Publications
2026
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Dual-Component Spidroin-Based Hydrogels: A Mechanically Tunable Platform for 2D and 3D Cell Culture
Hydrogels that recapitulate the biochemical and mechanical complexity of the extracellular matrix (ECM) are critical for advanced cell culture and tissue engineering. Here, we develop spider silk protein (spidroin)-based hydrogels from the recombinant miniature spidroin NT2RepCT mixed with VN-NT, a vitronectin peptide fused to the spidroin N-terminal (NT) domain. These hydrogels undergo spontaneous gelation at 37°C under physiological conditions and exhibit tunable stiffness. Structural and... -
Multispectral extended depth-of-field fluorescence microscopy with co-designed meta-optics and neural reconstruction
High numerical aperture fluorescence microscopy provides subcellular resolution, but its depth of field is extremely limited, so thick specimens quickly fall out of focus and typically require axial scanning. Multispectral imaging further compounds this problem because chromatic aberrations shift the best focus plane and distort registration across emission channels, especially in thick samples. In this work, we present MANTIS (Multispectral All-Depth meta-opTic Imaging System), a co-designed... -
Deep Invaginations of Nuclear Envelope Coordinate Spatial Organization of Chromatin in Epithelium
Cell nuclei are often used to assess cell health, but how their shapes vary in normal tissues and how they respond to mechanical forces is not well understood. Here, we describe deep invaginations of the nuclear envelope (DINEs) as common features of epithelial cell nuclei. After their formation, DINEs exist independently of the cytoskeleton, depend on A-type lamins, and emerge in response to cell crowding, contact inhibition, and tissue maturation. High-resolution imaging shows that, in... -
Nucleus softens during herpesvirus infection
Nuclear mechanics is remodeled not only by extracellular forces but also by internal modifications, such as those induced by viral infections. During herpes simplex virus type 1 infection, the nuclear structures undergo drastic reorganization, but little is known about how nuclear mechanobiology changes as a result. We show that the nucleus softens dramatically during the infection. To understand the phenomenon, we used advanced microscopy and computational modeling. We discovered that the...
2025
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Biomimetic hydrogel platform reveals active force transduction from retinal pigment epithelium to photoreceptors
In the eye, the retinal pigment epithelium (RPE) maintains the functionality and welfare of retinal photoreceptors and forms a tight, interlocked structure with photoreceptor outer segments (POSs). The RPE-retina interaction is difficult to recapitulate in vitro, limiting the studies addressing the retinal maintenance functions of the RPE. To overcome this challenge, we constructed a retina-mimicking structure using a soft polyacrylamide hydrogel coated with Matrigel. This structure was... -
Stabilizing light-responsive azobenzene films in an aqueous environment with thin polymer coatings
Reproducing cell-cell and cell-extracellular matrix (ECM) interactions remains a challenge when developing new biomaterials. Especially, the dynamic nature of the ECM is often neglected when cells are cultured in vitro. Light-responsive materials are promising candidates to mimic the natural behavior of the ECM. However, their long-term stability under cell culture conditions has not been widely studied. Here, we explore the impact of thin poly(dimethylsiloxane) (PDMS) and... -
Phagocytosed Photoreceptor Outer Segment Particles Within the Retinal Pigment Epithelium Show Diurnal Rhythmicity and Variation Between Cone Subtypes in Larval Zebrafish
Phagocytosis of retinal rod and cone outer segment (OS) tips by the retinal pigment epithelium (RPE) occurs daily to prevent the accumulation of harmful compounds in the photoreceptors. Rhythmic bursts seen as increased numbers of phagocytosed OS particles in the RPE are known to appear once or twice a day depending on the animal species. Yet, the variation of this rhythmicity between the distinct photoreceptor types is not well understood. We used zebrafish to compare the phagosome numbers and... -
Circadian Rhythms in Murine Ocular Tissues Including Sclera Are Affected by Neurobasal A Medium Preincubation and Mouse Strain, but Not Sex
CONCLUSIONS: We discovered a novel oscillator in the sclera. PER2::LUC bioluminescence rhythms in murine ocular tissues are affected by Neurobasal A medium preincubation mouse strain but not sex. -
Nucleus softens during herpesvirus infection
Nuclear mechanics is remodeled not only by extracellular forces but also by internal modifications, such as those induced by viral infections. During herpes simplex virus type 1 infection, the nuclear structures undergo drastic reorganization, but little is known about how nuclear mechanobiology changes as a result. We show that the nucleus softens dramatically during the infection. To understand the phenomenon, we used advanced microscopy and computational modeling. We discovered that the...
2024
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Dual-Component Spidroin-Based Hydrogels: A Mechanically Tunable Platform for 2D and 3D Cell Culture
Hydrogels that recapitulate the biochemical and mechanical complexity of the extracellular matrix (ECM) are critical for advanced cell culture and tissue engineering. Here, we develop spider silk protein (spidroin)-based hydrogels from the recombinant miniature spidroin NT2RepCT mixed with VN-NT, a vitronectin peptide fused to the spidroin N-terminal (NT) domain. These hydrogels undergo spontaneous gelation at 37°C under physiological conditions and exhibit tunable stiffness. Structural and... -
Iterative Immunostaining and NEDD Denoising for Improved Signal-To-Noise Ratio in ExM-LSCM
Expansion microscopy (ExM) has significantly reformed the field of super-resolution imaging, emerging as a powerful tool for visualizing complex cellular structures with nanoscale precision. Despite its capabilities, the epitope accessibility, labeling density, and precision of individual molecule detection pose challenges. We recently developed an iterative indirect immunofluorescence (IT-IF) method to improve the epitope labeling density, improving the signal and total intensity. In our... -
Whole mount immunofluorescence analysis of fresh and stored human donor corneas highlights changes in limbal characteristics during storage
CONCLUSIONS: WM-IF coupled with quantification of fluorescence intensities proved to be a valuable tool for investigating LSC marker expression in both human and porcine tissues ex vivo. Prolonged storage significantly influences the expression of LSC markers, underscoring the importance of fresh human or substitute control tissue when studying limbal stem cell biology.
2023
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Dual-Component Spidroin-Based Hydrogels: A Mechanically Tunable Platform for 2D and 3D Cell Culture
Hydrogels that recapitulate the biochemical and mechanical complexity of the extracellular matrix (ECM) are critical for advanced cell culture and tissue engineering. Here, we develop spider silk protein (spidroin)-based hydrogels from the recombinant miniature spidroin NT2RepCT mixed with VN-NT, a vitronectin peptide fused to the spidroin N-terminal (NT) domain. These hydrogels undergo spontaneous gelation at 37°C under physiological conditions and exhibit tunable stiffness. Structural and... -
The Effect of Substrate Stiffness on Elastic Force Transmission in the Epithelial Monolayers over Short Timescales
CONCLUSIONS: Our simulation results show that increased ECM stiffness, e.g., due to a tumor, can mechanically isolate cells and modulate rapid mechanical signaling between cells over distances. Furthermore, the developed model has the potential to facilitate future studies on the interactions between epithelial monolayers and elastic substrates. -
Mitochondrial temperature homeostasis resists external metabolic stresses
Based on studies with a fluorescent reporter dye, Mito Thermo Yellow (MTY), and the genetically encoded gTEMP ratiometric fluorescent temperature indicator targeted to mitochondria, the temperature of active mitochondria in four mammalian and one insect cell line was estimated to be up to 15°C above that of the external environment to which the cells were exposed. High mitochondrial temperature was maintained in the face of a variety of metabolic stresses, including substrate starvation or... -
Light-Induced Nanoscale Deformation in Azobenzene Thin Film Triggers Rapid Intracellular Ca<sup>2+</sup> Increase via Mechanosensitive Cation Channels
Epithelial cells are in continuous dynamic biochemical and physical interaction with their extracellular environment. Ultimately, this interplay guides fundamental physiological processes. In these interactions, cells generate fast local and global transients of Ca^(2+) ions, which act as key intracellular messengers. However, the mechanical triggers initiating these responses have remained unclear. Light-responsive materials offer intriguing possibilities to dynamically modify the physical... -
Substrate microtopographies induce cellular alignment and affect nuclear force transduction
Cellular physiology has been mainly studied by using two-dimensional cell culture substrates which lack in vivo-mimicking extracellular environment and interactions. Thus, there is a growing need for more complex model systems in life sciences. Micro-engineered scaffolds have been proven to be a promising tool in understanding the role of physical cues in the co-regulation of cellular functions. These tools allow, for example, probing cell morphology and migration in response to changes in... -
Toward Corneal Limbus In Vitro Model: Regulation of hPSC-LSC Phenotype by Matrix Stiffness and Topography During Cell Differentiation Process
A functional limbal epithelial stem cells (LSC) niche is a vital element in the regular renewal of the corneal epithelium by LSCs and maintenance of good vision. However, little is known about its unique structure and mechanical properties on LSC regulation, creating a significant gap in development of LSC-based therapies. Herein, the effect of mechanical and architectural elements of the niche on human pluripotent derived LSCs (hPSC-LSC) phenotype and growth is investigated in vitro.... -
Nuclear lamina strain states revealed by intermolecular force biosensor
Nuclear lamins have been considered an important structural element of the nucleus. The nuclear lamina is thought both to shield DNA from excessive mechanical forces and to transmit mechanical forces onto the DNA. However, to date there is not yet a technical approach to directly measure mechanical forces on nuclear lamins at the protein level. To overcome this limitation, we developed a nanobody-based intermolecular tension FRET biosensor capable of measuring the mechanical strain of lamin... -
Iterative immunostaining combined with expansion microscopy and image processing reveals nanoscopic network organization of nuclear lamina
Investigation of nuclear lamina architecture relies on superresolved microscopy. However, epitope accessibility, labeling density, and detection precision of individual molecules pose challenges within the molecularly crowded nucleus. We developed iterative indirect immunofluorescence (IT-IF) staining approach combined with expansion microscopy (ExM) and structured illumination microscopy to improve superresolution microscopy of subnuclear nanostructures like lamins. We prove that ExM is...
2022
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Light-Responsive Bilayer Cell Culture Platform for Reversible Cell Guidance
In vivo, cells are surrounded by a constantly changing microenvironment, which regulates many cell functions such as differentiation, migration, and cell death. Stimuli-responsive biomaterials aim to mimic this interaction between cells and extracellular matrix in vitro. However, reproducing dynamic signaling noninvasively without affecting the cell viability remains a challenge. Herein, a dynamic cell culturing platform consisting of a light-responsive azobenzene molecular glass film and a... -
G2/M checkpoint regulation and apoptosis facilitate the nuclear egress of parvoviral capsids
The nuclear export factor CRM1-mediated pathway is known to be important for the nuclear egress of progeny parvovirus capsids in the host cells with virus-mediated cell cycle arrest at G2/M. However, it is still unclear whether this is the only pathway by which capsids exit the nucleus. Our studies show that the nuclear egress of DNA-containing full canine parvovirus. capsids was reduced but not fully inhibited when CRM1-mediated nuclear export was prevented by leptomycin B. This suggests that... -
Talin variant P229S compromises integrin activation and associates with multifaceted clinical symptoms
Adhesion of cells to the extracellular matrix (ECM) must be exquisitely coordinated to enable development and tissue homeostasis. Cell-ECM interactions are regulated by multiple signalling pathways that coordinate the activation state of the integrin family of ECM receptors. The protein talin is pivotal in this process, and talin's simultaneous interactions with the cytoplasmic tails of the integrins and the plasma membrane are essential to enable robust, dynamic control of integrin activation... -
Pneumatic equiaxial compression device for mechanical manipulation of epithelial cell packing and physiology
It is well established that mechanical cues, e.g., tensile- compressive- or shear forces, are important co-regulators of cell and tissue physiology. To understand the mechanistic effects these cues have on cells, technologies allowing precise mechanical manipulation of the studied cells are required. As the significance of cell density i.e., packing on cellular behavior is beginning to unravel, we sought to design an equiaxial cell compression device based on our previously published cell... -
Parvovirus nonstructural protein 2 interacts with chromatin-regulating cellular proteins
Autonomous parvoviruses encode at least two nonstructural proteins, NS1 and NS2. While NS1 is linked to important nuclear processes required for viral replication, much less is known about the role of NS2. Specifically, the function of canine parvovirus (CPV) NS2 has remained undefined. Here we have used proximity-dependent biotin identification (BioID) to screen for nuclear proteins that associate with CPV NS2. Many of these associations were seen both in noninfected and infected cells,... -
Gap junctions and connexin hemichannels both contribute to the electrical properties of retinal pigment epithelium
Gap junctions are intercellular channels that permit the transfer of ions and small molecules between adjacent cells. These cellular junctions are particularly dense in the retinal pigment epithelium (RPE), and their contribution to many retinal diseases has been recognized. While gap junctions have been implicated in several aspects of RPE physiology, their role in shaping the electrical properties of these cells has not been characterized in mammals. The role of gap junctions in the electrical... -
Toward Xeno-Free Differentiation of Human Induced Pluripotent Stem Cell-Derived Small Intestinal Epithelial Cells
The small intestinal epithelium has an important role in nutrition, but also in drug absorption and metabolism. There are a few two-dimensional (2D) patient-derived induced pluripotent stem cell (iPSC)-based intestinal models enabling easy evaluation of transcellular transport. It is known that animal-derived components induce variation in the experimental outcomes. Therefore, we aimed to refine the differentiation protocol by using animal-free components. More specifically, we compared...
2021
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Light-Responsive Bilayer Cell Culture Platform for Reversible Cell Guidance
In vivo, cells are surrounded by a constantly changing microenvironment, which regulates many cell functions such as differentiation, migration, and cell death. Stimuli-responsive biomaterials aim to mimic this interaction between cells and extracellular matrix in vitro. However, reproducing dynamic signaling noninvasively without affecting the cell viability remains a challenge. Herein, a dynamic cell culturing platform consisting of a light-responsive azobenzene molecular glass film and a... -
Toward Xeno-Free Differentiation of Human Induced Pluripotent Stem Cell-Derived Small Intestinal Epithelial Cells
The small intestinal epithelium has an important role in nutrition, but also in drug absorption and metabolism. There are a few two-dimensional (2D) patient-derived induced pluripotent stem cell (iPSC)-based intestinal models enabling easy evaluation of transcellular transport. It is known that animal-derived components induce variation in the experimental outcomes. Therefore, we aimed to refine the differentiation protocol by using animal-free components. More specifically, we compared... -
Brick Strex: a robust device built of LEGO bricks for mechanical manipulation of cells
Cellular forces, mechanics and other physical factors are important co-regulators of normal cell and tissue physiology. These cues are often misregulated in diseases such as cancer, where altered tissue mechanics contribute to the disease progression. Furthermore, intercellular tensile and compressive force-related signaling is highlighted in collective cell behavior during development. However, the mechanistic understanding on the role of physical forces in regulation of cellular physiology,... -
Concepts to Reveal Parvovirus-Nucleus Interactions
Parvoviruses are small single-stranded (ss) DNA viruses, which replicate in the nucleoplasm and affect both the structure and function of the nucleus. The nuclear stage of the parvovirus life cycle starts at the nuclear entry of incoming capsids and culminates in the successful passage of progeny capsids out of the nucleus. In this review, we will present past, current, and future microscopy and biochemical techniques and demonstrate their potential in revealing the dynamics and molecular... -
Surface-Shaving Proteomics of Mycobacterium marinum Identifies Biofilm Subtype-Specific Changes Affecting Virulence, Tolerance, and Persistence
The complex cell wall and biofilm matrix (ECM) act as key barriers to antibiotics in mycobacteria. Here, the ECM and envelope proteins of Mycobacterium marinum ATCC 927, a nontuberculous mycobacterial model, were monitored over 3 months by label-free proteomics and compared with cell surface proteins on planktonic cells to uncover pathways leading to virulence, tolerance, and persistence. We show that ATCC 927 forms pellicle-type and submerged-type biofilms (PBFs and SBFs, respectively) after 2... -
Culture surface protein coatings affect the barrier properties and calcium signalling of hESC-RPE
Human pluripotent stem cell-derived retinal pigment epithelium (RPE) transplantation is currently under evaluation as treatment for macular degeneration. For therapeutic applications, cryostorage during cell production is typically needed with potential consequences to cell functionality. We have previously shown that the culture substrate affects human embryonic stem cell-derived RPE (hESC-RPE) properties in fresh cultures. Here, we aimed to further identify the role of RPE basement membrane...
2020
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A tube-source X-ray microtomography approach for quantitative 3D microscopy of optically challenging cell-cultured samples
Development and study of cell-cultured constructs, such as tissue-engineering scaffolds or organ-on-a-chip platforms require a comprehensive, representative view on the cells inside the used materials. However, common characteristics of biomedical materials, for example, in porous, fibrous, rough-surfaced, and composite materials, can severely disturb low-energy imaging. In order to image and quantify cell structures in optically challenging samples, we combined labeling, 3D X-ray imaging, and... -
Azobenzene-based sinusoidal surface topography drives focal adhesion confinement and guides collective migration of epithelial cells
Surface topography is a key parameter in regulating the morphology and behavior of single cells. At multicellular level, coordinated cell displacements drive many biological events such as embryonic morphogenesis. However, the effect of surface topography on collective migration of epithelium has not been studied in detail. Mastering the connection between surface features and collective cellular behaviour is highly important for novel approaches in tissue engineering and repair. Herein, we used... -
Cell adhesion and culture medium dependent changes in the high frequency mechanical vibration induced proliferation, osteogenesis, and intracellular organization of human adipose stem cells
High frequency (HF) mechanical vibration appears beneficial for in vitro osteogenesis of mesenchymal stem cells (MSCs). However, the current mechanobiological understanding of the method remains insufficient. We designed high-throughput stimulators to apply horizontal or vertical high magnitude HF (HMHF; 2.5 G(peak), 100 Hz) vibration on human adipose stem cells (hASCs). We analyzed proliferation, alkaline phosphatase (ALP) activity, mineralization, and effects on the actin cytoskeleton and...
2019
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Analysis of ATP-Induced Ca<sup>2+</sup> Responses at Single Cell Level in Retinal Pigment Epithelium Monolayers
Calcium is one of the most important second messengers in cells and thus involved in a variety of physiological processes. In retinal pigment epithelium (RPE), Ca^(2+) and its ATP-dependent signaling pathways play important roles in the retina maintenance functions. Changes in intracellular Ca^(2+) concentration can be measured from living cells by Ca^(2+) imaging. Combining these measurements with quantitative analysis of Ca^(2+) response properties enables studies of signaling pathways... -
Cell adhesion and culture medium dependent changes in the high frequency mechanical vibration induced proliferation, osteogenesis, and intracellular organization of human adipose stem cells
High frequency (HF) mechanical vibration appears beneficial for in vitro osteogenesis of mesenchymal stem cells (MSCs). However, the current mechanobiological understanding of the method remains insufficient. We designed high-throughput stimulators to apply horizontal or vertical high magnitude HF (HMHF; 2.5 G(peak), 100 Hz) vibration on human adipose stem cells (hASCs). We analyzed proliferation, alkaline phosphatase (ALP) activity, mineralization, and effects on the actin cytoskeleton and... -
Sodium channels enable fast electrical signaling and regulate phagocytosis in the retinal pigment epithelium
CONCLUSIONS: Taken together, our study shows that Na(v) channels are present in RPE, giving this tissue the capacity of fast electrical signaling. The channels are critical for the physiology of RPE with an important role in photoreceptor outer segment phagocytosis. -
Phasor-assisted nanoscopy reveals differences in the spatial organization of major nuclear lamina proteins
Phasor-assisted Metal Induced Energy Transfer-Fluorescence Lifetime Imaging Microscopy (MIET-FLIM) nanoscopy is introduced as a powerful tool for functional cell biology research. Thin metal substrates can be used to obtain axial super-resolution via nanoscale distance-dependent MIET from fluorescent dyes towards a nearby metal layer, thereby creating fluorescence lifetime contrast between dyes located at different nanoscale distance from the metal. Such data can be used to achieve axially... -
Structural dynamics of tight junctions modulate the properties of the epithelial barrier
Tight junctions are dynamic structures that are crucial in establishing the diffusion and electrical barrier of epithelial monolayers. Dysfunctions in the tight junctions can impede this barrier function and lead to many pathological conditions. Unfortunately, detailed understanding of the non-specific permeation pathway through the tight junctions, the so-called leak pathway, is lacking. We created computational models of the leak pathway to describe the two main barrier measures, molecular... -
Correction to: Depletion of nuclear import protein karyopherin alpha 7 (KPNA7) induces mitotic defects and deformation of nuclei in cancer cells
Following publication of the original article [1], the authors notified us that the Additional File 1 contains reviewer comments instead of the Supplementary tables. -
Characterization of the microstructure of hydrazone crosslinked polysaccharide-based hydrogels through rheological and diffusion studies
Microstructure plays an essential role in the control of hydrogel properties. It is also an important factor when cells or drugs are encapsulated inside the hydrogel. In this work, the microstructures of hydrazone crosslinked hyaluronan-, alginate- and gellan gum-based hydrogels were evaluated thoroughly for the first time by using rheology- and diffusion (fluorescence recovery after photobleaching, FRAP)-based methods. The effect of gel parameters on the viscoelastic and diffusion properties of...
2018
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Characterization of the microstructure of hydrazone crosslinked polysaccharide-based hydrogels through rheological and diffusion studies
Microstructure plays an essential role in the control of hydrogel properties. It is also an important factor when cells or drugs are encapsulated inside the hydrogel. In this work, the microstructures of hydrazone crosslinked hyaluronan-, alginate- and gellan gum-based hydrogels were evaluated thoroughly for the first time by using rheology- and diffusion (fluorescence recovery after photobleaching, FRAP)-based methods. The effect of gel parameters on the viscoelastic and diffusion properties of... -
Depletion of nuclear import protein karyopherin alpha 7 (KPNA7) induces mitotic defects and deformation of nuclei in cancer cells
CONCLUSIONS: Taken together, our data provide new important evidence on the contribution of KPNA7 to the regulation of cancer cell growth and the maintenance of nuclear envelope environment, and thus deepens our understanding on the impact of nuclear transfer proteins in cancer pathogenesis.
2017
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Direct Laser Writing of Tubular Microtowers for 3D Culture of Human Pluripotent Stem Cell-Derived Neuronal Cells
As the complex structure of nervous tissue cannot be mimicked in two-dimensional (2D) cultures, the development of three-dimensional (3D) neuronal cell culture platforms is a topical issue in the field of neuroscience and neural tissue engineering. Computer-assisted laser-based fabrication techniques such as direct laser writing by two-photon polymerization (2PP-DLW) offer a versatile tool to fabricate 3D cell culture platforms with highly ordered geometries in the size scale of natural 3D cell... -
Mechanical stability of talin rod controls cell migration and substrate sensing
Cells adhere to the surrounding tissue and probe its mechanical properties by forming cell-matrix adhesions. Talin is a critical adhesion protein and participates in the transmission of mechanical signals between extracellular matrix and cell cytoskeleton. Force induced unfolding of talin rod subdomains has been proposed to act as a cellular mechanosensor, but so far evidence linking their mechanical stability and cellular response has been lacking. Here, by utilizing computationally designed... -
Bioamine-crosslinked gellan gum hydrogel for neural tissue engineering
Neural tissue engineering and three-dimensional in vitro tissue modeling require the development of biomaterials that take into account the specified requirements of human neural cells and tissue. In this study, an alternative method of producing biomimetic hydrogels based on gellan gum (GG) was developed by replacing traditional crosslinking methods with the bioamines spermidine and spermine. These bioamines were proven to function as crosslinkers for GG hydrogel at +37 °C, allowing for the...
2016
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Transdifferentiation and Proliferation in Two Distinct Hemocyte Lineages in Drosophila melanogaster Larvae after Wasp Infection
Cellular immune responses require the generation and recruitment of diverse blood cell types that recognize and kill pathogens. In Drosophila melanogaster larvae, immune-inducible lamellocytes participate in recognizing and killing parasitoid wasp eggs. However, the sequence of events required for lamellocyte generation remains controversial. To study the cellular immune system, we developed a flow cytometry approach using in vivo reporters for lamellocytes as well as for plasmatocytes, the main... -
Promoter-Targeted Histone Acetylation of Chromatinized Parvoviral Genome Is Essential for the Progress of Infection
The association of host histones with parvoviral DNA is poorly understood. We analyzed the chromatinization and histone acetylation of canine parvovirus DNA during infection by confocal imaging andin situproximity ligation assay combined with chromatin immunoprecipitation and high-throughput sequencing. We found that during late infection, parvovirus replication bodies were rich in histones bearing modifications characteristic of transcriptionally active chromatin, i.e., histone H3 lysine 27...
2015
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Reorganization of Nuclear Pore Complexes and the Lamina in Late-Stage Parvovirus Infection
Canine parvovirus (CPV) infection induces reorganization of nuclear structures. Our studies indicated that late-stage infection induces accumulation of nuclear pore complexes (NPCs) and lamin B1 concomitantly with a decrease of lamin A/C levels on the apical side of the nucleus. Newly formed CPV capsids are located in close proximity to NPCs on the apical side. These results suggest that parvoviruses cause apical enrichment of NPCs and reorganization of nuclear lamina, presumably to facilitate... -
Differential basal-to-apical accessibility of lamin A/C epitopes in the nuclear lamina regulated by changes in cytoskeletal tension
Nuclear lamins play central roles at the intersection between cytoplasmic signalling and nuclear events. Here, we show that at least two N- and C-terminal lamin epitopes are not accessible at the basal side of the nuclear envelope under environmental conditions known to upregulate cell contractility. The conformational epitope on the Ig-domain of A-type lamins is more buried in the basal than apical nuclear envelope of human mesenchymal stem cells undergoing osteogenesis (but not adipogenesis),... -
His-tagged norovirus-like particles: A versatile platform for cellular delivery and surface display
In addition to vaccines, noninfectious virus-like particles (VLPs) that mimic the viral capsid show an attractive possibility of presenting immunogenic epitopes or targeting molecules on their surface. Here, functionalization of norovirus-derived VLPs by simple non-covalent conjugation of various molecules is shown. By using the affinity between a surface-exposed polyhistidine-tag and multivalent tris-nitrilotriacetic acid (trisNTA), fluorescent dye molecules and streptavidin-biotin conjugated... -
Non-structural proteins P17 and P33 are involved in the assembly of the internal membrane-containing virus PRD1
Bacteriophage PRD1, which has been studied intensively at the structural and functional levels, still has some gene products with unknown functions and certain aspects of the PRD1 assembly process have remained unsolved. In this study, we demonstrate that the phage-encoded non-structural proteins P17 and P33, either individually or together, complement the defect in a temperature-sensitive GroES mutant of Escherichia coli for host growth and PRD1 propagation. Confocal microscopy of fluorescent... -
Regulation of human mesenchymal stem cell osteogenesis by specific surface density of fibronectin: a gradient study
The success of synthetic bone implants requires good interface between the material and the host tissue. To study the biological relevance of fibronectin (FN) density on the osteogenic commitment of human bone marrow mesenchymal stem cells (hBM-MSCs), human FN was adsorbed in a linear density gradient on the surface of PCL. The evolution of the osteogenic markers alkaline phosphatase and collagen 1 alpha 1 was monitored by immunohistochemistry, and the cytoskeletal organization and the...
2014
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Switchavidin: reversible biotin-avidin-biotin bridges with high affinity and specificity
Switchavidin is a chicken avidin mutant displaying reversible binding to biotin, an improved binding affinity toward conjugated biotin, and low nonspecific binding due to reduced surface charge. These properties make switchavidin an optimal tool in biosensor applications for the reversible immobilization of biotinylated proteins on biotinylated sensor surfaces. Furthermore, switchavidin opens novel possibilities for patterning, purification, and labeling. -
Subcellular localization of bacteriophage PRD1 proteins in Escherichia coli
Bacteria possess an intricate internal organization resembling that of the eukaryotes. The complexity is especially prominent at the bacterial cell poles, which are also known to be the preferable sites for some bacteriophages to infect. Bacteriophage PRD1 is a well-known model serving as an ideal system to study structures and functions of icosahedral internal membrane-containing viruses. Our aim was to analyze the localization and interactions of individual PRD1 proteins in its native host...
2013
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Subcellular localization of bacteriophage PRD1 proteins in Escherichia coli
Bacteria possess an intricate internal organization resembling that of the eukaryotes. The complexity is especially prominent at the bacterial cell poles, which are also known to be the preferable sites for some bacteriophages to infect. Bacteriophage PRD1 is a well-known model serving as an ideal system to study structures and functions of icosahedral internal membrane-containing viruses. Our aim was to analyze the localization and interactions of individual PRD1 proteins in its native host... -
Mutations in DNA binding and transactivation domains affect the dynamics of parvovirus NS1 protein
The multifunctional replication protein of autonomous parvoviruses, NS1, is vital for viral genome replication and for the control of viral protein production. Two DNA-interacting domains of NS1, the N-terminal and helicase domains, are necessary for these functions. In addition, the N and C termini of NS1 are required for activation of viral promoter P38. By comparison with the structural and biochemical data from other parvoviruses, we identified potential DNA-interacting amino acid residues...
2012
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Distribution and dynamics of transcription-associated proteins during parvovirus infection
Canine parvovirus (CPV) infection leads to reorganization of nuclear proteinaceous subcompartments. Our studies showed that virus infection causes a time-dependent increase in the amount of viral nonstructural protein NS1 mRNA. Fluorescence recovery after photobleaching showed that the recovery kinetics of nuclear transcription-associated proteins, TATA binding protein (TBP), transcription factor IIB (TFIIB), and poly(A) binding protein nuclear 1 (PABPN1) were different in infected and...