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Wang, J.

Publications and source records attributed to Wang, J..

At least 613 records · Page 34Linked to original sources

Integrated Representations of Threat and Controllability in the Lateral Frontal Pole

Emotional processing is ubiquitous in everyday life, informing goal pursuit not only in response to current demands, but also in anticipation of future outcomes. Lateral prefrontal (LPFC) function supports cognitive control, and emerging evidence suggests a unique role for its anterior-most region--the lateral frontal pole (FPl)--in integrating putatively amygdala-originated emotion signals with goal information. However, whether these organizational properties of LPFC are expressed during the anticipation of future threat remains unknown. Here, we used FIR modeling and pattern similarity analysis to examine dynamic engagement and representational properties of distinct LPFC regions during threat anticipation requiring goal-directed action. Healthy participants (n=67) were scanned during a threat-of-shock paradigm consisting of a prolonged (18s) countdown to possible shock administration. Threat unpleasantness and controllability were manipulated orthogonally: in controllable trials, participants could avoid an unpleasant or mild shock by making a successful time-sensitive response; in uncontrollable trials, shocks were administered regardless of performance. LPFC robustly coded for anticipated threat unpleasantness, with FPl showing the strongest modulation by threat unpleasantness and controllability relative to caudal and mid-LPFC regions. Caudal and mid-LPFC maintained independent representations of threat unpleasantness and controllability. In contrast, FPl held conjunctive threat-and-controllability representations, which were associated with successful motor performance following anticipation of unpleasant shocks. Stronger conjunctive FPl representations were also associated with greater inverse amygdala-FPl coupling. Together, these findings provide insight into LPFC organization under naturalistic emotional challenges and highlight a key role for FPl in integrating affective and control-related information during threat anticipation to support goal-directed action. Significance StatementAnticipating emotionally-charged events--such as a painful outcome we may or may not be able to avoid--requires integrating emotion and control to guide behavior. However, the neural mechanisms through which emotional states influence goal-directed behavior in naturalistic, anticipatory emotional contexts remain unclear. Using a threat-of-shock paradigm and multivariate analyses we show that the anterior-most region of the lateral prefrontal cortex (LPFC)--the lateral frontal pole (FPl)--uniquely integrates information about the emotional unpleasantness and controllability of a future event, and that the strength of this integrated signal predicts better behavioral performance. These findings extend models of LPFC function to naturalistic, emotional contexts, and highlight the FPl as a key node for translating emotional and behavioral-control information into adaptive action.

neuroscience↗

The U1 snRNP protein U1C and Helix H of U1 snRNA are critical for small molecule splicing modulator function

Risdiplam and branaplam represent two classes of small-molecule splicing modulators that promote U1 snRNP recognition of weak non-canonical GA/GU-containing 5 splice sites (ss). We demonstrated that branaplam enhanced recognition of these 5 ss by reconstituted U1 snRNP in vitro, and that this effect depended on the ZnF domain of U1C and Helix H of U1 snRNA, but not U1A or U1-70K. In cells, depletion of U1C generally reduced compound-induced exon inclusion for most cassette exons. Interestingly, a subset of cassette exons became responsive to compound only upon U1C knockdown, supporting a model in which U1C stabilizes specific conformations at the 5 ss/U1 snRNA interface in a context-dependent manner that can either facilitate or hinder compound binding. Surprisingly, risdiplam shows no effect on weak 5 ss recognition in vitro, suggesting additional cellular factors are required for its activity.

biochemistry↗

Pathology-Specific Modulation of Corticostriatal Circuitry by Chronic Alcohol Consumption in Alzheimers Disease Mouse Models

Chronic alcohol use is a major modifiable risk factor for Alzheimers disease (AD), yet the mechanisms by which it modulates AD pathophysiology remain unclear. Here, we examined circuit-level and pathological changes in two distinct AD mouse models, humanized A{beta} knock-in (hAPP-KI) (A{beta}-driven) and PS19 (tau-driven), subjected to a chronic intermittent alcohol exposure paradigm. In hAPP-KI mice, alcohol increased A{beta} accumulation and excitatory transmission in the medial prefrontal cortex (mPFC) while reducing corticostriatal transmission and striatal cholinergic output. These alterations were accompanied by enhanced recruitment of microglia around A{beta} plaques. In contrast, alcohol-exposed PS19 mice displayed elevated mPFC-to-dorsomedial striatum (DMS) glutamatergic transmission and increased tau phosphorylation without significant changes in microglial activation or local mPFC excitatory drive. In wild-type mice, microglial depletion enhanced glutamatergic transmission onto cortical neurons, suggesting a homeostatic role for microglia in maintaining excitatory balance. Together, these findings reveal pathology-specific effects of alcohol on circuit dysfunction and propose microglia as an important modulator of alcohol-induced synaptic remodeling in the early stage of AD. HighlightsO_LIChronic alcohol exposure modulates glutamatergic transmission and neuroimmune responses in pathology-specific manners across A{beta}- and tau-driven Alzheimers disease mouse models. C_LIO_LIIn hAPP-KI mice, alcohol increases mPFC excitatory input, A{beta} plaque burden, and microglial activation, while impairing corticostriatal transmission and striatal cholinergic signaling. C_LIO_LIIn PS19 mice, alcohol enhances mPFC-to-striatum excitatory transmission and tau phosphorylation without altering local microglial activation or mPFC excitability. C_LIO_LIMicroglial depletion in wild-type mice recapitulates alcohol-induced glutamatergic changes in hAPP-KI mice, revealing a homeostatic role for microglia in regulating cortical excitatory balance. C_LI

neuroscience↗

Early-onset β-amyloidosis in human brains with hematological malignances and cardiovascular diseases: Revisiting injury/stress induced axonal pathology

{beta}-Amyloid (A{beta}) and tau pathologies are hallmarks of Alzheimers disease (AD) and they develop in human brain following differential spatiotemporal trajectories. As such, young/adult-onset tau-independent {beta}-amyloidosis is rare. We encountered four such cases among 397 banked brains, with the donors died of hematological malignances (blood cancers) or cardiovascular diseases. To explore the pathological implications, we examined 17 brains (10-87 year-old, y) from blood cancer patients and three (52-82 y) with cardiovascular diseases, focusing on vascular injury, axonal pathology and A{beta} formation. A{beta} plaques occurred in two adult brains (31 y, 63 y) with blood cancers and two (52 y, 65 y) with cardiovascular diseases in the absence of tau. In the blood cancer brains, 17/17 had vascular injuries seen in hematoxylin-eosin stained sections, 13/17 had iron leakage, and 13/17 had axonal pathology. Malignant cell infiltration was found in 5/14 brains with myeloid, lymphocytic and lymphoma malignances, with light chain infiltration in 3/3 brains with multiple myeloma. In the cardiovascular disease brains, A{beta} deposition primarily as diffuse plaques occurred in the cerebral cortex, with vascular and axonal pathologies in the white matter, striatum and internal capsule. Using a multi-labeling approach, the injury/stress induced axonal pathology was found to concur with {beta}-amyloid processor protein elevation and enhanced {beta}-secretase 1 processing but not intraneuronal A{beta} accumulation. The current findings suggest that hematological malignances and cardiovascular diseases are risk conditions for early-onset cerebral {beta}-amyloidosis, potentially attributable to vascular injury.

neuroscience↗

Light-Activated Nucleic Acid Amplification Systems Using Photo-caged DNA Polymerase or Primers

Precise control over nucleic acid amplification is essential for achieving reliable, quantitative, high-throughput, and multiplexed molecular diagnostics, particularly in point-of-care and field settings. However, conventional isothermal amplification methods, especially rapid assays at ambient temperature such as recombinase-aided amplification (RAA), suffer from spontaneous initiation and lack of synchronization across parallel reactions. Here, we report light-activatable RAA systems employing two distinct photocaging strategies to achieve spatiotemporal control. In the first, a photocaged DNA polymerase was engineered via site-specific incorporation of p-azido-L-phenylalanine and conjugation with a 2-nitrobenzyl-modified ssDNA blocker through click chemistry. This approach offers high stability, making it advantageous for long-term storage and lyophilized formats. In the second, 5'-nitrobenzyl-modified primers were synthesized to block hybridization or extension until UV activation, offering operational simplicity and rapid integration into existing workflows. Both strategies independently suppressed background activity in the dark and restored full amplification efficiency upon 365 nm UV exposure. The systems exhibited high sensitivity, low background, and compatibility with portable diagnostics. A custom-built device integrating UV activation and real-time fluorescence detection enabled seamless, on-demand operation. This modular platform provides flexible light-gated amplification solutions, allowing the selection of polymerase- or primer-based caging according to storage stability or workflow requirements, thereby advancing precise and field-ready molecular diagnostics.

molecular biology↗

Autism Mutations Preferentially Target Distributed Brain Circuits and Cell Types Associated with Sensory Integration and Decision Making

Autism spectrum disorder (ASD) is a highly heritable psychiatric condition characterized by difficulties in social communication and stereotypic, repetitive behaviors. Genetics studies have discovered many dozens of genes with causal roles in autism, and functional analyses have demonstrated that ASD-associated mutations affect a diverse range of brain regions and cell types. However, the precise mechanisms by which these genetic alterations lead to autism-related phenotypes remain unclear. Psychiatric cognitive and behavioral traits are believed to arise from dysfunction of specific brain circuits formed by anatomically and functionally connected brain areas. To identify the circuits and cell types primarily affected by ASD mutations, we developed an unbiased approach, GENCIC, which computationally integrates genome-wide genetic data with a brain-wide spatial mouse transcriptome and an anatomical mesoscale connectome. Applying this approach to ASD reveals a convergence of mutations on cohesive brain circuits that are enriched in long-distance connections and span both cortical and subcortical brain structures. Furthermore, our analysis of brain-wide single-cell spatial transcriptomics shows that the heterogeneity of circuit structures affected in ASD is matched by the substantial diversity of strongly impacted circuit cell types. Notably, the implicated circuits and cell types play a central role in the integration of multimodal sensory and emotional information and in decision-making based on this information. We also find that different circuit structures exhibit distinct vulnerability patterns that correlate with cognitive phenotypes in ASD. Overall, our study demonstrates how ASD-related genetic mutations impact multiple levels of brain organization, ultimately disrupting functional circuits that drive core autism-related behaviors.

systems biology↗

DeepHalo: Deep Learning-Powered Exploration of Halogenated Metabolites Uncovering Antibacterial Depsipeptides

In the omics era, confident high-throughput analytical tools are crucial for the efficient identification of metabolites. Here, we present DeepHalo, a deep learning-integrated and hierarchically optimized workflow designed for high-throughput exploration of halogenated metabolites from high-resolution mass spectrometry-based metabolomics. DeepHalo leverages deep learning models combined with a comprehensive scoring to enhance the reliability of halogen predictions. It integrates PyOpenMS for fast isotope pattern detection and incorporates a halogen-based dereplication algorithm with GNPS molecular networking to efficiently exploit and annotate halogenates from complex biological matrices. To validate its performance, DeepHalo was applied to explore halogenated metabolites from 1,296 microbial culture crude, leading to the discovery of six families of structurally diverse halogenated molecules. This included a new class of cyclic depsipeptides, aglomycins A-E, featuring rare 3-chloroanthranilic acid and/or epoxyvaline blocks. Additionally, a plausible biosynthetic pathway of aglomycins was proposed through bioinformatics analyses and targeted gene knockout experiments. Bioassays revealed that aglomycin A exhibits synergistic antibacterial activity with linezolid against vancomycin-resistant Enterococcus faecium (VRE) both in vitro and in vivo. We envision that DeepHalo (freely available at https://github.com/xieyying/DeepHalo) will become a powerful tool for accelerating the discovery of halogenated "dark matter".

biochemistry↗

Contribution of HMGB1 to Keratinocyte inflammation in Recessive Dystrophic Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is an inherited skin disorder characterized by fragile skin, blistering, and chronic wounds. Keratinocytes, the primary cells in the epidermis, are directly affected by persistent injury in RDEB, contributing to chronic inflammation. High mobility group box 1 (HMGB1) is elevated in the serum of individuals with RDEB. However, its role in keratinocyte inflammation remains unclear. Here, we report an increase in HMGB1 expression in keratinocytes at chronic wound sites compared to matched non-wounded skin from an RDEB individual, suggesting a potential link to local inflammation. Pharmacological inhibition of HMGB1 using inflachromene reduced lipopolysaccharide (LPS)-induced inflammatory responses in a keratinocyte cell line, supporting a role for keratinocyte-specific HMGB1 in inflammation. Surprisingly, deletion of HMGB1 alone or together with its paralogue HMGB2 did not suppress the inflammatory response to LPS. Furthermore, inflachromene still reduced inflammation in these knockout cells. This unexpected discrepancy between genetic deletion and pharmacologic inhibition points to a more complex role for HMGB1 or off-target effects of the compound. These findings suggest that HMGB1 may contribute to inflammation in keratinocytes, but its exact function needs further investigation.

molecular biology↗

Rationally Engineered Coronavirus-mimicking Protein Nanocage Platform for Glioblastoma Targeted Delivery and Immunity Regulation

Glioblastoma (GBM) is one of the most aggressive and treatment-resistant brain tumors, owing to the dual challenges of the blood-brain barrier (BBB) and a profoundly immunosuppressive tumor microenvironment. However, few existing strategies are capable of simultaneously overcoming these two barriers, underscoring a critical scientific gap and the need for innovative therapeutic platforms that enable both effective BBB traversal and tumor immune reprogramming. Here, we present a coronavirus-mimicking protein nanocage platform (EcomPC) derived from Thermotoga maritima encapsulin, rationally engineered for the targeted and sustained delivery of interferon- (IFN-) to GBM lesions. Through strategic insertion of flexible linkers, cysteine-to-serine mutations, and modular surface functionalization via SpyTag/SpyCatcher chemistry, EcomPC enables intracellular self-assembly of IFN- and glioma-specific targeting. In orthotopic GBM models, EcomPC-IFN demonstrates efficient BBB translocation, selective tumor accumulation, and potent anti-tumor efficacy. Mechanistically, localized IFN- release induces tumor cell apoptosis and reprograms the immune microenvironment--characterized by increased CD8 T cell infiltration, decreased Foxp3 regulatory T cells, and a favorable chemokine shift. These therapeutic effects are not recapitulated by free IFN- or untargeted nanocages, underscoring the essential role of both structural mimicry and ligand-guided delivery. Collectively, this work establishes EcomPC as a programmable, virus-inspired protein delivery platform capable of overcoming key physiological barriers in brain tumor immunotherapy, and lays the foundation for its broader application in CNS-targeted biologic delivery.

bioengineering↗

Defined human tri-lineage brain microtissues

Microglia are the immune cells of the central nervous system and are thought to be key players in both physiological and disease conditions. Several microglial features are poorly conserved between mice and human, such as the function of the neurodegeneration-associated immune receptor Trem2. Induced pluripotent stem cell (iPSC)-derived microglia offer a powerful opportunity to generate and study human microglia. However, human iPSC-derived microglia often exhibit activated phenotypes in vitro, and assessing their impact on other brain cell types remains challenging due to limitations in current co-culture systems. Here, we developed fully defined brain microtissues, composed of human iPSC-derived neurons, astrocytes, and microglia, co-cultured in 2D or 3D formats. Our microtissues are stable and self-sufficient over time, requiring no exogenous cytokines or growth factors. All three cell types exhibit morphologies characteristic of their in vivo environment and show functional properties. Co-cultured microglia develop more homeostatic phenotypes compared to microglia exposed to exogenous cytokines. Hence, these tri-cultures provide a unique approach to investigate cell-cell interactions between brain cell types. We found that astrocytes and not neurons are sufficient for microglial survival and maturation, and that astrocyte-derived M-CSF is essential for microglial survival. Single-cell and single-nucleus RNA sequencing analyses nominated a network of reciprocal communication between cell types. Brain microtissues faithfully recapitulated pathogenic -synuclein seeding and aggregation, suggesting their usefulness as human cell models to study not only normal but also pathological cell biological processes.

neuroscience↗

Structural assembly of maize CRY-GL2 photosignaling complex provides insights into its regulatory role in cuticular wax biosynthesis

Cryptochromes (CRYs) are blue-light photoreceptors in plants that regulate diverse physiological processes through oligomerization-dependent interactions with downstream effectors. While numerous light-inducible CRY-binding proteins have been identified, the structural basis for photoactivated CRY-effector assembly remains poorly understood. Here we report the crystal structure of a constitutively active maize CRY1c photolyase homology region (ZmCRY1c-PHRW368A) in complex with ZmGL2, a BAHD ptotein directing very-long-chain fatty acid (VLCFA) elongation for cuticular wax biosynthesis. Structural analysis reveals that light-activated ZmCRY1c forms a homotetrameric scaffold generating four symmetric binding sites at subunit interfaces. Each ZmCRY1c protomer engages one ZmGL2 molecule through conformational reorganization of its 16-17 loop and 17 helix, establishing a 4:4 hetero-octameric photosignaling complex validated by mutational profiling and optical design. Remarkably, structural alignment with the ZmCER6-ZmGL2 complex reveals substantial overlap (78%) in ZmGL2 binding interfaces. Biochemical quantification demonstrates that ZmCRY1c suppresses ZmCER6-GL2 enzyme activity in a dose dependent manner, unveiling a light-dependent regulatory switch controlling VLCFA elongation efficiency, though in vivo physiological investigation is awaited. Collectively, our work not only establishes the atomic model of light-activated plant CRY-effector assembly, but also uncovers a previously unrecognized spatial competition between photoreceptor and metabolic enzyme complexes that might function as a photoregulatory paradigm in cuticular wax biosynthesis.

plant biology↗

Reversible therapeutic resistance in EGFR mutant lung cancer caused by RB1 loss induced lineage plasticity

Treatment with EGFR tyrosine kinase inhibitors (EGFR TKI) is standard of care for patients with lung cancer initiated by activating mutations in the EGFR gene. While EGFR TKI treatment is effective, virtually all patients progress on therapy. Loss of function mutations in the RB1 tumor suppressor gene are associated with poor EGFR TKI outcomes, but underlying mechanisms remain unclear. Analysis of genetically engineered experimental models and human clinical specimens described here demonstrates RB1 loss has minimal impact on initial cell cycle responses to EGFR TKI but markedly accelerates acquired resistance over time. RB1 loss promotes transcriptional plasticity that enables rare cells to spontaneously assume reversible, resistance-conferring lineage states. These findings highlight the importance of non-genetic adaptations in driving acquired EGFR TKI resistance, advance our understanding of how RB1 impacts cancer, and identify opportunities to improve EGFR TKI treatment outcomes by targeting reversible epigenetic resistance mechanisms.

cancer biology↗

ZmCRY1s interact with GL2 in a blue light dependent manner to regulate epidermal wax composition in Zea mays

Cryptochromes (CRYs) are photolyase-like blue-light / ultraviolet-A (UV-A) receptors that regulate diverse aspects of plant growth. Maize (Zea mays), a major crop often grown under high UV-B radiation, possesses four copies of CRY. However, it remains unclear whether the multiple copies of CRY in maize have evolved to improve UV tolerance or to acquire new functions. In this study, CRISPR-Cas9-engineered Zmcry mutants were used to investigate the functions of four cryptochromes (ZmCRYs) in maize. The findings revealed that ZmCRYs play a redundant role in mediating blue light signaling and in inhibiting the elongation of the mesocotyl. The results also demonstrated that ZmCRYs mediated blue light-enhanced UV-B stress tolerance in Zea mays by upregulating the expression of genes involved in UV-B stress tolerance-related metabolites such as phenylpropanoid, flavonoid, and fatty acid biosynthesis. Furthermore, blue light was found to influence both the accumulation and composition of epidermal waxes, suggesting that blue light enhances epidermal wax accumulation for UV-B stress tolerance. Additionally, it was discovered that ZmCRY1 directly interacted with GLOSSY2 (GL2) in a blue light dependent manner to mediate blue light promoted C32 aldehyde accumulation, shedding new light on the enigma of aldehyde-forming. These results highlight the critical roles of ZmCRY1s in mediating blue light regulated epidermal wax biosynthesis and UV-B tolerance in Zea mays.

plant biology↗

Optimizing the In Vitro Neuronal Microenvironment to Mitigate Phototoxicity in Live-cell Imaging

Long-term imaging formats are ideal for capturing dynamic neuronal network formation in vitro, yet fluorescent techniques are often constrained by the impact of phototoxicity on cell survival. Here we present a live-imaging protocol that was optimised via quantitative analysis of 3 target culturing conditions on neuromorphological health: extracellular matrix (human- versus murine-derived laminin), culture media (Neurobasal versus Brainphys Imaging media), and seeding density (1x105 versus 2x105 cells/cm2). A cortical neuron reporter line was differentiated from human embryonic stem cells by transduction of Neurogenin-2 and green fluorescent protein, then fluorescently imaged in 8 different microenvironments daily for 33 days. Alongside viability analysis by PrestoBlue assay and gene quantification by digital polymerase chain reaction, an automated image analysis pipeline was developed to characterise network morphology and organisation over time. Brainphys Imaging medium was observed to support neuron viability, outgrowth, and self-organisation to a greater extent than Neurobasal medium with either laminin type, while the combination of Neurobasal medium and human laminin reduced cell survival. Further, a higher seeding density fostered somata clustering, but did not significantly extend viability compared to low density. These findings suggest a synergistic relationship between species-specific laminin and culture media in phototoxic environments, which is positively mediated by light-protective compounds found in Brainphys Imaging medium.

cell biology↗

Hedyotis Diffusae Herba Mitigates Rotenone-Induced Neurotoxicity via Akt Pathway in SH-SY5Y Cells

Hedyotis Diffusae Herba (HDH), known in traditional Chinese medicine for its heat-clearing and detoxifying properties, has been widely used to manage inflammation-related conditions. However, its neuroprotective potential and mechanism in the context of Parkinsons disease (PD) remain unclear.Network pharmacology and molecular docking were applied to predict the interactions between HDH components and PD-associated targets. Molecular dynamics simulations assessed the binding stability of major compounds to core targets. Rotenone-induced SH-SY5Y cell injury served as an in vitro PD model to evaluate HDHs biological effects. Cell viability, reactive oxygen species (ROS), IL-6 secretion, and Akt phosphorylation were assessed by CCK-8 assay, ROS detection kit, ELISA, and western blot, respectively. MK2206, an Akt inhibitor, was used to validate pathway involvement.Seven bioactive compounds were identified in HDH, among which stigmasterol and quercetin exhibited strong binding affinities with AKT1, IL-6, and JUN. Simulations confirmed stable interactions. HDH significantly increased cell viability and decreased intracellular ROS and IL-6 levels in rotenone-treated SH-SY5Y cells. Akt phosphorylation was restored by HDH, and the effect was blocked by MK2206, indicating Akt pathway participation.HDH exerts neuroprotective effects against rotenone-induced toxicity via antioxidant and anti-inflammatory activities and Akt pathway activation. These findings provide mechanistic insight and pharmacological support for HDH as a potential candidate in complementary therapy for PD.

cell biology↗

Rewiring amino acid metabolism to boost nonnatural polyketide production in Yarrowia lipolytica

Malonyl-CoA is a central precursor involved in the synthesis of various bio-based chemicals, including polyketides, fatty acids, and flavonoids. However, the production of these chemicals is often limited by the availability of malonyl-CoA. Based on retrosynthesis principles, we designed two thermodynamically favorable malonyl-CoA pathways using L-glutamate and L-aspartate as substrates. The novel pathways leverage oxidative deamination and decarboxylation reactions and efficiently channel metabolic flux toward malonyl-CoA, resulting in increased production of total polyketides beyond the capacity of the native acetyl-CoA carboxylase route using glucose as substrate. We also discovered a new-to-nature polyketide (4-hydroxy-6-hydroxyethyl-2-pyrone) derived from the side activity of the TAL pathway, reaching 6.4 g/L in Y. lipolytica. This work highlights the utility of the novel malonyl-CoA pathways in enhancing polyketide production, and the possibility of upcycling abundant amino acids or protein waste in the animal farming or meat industry to produce high-value nonnatural polyketides. HighlightsO_LITwo thermodynamically favorable malonyl-CoA pathways in Yarrowia lipolytica using L-glutamate and L-aspartate as substrates were engineered. C_LIO_LIThe novel oxygen-dependent malonyl-CoA pathways outperformed the canonical acetyl-CoA carboxylase pathway in polyketide production. C_LIO_LIA new-to-nature polyketide, 4-hydroxy-6-hydroxyethyl-2-pyrone (HHEP), was produced at a remarkably high titer of 6.4 g/L in shaking flask. C_LIO_LIThe engineered pathway improved the total production of malonyl-CoA-derived compounds (TAL, HHEP, and lipids). C_LI

synthetic biology↗

Production of unreduced microspores in Arabidopsis flowers cultivated in culture medium suggests a role of sucrose in facilitating meiotic cytokinesis

Live-imaging microscopy technology has been increasingly applied for meiosis study in plants, which largely relies on the set up of a healthy ex vivo culture system for inflorescences ensuring that the captured chromosomes dynamics approaches the natural features of meiosis. Here, we report that Arabidopsis thaliana flowers cultivated in a culture medium (CCM) composed of the half-strength Murashige and Skoog basal salt, MES, Myo-inositol, sucrose and agar produce diploid microspores due to occurrence of meiotic restitution. Cytological studies revealed adjacent nuclei distribution and incomplete cytokinesis at late meiosis II in meiocytes within the CCM flowers. Immunolocalization of -tubulin and the microtubule-associated protein MAP65-3 showed that the orientation of spindles at metaphase II and the organization of radial microtubule arrays at the tetrad stage are interfered, which explains the production of meiotically-restituted microspores. Moreover, the CCM flowers showed a gradually impaired expression of Aborted Microspores (AMS), a key transcription factor regulating tapetum development and meiotic cytokinesis. Interestingly, an increased supply of sucrose in culture medium promoted the expression of AMS and partially rescued haploid microspore formation in the CCM flowers. Taken together, this study suggests a role of sucrose in facilitating meiotic cytokinesis and gametophytic ploidy stability in plants. One-sentence summaryArabidopsis flowers cultivated in culture medium produce unreduced microspores due to interfered meiotic cytokinesis, which is partially rescued by increased sucrose supply.

plant biology↗

Genomics of sable (Martes zibellina) x pine marten (Martes martes) hybridization

The sable (Martes zibellina) and pine marten (Martes martes) are two Palearctic mustelids with long-recognized hybrids (kidases), whose fertility was controversial for years. Early genetic studies confirmed hybrids beyond F1, but details remained unclear due to low-resolution methods. Both species were hunted for centuries, but anthropogenic pressures during the 20th-century caused severe bottlenecks in the sable followed by hunting bans and large-scale reintroduction programs across much of its range, including the sympatric zone, potentially affecting hybridization. We resequenced 30 individuals from most of the sables range and Eastern part of pine martens. Among samples, we found a broad spectrum of hybrid types with mosaic recombinant chromosomes that confirm hybrid fertility and indicate crossover is not suppressed in kidases. This necessitates re-evaluation of previous research, as we detected notable discrepancies between STR-based ancestry and whole-genome analysis. In pine martens, we revealed mitochondrial DNA introgression from sables, indicating displacement of native pine marten mitochondrial sequences. Pine marten heterozygosity is relatively low ([~]0.5-0.6 hetSNPs/kbp) while sable diversity ([~]1.5-1.8 hetSNPs/kbp) is unexpectedly high for a species with its demographic history, likely reflecting successful reintroduction programs. We dated species divergence at 1.52 (CI: 1.05-2.06) Mya and identified candidate genes associated with ecological, morphological, and dietary differences, as well as hybrid fertility issues. This study is the first to elucidate marten hybridization at the whole-genome level, opening new research directions for understanding hybridization among Holarctic martens, the genetic consequences of reintroduction programs, and comparative adaptomics.

genomics↗