bioRxiv Science⌕ Search

Biology subjects

Tanase, D. A.

Publications and source records attributed to Tanase, D. A..

5 recordsLinked to original sources

Organization and triggered release of liposomes with DNA-based synthetic condensates

Cells use a combination of membrane-bound and membrane-less compartments to dynamically orchestrate internal biochemical processes and sustain intracellular communication. Recapitulating the hierarchical integration and interplay between these physically and chemically diverse structures is required to enhance the functionalities of synthetic cells and other advanced biomimetic systems. Here, we describe the use of synthetic DNA condensates to selectively uptake and spatially organize lipid vesicles, interacting with the condensates thanks to cholesterol-DNA anchors. By modulating anchor density, the liposomes can be programmably localized on the surface or interior of the condensates, while base-pairing selectivity can be leveraged to target individual internal domains in multi-phasic condensates. The embedded liposomes can be released by adding a nucleic acid trigger and captured by a second condensate population, thus imitating extracellular vesicles in their ability to support long-range cellular communication. This modular platform demonstrates the potential of DNA-based condensates to program the spatial distribution of membranous subcompartments and to support dynamic cargo-handling capabilities. These features are valuable for engineering cell mimics, microreactors, and delivery systems.

synthetic biology↗

Cation-controlled assembly, activity, and organisation of biomimetic DNA receptors in synthetic cell membranes

Biological cells use cations as signalling messengers to regulate a variety of responses. Linking cations to the functionality of synthetic membranes is thus crucial to engineering advanced biomimetic agents, such as synthetic cells. Here, we introduce bio-inspired DNA-based receptors that exploit non-canonical G-quadruplexes for cation-actuated structural and functional responses in synthetic lipid membranes. Membrane confinement grants cationdependent control over receptor assembly and, when supplemented with hemin co-factors, their peroxidase DNAzyme activity. Cationmediated control extends to receptor lateral distribution to localise DNA-based catalysis within phase-separated membrane domains of model synthetic cells, imitating the localisation of multimeric membrane complexes to signalling hubs in living cells. Our modular strategy paves the way for engineering from the bottom-up cation-responsive pathways for sensing, signalling, and communication in synthetic cellular systems.

biophysics↗

Internal phase separation in synthetic DNA condensates

Biomolecular condensates regulate cellular biochemistry by organizing enzymes, substrates and metabolites, and often acquire partially de-mixed states whereby distinct internal domains play functional roles. Despite their physiological relevance, questions remain about the principles underpinning the emergence of multi-phase condensates. Here, we present a model system of synthetic DNA nanostructures able to form monophasic or biphasic condensates. Key condensate features, including the degree of interphase mixing and the relative size and spatial arrangement of domains, can be controlled by altering nanostructure stoichiometries. The modular nature of the system facilitates an intuitive understanding of phase behavior, and enables mapping of the experimental phenomenology onto a predictive Flory-Huggins model. The experimental and theoretical framework we introduce will help address open questions on multiphase condensation in biology and aid the design of functional biomolecular condensates in vitro, in synthetic cells, and in living cells.

biophysics↗

Enzyme-Responsive DNA Condensates

Membrane-less compartments and organelles are widely acknowledged for their role in regulating cellular processes, and there is an urgent need to harness their full potential as both structural and functional elements of synthetic cells. Despite rapid progress, synthetically recapitulating the nonequilibrium, spatially distributed responses of natural membrane-less organelles remain elusive. Here we demonstrate that the activity of nucleic-acid cleaving enzymes can be localised within DNA-based membrane-less compartments by sequestering the respective DNA or RNA substrates. Reaction-diffusion processes lead to complex nonequilibrium patterns, dependent on enzyme concentration. By arresting similar dynamic patterns, we spatially organise different substrates in concentric sub-compartments, which can be then selectively addressed by different enzymes, demonstrating spatial distribution of enzymatic activity. Besides advancing our ability to engineer advanced biomimetic functions in synthetic membrane-less organelles, our results may facilitate the deployment of DNA-based condensates as microbioreactors or platforms for the detection and quantitation of enzymes and nucleic acids.

synthetic biology↗

Sculpting DNA-based synthetic cells through phase separation and phase-targeted activity

Synthetic cells, like their biological counterparts, require internal compartments with distinct chemical and physical properties where different functionalities can be localised. Inspired by membrane-less compartmentalisation in biological cells, here we demonstrate how micro-phase separation can be used to engineer heterogeneous cell-like architectures with programmable morphology and compartment-targeted activity. The synthetic cells selfassemble from amphiphilic DNA nanostructures, producing core-shell condensates due to size-induced de-mixing. Lipid deposition and phase-selective etching are then used to generate a porous pseudo-membrane, a cytoplasm analogue, and membrane-less organelles. The synthetic cells can sustain RNA synthesis via in vitro transcription, leading to cytoplasm and pseudo-membrane expansion caused by an accumulation of the transcript. Our approach exemplifies how architectural and functional complexity can emerge from a limited number of distinct building blocks, if molecular-scale programmability, emergent biophysical phenomena, and biochemical activity are coupled to mimic those observed in live cells.

biophysics↗