Biology subjects

Nakano, M.

Publications and source records attributed to Nakano, M..

At least 19 recordsLinked to original sources

bioRxiv2026

cBAF drives AR-V7 expression through regulation of transcriptional termination in castration-resistant prostate cancer

The androgen receptor splice variant AR-V7 drives resistance to androgen receptor-targeted therapies in castration-resistant prostate cancer (CRPC), but the mechanisms governing its expression remain incompletely understood. Here, we identify the canonical BAF (cBAF) chromatin remodeling complex as a selective regulator of AR-V7 expression. Pharmacologic and genetic disruption of cBAF reduced AR-V7 levels, suppressed AR-V7-dependent transcriptional programs, and impaired CRPC cell proliferation. Mechanistically, cBAF binds an intronic regulatory element downstream of AR cryptic exon 3, where it maintains chromatin accessibility, enhancer activity, and promoter-enhancer looping. cBAF loss decreases recruitment of transcription termination machinery, reduces RNA polymerase II Thr4 phosphorylation, and promotes transcriptional readthrough beyond the AR-V7 polyadenylation site. POINT-seq revealed that cBAF-dependent transcriptional termination is required for AR-V7 biogenesis and regulates termination at a subset of genes genome-wide. Together, these findings uncover a role for cBAF in chromatin-mediated control of transcriptional termination and establish this mechanism as a critical determinant of AR-V7 expression.

molecular biology↗

bioRxiv2026

Patient-Derived Melanoma Organoids Preserve Tumor-Immune Heterogeneity and Reveal Context-Dependent Responses to Immune Checkpoint Blockade

Abstract Background: Experimental models that retain endogenous tumor immune complexity are needed to investigate heterogeneous responses to immune checkpoint inhibitors (ICIs) in melanoma. We established patient-derived melanoma organoids (PDMOs) to examine retention of parental tumor cellular components and investigate patient-specific and context-dependent responses to checkpoint blockade. Methods: Fresh melanoma specimens (n=50), including primary tumors, neoadjuvant-treated tumors and tumor-infiltrating lymphocyte (TIL) associated samples were processed for Matrigel-embedded culture of patient-derived melanoma organoids (PDMOs). Characterization and functional studies were performed in subsets of established cultures. Immunofluorescence assessed tumor, stromal, immune, and checkpoint-marker expression in PDMOs and matched parental tissues. NGFR expression was evaluated in relation to organoid establishment and growth. Responses to anti PD1 alone or combined with anti-LAG3 or anti-CTLA4 therapies were evaluated using viability and morphological analyses, with selected models undergoing immune phenotyping and multiplex cytokine profiling. Available clinical outcomes were used for exploratory comparison. PDMOs and matched two-dimensional cultures were evaluated under 21% and 5% oxygen conditions. Results: PDMOs were established from 30 of 50 specimens (60%) and retained melanoma, stromal, lymphoid, and myeloid components identified in matched parental tissues during early culture, together with immune checkpoint expression. Higher NGFR (CD271) expression was associated with greater organoid-forming capacity in an exploratory subset. Responses to checkpoint blockade varied across patient-derived models and regimens, with combination blockade not uniformly producing lower viability than PD1 monotherapy. Ex vivo responses showed parallels with available clinical outcomes, with discordant cases also observed. In three selected PDMOs, divergent PD-1 responses were accompanied by differences in T-cell and myeloid representation, MHCII and AXL expression, and inflammatory versus immunoregulatory cytokine profiles. Under normoxic conditions, PDMOs and matched two-dimensional cultures exhibited divergent treatment sensitivities, including clinically responding cases in which sensitivity was retained in PDMOs but attenuated in monolayers. Changing oxygen tension further altered checkpoint sensitivity within individual PDMOs, with the direction and magnitude of the observed shifts varying by model and regimen. Conclusions: Early passage PDMOs retain key endogenous tumor, immune, and stromal components and support functional investigation of patient-derived melanoma biology. Their heterogenous responses across checkpoint regimens and oxygen conditions provide a platform for investigating how tumor-immune composition and environmental context influence treatment sensitivity.

immunology↗

bioRxiv2026

Prefrontal control of hippocampal map reorganization during sleep

During wakefulness, exposure to novel experiences induces hippocampal remapping, in which place cell ensembles reorganize to form distinct representations of new information. Classical models of systems consolidation posit that subsequent sleep stabilizes these wake-formed representations and supports their gradual transfer to medial prefrontal cortex (mPFC) networks primarily via bottom-up hippocampal reactivations. Using miniscope Ca2+ imaging of CA1 place cells, we monitored hippocampal activity as mice explored a familiar environment followed by a similar novel one. As expected, place cells remapped in the novel context. However, a single episode of post-encoding sleep selectively reversed remapping dynamics by promoting the reinstatement of familiar place cell representations in the novel environment, an effect that was absent in the wake condition. This neural reinstatement was accompanied by behavioral indicators of familiarity, including reduced exploration and rearing. Chemogenetic inactivation of the mPFC during post-encoding sleep abolished this generalization effect, and instead preserved the novel hippocampal map. Thus, our results extend current models by showing that sleep not only consolidates wake-established hippocampal patterns, but actively shapes hippocampal maps via prefrontal control, thereby supporting memory generalization.

neuroscience↗

bioRxiv2026

Antibody-mediated VWF targeting reconstitutes ADAMTS13 metalloproteinase activity and prevents thrombocytopenia in mice

ADAMTS13 (a multidomain metalloproteinase) cleaves von Willebrand factor (VWF), thereby preventing the accumulation of ultra-large VWF multimers that promote platelet-rich thrombus formation. Severe ADAMTS13 deficiency causes thrombotic thrombocytopenic purpura (TTP). In immune-mediated TTP (iTTP), anti-ADAMTS13 autoantibodies inhibit ADAMTS13 activity, often by targeting non-catalytic domains that mediate substrate recognition. We developed ADAMTS13 mimetics by fusing the ADAMTS13 metalloproteinase domain to anti-human VWF A2 domain antibodies, aiming to replace native substrate-recognition domains with antibody-mediated substrate targeting while removing major autoantibody-targeted ADAMTS13 domains. The resulting mimetics bound to the recombinant VWF A2 domain and showed proteolytic activity toward both the recombinant VWF A2 domain and FRETS-VWF73 substrate. Kinetic analysis showed that the mimetics had not only lower kcat values than ADAMTS13 but also lower Km values, thereby maintaining overall catalytic efficiency. Importantly, ADAMTS13 mimetics retained VWF A2-cleaving activity in the presence of a spacer domain-directed anti-ADAMTS13 autoantibody both in vitro and in vivo. In an iTTP mouse model, ADAMTS13 mimetics prevented recombinant VWF-induced thrombocytopenia, whereas the parental anti-VWF A2 domain antibody did not. Platelet-preserving activity was also observed in ADAMTS13-deficient mice. In further analyses, some mimetics showed reduced binding to a conformationally restricted VWF A2 domain, resulting in reduced cleavage activity. Antibody binding correlated with platelet recovery in the iTTP mouse model, suggesting that epitope accessibility and antibody-mediated positioning contribute to in vivo activity. These findings demonstrate that antibody-mediated substrate targeting can reconstitute the VWF-cleaving activity of the ADAMTS13 metalloproteinase domain and suggest that ADAMTS13 mimetics represent a potential therapeutic approach for iTTP.

biochemistry↗

bioRxiv2026

CATaN maps gene regulatory programs that shape genetic risk across complex diseases

Causal variants of complex traits are enriched at transcription factor (TF) binding sites and are thought to contribute to pathology by disrupting TF activity and thereby causing transcriptome dysregulation. However, existing approaches typically address TF-mediated gene regulatory networks (TF-GRNs) and transcriptomes separately, and methods that jointly leverage both to systematically assess disease heritability remain limited. We aimed to develop a framework that jointly leverages TF-GRNs and transcriptomes to assess disease heritability. Here, we constructed a matrix encoding TF-GRNs and developed an unsupervised analytical pipeline, Canonical correlation Analysis of Transcriptome and TF-gene regulatory Networks (CATaN). CATaN applies canonical correlation analysis (CCA) to extract canonical correlation (CC) components, i.e., shared variation components between transcriptomes and TF-GRNs, and converts them into genome-wide functional annotation scores connected to stratified LD score regression (S-LDSC) for heritability analysis. We applied CATaN to eight datasets, including 19,198 bulk samples and 611,772 single cells from human and mouse sources, identifying 588 CC components that are significantly enriched for SNP heritability across 69 complex traits. Notably, functional annotation tracks based on these TF-GRNs are distinct from transcriptome signatures prioritized by LDSC-SEG, with greater heritability enrichment for a subset of traits. Finally, we suggest that CATaN may help prioritize candidate causal variants for experimental fine-mapping using genome editing. Together, integrating TF-GRNs with transcriptomes reveals disease-relevant regulatory programs that are not fully captured by transcriptome-based analyses alone.

genetics↗

bioRxiv2026

Modeling interregional propagation of α-synuclein in human striatal-midbrain assembloids

Parkinsons disease is characterized by the progressive degeneration of dopaminergic (DA) neurons in the substantia nigra that project to the striatum. Postmortem studies have found that -synuclein pathology spreads across brain regions in a prion-like manner. Human three-dimensional neural tissues provide experimentally tractable platforms for clarifying the molecular pathology of synucleinopathy that overcome the limitations of postmortem brain studies. In this study, we established a human striatal-midbrain assembloid model enabling spatially and temporally controlled -synuclein induction after formation of the nigrostriatal pathway within hStrMAs. Human induced pluripotent stem cells (hiPSCs) were differentiated into striatal spheroids and midbrain spheroids, which were fused to reconstruct the nigrostriatal pathway in vitro. Histological, electrophysiological, and single-cell RNA sequencing analyses confirmed the generation of region-specific neuronal populations, including striatal GABAergic neurons and midbrain DA neurons, and demonstrated that distinct forebrain and ventral midbrain identities were preserved within assembloids. To model synucleinopathy, we generated a doxycycline-inducible -synuclein hiPSC line, permitting selective induction of -synuclein expression in the striatal region after assembloid formation. Spatially restricted -synuclein induction resulted in the progressive accumulation of phosphorylated and fibrillar -synuclein in midbrain DA neurons, indicating interregional propagation through established neural circuits. Transcriptomic analysis of the midbrain region revealed significant downregulation of DA identity and synaptic function genes, suggesting functional impairment of DA neurons following -synuclein propagation. These findings demonstrate that the human neural circuit architecture contributes to the interregional propagation of -synuclein pathology. Our controllable human assembloid platform provides a powerful experimental framework for dissecting the mechanisms of pathological protein spread and developing therapeutic strategies targeting molecular pathology in neurodegenerative diseases. Significance statementOne pathological feature of Parkinsons disease is the progressive spread of -synuclein pathology across brain regions. However, the molecular mechanisms underlying this process remain poorly understood. In this study, we established a human striatal-midbrain assembloid model in which -synuclein expression can be spatially restricted and temporally induced after the nigrostriatal pathway is formed, thus enabling the experimental dissection of interregional -synuclein propagation across brain regions. We demonstrated that -synuclein pathology initiated in the striatal region propagated to midbrain dopaminergic neurons, leading to disease-relevant molecular and transcriptional alterations. These findings provide direct evidence that human neural circuits contribute to the spread of synucleinopathy and offer a controllable human model for studying disease progression and therapeutic strategies.

neuroscience↗

bioRxiv2026

Organoid modeling of tumor-associated macrophages reveals phagocytosis checkpoint blockade-induced conversion to an immunosuppressive SPP1+ phenotype

Tumor-associated macrophages (TAM) exert essential functions during the immune response to cancer. However, investigations of TAM within a native human tumor microenvironment (TME) have been impeded by a lack of appropriate model systems. Here, patient-derived organoids (PDO) from air-liquid interface (ALI)-grown tumor fragments, containing a human TME that encompassed stroma and immune subsets, robustly preserved TAM that were maintained by endogenous CSF-1 and appropriately responded to polarization signals. Antibody blockade of the CD47 regulatory checkpoint in organoids stimulated phagocytosis and remodeled TAM cytokine secretion profiles that were confirmed in anti-CD47 phase I trial patients. Amongst PDO histologies screened, anti-CD47 tumor killing was notable in clear cell renal cell carcinoma (ccRCC) which was associated with increased TAM infiltration. PDO contained diverse previously described TAM subsets; however, anti-CD47 reprogrammed organoid TAM toward an immunosuppressive SPP1+ phenotype, highlighting a negative feedback mechanism. Our findings uncover a resistance circuit engaged by macrophage checkpoint blockade and position ALI PDO as a robust translational platform for dissecting human macrophage biology and informing precision immunotherapy.

cancer biology↗

bioRxiv2026

Identification of a microRNA with a mutation in the loop structure in the silkworm Bombyx mori

MicroRNAs (miRNAs) play essential roles in the posttranscriptional regulation of gene expression in organisms. In the process of synthesizing mature miRNAs from miRNA precursors, the miRNA precursors are cleaved via Dicer at their loop structure, after which the miRNA precursors become mature and regulate transcription. However, the consequences of altering the loop sequence are not fully understood. The silkworm Bombyx mori is a lepidopteran insect with many genetic strains. We identified a mutant of the miRNA miR-3260 whose the part of the loop structure was lacking in a silkworm strain with translucent larval skin. Here, we aimed to analyze the role of wild-type miR-3260 and the influence of the mutation of the loop structure in B. mori. First, we identified the genomic region responsible for the translucent larval skin phenotype and determined that the mutated miR-3260 nucleotide sequences. Then, we predicted the binding partners of wild-type miR-3260 using the RNA hybrid tool and found two juvenile hormone (JH)-related genes as targets of wild-type miR-3260. Next, we assessed the relationships between miR-3260 and JH and found that miR-3260 was highly expressed in the Corpora allata and its expression responded to JH treatment. Meanwhile, miR-3260 mimic and inhibitor did not induce the typical phenotypes associated with JH in B. mori. Then, we compared the dicing products from wild-type and mutant miR-3260 precursors and observed that neither form underwent Dicer-mediated cleavage when the loop structure was altered. These results suggest that loop mutations in the miR-3260 precursor may not influence dicing activity, consistent with the lack of observable phenotypic effects.

molecular biology↗

bioRxiv2025

Decoding medial entorhinal cortical dynamics produces planning-like alternations in hippocampal theta sequences

The hippocampus is central to memory and spatial planning. A prominent candidate mechanism supporting navigational decision making is hippocampal theta sequences--brief ([~]120ms) place-cell sequences representing future trajectories--which have been interpreted as planning signals based on their alternation between maze arms in T-maze tasks. However, recent work suggests that intrinsic left-right alternation in medial entorhinal cortex (MEC) theta sequences may underlie this phenomenon. Here, we test this hypothesis using a model of MEC theta dynamics in a T-maze and show that standard Bayesian decoding yields hippocampal theta sequences that alternate between arms. Analysis of simultaneous MEC-hippocampal recordings reveals tight coupling of MEC and hippocampus and coordinated left-right alternation. Notably, this alternation occurs not only at choice points but also during inbound and forced-turn trials. These findings suggest that left-right alternation in hippocampal theta sequences is a ubiquitous phenomenon driven by MEC dynamics, challenging the interpretation that these specifically reflect intentional decision-making or planning processes.

neuroscience↗

bioRxiv2025

Genome editing of the flavanone 3-hydroxylase gene produces a green Perilla line with elevated luteolin accumulation

Perilla frutescens var. crispa is widely cultivated in East Asia and produces a diverse range of secondary metabolites with nutritional and medicinal value. Based on anthocyanin content, perilla is classified into red and green chemotypes. The anthocyanin biosynthetic pathway is highly conserved among plants, and the flavanone 3-hydroxylase gene (F3H) in red perilla is considered essential for this pathway. Here, we used CRISPR-Cas9 genome editing to generate novel Perilla lines with altered metabolite profiles. In four edited T plants, multiple biallelic indels, including a -3 bp in-frame deletion, were introduced at the target site. In the T generation, these mutations and the transgene segregated in a Mendelian manner, resulting in recovery of null-segregant plants. Metabolite analysis revealed strong suppression of anthocyanin biosynthesis and a significant increase in luteolin accumulation in edited lines compared with the wild type. Transcriptome analysis further confirmed the loss of F3H function, demonstrating a metabolic shift of the flavonoid pathway toward luteolin production. This study provides the first functional validation of F3H in perilla and highlights its potential application in breeding cultivars with controlled bioactive compound contents. Our findings also demonstrate practical strategies for implementing genome editing in non-model crops and developing high-value functional cultivars. Practitioner PointsO_LIEditing a single flavonoid biosynthetic gene (F3H) effectively alters pigment composition in perilla leaves. C_LIO_LIIncreased accumulation of luteolin-related compounds suggests potential for enhancing functional metabolites without complex pathway engineering. C_LIO_LIGenome editing offers a feasible tool for perilla improvement in breeding and functional food development. C_LI

plant biology↗

bioRxiv2025

Cellular and molecular fine mapping pinpoints new immunopathology of lupus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with an unknown etiology. To pinpoint new disease-relevant cell states and their molecular profiles, we performed an in-depth investigation of multimodal single-cell datasets comprising [~]2.1 million peripheral blood mononuclear cells from 346 donors. By resolving 123 fine-grained cell states across 27 cell types, we identified previously uncharacterized populations distinctively associated with clinical severity and treatment status, including GZMK+GZMH+HLA-DR+ effector memory CD8+ T cells (double-positive [DP] EMCD8) and FOXO1+ARHGAP15+ T cells. Through extensive statistical frameworks and multimodal approaches, we delineated their aberrant immune signaling networks, transcriptional regulators, key surface proteins, T cell receptor repertoires, and genetic/epigenetic landscapes, underscoring them as candidate drivers of SLE immunopathology. These findings provide new insights into therapeutic target discovery in SLE.

immunology↗

bioRxiv2025

Lightweight open-source fine-tuning of SAM2 enables domain-specific microscopy segmentation

Quantitation of structures is a critical step in analyzing images. Automated segmentation of biological samples remains a central challenge in microscopy, where variations in signal/noise, intensity, texture, and edges hinder accurate delineation of cellular and tissue structures. Adaptations of foundation models such as Segment Anything Model (SAM) remain computationally intensive and require large training datasets. Here, we introduce a lightweight, open-source Google Colab pipeline that enables efficient fine-tuning of SAM2 on domain-specific datasets without additional architectural layers or specialized hardware. By coupling mask-decoder fine-tuning with biologically informed post-processing, our framework achieves robust segmentation across diverse imaging modalities. Applied to hippocampal segmentation in brain images and single-cell segmentation in cell images, fine-tuned SAM2 demonstrates substantial gains of accuracy relative to basic SAM2 and matches leading tools. This work establishes a scalable and accessible paradigm for domain-specific adaptations of SAM2 in microscopy, lowering computational and data barriers to advanced image segmentation. HighlightsO_LILightweight fine-tuning with no added architectural complexity. C_LIO_LIHigh segmentation accuracy (Dice/Jaccard scores) achieved with small datasets. C_LIO_LICross-domain generalization across tissue and cell imaging with biologically informed post-processing. C_LIO_LIComparable or superior performance to widely used tools (Cellpose, Imaris, ilastik) at substantially lower computational cost. C_LIO_LIOpen-source and executable in a single Colab notebook, ensuring reproducibility and accessibility for non-computational users. C_LIO_LITurnkey adaptability, allowing researchers to transform raw microscopy data into fine-tuned SAM2 models with minimal input. C_LI

cell biology↗

bioRxiv2025

Inflammatory reprogramming of human brain endothelial cells compromises blood-brain barrier integrity in Alzheimer's disease

Blood-brain barrier (BBB) dysfunction is an early feature of Alzheimers disease (AD), yet the endothelial gene-regulatory programs involved remain incompletely understood. We integrate postmortem human single-nucleus transcriptomics with iPSC-based BBB models to define a conserved, inflammation-driven pathway that compromises barrier integrity. We identify an NF-{kappa}B-associated endothelial gene module endoM2 that is elevated in AD, inversely correlated with cognition, and enriched for inflammation and endothelial-to-mesenchymal transition signatures. Cytokine stimulation of iPSC-derived brain endothelial cells induces morphological remodeling, lipid accumulation, junctional disruption, and transcriptomic shifts that mirror endoM2. A targeted drug screen identifies the NF-{kappa}B inhibitor BAY11-7082 as protective against cytokine-induced changes. In our perfusable iPSC-derived BBB-Chip that recapitulates human BBB signatures, single-cell profiling reveals inflammatory endothelial state-specific programs reflecting those in AD brains and demonstrates that BAY11-7082 suppresses cytokine-triggered dysfunction and reverses inflammation-associated gene activation. Together, these findings position cerebrovascular inflammation as a therapeutic target to preserve BBB integrity in AD.

neuroscience↗

bioRxiv2025

Vascular-Perfusable Human 3D Brain-on-Chip

Development and delivery of treatments for neurological diseases are limited by the tight and selective human blood-brain barrier (BBB). Although animal models have been important research and preclinical tools, the rodent BBB exhibits species differences and fails to capture the complexity of human genetics. Microphysiological systems incorporating human-derived cells hold great potential for modeling disease and therapeutic development, with advantages in screening throughput, real-time monitoring, and tunable genetic backgrounds when combined with induced pluripotent stem cell (iPSC) technology. Existing 3D BBB-on-chip systems have incorporated iPSC-derived endothelial cells but not the other major brain cell types from iPSCs, each of which contributes to brain physiology and disease. Here we developed a 3D Brain-Chip system incorporating endothelial cells, pericytes, astrocytes, neurons, microglia, and oligodendroglia from iPSCs. To enable this multicellular 3D co-culture in-chip, we designed a GelChip microfluidic platform using a 3D printing-based approach and dextran-based engineered hydrogel. Leveraging this platform, we co-cultured and characterized iPSC-derived brain-on-chips and modeled the brain microvasculature of APOE4, the strongest known genetic risk factor for sporadic Alzheimers disease. These 3D brain-on-chips provide a versatile system to assess BBB vascular morphology and function, investigate downstream neurological effects in disease, and screen therapeutics to optimize delivery to the brain. Significance StatementThe blood-brain barrier (BBB) is both a contributing factor to neurological disease and a major obstacle to its treatment, yet human-relevant models remain limited. Most existing brain-on-chip systems incorporate only subsets of BBB cell types and cannot capture the full cellular complexity of the human neurovascular unit. Here, we establish a vascular-perfusable 3D Brain-Chip using human induced pluripotent stem cell-derived brain cells including endothelial cells, pericytes, astrocytes, neurons, microglia, and oligodendroglia. This system enables systematic analysis of human genetic risk factors, such as APOE4 in Alzheimers disease, and provides a powerful platform to investigate BBB function and dysfunction and accelerate the development of more effective neurological therapies.

neuroscience↗

bioRxiv2025

Distributed Biomarker Discovery for Immuno-Oncology

BackgroundIdentifying robust predictive biomarkers for immuno-oncology (IO) therapy response remains challenging due to the complexity of tumor host interactions and the limited availability of public datasets. While achieving clinical relevance requires biomarkers that generalize across diverse datasets, privacy concerns surrounding sensitive clinical and molecular data further restrict data sharing, impeding progress in biomarker discovery. Materials and MethodsWe developed a scalable, cloud-based distributed pipeline, implemented as an in-silico simulation of federated learning, to enable privacy-preserving integration of clinical and molecular data across institutions. This approach supports the development of genomic prediction algorithms without sharing sensitive patient data. Using curated gene expression profiles, we evaluated the association of tumor microenvironment and IO gene expression signatures with clinical outcomes across pan-cancer, cancer-specific, and treatment-specific settings, and developed a multivariable distributed model to predict IO response. ResultsWe implemented an integrated meta-analysis pipeline using harmonized data across 18 datasets comprising 967 patients and seven cancer types treated with PD-1/PD-L1, CTLA-4, or combination immunotherapies. This approach identified biomarkers specific to lung cancer and CTLA-4 therapy previously unreported in pan-cancer and pan-IO analyses, highlighting the value of context-specific associations. Similar gene expression signatures were associated with progression-free survival and response in both pan-cancer and melanoma datasets, with notable overlap between dual checkpoint blockade and PD-1/PD-L1 therapies. Distributed multivariable XGBoost models outperformed the average of locally trained models, indicating improved generalizability. ConclusionWe present a new distributed pipeline for biomarker discovery in immuno-oncology that preserves patient privacy through federated analysis and secure data handling. This study highlights the importance of larger, diverse datasets to refine cancer- and treatment-specific biomarkers, paving the way for more precise and personalized IO therapies.

bioinformatics↗

bioRxiv2025

Pseudovirus-Mediated Proximity Labeling Identifies Candidate Host Cell Membrane Proteins Involved in Viral Attachment

Viral infections represent a significant threat to humanity, as exemplified by the COVID-19 pandemic. To mitigate the associated damage, it is essential to understand the biological characteristics of causative viruses. In this study, we report a novel method for identifying host cell molecules (including virus receptor) required for viral attachment, referred to here as "Host Cell Attachment Factors (HCAFs)". Our approach utilizes proximity labeling (PL) technology: pseudoviruses engineered to express a PL enzyme are applied to host cells, where they bind and initiate proximity labeling. Since HCAFs are expected to be localized near viral attachment sites, candidate HCAFs are specifically tagged by the PL process. Analysis of influenza HCAFs enabled the identification of multiple candidate molecules. Subsequent virus attachment experiments using CHO cells suggested that NRP1 may serve as an HCAF for influenza viruses. Given its simplicity and rapid turnaround, this method is adaptable to a wide range of enveloped viruses, including pandemic viruses that require emergency analysis.

microbiology↗

bioRxiv2025

Evolutionary Trade-off Between Stomatal Defense and Gas Exchange in Brassicaceae

Stomatal opening is crucial for gas exchange, but it unavoidably offers invasion by pathogens. In response, plants close stomata to prevent pathogen entry, while the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pto) produces coronatine (COR), a jasmonate (JA) mimic, to counteract this plant response. Here, we demonstrate that by COR, Pto exploits CYP707A1 activation in Arabidopsis thaliana, encoding an enzyme that degrades abscisic acid, essential for stomatal closure. Notably, COR-induction of CYP707A1 is absent in other Brassicaceae species, such as Capsella rubella and Eutrema salsugineum, rendering them resistant to Pto invasion. In contrast, in A. thaliana, CYP707A1 enables rapid stomatal opening at dawn in a JA-dependent manner, enhancing gas exchange and chlorophyll content, unlike C. rubella and E. salsugineum. Promoter-swap experiments confirm that the regulatory region of CYP707A1 underlies these evolutionary diversifications. Together, our study presents a mechanism underlying an evolutionary trade-off between stomatal defense and gas exchange.

plant biology↗

bioRxiv2025

Promoter replacement by genome editing creates gain-of-function traits in Arabidopsis

We introduced two targeted DNA double-strand breaks on the same Arabidopsis chromosome using CRISPR-Cas9 and replaced the FLOWERING LOCUS T (FT) promoter with that of a histone variant gene through chromosomal inversion. The resulting lines misexpressed FT and flowered early, like FT-overexpressing transgenic plants. This system can be used to create gain-of-function mutations that modify target gene expression as desired without incorporating foreign DNA sequences.

plant biology↗