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Marina Garcia-Jove Navarro

Bio: Marina Garcia-Jove Navarro is an academic researcher from École Normale Supérieure. The author has contributed to research in topics: RNA & Stress granule. The author has an hindex of 3, co-authored 5 publications receiving 120 citations.

Papers
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Journal ArticleDOI
TL;DR: The versatile scaffold ArtiG is employed to generate concentration-dependent RNA–protein condensates within living cells, as a bottom-up approach to study the impact of co-segregated endogenous components on phase separation and shows the role of intracellular RNA in nucleation and sizing of the phase separated Condensates.
Abstract: Liquid-liquid phase separation is thought to be a key organizing principle in eukaryotic cells to generate highly concentrated dynamic assemblies, such as the RNP granules. Numerous in vitro approaches have validated this model, yet a missing aspect is to take into consideration the complex molecular mixture and promiscuous interactions found in vivo. Here we report the versatile scaffold ArtiG to generate concentration-dependent RNA-protein condensates within living cells, as a bottom-up approach to study the impact of co-segregated endogenous components on phase separation. We demonstrate that intracellular RNA seeds the nucleation of the condensates, as it provides molecular cues to locally coordinate the formation of endogenous high-order RNP assemblies. Interestingly, the co-segregation of intracellular components ultimately impacts the size of the phase-separated condensates. Thus, RNA arises as an architectural element that can influence the composition and the morphological outcome of the condensate phases in an intracellular context.

152 citations

Posted ContentDOI
08 Nov 2018-bioRxiv
TL;DR: It is demonstrated that intracellular RNA seeds the nucleation of the condensates, as it provides molecular cues to locally coordinate the formation of endogenous high order RNP assemblies, and Interestingly, the co-segregation of intrusion components ultimately impacts the size of the phase-separated condensate phases.
Abstract: Liquid-liquid phase separation is thought to be a key organizing principle in eukaryotic cells to generate highly concentrated dynamic assemblies, such as the RNP granules. Numerous in vitro approaches have validated this model, yet a missing aspect is to take into consideration the complex molecular mixture and promiscuous interactions found in vivo. Here we report the versatile scaffold "ArtiG" to generate concentration-dependent RNA-protein condensates within living cells, as a bottom-up approach to study the impact of co-segregated endogenous components on phase separation. We demonstrate that endogenous RNA seeds the nucleation of the condensates, as it provides molecular cues to locally coordinate the formation of endogenous high order RNP assemblies. Interestingly, the co-segregation of intracellular components ultimately impacts the size of the phase-separated condensates. Thus, RNA arises as an architectural element that can influence the composition and the morphological outcome of the condensate phases in an intracellular context.

18 citations

Posted ContentDOI
22 Jun 2021-bioRxiv
TL;DR: In this article, a methodology to form RNA-containing condensates in living cells with controlled RNA and protein composition is presented, based on physical constraints, provided by RNAs localized on condensate surface.
Abstract: Membrane-less organelles, by localizing and regulating complex biochemical reactions, are ubiquitous functional subunits of intracellular organization. They include a variety of nuclear and cytoplasmic ribonucleoprotein (RNP) condensates, such as nucleoli, P-bodies, germ granules and stress granules. While is it now recognized that specific RNA and protein families are critical for the biogenesis of RNP condensates, how these molecular constituents determine condensate size and morphology is unknown. To circumvent the biochemical complexity of endogenous RNP condensates, the use of programmable tools to reconstitute condensate formation with minimal constituents can be instrumental. Here we report a methodology to form RNA-containing condensates in living cells with controlled RNA and protein composition. Our bioengineered condensates are made of ArtiGranule scaffolds undergoing liquid-liquid phase separation in cells and programmed to specifically recruit a unique RNA species. We found that RNAs localized on condensate surface, either as isolated RNA molecules or as a homogenous corona of RNA molecules around the condensate. This simplified system allowed us to demonstrate that the size of the condensates scales with RNA surface density, the higher the RNA density is, the smaller and more frequent the condensates are. Our observations suggest a mechanism based on physical constraints, provided by RNAs localized on condensate surface, that limit condensate growth and coalescence.

17 citations

Journal ArticleDOI
TL;DR: This work reports a general approach to design genetically encoded protein-based scaffolds with modular biochemical and magnetic functions, and engineered ferritin nanocages to nucleate and manipulate microtubule structures upon magnetic actuation.
Abstract: Artificial bio-based scaffolds offer broad applications in bioinspired chemistry, nanomedicine, and material science. One current challenge is to understand how the programmed self-assembly of biomolecules at the nanometre level can dictate the emergence of new functional properties at the mesoscopic scale. Here we report a general approach to design genetically encoded protein-based scaffolds with modular biochemical and magnetic functions. By combining chemically induced dimerization strategies and biomineralisation, we engineered ferritin nanocages to nucleate and manipulate microtubule structures upon magnetic actuation. Triggering the self-assembly of engineered ferritins into micrometric scaffolds mimics the function of centrosomes, the microtubule organizing centres of cells, and provides unique magnetic and self-organizing properties. We anticipate that our approach could be transposed to control various biological processes and extend to broader applications in biotechnology or material chemistry.

11 citations

Journal ArticleDOI
TL;DR: This work reports a strategy to functionalize and manipulate active microtubule-based structures upon magnetic actuation and highlights how genetically encoded magnetic elements, behaving as magnetic actuators, could perturb active gels.
Abstract: The diversity of functions achieved by living cells result from the collective behavior of biological components that interact through multiple scales in time and space. The cytoskeleton constitutes one canonical system forming dynamic organizations when interacting with molecular motors. These materials constitute a state of active matter that exhibit out-of-equilibrium behavior with oriented order in the presence of energy. However, such active materials are highly dependent on the intrinsic properties of their constituents (fibers, molecular motors, and energy), which makes it difficult to control their behavior. Being able to manipulate directly the constitutive elements of the active gel could provide additional control parameters. Here, we report a strategy to functionalize and manipulate active microtubule-based structures upon magnetic actuation. We engineered protein nanocage ferritins as magnetic labels targeting molecular motors (Eg5 kinesin motors). We first mixed these magnetic motors with individual microtubules, allowing for their manipulation. In order to generate a magnetic-responsive gel, we then mixed the magnetic motors with active microtubule-based structures and characterized their dynamic behavior. We found that the magnetic forces applied on magnetic motors slowed down the dynamics of the microtubule structures as well as constrained their rotation. Our results highlight how genetically encoded magnetic elements, behaving as magnetic actuators, could perturb active gels.

1 citations


Cited by
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Journal ArticleDOI
TL;DR: The findings suggest that condensate immiscibility may be a very general feature in biological systems, which could be exploited to design self-organized synthetic compartments to control biomolecular processes.
Abstract: Liquid-liquid phase separation plays an important role in cellular organization. Many subcellular condensed bodies are hierarchically organized into multiple coexisting domains or layers. However, our molecular understanding of the assembly and internal organization of these multicomponent droplets is still incomplete, and rules for the coexistence of condensed phases are lacking. Here, we show that the formation of hierarchically organized multiphase droplets with up to three coexisting layers is a generic phenomenon in mixtures of complex coacervates, which serve as models of charge-driven liquid-liquid phase separated systems. We present simple theoretical guidelines to explain both the hierarchical arrangement and the demixing transition in multiphase droplets using the interfacial tensions and critical salt concentration as inputs. Multiple coacervates can coexist if they differ sufficiently in macromolecular density, and we show that the associated differences in critical salt concentration can be used to predict multiphase droplet formation. We also show that the coexisting coacervates present distinct chemical environments that can concentrate guest molecules to different extents. Our findings suggest that condensate immiscibility may be a very general feature in biological systems, which could be exploited to design self-organized synthetic compartments to control biomolecular processes.

192 citations

Journal ArticleDOI
TL;DR: The mechanisms of mRNA transport and local mRNA translation across the kingdoms of life and at organellar, subcellular and multicellular resolution are discussed and the properties of messenger ribonucleoprotein and higher order RNA granules and how they may influence mRNA Transport and local protein synthesis are discussed.
Abstract: Fine-tuning cellular physiology in response to intracellular and environmental cues requires precise temporal and spatial control of gene expression. High-resolution imaging technologies to detect mRNAs and their translation state have revealed that all living organisms localize mRNAs in subcellular compartments and create translation hotspots, enabling cells to tune gene expression locally. Therefore, mRNA localization is a conserved and integral part of gene expression regulation from prokaryotic to eukaryotic cells. In this Review, we discuss the mechanisms of mRNA transport and local mRNA translation across the kingdoms of life and at organellar, subcellular and multicellular resolution. We also discuss the properties of messenger ribonucleoprotein and higher order RNA granules and how they may influence mRNA transport and local protein synthesis. Finally, we summarize the technological developments that allow us to study mRNA localization and local translation through the simultaneous detection of mRNAs and proteins in single cells, mRNA and nascent protein single-molecule imaging, and bulk RNA and protein detection methods.

112 citations

Journal ArticleDOI
TL;DR: A novel active mechanism is described that splits, segregates, and localizes non-canonical LLPS condensates in the subcellular space by focusing on the ParABS DNA segregation system, composed of a centromeric-like sequence, a DNA-binding protein, and a motor.

81 citations

Journal ArticleDOI
10 Sep 2021-Science
TL;DR: In this paper, the P granules of Caenorhabditis elegans were studied and it was shown that condensate cells can form by phase separation in the absence of limiting membranes.
Abstract: Biomolecular condensates are cellular compartments that can form by phase separation in the absence of limiting membranes. Studying the P granules of Caenorhabditis elegans, we find that condensate...

71 citations

Journal ArticleDOI
TL;DR: The definition and nomenclature of long non-coding RNAs and their conservation, expression, phenotypic visibility, structure, and functions are discussed in this paper , where the authors also discuss research challenges and recommendations to advance the understanding of the roles of lncRNAs in development, cell biology and disease.
Abstract: Genes specifying long non-coding RNAs (lncRNAs) occupy a large fraction of the genomes of complex organisms. The term 'lncRNAs' encompasses RNA polymerase I (Pol I), Pol II and Pol III transcribed RNAs, and RNAs from processed introns. The various functions of lncRNAs and their many isoforms and interleaved relationships with other genes make lncRNA classification and annotation difficult. Most lncRNAs evolve more rapidly than protein-coding sequences, are cell type specific and regulate many aspects of cell differentiation and development and other physiological processes. Many lncRNAs associate with chromatin-modifying complexes, are transcribed from enhancers and nucleate phase separation of nuclear condensates and domains, indicating an intimate link between lncRNA expression and the spatial control of gene expression during development. lncRNAs also have important roles in the cytoplasm and beyond, including in the regulation of translation, metabolism and signalling. lncRNAs often have a modular structure and are rich in repeats, which are increasingly being shown to be relevant to their function. In this Consensus Statement, we address the definition and nomenclature of lncRNAs and their conservation, expression, phenotypic visibility, structure and functions. We also discuss research challenges and provide recommendations to advance the understanding of the roles of lncRNAs in development, cell biology and disease.

70 citations