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Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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Conditional Myeloid-Specific Inhibition of UBE2N Hinders YUMM1.7 Growth

The role of UBE2N in myeloid cell-mediated immune suppression in cancer remains undefined. Here, we examined the function of UBE2N in myeloid cell-mediated tumor progression using a temporally inducible myeloid-specific knockout model (LysMCreERUbe2nfl/fl). Temporally induced deletion of Ube2n in myeloid cells (Ube2nMyeKO) significantly hindered growth of YUMM1.7 melanoma. This was accompanied by reduced myeloid cell burden within the tumor microenvironment. We observed altered abundance of PD-1, PD-L1, and SPP1 in the Ube2nMyeKO tumor microenvironment at the tissue level. In vitro analysis showed that knock-in expression of a catalytically deficient UBE2NC87S mutant in bone marrow-derived macrophages (BMDMs) markedly decreased expression of Spp1. We observed decreased SPP1 secretion in Ube2nMyeKO BMDM-conditioned media (CM). Treatment with Ube2nMyeKO BMDM-CM decreased co-expression of PD-1, TIM-3, and LAG-3 on chronically stimulated T cells. Antibody-mediated neutralization of SPP1 in Ube2nWT BMDM-CM decreased PD-1 expression on CD8+ T cells. Together, these findings suggest a role for myeloid UBE2N in YUMM1.7 progression.

cancer biology

Designing antimicrobials with programmable mechanism and safety

Antimicrobial peptides (AMPs) are a promising solution to antimicrobial resistance, yet generative models for their design cannot control the physicochemical properties and motifs that shape activity and selectivity. Here, we present OmegAMP, a conditional diffusion framework controlling net charge, mean hydrophobicity, and sequence length, supporting de novo, analog, and motif-guided design. Across 204 wet-lab characterized peptides, de novo generation yielded antimicrobials with broad activity against multidrug-resistant Gram-negative isolates. Analog generation converted six inactive prototypes into antimicrobials, with the prototype determining each analog's membrane-disruption mode and mammalian-cell safety. Motif-guided analog generation preserved lipopolysaccharide engagement of active prototypes, and a redesigned non-antimicrobial leucine zipper acquired antimicrobial activity while retaining DNA-perturbing character in vitro. In murine skin and thigh infection models, leads reduced bacterial burden, with a motif-guided DNA-perturbing lead matching the fluoroquinolone control systemically. OmegAMP opens a programmable route to new peptide antibiotics whose mechanism and safety follow from the chosen prototype.

bioinformatics

A Sequential Assembly Mechanism for Stable Cdc13 Dimerization on Telomeric DNA

The telomere-binding protein Cdc13 specifically binds to single-stranded telomeric DNA, playing a critical role in telomere protection and length regulation. While extensive biochemical, molecular biological, and genetic studies have shown that Cdc13 can form dimers or oligomers in solution and bind telomeric DNA with high specificity, the dynamic mechanism of its loading onto telomeres is less well characterized. Using two single-molecule methods, single-molecule fluorescence resonance energy transfer (smFRET) and colocalization single-molecule spectroscopy (CoSMoS), we demonstrate that Cdc13 initially loads onto telomeres as a monomer. This is followed by the recruitment of a second monomer, forming a stable Cdc13 dimer on a 12-nucleotide telomeric DNA segment. Although genetic studies suggest that monomeric Cdc13 binding alone is insufficient to maintain telomere length, it underscores the Cdc13 monomers regulatory importance in coordinating telomere synthesis and protection. This monomer-to-dimer transition provides a mechanistic basis for understanding the multi-tasked roles of Cdc13 in telomere replication and protection.

biophysics

Learning and forecasting shared evolutionary pathways to multi-drug resistance across global pathogens

Infections with bacteria which have evolved multi-drug resistance (MDR) cause millions of deaths worldwide. Large-scale efforts are gathering genotypic and phenotypic data on MDR bacteria, but methods for learning the structure, diversity, and predictors of evolutionary pathways to MDR have yet to take full advantage of these data. Here, we use evolutionary accumulation modelling (EvAM), an emerging class of machine learning methods with roots in cancer progression, to infer these evolutionary pathways across ESKAPEE pathogens (seven bacterial species that dominate health burdens), using a database of over 635k genotyped phenotypic observations from around the world. We identify global patterns in MDR evolutionary pathways, remarkably shared across multiple ESKAPEE species. Species-specific deviations from these stereotypical pathways are connected with geographical and demographic covariates, facilitating predictions of future MDR evolution. We verify these predictions with several hundred new phenotypes from ESKAPEE samples spanning decades of clinical infections in sub-Saharan Africa, demonstrating the capacity to forecast future MDR evolution from these inferred shared pathways.

evolutionary biology

Euchromatin Peripheral Organization Follows Anterograde Signalling Under Anaesthetic Stress

Anterograde and retrograde signalling establish bidirectional communication between the nucleus and chloroplasts. Retrograde signals from chloroplasts regulate nuclear gene expression while anterograde signals from the nucleus coordinate chloroplast development and maintain cellular homeostasis. How this bidirectional signalling framework extends beyond locus-specific regulation to shape the global spatial organization of nuclear chromatin across tissues remains unclear. Although anaesthesia can alter chromatin organisation, the role of chloroplast dysfunction in these changes remains unclear. Here, we investigate how chloroplast dysfunction and anaesthesia influence euchromatin and heterochromatin organisation in Solanum lycopersicum seedlings across tissues with contrasting photosynthetic competence. Using confocal and super-resolution radial fluctuation (SRRF) imaging with quantitative multiparameter analysis, we identify distinct, tissue-specific chromatin responses to chloroplast disruption and anaesthesia. Notably, anaesthesia induces distinct spatial chromatin changes across tissues that are independent of chloroplast dysfunction, suggesting a direct nuclear response to anaesthesia rather than a chloroplast-mediated retrograde effect. These findings highlight chromatin topology as a potential quantitative biomarker of cellular disruption and provide a framework for investigating anterograde chloroplast-nucleus coordination and stress-responsive nuclear organisation in plants.

plant biology

Nuclear Myosin VI stabilises Ku-associated DNA ends during non-homologous end joining

DNA double-strand breaks (DSBs) require rapid signalling and physical stabilisation of broken DNA ends to preserve genome integrity. Here, we identify myosin VI (MVI) as an ATM-regulated component of the DSB response. DNA damage induces rapid nuclear accumulation and nanoscale reorganisation of MVI across multiple cell models, in an ATM-dependent manner. Pharmacological or genetic perturbation of MVI attenuates {gamma}H2AX signalling and disrupts Ku80 organisation, while DNA damage persists. This leads to increased sensitivity to cisplatin and bleomycin. Super-resolution imaging reveals spatial association of MVI with Ku80-containing repair structures, implicating MVI in non-homologous end joining (NHEJ). In a minimal reconstituted system, MVI and actin enhance the proximity of Ku70/80-bound DNA ends. Together, our findings identify MVI as a regulator of DSB repair that links ATM signalling to Ku-associated DNA-end stabilisation and suggest that targeting MVI may sensitise tumour cells to genotoxic therapy.

cancer biology

Dendritic hotspots support switching between competing rules without expanding the cortical engram

Adaptive behavior requires updating responses when contingencies change while preserving prior associations and the capacity to learn a new. How this trade-off is resolved remains unknown. Here, we combined in vivo imaging of apical tuft spines in the secondary motor cortex (M2) with biologically constrained network modeling in mice performing a cross-modal rule-switch task. M2 inactivation impaired rule-switching but not learning or maintenance, identifying it as a conflict resolution substrate. Adaptation was accompanied by elevated spine turnover concentrated within stable dendritic hotspots, in which the formation, elimination and clustering of new spines were coupled and pre-existing spines were lost early. A network model reproduces these dynamics and predicts that dendritic hotspots are critical for resource-efficient adaptation. Within these reusable domains, spines encoding the prior rule are replaced by newly-relevant ones via sharing of plasticity-related resources. Preventing reuse increases both the plasticity and the engram size requirements to encode the two rules. We propose that dendritic hotspots provide a mechanistic substrate for efficient adaptive learning.

neuroscience

Male Age and Sexual Maturity: Lipopolysaccharide-induced tumor necrosis factor influences sperm quality and reproduction in Anopheles culicifacies

Elucidating the biological and molecular mechanisms that govern male fertility and mating behavior in mosquitoes is critical for optimizing genetic and sterile insect technique-based vector control strategies. Here, we examined age-related changes in male reproductive capacity in Anopheles culicifacies, using female egg output as an indirect indicator of male fertility. Our results demonstrated that male reproductive age follows a non-linear pattern of fertility. Morphometric analysis from emergence to day 13 post-eclosion revealed a strong correlation between seminal vesicle capacity and female fecundity, suggesting that age-dependent gonadal development directly influences reproductive potential. At the molecular level, we identified AcLITAF6 as a key regulator of male reproductive homeostasis. RNAi-mediated knockdown of AcLITAF6 impaired apoptosis-associated and phagocytic clearance, reduced sperm viability, and decreased female productive outcomes. Conclusively, we reveal a previously unrecognized role of LITAF in sperm quality control and male reproductive fitness, highlighting AcLITAF6 as a potential target for mosquito population suppression strategies.

developmental biology

Estimating age and annual tooth growth rates in narwhals (Monodon monoceros) using computed tomography

The spiraling tooth of the narwhal (Monodon monoceros) has long intrigued scientists, but the growth rates of its "tusk" are poorly constrained due to the difficulty to age narwhal. To learn more about the population dynamics and life history of this exploited species, previous studies have used sectioned teeth to age narwhals and calibrate other ageing methods based on aspartic acid racemization, radiocarbon or trace element analysis. However, few such studies have been conducted due to the method's difficulty and the need to sacrifice the tooth. In this study, computed tomography (CT) was used on five teeth as a non-destructive means of estimating the age of narwhals, revealing different growth rates between erupted and embedded teeth during adolescence. Moreover, in combination with our reanalysis of all relevant literature, CT data clarify the annual growth rates of narwhal tusks, which peak before the age of 10 (~100 mm yr-1). This approach will be useful for investigating private and museum collections, and might also better constrain the use of trace element proxies in narwhal teeth and support sustainable harvest management.

zoology

Seed Microbiome Transfer Mitigates Intergenerational Dysbiosis, Modulates Plant Defenses and Suppresses Foliar Disease

Antibiotic-induced disruption of plant-associated microbiomes has the potential to alter host health beyond the directly exposed generation, yet whether the effects of dysbiosis are transmitted through the seed microbiome remains unknown. Here, we investigated the intergenerational impacts of streptomycin-induced dysbiosis in tomato (Solanum lycopersicum), demonstrated that seed microbiome transfer (SMT) restores progeny microbiome function and disease resistance, and characterized the underlying physiological and genetic mechanisms. Parental streptomycin exposure altered the composition of progeny rhizosphere bacterial communities, reduced expression of defense-associated genes, and increased susceptibility to Xanthomonas perforans. Suppression of immune gene expression was strongly associated with increased disease severity, indicating that parental dysbiosis impaired progeny plants ability to mount effective immune responses. Transfer of the seed microbiome from healthy plant donors partially restored rhizosphere community composition, reduced disease severity and recovered defense gene expression of three genes. Together, our findings demonstrated that antibiotic exposure microbiome disturbance generates intergenerational legacy effects that influence plant immunity and disease susceptibility and seed microbiome transfer can counteract this dysbiosis across generations.

plant biology

A structural census links penultimate-residue class to N-terminal burial in human protein assemblies

Initiator-methionine excision is among the earliest protein modifications, yet its relationship to assembly geometry is unknown. Burial of the mature first residue was measured across 7,246 deposited human biological assemblies (22,291 chain-level observations; 1,191 proteins). Among 1,143 analyzable proteins, termini in MetAP-permissive penultimate-residue sequence classes were less often interface-engaged than termini in MetAP-nonpermissive classes (37.4% versus 47.4%; adjusted odds ratio 0.65, p = 7.2e-4). Curated processing annotations did not show a corresponding burial difference, and correlated residue properties preclude attributing the sequence-class association specifically to iMet removal. The analysis identified 264 interface-engaged MetAP-permissive candidates concentrated in cellular machines. In a fully recomputed conformer scan of deeply buried proteasome positions, modeled methionine accommodation was less favorable than at observed-methionine controls (median overlap -0.30 versus -1.12 angstrom, p = 0.0049), although most scoreable sites permitted a nonoverlapping placement. The census therefore reveals a graded structural constraint - not universal steric failure - and prioritizes complexes in which altered packing, assembly kinetics, lipidation or N-terminal methylation can be tested.

biochemistry

Comparison of evolutionary rescue via biological and cultural evolution

Rapid evolution allows populations to persist in environments where they would otherwise go extinct. This phenomenon, known as evolutionary rescue, is typically studied in the framework of biological evolution, yet adaptive traits can also arise and spread through cultural evolution. The present study developed a stochastic eco-evolutionary model to compare rescue probabilities through biological and cultural evolution. Transmission bias governed the rescue probability under cultural evolution by setting how readily a rare adaptive trait was copied. Conformity bias suppressed population persistence because a rare trait was the least likely to be copied. Content bias toward the adaptive trait enabled evolutionary rescue when social learning was rapid, but it typically yielded a lower rescue probability than biological evolution. Only anticonformity bias, together with a high social learning rate, exceeded the rescue probability of biological evolution by enabling the adaptive trait to be established more rapidly. These results demonstrate that transmission bias alters the demographic consequences of cultural evolution and highlight the importance of transmission processes in evolutionary rescue theory. Understanding how adaptive behaviours are socially transmitted may also improve predictions of animal population persistence and inform conservation efforts in rapidly changing environments.

evolutionary biology

Integrated Transcriptomic and CRISPR Dependency Analysis Prioritizes a CDK1-AURKB Mitotic Vulnerability Axis in Diffuse Intrinsic Pontine Glioma

Diffuse intrinsic pontine glioma (DIPG), now classified within diffuse midline glioma, H3K27-altered, remains a lethal pediatric brainstem tumor with limited therapeutic options. Here, we integrated public DIPG transcriptomic datasets, protein-protein interaction modeling, functional enrichment, immune deconvolution, survival analysis, and DepMap CRISPR dependency data to nominate candidate mitotic vulnerabilities. Differential expression analysis comparing 27 DIPG tumors with 6 brainstem low-grade glioma comparator samples identified a proliferative transcriptional program enriched for chromosome segregation, nuclear division, and cell-cycle pathways. Network analysis prioritized a compact mitotic hub module containing CDK1, AURKB, TOP2A, CDC20, CDCA8, and related G2/M regulators. CIBERSORT analysis of an independent DIPG cohort inferred low cytotoxic T-cell signal, consistent with an immune-cold phenotype, although immune-cell fractions require orthogonal validation. Survival analysis showed that neither inferred immune scores nor a composite mitotic hub score significantly stratified overall survival. DepMap CRISPR gene-effect data nominated CDK1, AURKB, TOP2A, and BIRC5 as candidate dependencies across brain tumor models. These findings provide a computational framework for prioritizing mitotic vulnerabilities in DIPG and support experimental validation in disease-relevant models.

bioinformatics

An egocentric map prioritizing peri-personal space in the mouse rostro-lateral visual area

All physical interactions between an organism and its environment occur within the space immediately adjacent to and surrounding its body, its peripersonal space (PPS). This space has been extensively studied behaviorally in humans, and through sparse single-neuron recordings in primates. However, how PPS is represented and organized at cellular and circuit scales remains poorly understood. Here, using dense extracellular recordings in the mouse rostro-lateral visual cortex (VISrl; >19,000 single units), we reveal the cellular and circuit organization of PPS in mice. Visuo-tactile neurons prioritize near-body space while also representing farther space in a direction-selective manner, tracking approaching but not receding objects across the environment. VISrl PPS neurons integrate vision and touch nonlinearly, and their tactile responses are progressively facilitated as visual objects near the body. PPS neurons are embedded in structured networks characterized by "like-to-like" functional connectivity and remap according to recent visuo-tactile statistics. Together, these findings establish VISrl as a circuit-accessible substrate for PPS, and reveal how near-body space is represented by a dynamic, plastic, multisensory cortical network.

neuroscience

A patient-derived LMX1B variant causes tissue-specific manifestations of nail-patella syndrome in mice

Nail-patella syndrome (NPS) is a multisystem disorder caused by pathogenic variants in LMX1B and is characterized by dysplasia of the nails and patellae as well as extraskeletal complications such as progressive nephropathy and glaucoma. We generated a CRISPR/Cas9 knock-in mouse carrying the R252Q substitution, corresponding to a human LMX1B variant associated with renal-predominant disease. Phenotypic analysis revealed that homozygous mice were viable, but they displayed marked growth retardation and severe bilateral ocular opacity. Interestingly, while this model exhibited clear skeletal and ocular defects, the renal phenotype was relatively mild, although increased urinary albumin excretion, focal glomerular basement membrane abnormalities, and subtle changes in renal gene expression were detected. Beyond the classical NPS hallmarks, mutant mice also displayed midbrain morphological abnormalities, suggesting broader developmental consequences of this LMX1B variant. This patient-derived variant model not only recapitulates the pleiotropic features of NPS but also demonstrates organ-specific susceptibility to the R252Q substitution, providing a foundation for elucidating the complex molecular mechanisms underlying multisystem disease.

genetics

Dog-wise canine gut metagenome assemblies with reconstructed bacterial genomes and viral candidates

Long-read metagenomic sequencing can improve genome recovery from complex gut microbial communities, yet directly reusable canine gut genome resources remain limited. Here we describe DogMAG, a canine gut metagenome resource based on dog-wise long-read and hybrid assemblies generated by grouping sequencing libraries according to canonical dog identity before assembly. The final dataset comprises 41 assemblies linked to 277 FASTQ records, including 30 Flye long-read-only and 11 OPERA-MS hybrid assemblies. A single integrated BASALT workflow produced 11,276 selected bin/version records, followed by explicit quality-based re-selection of 3,418 medium-quality-or-better metagenome-assembled genome candidates. External dRep dereplication yielded 792 strain-like representatives at 99% average nucleotide identity and 135 species/SGB-like representatives at 95%. GTDB-Tk classified all 792 representatives as Bacteria. Viral screening identified 22,068 geNomad predictions, of which 3,374 Complete, High-quality or Medium-quality viral/proviral candidate rows passed CheckV filtering with contamination [≤]10%. DogMAG provides assemblies, genome and viral candidate sequences, metadata, provenance tables and workflow scripts for reuse, benchmarking and reanalysis.

microbiology

Uncertainty Quantification in Stochastic Dynamical Gene Regulatory Networks

The dynamics of gene regulatory networks are governed by intrinsic noise, stemming from the random nature of biochemical reactions, and by extrinsic noise, arising from fluctuations in cellular components and environmental conditions. Together, these sources can compromise the reliability of predictive computational models if not properly accounted for, and capturing both effects within a single framework remains a non-trivial task in computational biology. In this work, we propose an uncertainty quantification framework that addresses these two contributions jointly: intrinsic stochasticity is described through a partial integro-differential equation (PIDE) for the protein probability density function, whereas extrinsic noise is represented as parametric uncertainty in the kinetic parameters. The propagation of the uncertainty is carried out via an intrusive polynomial chaos expansion (PCE), in which the PCE coefficients are obtained from a stochastic Galerkin projection of the PIDE, yielding a coupled deterministic system that is solved with standard numerical methods. We illustrate the approach on a positive autoregulatory gene network with one and two uncertain kinetic parameters. The proposed approach accurately reproduces the mean, variance, and full protein probability density function, including the bimodal distributions, at a substantially lower computational cost.

synthetic biology

Proteolytic Remodeling of Cargo Receptor Networks by RHBDL4 Tunes Secretory Pathway Flux

Cargo receptors are central organizers of the secretory pathway, yet the mechanisms controlling their abundance remain poorly understood. The endoplasmic reticulum (ER)-resident intramembrane protease RHBDL4 promotes substrate turnover via a non-canonical branch of ER-associated degradation and has recently been implicated in regulating secretory pathway components. We previously identified the p24 cargo receptor TMED7 as an RHBDL4 substrate, suggesting that cargo receptor turnover contributes to secretory pathway regulation. Here, quantitative proteomics identify members of the ER-Golgi intermediate compartment (ERGIC) cargo receptor family as endogenous RHBDL4 substrates, demonstrating that RHBDL4 targets multiple cargo receptor families within the early secretory pathway. Accordingly, RHBDL4 modulates multiple ERGIC-dependent transport pathways. In addition, unbiased secretome analysis reveals increased secretion of lysosomal precursor proteins upon RHBDL4 ablation. Mechanistically, we show that this phenotype is mediated, at least in part, by RHBDL4-dependent cleavage of the lysosomal cargo receptor sortilin/SORT1. Together, these findings identify cargo receptors as a major class of RHBDL4 substrates and establish proteolytic remodeling of cargo receptor networks as a mechanism for regulating secretory pathway flux.

cell biology