motility; however, the identity of the neuronal populations, the molecules involved, and the functional consequences of this sensation are unknown. Here, we show that humans lacking PIEZO2 exhibit impaired bowel sensation and motility. Piezo2 in mouse dorsal root, but not nodose ganglia is required to sense gut content, and this activity slows down food transit rates in the stomach, small intestine, and colon. Indeed, Piezo2 is directly required to detect colon distension in vivo. Our study unveils the mechanosensory mechanisms that regulate the transit of luminal contents throughout the gut, which is a critical process to ensure proper digestion, nutrient absorption, and waste removal.
Assuntos
Trânsito Gastrointestinal , Canais Iônicos , Mecanotransdução Celular , Animais , Humanos , Camundongos , Digestão , Canais Iônicos/metabolismo , Neurônios/metabolismoRESUMO
Tissue immunity and responses to injury depend on the coordinated action and communication among physiological systems. Here, we show that, upon injury, adaptive responses to the microbiota directly promote sensory neuron regeneration. At homeostasis, tissue-resident commensal-specific T cells colocalize with sensory nerve fibers within the dermis, express a transcriptional program associated with neuronal interaction and repair, and promote axon growth and local nerve regeneration following injury. Mechanistically, our data reveal that the cytokine interleukin-17A (IL-17A) released by commensal-specific Th17 cells upon injury directly signals to sensory neurons via IL-17 receptor A, the transcription of which is specifically upregulated in injured neurons. Collectively, our work reveals that in the context of tissue damage, preemptive immunity to the microbiota can rapidly bridge biological systems by directly promoting neuronal repair, while also identifying IL-17A as a major determinant of this fundamental process.
Assuntos
Interleucina-17 , Microbiota , Regeneração Nervosa , Células Th17 , Axônios , Regeneração Nervosa/fisiologia , Células Receptoras Sensoriais , Animais , Camundongos , Células Th17/citologiaRESUMO
The extracellular pH is a vital regulator of various biological processes in plants. However, how plants perceive extracellular pH remains obscure. Here, we report that plant cell-surface peptide-receptor complexes can function as extracellular pH sensors. We found that pattern-triggered immunity (PTI) dramatically alkalinizes the acidic extracellular pH in root apical meristem (RAM) region, which is essential for root meristem growth factor 1 (RGF1)-mediated RAM growth. The extracellular alkalinization progressively inhibits the acidic-dependent interaction between RGF1 and its receptors (RGFRs) through the pH sensor sulfotyrosine. Conversely, extracellular alkalinization promotes the alkaline-dependent binding of plant elicitor peptides (Peps) to its receptors (PEPRs) through the pH sensor Glu/Asp, thereby promoting immunity. A domain swap between RGFR and PEPR switches the pH dependency of RAM growth. Thus, our results reveal a mechanism of extracellular pH sensing by plant peptide-receptor complexes and provide insights into the extracellular pH-mediated regulation of growth and immunity in the RAM.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Concentração de Íons de Hidrogênio , Meristema/metabolismo , Peptídeos/metabolismo , Células Vegetais , Raízes de Plantas/metabolismo , Plantas/metabolismo , Receptores de Superfície Celular/metabolismo , Transdução de SinaisRESUMO
Plant species have evolved myriads of solutions, including complex cell type development and regulation, to adapt to dynamic environments. To understand this cellular diversity, we profiled tomato root cell type translatomes. Using xylem differentiation in tomato, examples of functional innovation, repurposing, and conservation of transcription factors are described, relative to the model plant Arabidopsis. Repurposing and innovation of genes are further observed within an exodermis regulatory network and illustrate its function. Comparative translatome analyses of rice, tomato, and Arabidopsis cell populations suggest increased expression conservation of root meristems compared with other homologous populations. In addition, the functions of constitutively expressed genes are more conserved than those of cell type/tissue-enriched genes. These observations suggest that higher order properties of cell type and pan-cell type regulation are evolutionarily conserved between plants and animals.
Assuntos
Arabidopsis/genética , Genes de Plantas , Invenções , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/genética , Solanum lycopersicum/genética , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Proteínas de Fluorescência Verde/metabolismo , Solanum lycopersicum/citologia , Meristema/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/citologia , Regiões Promotoras Genéticas/genética , Biossíntese de Proteínas , Especificidade da Espécie , Fatores de Transcrição/metabolismo , Xilema/genéticaRESUMO
This commentary introduces a new clinical trial construct, the Master Observational Trial (MOT), which hybridizes the power of molecularly based master interventional protocols with the breadth of real-world data. The MOT provides a clinical venue to allow molecular medicine to rapidly advance, answers questions that traditional interventional trials generally do not address, and seamlessly integrates with interventional trials in both diagnostic and therapeutic arenas. The result is a more comprehensive data collection ecosystem in precision medicine.
Assuntos
Estudos Observacionais como Assunto/métodos , Medicina de Precisão/métodos , Projetos de Pesquisa/normas , Big Data , Protocolos de Ensaio Clínico como Assunto , Humanos , Terapia de Alvo Molecular/métodos , Terapia de Alvo Molecular/tendências , Estudos Observacionais como Assunto/normasRESUMO
Recognition of microbe-associated molecular patterns (MAMPs) is crucial for the plant's immune response. How this sophisticated perception system can be usefully deployed in roots, continuously exposed to microbes, remains a mystery. By analyzing MAMP receptor expression and response at cellular resolution in Arabidopsis, we observed that differentiated outer cell layers show low expression of pattern-recognition receptors (PRRs) and lack MAMP responsiveness. Yet, these cells can be gated to become responsive by neighbor cell damage. Laser ablation of small cell clusters strongly upregulates PRR expression in their vicinity, and elevated receptor expression is sufficient to induce responsiveness in non-responsive cells. Finally, localized damage also leads to immune responses to otherwise non-immunogenic, beneficial bacteria. Damage-gating is overridden by receptor overexpression, which antagonizes colonization. Our findings that cellular damage can "switch on" local immune responses helps to conceptualize how MAMP perception can be used despite the presence of microbial patterns in the soil.
Assuntos
Arabidopsis/imunologia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Raízes de Plantas/imunologia , Receptores de Reconhecimento de Padrão/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/microbiologia , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/efeitos da radiação , Ascorbato Peroxidases/metabolismo , Ascorbato Peroxidases/efeitos da radiação , Flagelina/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Terapia a Laser/métodos , Proteínas de Membrana/metabolismo , Proteínas de Membrana/efeitos da radiação , Microscopia Confocal , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Raízes de Plantas/efeitos da radiação , Proteínas Quinases/metabolismo , Proteínas Quinases/efeitos da radiação , Receptores de Reconhecimento de Padrão/efeitos da radiação , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/efeitos da radiação , Imagem com Lapso de TempoRESUMO
Banyan trees are distinguished by their extraordinary aerial roots. The Ficus genus includes species that have evolved a species-specific mutualism system with wasp pollinators. We sequenced genomes of the Chinese banyan tree, F. microcarpa, and a species lacking aerial roots, F. hispida, and one wasp genome coevolving with F. microcarpa, Eupristina verticillata. Comparative analysis of the two Ficus genomes revealed dynamic karyotype variation associated with adaptive evolution. Copy number expansion of auxin-related genes from duplications and elevated auxin production are associated with aerial root development in F. microcarpa. A male-specific AGAMOUS paralog, FhAG2, was identified as a candidate gene for sex determination in F. hispida. Population genomic analyses of Ficus species revealed genomic signatures of morphological and physiological coadaptation with their pollinators involving terpenoid- and benzenoid-derived compounds. These three genomes offer insights into and genomic resources for investigating the geneses of aerial roots, monoecy and dioecy, and codiversification in a symbiotic system.
Assuntos
Evolução Biológica , Ficus/genética , Genoma de Planta , Polinização/fisiologia , Árvores/genética , Vespas/fisiologia , Animais , Cromossomos de Plantas/genética , Elementos de DNA Transponíveis/genética , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Ácidos Indolacéticos/metabolismo , Anotação de Sequência Molecular , Filogenia , Raízes de Plantas/crescimento & desenvolvimento , Duplicações Segmentares Genômicas/genética , Cromossomos Sexuais/genética , Compostos Orgânicos Voláteis/análiseRESUMO
The root cap surrounding the tip of plant roots is thought to protect the delicate stem cells in the root meristem. We discovered that the first layer of root cap cells is covered by an electron-opaque cell wall modification resembling a plant cuticle. Cuticles are polyester-based protective structures considered exclusive to aerial plant organs. Mutations in cutin biosynthesis genes affect the composition and ultrastructure of this cuticular structure, confirming its cutin-like characteristics. Strikingly, targeted degradation of the root cap cuticle causes a hypersensitivity to abiotic stresses during seedling establishment. Furthermore, lateral root primordia also display a cuticle that, when defective, causes delayed outgrowth and organ deformations, suggesting that it facilitates lateral root emergence. Our results show that the previously unrecognized root cap cuticle protects the root meristem during the critical phase of seedling establishment and promotes the efficient formation of lateral roots.
Assuntos
Arabidopsis/crescimento & desenvolvimento , Coifa/metabolismo , Coifa/fisiologia , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Parede Celular/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Lipídeos de Membrana/biossíntese , Lipídeos de Membrana/metabolismo , Meristema/metabolismo , Mutação , Raízes de Plantas/citologia , Plântula/genética , Plântula/crescimento & desenvolvimentoRESUMO
Root system architecture (RSA), the distribution of roots in soil, plays a major role in plant survival. RSA is shaped by multiple developmental processes that are largely governed by the phytohormone auxin, suggesting that auxin regulates responses of roots that are important for local adaptation. However, auxin has a central role in numerous processes, and it is unclear which molecular mechanisms contribute to the variation in RSA for environmental adaptation. Using natural variation in Arabidopsis, we identify EXOCYST70A3 as a modulator of the auxin system that causes variation in RSA by acting on PIN4 protein distribution. Allelic variation and genetic perturbation of EXOCYST70A3 lead to alteration of root gravitropic responses, resulting in a different RSA depth profile and drought resistance. Overall our findings suggest that the local modulation of the pleiotropic auxin pathway can gives rise to distinct RSAs that can be adaptive in specific environments.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Ácidos Indolacéticos/metabolismo , Alelos , Apomorfina/análogos & derivados , Apomorfina/farmacologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Secas , Exocitose , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Estudo de Associação Genômica Ampla , Proteínas de Membrana Transportadoras/metabolismo , Mutação , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismoRESUMO
Sensory axons degenerate following separation from their cell body, but partial injury to peripheral nerves may leave the integrity of damaged axons preserved. We show that an endogenous ligand for the natural killer (NK) cell receptor NKG2D, Retinoic Acid Early 1 (RAE1), is re-expressed in adult dorsal root ganglion neurons following peripheral nerve injury, triggering selective degeneration of injured axons. Infiltration of cytotoxic NK cells into the sciatic nerve by extravasation occurs within 3 days following crush injury. Using a combination of genetic cell ablation and cytokine-antibody complex stimulation, we show that NK cell function correlates with loss of sensation due to degeneration of injured afferents and reduced incidence of post-injury hypersensitivity. This neuro-immune mechanism of selective NK cell-mediated degeneration of damaged but intact sensory axons complements Wallerian degeneration and suggests the therapeutic potential of modulating NK cell function to resolve painful neuropathy through the clearance of partially damaged nerves.
Assuntos
Células Matadoras Naturais/fisiologia , Proteínas Associadas à Matriz Nuclear/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Traumatismos dos Nervos Periféricos/metabolismo , Animais , Axônios , Gânglios Espinais/citologia , Gânglios Espinais/metabolismo , Células Matadoras Naturais/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismo , Regeneração Nervosa , Neurônios/citologia , Neurônios Aferentes/imunologia , Neurônios Aferentes/metabolismo , Proteínas Associadas à Matriz Nuclear/fisiologia , Proteínas de Transporte Nucleocitoplasmático/fisiologia , Dor , Traumatismos dos Nervos Periféricos/imunologia , Doenças do Sistema Nervoso Periférico , Nervo Isquiático , Células Receptoras Sensoriais/metabolismoRESUMO
Plants are sessile and have to cope with environmentally induced damage through modification of growth and defense pathways. How tissue regeneration is triggered in such responses and whether this involves stem cell activation is an open question. The stress hormone jasmonate (JA) plays well-established roles in wounding and defense responses. JA also affects growth, which is hitherto interpreted as a trade-off between growth and defense. Here, we describe a molecular network triggered by wound-induced JA that promotes stem cell activation and regeneration. JA regulates organizer cell activity in the root stem cell niche through the RBR-SCR network and stress response protein ERF115. Moreover, JA-induced ERF109 transcription stimulates CYCD6;1 expression, functions upstream of ERF115, and promotes regeneration. Soil penetration and response to nematode herbivory induce and require this JA-mediated regeneration response. Therefore, the JA tissue damage response pathway induces stem cell activation and regeneration and activates growth after environmental stress.
Assuntos
Ciclopentanos/metabolismo , Oxilipinas/metabolismo , Raízes de Plantas/metabolismo , Células-Tronco/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Ciclinas/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Herbivoria , Ácidos Indolacéticos/metabolismo , Regeneração/fisiologia , Transdução de Sinais/fisiologia , Estresse Fisiológico , Fatores de Transcrição/metabolismoRESUMO
Aerobic organisms survive low oxygen (O2) through activation of diverse molecular, metabolic, and physiological responses. In most plants, root water permeability (in other words, hydraulic conductivity, Lpr) is downregulated under O2 deficiency. Here, we used a quantitative genetics approach in Arabidopsis to clone Hydraulic Conductivity of Root 1 (HCR1), a Raf-like MAPKKK that negatively controls Lpr. HCR1 accumulates and is functional under combined O2 limitation and potassium (K(+)) sufficiency. HCR1 regulates Lpr and hypoxia responsive genes, through the control of RAP2.12, a key transcriptional regulator of the core anaerobic response. A substantial variation of HCR1 in regulating Lpr is observed at the Arabidopsis species level. Thus, by combinatorially integrating two soil signals, K(+) and O2 availability, HCR1 modulates the resilience of plants to multiple flooding scenarios.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , MAP Quinase Quinase Quinases/metabolismo , Oxigênio/metabolismo , Raízes de Plantas/metabolismo , Potássio/metabolismo , Água/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Ligação a DNA , Regulação da Expressão Gênica de Plantas , MAP Quinase Quinase Quinases/genética , Permeabilidade , Fatores de Transcrição/genéticaRESUMO
While studying the aortic valve in isolation has facilitated the development of life-saving procedures and technologies, the dynamic interplay of the aortic valve and its surrounding structures is vital to preserving their function across the wide range of conditions encountered in an active lifestyle. Our view is that these structures should be viewed as an integrated functional unit, herein referred to as the aortic valve apparatus (AVA). The coupling of the aortic valve and root, left ventricular outflow tract, and blood circulation is crucial for AVA's functions: unidirectional flow out of the left ventricle, coronary perfusion, reservoir function, and supporting left ventricular function. In this review, we explore the multiscale biological and physical phenomena that underly the simultaneous fulfilment of these functions. A brief overview of the tools used to investigate the AVA is included, such as: medical imaging modalities, experimental methods, and computational modelling, specifically fluid-structure interaction (FSI) simulations, is included. Some pathologies affecting the AVA are explored, and insights are provided on treatments and interventions that aim to maintain quality of life. The concepts explained in this paper support the idea of AVA being an integrated functional unit and help identify unanswered research questions. Incorporating phenomena through the molecular, micro, meso and whole tissue scales is crucial for understanding the sophisticated normal functions and diseases of the AVA.
RESUMO
The Casparian strip is a barrier in the endodermal cell walls of plants that allows the selective uptake of nutrients and water. In the model plant Arabidopsis thaliana, its development and establishment are under the control of a receptor-ligand mechanism termed the Schengen pathway. This pathway facilitates barrier formation and activates downstream compensatory responses in case of dysfunction. However, due to a very tight functional association with the Casparian strip, other potential signaling functions of the Schengen pathway remain obscure. In this work, we created a MYB36-dependent synthetic positive feedback loop that drives Casparian strip formation independently of Schengen-induced signaling. We evaluated this by subjecting plants in which the Schengen pathway has been uncoupled from barrier formation, as well as a number of established barrier-mutant plants, to agar-based and soil conditions that mimic agricultural settings. Under the latter conditions, the Schengen pathway is necessary for the establishment of nitrogen-deficiency responses in shoots. These data highlight Schengen signaling as an essential hub for the adaptive integration of signaling from the rhizosphere to aboveground tissues.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Nitrogênio , Brotos de Planta , Transdução de Sinais , Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Nitrogênio/metabolismo , Brotos de Planta/metabolismo , Brotos de Planta/crescimento & desenvolvimento , Solo/química , Regulação da Expressão Gênica de Plantas , Proteínas Quinases/metabolismo , Proteínas Quinases/genética , Parede Celular/metabolismo , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genéticaRESUMO
The RNA-silencing effector ARGONAUTE10 influences cell fate in plant shoot and floral meristems. ARGONAUTE10 also accumulates in the root apical meristem (RAM), yet its function(s) therein remain elusive. Here, we show that ARGONAUTE10 is expressed in the root cell initials where it controls overall RAM activity and length. ARGONAUTE10 is also expressed in the stele, where post-transcriptional regulation confines it to the root tip's pro-vascular region. There, variations in ARGONAUTE10 levels modulate metaxylem-vs-protoxylem specification. Both ARGONAUTE10 functions entail its selective, high-affinity binding to mobile miR165/166 transcribed in the neighboring endodermis. ARGONAUTE10-bound miR165/166 is degraded, likely via SMALL-RNA-DEGRADING-NUCLEASES1/2, thus reducing miR165/166 ability to silence, via ARGONAUTE1, the transcripts of cell fate-influencing transcription factors. These include PHABULOSA (PHB), which controls meristem activity in the initials and xylem differentiation in the pro-vasculature. During early germination, PHB transcription increases while dynamic, spatially-restricted transcriptional and post-transcriptional mechanisms reduce and confine ARGONAUTE10 accumulation to the provascular cells surrounding the newly-forming xylem axis. Adequate miR165/166 concentrations are thereby channeled along the ARGONAUTE10-deficient yet ARGONAUTE1-proficient axis. Consequently, inversely-correlated miR165/166 and PHB gradients form preferentially along the axis despite ubiquitous PHB transcription and widespread miR165/166 delivery inside the whole vascular cylinder.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas Argonautas , Regulação da Expressão Gênica de Plantas , Meristema , MicroRNAs , Raízes de Plantas , Xilema , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , MicroRNAs/metabolismo , MicroRNAs/genética , Meristema/metabolismo , Meristema/crescimento & desenvolvimento , Meristema/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas Argonautas/metabolismo , Proteínas Argonautas/genética , Xilema/metabolismo , Xilema/crescimento & desenvolvimento , Xilema/genética , Raízes de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/genéticaRESUMO
In eukaryotes, three-dimensional genome organization is critical for transcriptional regulation of gene expression. Long noncoding RNAs (lncRNAs) can modulate chromatin conformation of spatially related genomic locations within the nucleus. Here, we show that the lncRNA APOLO (AUXIN-REGULATED PROMOTER LOOP) recognizes multiple distant independent loci in the Arabidopsis thaliana genome. We found that APOLO targets are not spatially associated in the nucleus and that APOLO recognizes its targets by short sequence complementarity and the formation of DNA-RNA duplexes (R-loops). The invasion of APOLO to the target DNA decoys the plant Polycomb Repressive Complex 1 component LHP1, modulating local chromatin 3D conformation. APOLO lncRNA coordinates the expression of distal unrelated auxin-responsive genes during lateral root development in Arabidopsis. Hence, R-loop formation and chromatin protein decoy mediate trans action of lncRNAs on distant loci. VIDEO ABSTRACT.
Assuntos
Arabidopsis/metabolismo , Montagem e Desmontagem da Cromatina , Cromatina/metabolismo , Regulação da Expressão Gênica de Plantas , Plantas Geneticamente Modificadas/metabolismo , RNA Longo não Codificante/metabolismo , RNA de Plantas/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Cromatina/genética , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácidos Indolacéticos/farmacologia , Modelos Genéticos , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/genética , Estruturas R-Loop , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , RNA Longo não Codificante/genética , RNA de Plantas/genética , Relação Estrutura-Atividade , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Roots are highly plastic organs enabling plants to adapt to a changing below-ground environment. In addition to abiotic factors like nutrients or mechanical resistance, plant roots also respond to temperature variation. Below the heat stress threshold, Arabidopsis thaliana seedlings react to elevated temperature by promoting primary root growth, possibly to reach deeper soil regions with potentially better water saturation. While above-ground thermomorphogenesis is enabled by thermo-sensitive cell elongation, it was unknown how temperature modulates root growth. We here show that roots are able to sense and respond to elevated temperature independently of shoot-derived signals. This response is mediated by a yet unknown root thermosensor that employs auxin as a messenger to relay temperature signals to the cell cycle. Growth promotion is achieved primarily by increasing cell division rates in the root apical meristem, depending on de novo local auxin biosynthesis and temperature-sensitive organization of the polar auxin transport system. Hence, the primary cellular target of elevated ambient temperature differs fundamentally between root and shoot tissues, while the messenger auxin remains the same.