Biology subjects

Zheng, L.

Publications and source records attributed to Zheng, L..

At least 19 recordsLinked to original sources

bioRxiv2026

Forward reactivation in human hippocampal CA1 supports repetition learning and is preserved in the aging brain

Repetition is a fundamental mechanism for strengthening episodic memory, yet the neural computations engaged during re-exposure remain disputed. Competing accounts attribute repetition-related gains either to retrospective reinstatement of prior events or to the prospective use of learned structure to anticipate what comes next. Using high-resolution functional MRI and representational similarity analysis in a lifespan cohort (N = 418, ages 36 -100), we tracked hippocampal representations as participants twice encoded two fixed sequences of face-name pairs, resolving reactivation by direction, distance and sequence. During repeated encoding, CA1 and CA2/3/DG representations spontaneously anticipated immediate next states, unprompted by explicit task demands. Forward, but not backward, reactivation predicted repetition-related gains, and showed no detectable age dependence. Only CA1 forward reactivation predicted memory gains after accounting for reactivation in other medial temporal lobe regions. Repetition learning is thus an active, temporally local prospective computation with a distinctive CA1 contribution that appears preserved well into old age.

neuroscience↗

bioRxiv2026

Establishment of Rabbit Formative-like Pluripotent Cells by Bidirectional Modulation of WNT Signaling Pathway

The generation of embryonic stem cells (ESCs) with full developmental capacity and robust chimera-forming potential remains a major bottleneck for most non-rodent mammalian species including rabbits, an important animal both for biomedicine and agriculture. Formative pluripotency is a unique intermediate state bridging the naive and primed pluripotent states, which is defined by distinct molecular signatures, intrinsic competence for primordial germ cell (PGC) specification, and unique developmental adaptability to early embryonic microenvironments. Here, we established a novel culture medium termed KFiC, which could bidirectionally and coordinately modulate the WNT/{beta}-catenin signaling pathway via combined treatment of WNT activator CHIR99021 and inhibitor IWR-1. The KFiC culture system enables efficient derivation and stable long-term self-renewal of rbESCs with consistent formative-like pluripotent characteristics. KFiC-cultured rbESCs (KFiC-rbESCs) form compact, undifferentiated colonies, maintain intact genomic stability, and recapitulate the transcriptional landscape of pre-implantation epiblast cells, accompanied by sustained high expression of the core formative pluripotency marker OTX2. Functionally, KFiC-rbESCs possess efficient PGC differentiation competence and extensively contribute to embryonic development after microinjection into rabbit morulae, displaying their superior developmental plasticity. Notably, the KFiC system can stabilize an intermediate formative-like pluripotent state in mouse, human, and porcine pluripotent stem cells, and KFiC-adapted mouse ESCs retain potent chimera-forming ability. Collectively, this study establishes a reliable culture platform for generating and maintaining formative-like rbESCs. This cross-species compatible system provides a promising foundation for further optimizing naive-level pluripotency in rbESCs and facilitates the generation of genetically engineered rabbit disease models.

developmental biology↗

bioRxiv2026

Fast Generalized Longitudinal Functional Principal Components Analysis with Applications to Population-Level Neuronal Dynamics

Functional data are widely collected across many fields. One approach for modeling functional data collected across repeated measures is longitudinal functional PCA (LFPCA), which allows for the decomposition of variability at multiple levels. However, existing estimation approaches for LFPCA can be computationally demanding for large or high-dimensional datasets. Here, we propose fast generalized LFPCA, a novel estimation technique that bins data along the functional domain and fits a marginal mixed model at each bin. Simulation results show that the proposed method is orders of magnitude faster than existing techniques while achieving similar accuracy, making LFPCA scalable to datasets with more densely sampled observations and larger sample sizes. We apply the proposed technique to model neuronal firing rate data both on and off deep brain stimulation (DBS) to investigate how the intervention modulates population-level neuronal activity. Our results suggest that the vast majority of between-neuron variation can be explained by four principal components, which relate to individual differences in neuronal firing as well as the arm manipulation paradigm under study. We also find that DBS significantly increases the variability of firing activity, likely driven by increased firing from a subset of neurons in response to DBS, a novel insight not obtained in previous analyses. Code to implement the proposed method and run simulation studies is included in the supplement.

neuroscience↗

bioRxiv2026

Filling the Missing Puzzle: Integrating Interaction and Evolutionary Information to Enhance Protein Fitness Prediction in Inverse Folding

Protein inverse folding, which infers compatible amino acid sequences from a given backbone structure, is central to rational protein design. Current methods rely largely on sequence recovery rate as the evaluation metric, emphasizing structural compatibility but seldom addressing function. Yet functional activity depends on the proper network of non-covalent interactions-protein-ligand contacts being a prime example. We argue that function-oriented protein design is governed by three complementary constraints: structural, interaction, and evolutionary, none of which are handled in a unified manner by existing pretrained models. To bridge this gap, we introduce zPolaron, a graph neural network built on protein-ligand complexes for functional protein design. zPolaron represents residues and ligand atoms as a heterogeneous graph and jointly encodes structural, interaction, and evolutionary information by fusing physical-interaction-enhanced graph representations with ESM-2 embeddings. Across multiple fitness prediction benchmarks, zPolaron outperforms all baselines, with gains evident across structural, interaction, and evolutionary dimensions. Wet-lab experiments further confirm its utility in functional enzyme screening and design: the optimized CalA6-D205A-S160G mutant achieves a 17.84-fold improvement in activity, while the CalB-I121M mutant yields a 1.91-fold increase. Together, these results show that integrating interaction and evolutionary information fills the missing puzzle of inverse folding, enhancing protein fitness prediction beyond structural compatibility. zPolaron is available at https://github.com/zelixirSH/zPolaron.

bioinformatics↗

bioRxiv2026

The uplift of the Qinghai-Tibetan Plateau reshaped genome architecture and diversification of Asian torrent catfishes

Tectonic uplift and mountain building are major drivers of species diversification and adaptation, yet how they reshape genome architecture and promote evolutionary innovation remains poorly understood. Here, we generated multiple chromosome-level genomes for Asian torrent catfishes (Sisoridae) and performed phylogenomic and comparative genomic analyses. Our results support an Asian origin of Sisoridae and provide a refined phylogenetic topology for catfishes. Comparative analyses revealed extensive chromosomal rearrangements during sisorid evolution, indicating highly dynamic genome architectures. The timing of sisorid diversification overlaps with major phases of regional tectonic change, and analyses of phylogenetic discordance indicate heterogeneous contributions from incomplete lineage sorting and introgression. Elevational distribution was associated with variation in estimated molecular evolutionary rates, while exploratory scans identified lineage-specific candidates for selection and convergent evolution. Candidate coding and non-coding changes occur near genes with known roles in fin development, body patterning, and liver biology, but their effects on sisorid traits remain to be tested. Together, our results demonstrate how tectonic uplift reshaped genome architecture and diversification in Asian torrent catfishes and provide new insights into the genomic basis of adaptation in mountainous freshwater ecosystems.

evolutionary biology↗

bioRxiv2026

Accessing Enzyme Kinetic Data and Prediction Methods at Scale

Enzyme kinetic parameters inform metabolic models, yet experimental measurements are sparse. A growing body of work predicts them from protein and substrate features, but software fragmentation hinders adoption, so downstream tools lock into the most accessible method. We present OpenKinetics Predictor (at predictor.openkinetics.org), an open-source platform integrating thirteen methods in isolated environments behind one interface. The platform optionally reports similarity between query proteins and each method's training data to contextualise reliability. A common featurisation-prediction abstraction keeps it extensible, and independent parties, including original authors, contributed many methods. We pair it with a data portal (at data.openkinetics.org) that exposes CatLog, a curated kinetic dataset, with precomputed embeddings, predicted binding sites, and standardised splits. Both offer a web interface and an API, and the GECKO modelling toolbox already calls the predictor API. As a case study, we predict across an E. coli model and find inter-predictor agreement varies with metabolic context and data availability.

systems biology↗

bioRxiv2026

Transcription factors read a second regulatory code in chromatin

Transcription factors (TFs) decode gene regulatory information written in DNA, yet how this vocabulary is interpreted within chromatin remains largely unexplored. Here, using an upgraded NCAP-SELEX platform, we systematically map the nucleosomal DNA recognition landscapes of 269 human TFs. We uncover a widespread, chromatin-dependent mode of sequence recognition: many TFs recognize motifs on nucleosomal DNA that are distinct from their canonical naked-DNA binding sites, revealing that nucleosome architecture encodes a second gene regulatory code in chromatin. Cryo-electron microscopy structures of TF-nucleosome complexes demonstrate that this second code is read through a combination of nucleosome-induced DNA deformation and direct protein-histone contacts. Functional analyses show that these chromatin-encoded motifs actively promote chromatin accessibility and drive cell-type-specific cis-regulatory activity in vivo. Strikingly, a single TF can deploy its canonical and nucleosome-derived motif repertoires to partition and govern entirely distinct physiological programs. Together, our findings establish that TFs interpret two complementary layers of genomic information: the primary DNA sequence and a second code written into the nucleosome architecture. This chromatin-encoded layer of regulatory information fundamentally expands our understanding of how TF specificity is achieved and how gene regulatory networks are wired in multicellular organisms.

systems biology↗

bioRxiv2026

Combining 3D-multispectral and hyperspectral imaging to identify environmental stress treatments imposed during plant growth

Non-invasive, high-throughput phenotyping tools are needed that can identify environmental effects on plant structure and function to diagnose factors responsible for reduced growth in commercial and non-commercial settings. In this study, we explored whether the integration of 3D-multispectral (3D) and 2D-hyperspectral imaging (HSI), aided by machine learning (ML), could be used to identify environmental stress treatments imposed during plant growth. Controlled environment-grown Nicotiana Benthamiana plants were subjected to a range of abiotic treatments - including different growth irradiances, heat treatment and drought stress - with the treatments resulting in differences in shoot height, biomass, leaf area and spectral reflectance. ML models were trained to identify these treatments using morphological and spectral traits measured at 27, 29, 31, and 34 days after sowing (DAS). A 3D-multispectral scanner was used to obtain information on plant height, biomass, and leaf area. A visible and near-infrared (VNIR) HSI camera provided detailed spectral information for deriving spectral indices including the Normalised Difference Vegetation Index (NDVI), Photochemical Reflectance Index (PRI) and Normalized Difference Red Edge (NDRE). Manual measurements provided baseline comparative data. The 3D-multispectral scanner reliably estimated above-ground traits, with high correlations between manual and scanner-derived measurements. The ML models accurately differentiated among environmental stress treatments, with the fused 3D+HSI model achieving the best overall predictive performance across all evaluated metrics compared with models based on either imaging modality alone. Results demonstrated the effectiveness of combining 3D-multispectral and 2D-HSI data with ML analyses for non-destructive, high-throughput phenotyping. The integration of these techniques enabled non-destructive, high-throughput identification of environmental stress treatments imposed during plant growth.

plant biology↗

bioRxiv2026

A lenvatinib-resistance-derived transcriptional program identifies metabolic identity remodeling associated with unfavorable survival in hepatocellular carcinoma

Background: Metabolic adaptation is a recognized feature of therapeutic resistance in hepatocellular carcinoma (HCC), but it is unclear whether transcriptional states exposed during acquired resistance are restricted to drug adaptation or reflect broader aggressive tumor biology. We tested whether metabolic programs derived from a lenvatinib-resistance model identify a clinically adverse transcriptional state in an independent HCC patient cohort. Methods: The discovery framework was based on GSE186191, comprising parental and acquired lenvatinib-resistant Hep3B and Huh7 cells. A pre-specified 33-gene lipid-source ledger served as a biological anchor, and three discovery-derived programs, MYC Targets V2, mTORC1 Signaling, and Fatty Acid Metabolism, were frozen before patient-level evaluation. In TCGA-LIHC, single-sample enrichment scores for the three programs were population-standardized and summed to generate an integrated metabolic score. Overall survival was assessed by Kaplan-Meier and Cox analyses. Whole-transcriptome differences between high- and low-score tumors were characterized by preranked gene set enrichment analysis (GSEA). Results: The survival cohort comprised 282 patients (118 deaths), with 141 patients in each median-defined score group. High-score patients had shorter overall survival (log-rank P=0.000419). The continuous score was associated with mortality in univariable analysis (HR 1.86, 95% CI 1.33-2.61; P=0.000293) and in the frozen model adjusted for age, sex, and stage indicators (HR 1.93, 95% CI 1.35-2.76; P=0.000350; n=277). In 327 primary tumors, Fatty Acid Metabolism was strongly depleted in high-score tumors (NES -2.06; FDR<0.001). MYC Targets V2 (NES 1.18; FDR=0.232) and mTORC1 Signaling (NES 1.11; FDR=0.229) showed positive directional enrichment without FDR significance. Conclusions: A lenvatinib-resistance-derived transcriptional program is associated with an adverse-survival state in HCC. The strongest patient-level pathway feature is depletion of canonical fatty-acid metabolism, accompanied by directional MYC/mTORC1 features rather than statistically established pathway activation. These findings support a testable model of metabolic identity remodeling but do not establish causality or clinical prediction of lenvatinib response.

cancer biology↗

bioRxiv2026

Spatial vascular/BTB remodeling and malignant-state plasticity in glioblastoma

Background: Glioblastoma (GBM) contains spatially heterogeneous malignant and vascular states, but blood-tumor barrier (BTB) remodeling is often described as a binary functional phenotype. We asked whether anatomically distinct GBM compartments contain separable vascular programs that coexist with malignant-state plasticity. Methods: We performed donor-aware cross-sectional analyses of 38 histopathology-annotated spatial transcriptomic sections from 6 donors and a separately analyzed endothelial single-nucleus layer from the same GBM-Space atlas. Complementary external datasets tested patient-paired regional remodeling, anatomical replication, cross-technology source localization, and malignant-state architecture. Results: THSD1-FLT4 Recognition increased from leading edge to infiltrative tumor (median adjusted effect +0.02875; 4/4 donors positive). Priming increased across this boundary (+0.14814; 3/4) but decreased from infiltrative to cellular tumor (-0.16409; 0/4), whereas Gate remodeling increased from infiltrative to cellular tumor (+0.21296; 4/4). Remodeled endothelium showed higher PLVAP detection (+0.26409; 12/12 donors) and PLVAP pseudobulk expression (+1.61784 log1pCPM; 11/12), with lower MFSD2A pseudobulk expression (-0.71448; 10/12 negative). External cohorts supported regional vascular/BTB remodeling, while GSE131928 supported broad malignant-state architecture and an exploratory within-tumor pseudotemporal continuum. Conclusions: GBM contains spatially partitioned vascular/BTB-associated programs alongside malignant-state plasticity. Recognition-Priming-Gate is a cross-sectional discovery framework, not a validated temporal cascade, and the data do not establish BTB permeability, causal tumor-vascular signaling, or therapeutic-delivery benefit.

cancer biology↗

bioRxiv2026

Discovery of a taxusin-mediated route to baccatin III enables its complete biosynthesis in engineered microbes

Taxol (paclitaxel) is a frontline anticancer drug widely applied for the treatment of breast, ovarian and lung cancers. Currently, its supply mainly relies on the semi-synthesis using baccatin III from Taxus plants. Heterologous biosynthesis of baccatin III in microorganisms offers a promising solution to alleviate global Taxol supply shortage, but remains challenging due to pathway complexity. Here, we report a novel taxusin-mediated biosynthetic pathway for baccatin III production via the identification of C13 deacetylase, elucidation of the exact sequence underlying C1 hydroxylation, and stepwise enzymatic functional validation. Through protein engineering of the promiscuous C1 and C5 hydroxylases, coupled with the distribution of pathway modules in Saccharomyces cerevisiae and Escherichia coli, we achieved the de novo biosynthesis of baccatin III. Collectively, our findings remodel the current biosynthetic framework governing the formation of Taxol precursors and highlight the great potential of microbial cell factories for the production of complex plant-derived therapeutic compounds. Highlights* Discovery of C13 deacetylase reveals a novel biosynthetic route to baccatin III via taxusin * Stepwise verification of the complete biosynthetic route to baccatin III through taxusin and baccatin VI * Single-site mutation reversed the product selectivity of T1OH and converted T5OH into a specific taxoid C5 hydroxylase * Complete biosynthesis of baccatin III in engineered microbes

synthetic biology↗

bioRxiv2026

Protracted Maturation of Proactive and Reactive Systems Predicts Cognitive Stability and Psychopathology : A longitudinal multi-cohort study

Inhibitory control matures progressively from childhood to early adulthood, yet the neural mechanisms driving this development and their relevance to psychiatric risk remain poorly understood. Guided by the Dual Cognitive Control model, we leveraged longitudinal fMRI from two independent cohorts in the US (ABCD, ages 9-12) and Europe (IMAGEN, ages 14-22) to map the spatiotemporal dynamics of reactive and proactive control using novel single-trial modeling and representational similarity analysis. We found both reactive and proactive stopping networks stabilize after mid-adolescence, tracking the developmental patterns of inhibitory control and behavioral stability. By decoding trial-by-trial fluctuations along a speed-caution continuum, we demonstrate that brain-behavior coupling to a proactive "Safe state" tightens progressively with age. Furthermore, network-level representational coherence of this Safe state emerged as a scanner-invariant, trait-like biomarker that robustly predicted inhibitory control, behavioral stability, and transdiagnostic psychopathology across multiple developmental windows, providing a validated neural phenotype for precision psychiatry.

neuroscience↗

bioRxiv2026

SALL2 constrains TEAD4 by maintaining repressive chromatin to restrict trophectoderm identity

Embryonic development is marked by the successive restriction of developmental potential and the specification of embryonic and extraembryonic lineages. Yet, how these lineage decisions are established, and how the epigenome is remodelled to promote and restrict cell fate transitions, remains poorly understood. Here, we demonstrate that SALL2 knockdown in primed human pluripotent stem cells (hPSCs) triggers a trophectoderm (TE)-like phenotype, characterized by palisade-like morphology and the up-regulation of TE-associated genes. Mechanistically, SALL2 physically interacts with the key TE driver TEAD4 and maintains bivalent, repressive chromatin (H3K4me3/H3K27me3) at TE-specific loci. Reduced SALL2 led to enhanced TEAD4 occupancy and disrupted H3K27me3 and increased active chromatin marks at TE genes. Importantly, depletion of TEAD4 abolished the TE-like phenotype induced by SALL2 knockdown, demonstrating that TEAD4 is required for the downstream effects of SALL2 loss. In support of this, blastoid-like aggregates can be generated from primed hPSCs with SALL2 knocked down. Together, our findings identify SALL2 as a key epigenetic barrier that restrains TE lineage commitment by limiting TEAD4-dependent activation of the trophoblast transcriptional program. Key findingsO_LISALL2 acts as a molecular barrier to trophectoderm differentiation. C_LIO_LISALL2 suppresses the trophectoderm by maintaining bivalent repressive chromatin at TEAD4-bound loci. C_LIO_LIBlastoid-like structures can be generated from primed-state media when SALL2 was knocked down. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=91 SRC="FIGDIR/small/737659v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@42cafaorg.highwire.dtl.DTLVardef@11c040borg.highwire.dtl.DTLVardef@4d9ffborg.highwire.dtl.DTLVardef@42546a_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2026

A glycoRNA switch for malignancy: SNORA73B activates TIAR-dependent oncogenic signaling in lung adenocarcinoma

Although glycosylated small non-coding RNAs are emerging players in cancer, their functions in lung adenocarcinoma (LUAD) are largely unknown. We identify SNORA73B as a glycosylated small nucleolar RNA (glycol-snoRNA) that carries sialic acid-capped O-glycans in both normal lung epithelial and LUAD cells. SNORA73B is markedly elevated in LUAD, and its plasma levels distinguish early-stage LUAD from healthy controls with an area under the curve (AUC) of 0.7903. Subcellular fractionation reveals predominant nuclear localization. Functional assays demonstrate that SNORA73B depletion curbs LUAD cell proliferation, migration, and invasion, whereas its overexpression fosters these malignant phenotypes and accelerates tumor growth. Mechanistically, SNORA73B directly binds the T-cell-restricted intracellular antigen-related protein (TIAR), thereby enhancing TIAR protein abundance without affecting its mRNA levels. TIAR then recognizes the 3-untranslated region (3-UTR) of MYC mRNA to upregulate c-Myc, which subsequently augments AKT phosphorylation. Importantly, c-Myc knockdown largely rescues the oncogenic phenotypes and tumorigenesis induced by SNORA73B overexpression. Collectively, our data unveil a glycoRNA-dependent oncogenic axis SNORA73B-TIAR-c-Myc-AKT that drives LUAD progression. These findings position SNORA73B as a promising early diagnostic biomarker and a candidate therapeutic target in LUAD.

Cancer Biology↗

bioRxiv2026

Targeting pathogenic VWF/ADAMTS13 dysregulation attenuates CTEPH progression

Chronic thromboembolic pulmonary hypertension (CTEPH) is a life-threatening pulmonary vascular disease, characterized by persistent thrombotic obstruction and progressive pulmonary vascular remodeling, yet the molecular mechanisms linking persistent thrombosis to vascular remodeling remain incompletely understood. Clinical studies have reported elevated plasma von Willebrand factor (VWF) levels and reduced ADAMTS13 in patients with CTEPH, but whether VWF/ADAMTS13 dysregulation contributes directly to disease pathogenesis remains unclear. Here, using newly established rat models of CTEPH, we identify a causative role for dysregulation of the VWF-ADAMTS13 axis in chronic thromboembolic progression. CTEPH rats developed persistent, unresolved VWF- and fibrin-rich thrombi accompanied by markedly increased endothelial VWF deposition. In contrast, ADAMTS13 expression and activity were significantly reduced in CTEPH rats. Consistent with these findings, genetic Adamts13 deficiency further exacerbates pulmonary microvascular thrombosis and accelerated early mortality following disease induction. Mechanistically, ultra-large (UL)-VWF accumulated on the pulmonary endothelial surface, promoting robust platelet recruitment under shear. This platelet-VWF interaction stimulated the release of platelet-derived pro-remodeling mediators, including TGF-{beta}1 and PDGF-BB. Genetic ablation of Vwf markedly reduced in situ microvascular thrombosis within pulmonary arterioles, attenuated pulmonary arterial remodeling, and improved pulmonary hemodynamics. Moreover, treatment with recombinant ADAMTS13 reduced endothelial UL-VWF accumulation, suppressed platelet activation, and effectively prevented thrombosis and platelet-driven pro-remodeling signaling in CTEPH rats. Collectively, these findings identify dysregulation of the VWF-ADAMTS13 axis as a key driver of pulmonary thrombosis and vascular remodeling in CTEPH and support therapeutic targeting of this pathway as a potential disease-modifying strategy. Key PointsO_LIVWF-ADAMTS13 dysregulation promotes persistent pulmonary thrombosis and platelet-driven arterial remodeling within pulmonary arterioles. C_LIO_LIRecombinant ADAMTS13 treatment or VWF ablation abrogates pulmonary arterial thrombosis and halts vascular remodeling in CTEPH. C_LI

pathology↗

bioRxiv2026

Genetically encoded systems for cytosolic activity recording and molecular archiving across time

Cellular functions are governed by dynamic changes in molecular abundance, state, activity, and interactions within the cytosol. Current molecular tape recorders leverage nuclear transcriptional programs in eukaryotic cells to provide scalable readout of gene regulation dynamics, but cytosolic activity, molecular abundance, and state remain inaccessible. Here, we introduce CyTRACE, a genetically encoded, scalable framework for cytosolic activity recording and molecular archiving across time. CyTRACE ventures beyond the cell nucleus, deploys cytosol-localized protein tape monomers as direct activity sensors and molecule catchers, and offers physiological sensitivity, spatiotemporal resolution, and programmability. Within this modular framework, CytoSense records protease and kinase signaling activities while CytoCatch archives cytosolic proteins, each with temporal continuity in single mammalian cells. CyTRACE thus opens cytosolic biology to scalable activity readout and molecular interrogation.

Synthetic Biology↗

bioRxiv2026

Structural Basis of Nidovirus Replication Organelle Evolution Revealed by the Arterivirus DMV Pore Complex

Positive-strand RNA viruses of the order Nidovirales - which include coronaviruses and arteriviruses - remodel host membranes into double-membrane vesicles (DMVs) as replication organelle to shield viral RNA synthesis from immune sensors. In coronaviruses, newly synthesized RNA is exported to the cytoplasm through a massive DMV pore complex formed by viral non-structural proteins (nsps). However, it remains unknown whether this elaborate architecture is unique to large-genome coronaviruses or a universal hallmark of the order. Here, we integrate in situ cryo-electron tomography and single-particle cryo-electron microscopy to resolve the atomic structure of DMV pore complex within its native membrane environment, from Equine Arteritis Virus (EAV), a prototype arterivirus with small genome. Despite lacking obvious sequence homology, the minimal EAV pore shares conserved architectural principles with its elaborate coronavirus counterpart. EAV pore complex is formed by a 12:12 stoichiometry of nsp2 and nsp3 protomers organized into four stacked concentric rings on double-membrane, yet generating pronounced structure symmetry mismatch. Functionally, the complex displays a distinct pore profile while preserving a positively charged central channel, essential for viral replication and transport. These findings demonstrate that, despite diversity in genome size and virion morphology, nidovirus replication organelles exhibit striking evolutionary conservation at the atomic structural level. Collectively, we propose that the order Nidovirales can be unified at the ultrastructural level by this conserved signature pore complex on the DMV-based replication organelle.

microbiology↗

bioRxiv2026

EXO1 Facilitates MiDAS and Prevents Genome Instability and Cell Death in Ewing Sarcoma

Ewing sarcoma (EwS) is an aggressive malignancy driven by EWSR1::ETS fusions, predominantly EWSR1::FLI1. Previous efforts using both direct and indirect approaches to target these chimeric oncoproteins have yielded limited clinical benefit. Although EWSR1::FLI1 is a well-known source of replication stress and genome instability, targeting DNA damage response (DDR) factors that mitigate these effects remain poorly understood. Here, we identified a marked dependency of EwS cells on exonuclease 1 (EXO1). We demonstrate that EXO1 is essential for EwS cell survival and tumor growth, highlighting its potential as a novel therapeutic target. Intriguingly, we unveil that EXO1 loss impairs mitotic DNA synthesis (MiDAS), promoting EWSR1::FLI1-associated genome instability and cell death. Collectively, our results support the idea that targeting DDR factors, which counteract replication stress and/or DNA damage induced by fusion oncoproteins, represents a promising therapeutic option for EwS.

cancer biology↗