Biology subjects

Gao, Y.

Publications and source records attributed to Gao, Y..

At least 73 records · Page 4Linked to original sources

bioRxiv2026

Perturbation of genes linked to common schizophrenia risk variants identifies cilia programs

Schizophrenia (SCZ) is a common psychiatric disorder characterized by psychosis, emotional withdrawal, and cognitive deficits. Most SCZ risk variants reside in non-coding regions of the genome and are thought to influence disease risk by modulating gene regulation. However, the target genes, biological pathways, and cell types through which these variants exert their effects remain poorly understood. To address this gap, we employed in vivo CRISPR droplet sequencing (CROP-seq) in the postnatal mouse neocortex. We perturbed 12 SCZ risk genes previously linked to functionally validated risk variants, followed by single-cell RNA sequencing. We identified 3,031 differentially expressed genes (DEGs) that recapitulate transcriptional alterations observed in postmortem SCZ brains. Integrative analysis using DEG clustering, factor analysis, and gene regulatory network inference uncovered convergent gene programs with distinct biological functions and cell type specificity. Notably, ciliary transcriptional programs consistently emerged across analytical frameworks. The primary cilium is a neurocircuit modulating signaling organelle in neurons and glia that remains understudied in SCZ. Perturbation of key contributors to the ciliary transcriptional programs led to significant alterations in ciliary structure, suggesting that SCZ genetic risk factors may influence how brain cells sense and transduce extracellular signals through synapse-independent mechanisms. Together, this study provides the first in vivo characterization of the functional consequence of common variant architecture in SCZ and implicates ciliary dysfunction as a convergent downstream mechanism.

neuroscience↗

bioRxiv2026

TetraFuse: A Synergistic Four-Dimensional Dynamic Fusion Framework for Efficient and Robust Medical Image Classification

Accurate and robust classification of medical pathology images is pivotal for computer-aided diagnosis. However, the deployment of deep learning models in high-throughput clinical screening faces a fundamental challenge: the trade-off between diagnostic accuracy and computational efficiency. Current lightweight architectures, while reducing parameter complexity through grouped convolutions, often lead to cross-channel information isolation and diminished representational capacity. In this paper, we propose TetraFuse, a novel framework that systematically integrates features from four complementary domains: space, channel, statistics, and frequency. TetraFuse introduces a novel Cross-Channel Dynamic Aggregation (CCDA) paradigm that reconstructs global channel topology with negligible computational overhead, resolving the inter-group isolation issue. To balance perceptual fidelity and efficiency, we design a stage-aware local enhancement mechanism: Local Variance-Guided Enhancer (LVGE) is employed to filter out shallow-stage background noise, while High-Frequency Boundary Injection (HFBI) reinforces deep-stage pathological contours, preventing spatial over-smoothing. Experimental results on the COVID-19, ISIC 2018, and Kvasir datasets confirm that TetraFuse outperforms state-of-the-art (SOTA) methods. Notably, TetraFuse-Tiny achieves a transformative 91.53% reduction in FLOPs compared to ResNet50; on the Kvasir dataset, it achieved an accuracy of 0.926 and an AUC of 0.994 with only 0.345G FLOPs. By combining high representational power with minimal computational demand, TetraFuse offers a scalable solution for large-scale medical image analysis, especially in resource-constrained clinical environments.

bioinformatics↗

bioRxiv2026

Fluorescently-labeled split-QF hemidrivers: simplifying and enhancing methods enabling intersectional targeting of discrete cell types

Single cell transcriptomics data predict greater cell type diversity than previously appreciated, defined by combinatorial gene expression "codes". These codes can enable intersectional targeting strategies for selectively labeling and manipulating predicted cell types, thereby facilitating functional tests to resolve cell-specific roles and refine cell-type definitions. One such approach cleaves driver components of binary expression systems (e.g., Gal4/UAS and QF/QUAS) into two co-dependent halves, an Activation Domain (AD) and a DNA Binding Domain (DBD). The transcriptional activity of these "split-drivers" (aka, hemidrivers) is only reconstituted in cells that co-express them. While widely used in invertebrates, these systems have yet to be systematically deployed in vertebrates. Here, we developed a series of fluorescently labeled split-QF and QF2 hemidrivers via direct reporter fusions or the 2A viral peptide co-expression system. Fluorescent labeling serves to 1) simplify hemidriver transgenic line creation and maintenance, 2) allow AD and DBD intersects to be visualized directly, and 3) enable robust quality control assessments of on-target efficacy and off-target activity. These resources can enhance transgenic targeting specificity, enabling functional dissections of cell types revealed by single cell transcriptomics. SUMMARYWe engineered fluorescently labeled split-QF and -QF2 hemidrivers in zebrafish to simplify intersectional targeting tool generation and enable robust quality control assessments of split-driver function.

genetics↗

bioRxiv2026

Bacillus subtilis YpeB holds SleB inactive preventing cortex peptidoglycan degradation during spore dormancy

Bacterial endospores are encased in a thick layer of specialized peptidoglycan called the cortex that is essential for core dehydration and heat resistance. Spore germination and outgrowth requires cortex degradation by enzymes that are deposited in the spore during sporulation. How these enzymes are held inactive during dormancy and activated during germination remains poorly understood. In Bacillus subtilis and many other endospore-forming bacteria, one of the lytic enzymes, SleB, is encoded in an operon with its putative regulator YpeB. The two proteins depend on each other for stability, but whether and how YpeB inhibits SleB were unknown. AlphaFold predicts a high-confidence interaction between the two proteins with YpeBs PepSY domains embracing SleBs catalytic domain. Here, we demonstrate that the two proteins can be co-purified when expressed in E. coli. Furthermore, in B. subtilis spores, amino acid substitutions at the predicted SleB/YpeB interface destabilized both proteins, resulting in impaired spore germination in the absence of the functionally redundant cortex lytic enzyme CwlJ. Selection for germination-competent suppressors identified general and allele-specific suppressors in sleB or, separately, ypeB that stabilized both proteins. Altogether, our data support a model in which YpeB inhibits SleB in the dormant spore through direct interaction. We propose that YpeBs PepSY domains function as chaperone-inhibitors of SleB, akin to the role of pro-domains in protease zymogens. Chaperone dependence ensures that SleB proteins that fail to interact with YpeB remain unfolded and are ultimately degraded, while YpeB-bound SleB enzymes persist but are inhibited, preventing inappropriate cortex degradation during dormancy. IMPORTANCEBacterial spores are among the most resilient cell types in nature. Their ability to resist sterilization during dormancy yet rapidly germinate and resume growth are central to the transmission and pathogenesis of spore-forming pathogens. A key component of their resistance is a thick layer of specialized peptidoglycan called the cortex that encases them. The cortex maintains the spore core in a highly desiccated state by physically restricting its expansion. Germination and outgrowth requires the degradation of this essential envelope layer. The enzymes responsible for cortex degradation are deposited in the spore during sporulation. How these lytic enzymes are held in active during dormancy has been a longstanding question. One of these enzymes, SleB, is encoded in the same operon as its putative regulator YpeB. Here, we provide biochemical and genetic evidence that YpeB interacts with and inhibits SleB during dormancy. These findings lay the groundwork for elucidating how SleB is activated during germination.

microbiology↗

bioRxiv2026

Trichome acylsugar defenses are equally effective against leaf-mining and free-living insects

Trichomes are epidermal projections, crucial components of plant defense systems. Whether these epidermal defenses are effective against leafminers, which infest the internal mesophyll layers, remains unclear. Using the devasting invasive tomato pest, Phthorimaea absoluta (tomato leafminer), and the trichome-rich wild tomato, Solanum pennellii, we demonstrate that trichome produced acylsugars effectively inhibit the growth of endophagous P. absoluta larvae feeding inside leaves. High spatial resolution leaf- and frass-metabolite analysis by MALDI-MSI and Stimulated Raman Scattering microscopy revealed that trichome-synthesized acylsugars are translocated into the mesophyll tissues when larvae infest leaves. We identified an ATP-binding cassette (ABC) transporter, SpABCB5, as the mediator of this translocation and as an essential component of defense against leafminers. These data reveal that epidermal trichomes not only defend against free-living (ectophagous) herbivores through direct contact or rapid deposition of chemical defenses onto leaf surfaces, but also defend against endophagous leafminers by rapidly depositing chemical defenses into internal tissues. By delivering mines against leaf miners, trichomes offer new avenues for breeding crops with resistance to leafminers.

plant biology↗

bioRxiv2026

Restoring hippocampal sharp-wave ripples under glutamate transporter dysfunction

Disruption of glutamate homeostasis is believed to contribute to the early progression of Alzheimers disease (AD) and associated neurodegeneration. Soluble amyloid-{beta} oligomers impair excitatory amino acid transporters (EAATs), reducing glutamate clearance, while also enhancing glutamate release from neurons and astrocytes. Together, these effects produce persistent glutamatergic dysregulation that disrupts synaptic and network function. Here, we asked whether the effects of EAAT attenuation can be mitigated through ion-channel modulation. TBOA, a selective EAAT inhibitor, was used to model early-stage glutamatergic dysregulation. TBOA reduced the local field potential amplitude of hippocampal sharp-wave ripples (SWRs) in mouse hippocampal slices, suggesting that glutamate accumulation disrupts network synchrony. Calcium imaging further showed that TBOA diminished SWR-associated population calcium transients while promoting spontaneous calcium transients in individual neurons, indicating a shift from coordinated population activity toward disorganized cellular activity. KCNQ-channel openers ML213 and ICA-27243 partially restored the TBOA-induced decline in SWR amplitude. In contrast, similar restorative effects were not observed following modulation of other ion channels, including blockade of AMPA and NMDA receptors or HCN/Ih channels, or activation of large-conductance Ca2+-activated K+ (BK) channels and G-protein-activated inwardly rectifying potassium (GIRK) channels. Together, these findings suggest that KCNQ-channel openers may occupy a unique position in mitigating glutamate-related hyperexcitability during early AD-associated network dysfunction.

neuroscience↗

bioRxiv2026

A Moonlighting Function of Kinetochore Complex Proteins in Golgi Assembly of Neural Stem Cells

Kinetochores play an essential role in mitosis, and human kinetochore variants are associated with microcephaly. However, their functions in quiescent/interphase cells are unknown. Here, we demonstrate that Drosophila kinetochore proteins promote the reactivation of quiescent NSCs and their regeneration upon injury by organizing Golgi-dependent acentrosomal microtubules. Drosophila kinetochore proteins localize to the Golgi vicinity in quiescent NSCs and are required for proper localization of Golgi proteins, including the Golgi-resident small GTPase Arf1 known to regulate quiescent NSC reactivation and regeneration. Moreover, Drosophila kinetochore proteins physically associate with Arf1 and function upstream of it during reactivation. Remarkably, human kinetochore protein SPC25 localizes to Golgi in interphase NSCs and HEK293T cells. Furthermore, human kinetochores have a conserved function in promoting Golgi organization and, in turn, microtubule dynamics, in interphase cells. Together, our findings reveal a conserved moonlighting role for kinetochores in Golgi assembly in quiescent Drosophila NSCs and human interphase cells.

neuroscience↗

bioRxiv2026

Structural brain networks shape individual-level progression of brain atrophy after stroke

Stroke starts as a focal vascular lesion, but its structural consequences often extend beyond the lesion site, resulting in distributed brain atrophy whose organizing principles remain unclear. Here, using longitudinal MRI data from two stroke cohorts spanning the hyperacute to chronic stages, we tested whether and how post-stroke grey matter volume (GMV) change over time is constrained by large-scale brain networks across individuals. Coordinated deformation modelling showed that longitudinal GMV atrophy patterns were more strongly shaped by structural than by functional connectivity, with structural constraints already detectable in the acute phase. Network diffusion modelling further showed that atrophy patterns at 3 and 12 months were consistent with lesion-initiated propagation on the structural connectome, whereas model performance was weak in the early acute stage. The model-derived propagation stage did not increase monotonically with chronological time, indicating that it reflects the degree to which observed atrophy conforms to a network-consistent diffusion-like pattern rather than elapsed biological time. Inter-individual variation in propagation stage was associated with lesion size and with the topological and molecular properties of lesioned regions. Finally, lesion information combined with network diffusion modelling supported individualized prediction of later GMV atrophy patterns. These findings provide a network-based account of secondary degeneration after stroke and may inform individualized characterization of post-stroke structural reorganization.

neuroscience↗

bioRxiv2026

A graph-based pangenome reveals the genetic basis of climate-resilient and horticultural traits in pear

Climate change poses an increasing threat to the cultivation of deciduous fruit trees, placing greater demands on modern pear breeding. Using pear germplasm adapted to diverse environments, we assembled 11 chromosome-level genomes. In combination with 13 publicly accessible pear genomes, we analyzed presence-absence variations (PAVs) and constructed a graph-based pangenome for pear. By performing a PAV-eQTL analysis of the fruit of 123 pear accessions, we identified PAVs significantly associated with expression levels of genes that may be involved in regulating agronomic traits. Population analysis of 268 pear accessions revealed two stop-gained variants in DAM1 of independent origin, which may function in advancing the blooming date and reducing the chilling requirement. We detected complex PAVs at the NOR1 locus, including two copy-number variations and one deletion. These PAVs contributed to the rapid diversification of the NOR1 locus and the fruit development period through regulating ARF5 and other ripening-related genes. We revealed the selection history of the NOR1 locus and developed novel pear individuals that accumulated alleles for low chilling requirement, early blooming date, and short fruit development period. The results provide valuable resources for pear genomics research and offer a guideline for breeding modern pears with climate resilience.

plant biology↗

bioRxiv2026

Loss of nuclear-cytoplasmic compartmentalization is a hallmark of aging in podocytes

The nuclear envelope, with its nuclear pore complexes, establishes a selective barrier that maintains the spatial organization of the cellular proteome. Whether this barrier remains intact in long-lived postmitotic cells during aging is largely unknown. Here, we show that aging podocytes experience a progressive loss of nuclear-cytoplasmic compartmentalization. Using subcellular proteomics and quantitative imaging, we identify a global redistribution of proteins between the nucleus and cytoplasm, affecting key regulators of RNA processing, chromatin organization, and cellular metabolism. Loss of compartmentalization is accompanied by mitochondrial dysfunction, increased reactive oxygen species production, and aberrant nuclear accumulation of YAP1, linking nuclear barrier failure to metabolic and transcriptional dysregulation. These findings identify nuclear envelope dysfunction as a driver of proteome disorganization and cellular decline in aging podocytes and suggest that loss of nuclear-cytoplasmic compartmentalization represents a general mechanism contributing to dysfunction in long-lived cells.

cell biology↗

bioRxiv2026

Structural Activation of DNA Unwinding by MCM8/9/HROB

The minichromosomal maintenance MCM8 and MCM9 proteins form a heterohexameric complex that acts to unwind or remodel duplex DNA in DNA recombination and repair pathways. Mutations or absence of MCM8/9 have been linked to infertility, sex-specific deficiencies, and several cancers. Recently, HROB has been identified as a critical cofactor of MCM8/9; however, the mechanism underlying activation of MCM8/9 DNA binding and unwinding remain unclear. Here, we present dynamic structures of MCM8/9 with DNA, HROB and ATP analogs using cryo-electron microscopy. DNA binding induces a pronounced rotational rearrangement between the N-terminal DNA binding and C-terminal AAA+ ATPase domains, reorganizing DNA-binding loops into a staircase configuration that supports DNA engagement. Remarkably, HROB associates with both halves of the heterohexamer and drives a similar rotation prior DNA binding for localizing MCM8/9 to sites of crosslink damage and unwinding, culminating in a unified mechanistic model for MCM8/9 helicase function and its activation by HROB.

biochemistry↗

bioRxiv2026

cellNexus: Quality control, annotation, aggregation and analytical layers for the Human Cell Atlas data

Large-scale single-cell atlases such as the Human Cell Atlas have transformed our understanding of human biology. Yet, the lack of a robust framework that standardises quality control, expands cellular annotation, and adds normalisation and analytical layers, limits multi-study analyses and the usefulness of this resource. Here we present cellNexus, a comprehensive resource that enhances the Human Cell Atlas collection into analysis-ready data by linking quality control layers, metadata enrichment, expression normalisation, analysis and data aggregation. These enhancements enable robust large-scale statistical modelling across studies, exemplified here by a multi-tissue map of immune cell communication during ageing. All harmonised layers are accessible via a public web interface and with R and Python APIs. By providing continuous integration with CELLxGENE releases, cellNexus transforms large cell atlas corpora into an accessible, reproducible, interoperable foundation for large-scale biological discovery and the next generation of single-cell foundation models.

bioinformatics↗

bioRxiv2026

Multiscale Mechanisms of Human Memory Modulation by Deep Brain Stimulation

The highly variable effects of deep brain stimulation (DBS) on cognition highlight a fundamental gap in our understanding of how external perturbations interface with the brains ongoing, task-engaged state. The current study addressed this challenge by combining intracranial EEG recordings with hippocampal DBS stimulation in human participants during spatial sequence memory task. We found 50 Hz stimulation targeting hippocampal white matter enhanced memory performance, whereas 5 Hz stimulation targeting hippocampal gray matter impaired memory. These opposing behavioral outcomes were both governed by two dissociated mechanisms: a region-specific modulation of theta rhythms in an engagement-dependent fashion, and a global modulation of the fidelity of memory representations across the cortex. Our results suggest targeted stimulation can concurrently fine-tune specialized circuits and govern the brains global state, which not only offers a novel roadmap for understanding how external inputs shape human cognition, but also helps to design precise, state-dependent neuromodulation therapies.

neuroscience↗

bioRxiv2026

Ultra-sensitive FLORA-seq links cell-type-specific tRNAome dynamics to differentiation trajectories guiding therapeutic suppressor tRNA candidate selection

Mammalian genomes encode hundreds of tRNA genes, but the role of individual tRNAs in development and cell identity remains unclear. Here, we introduce FLORA-seq, a method for simultaneous, low-input profiling of tRNAs, tRNA-derived RNAs (tdRs) and their modifications from as few as 5-20 cells. Applying FLORA-seq to mouse hematopoiesis revealed 50 high-variance isodecoders whose expression profiles recapitulate known hematopoietic cell types and correlate with differentiation trajectories. At the isoacceptor level, tRNA pools are largely stable within hematopoietic stem and progenitor cells (HSPCs), showing only subtle, specific variations, but become both distinct from HSPCs and internally stable within each terminally differentiated lineage. We further detected dynamic changes in tdR ratios and modification patterns, underscoring precise tRNA regulation during differentiation. Crucially, analysis of 54 endogenous tRNA isodecoders and their engineered suppressor counterparts showed that efficient premature termination codon readthrough preferentially arises from highly expressed cognate isodecoders. This correlation provides a rational framework for prioritizing suppressor tRNA candidates and implies non-redundant functions for individual isodecoders.

molecular biology↗

bioRxiv2026

SIK3-HDAC4-Warts Axis Functions as a Gatekeeper of Neural Stem Cell Reactivation in Drosophila

A delicate balance between the quiescent and proliferative states of neural stem cells (NSCs) is important for neurogenesis and homeostasis. Histone deacetylase 4 (HDAC4) variants are associated with neurodevelopmental disorders, however, its role in early brain development remains elusive. In this study, we demonstrate that Drosophila HDAC4 plays a crucial role in neural stem cells (NSCs) reactivation and brain development. Depletion of HDAC4 results in notable defects in NSC reactivation, while its overexpression leads to premature reactivation. HDAC4 is SUMOylated at Lys902, which enhances its protein stability by preventing HDAC4 from undergoing ubiquitin-proteasome-mediated degradation. Moreover, phosphorylation of HDAC4 by salt-inducible kinase 3 (SIK3), an AMPK-related kinase, allows cytoplasmic localization of HDAC4 and enhances the association between HDAC4 and Warts, a core kinase of the Hippo pathway. This HDAC4-Wts association inhibits Warts activity, and in turn, the inactivation of the Hippo pathway, triggering NSC reactivation. Finally, genetic epistasis experiments support the SIK3-HDAC4-Warts axis during NSC reactivation. In conclusion, our findings identify HDAC4 as a molecular switch that integrates SUMOylation, ubiquitination, and the Hippo pathway to govern NSC reactivation.

neuroscience↗

bioRxiv2026

Structural Basis of Mitochondrial Transcription Regulation via Interactions of PolRMT and TFAM with Upstream Promoter DNA

Mitochondrial DNA (mtDNA) transcription is essential for cellular energy production and is carried out by a streamlined transcription system in which transcription factor A (TFAM), transcription factor B2 (TFB2M), and the mitochondrial RNA polymerase (PolRMT) assemble at defined promoters to initiate transcription. Previous structural studies elucidated the core initiation mechanism but relied on truncated promoter templates that excluded upstream regulatory DNA interactions. Here, we present two conformations of mitochondrial transcription initiation complexes assembled on the heavy-strand promoter (HSP): a TFAM-bound complex with extended upstream DNA and a TFAM-free complex containing short linear DNA. The TFAM-bound structure reveals a transcription-stimulatory interface between PolRMT and the upstream promoter region (UPR) enabled by TFAM-induced promoter bending. Consistent with this structural observation, UPR truncation reduces transcription from all mtDNA promoters, an effect abolished by mutation of the PolRMT interface. In contrast, the TFAM-free structure reveals a transcription-inhibitory interaction of linear upstream DNA with the PolRMT tether helix, which would sterically clash with TFAM binding. Deletion of the tether helix increases off-target transcription, supporting an autoinhibitory role that enhances promoter specificity. Together, these findings reveal how interactions of TFAM and PolRMT with upstream promoter DNA influence activity and specificity of mitochondrial transcription initiation.

biochemistry↗

bioRxiv2026

Density-dependent facilitation of livestock by small mammal ecosystem engineers

Small mammals and large herbivores have co-evolved in grasslands for millions of years, yet how they interplay remains unclear. Although large herbivores can significantly affect the smaller ones, the reversal effect is largely unknown. On the Qinghai-Tibetan Plateau, plateau pikas (Ochotona curzoniae) are often considered pests that compete with livestock at high densities. Using field experiments, we show that the presence of pikas facilitates weight gains of yaks (Bos grunniens) by improving vegetation composition at a moderate density level. Compared to the pika-present treatment, pika removal dramatically increased cover of the poisonous Stellera forbs by two-fold, reducing the abundance and protein content of palatable grasses and sedges, yak foraging efficiency, and yak weight gain by up to 42%. Notably, we found a humped relationship between yak weight gains and pika burrow densities in the pika-present plots; the facilitative effect of pikas on yaks was highest at about 200 burrows/ha, but shifted to a competitive effect at pika densities exceeding 400 burrows/ha. These results provide the first empirical evidence that maintaining a moderate density of small mammalian herbivores can benefit growth performance of livestock by improving vegetation composition. Our study highlights the significance of moderate populations of ecosystem-engineering small mammals in sustaining pastoral productivity in rangelands.

ecology↗

bioRxiv2026

The anaerobic fungus Caecomyces churrovis produces H2 via a non-bifurcating NADH-dependent enzyme complex

Hydrogenosomes are mitochondria-derived organelles that produce ATP and H2 to support energy metabolism in anaerobic eukaryotes. H2 production allows reoxidation of reduced cofactors generated during fermentative metabolism; however, the metabolic mechanisms for H2 production in anaerobic eukaryotes remains incompletely understood. In particular, it remains unclear whether anaerobic fungi (AF) hydrogenosomes use a ferredoxin-dependent pathway or a distinct mechanism to regenerate NAD(P)+ and link electron transfer to H2 formation. Here, by combining genomic search, proteomic analysis, and enzymology, we reveal the molecular mechanism for H2 production in the AF strain Caecomyces churrovis. Our enzyme assays on the organelle fraction of C. churrovis revealed the activity of H2:NAD+ oxidoreductase but not pyruvate:ferredoxin oxidoreductase, which is usually linked to H2 formation. We identified genes encoding [FeFe] hydrogenase (Hyd) and NADH dehydrogenase subunits E and F (NuoE, NuoF) in C. churrovis, and confirmed their expression in the isolated hydrogenosomal fractions by proteomic analysis. Combining the individually purified enzymes, we found Hyd and NuoEF proteins formed H2 directly from NADH independently of ferredoxin, functioning as a non-bifurcating NADH-dependent enzyme rather than an electron-bifurcating enzyme. We identified homologs of hydrogenosomal NuoE, NuoF, and Hyd in many other AF, indicating this pathway is commonly shared among the AF. This work demonstrates the existence of a non-bifurcating NADH-dependent enzyme complex in eukaryotes. Moreover, this complex could potentially be exploited as a target for controlling AF H2 production and altering fungal metabolism. IMPORTANCEH2 production is a prominent feature of anaerobic energy metabolism, yet our understanding of eukaryotic mechanisms remains limited. Anaerobic fungi (AF) are key decomposers of lignocellulose and contribute to hydrogen flux in anaerobic environments. Although it has been more than 40 years since the H2 production from AF was first reported, the molecular mechanism for hydrogenosomal H2 production and redox balance remains unclear. We demonstrate that AF produce H2 from NADH utilizing a non-bifurcating NADH-dependent enzyme complex rather than an electron-bifurcating, ferredoxin-dependent variant. We show that this enzyme complex is conserved across multiple AF lineages and thus demonstrate the occurrence of a non-bifurcating NADH-dependent enzyme in eukaryotes. This discovery expands our understanding of eukaryotic hydrogenosomal metabolism, reveals a previously unknown strategy for redox balancing, and highlights potential targets for manipulating H2 production. These insights have broad implications for microbial energy metabolism, anaerobic ecosystems, and bioengineering of H2-producing systems.

microbiology↗