Biology subjects

Fujiwara, M.

Publications and source records attributed to Fujiwara, M..

18 recordsLinked to original sources

bioRxiv2026

In vivo brain temperature measurement using quantum dot imaging temperature sensors

Temperature regulation in the brain is essential for maintaining neuronal function and preventing thermally induced damage. Here, we report the development and in vivo application of quantum dots (QDs) to high-resolution thermometry in the mouse brain using two-photon excitation microscopy. These QDs, via the red-to-green photoluminescence (PL) intensity ratios, enabled stable temperature measurements in both normal and chronically hypo-perfused cerebral tissue. Our findings show that localized neuronal activity leads to transient heat generation, which is rapidly dissipated by cerebrovascular responses. In a chronic hypoperfusion model, impaired vascular function resulted in exaggerated and prolonged brain temperature elevations. This thermometry system provides unprecedented insight into the mechanisms of cerebral thermoregulation and highlights the importance of vascular cooling in protecting the brain from heat-induced stress, particularly in pathological conditions such as stroke.

bioengineering↗

bioRxiv2026

Evenness and Taylor's law scaling shape biodiversity-stability relationships in subtropical estuarine communities

Understanding the mechanisms that link biodiversity to ecological stability is crucial for predicting ecosystem responses to global change. Using three decades of standardized monitoring data from eight subtropical estuaries, we analyze diversity components (richness, evenness, dissimilarity, and variance-mean scaling) and interpret stability patterns through synchrony or portfolio mechanisms. Regional {gamma}-diversity increased steadily over time, reflecting sustained gains in fish and invertebrate assemblages. Community stability, defined here as community invariability, was strongly and consistently predicted by Shannon diversity index but not by species richness, underscoring the stabilizing role of evenness. Portfolio effects were robust, with community stability averaging approximately threefold higher than mean population stability, and the strength of this effect more than doubled with each unit increase in Shannon diversity. Structural equation models paired with a null model revealed that shared environmental forcing synchronizes estuarine populations. Shannon diversity generated a large portfolio effect that stabilized the community despite this environmental forcing, whereas richness effects were weak or absent. Taylors law scaling confirmed that abundant, persistent taxa such as blue crab (Callinectes sapidus), brown shrimp (Farfantepenaeus aztecus), and pinfish (Lagodon rhomboides) exhibited higher baseline invariability, contributing to community buffering, while rarer, more variable taxa introduced volatility. In contrast, compositional turnover strongly eroded stability, with high Bray-Curtis dissimilarity predicting reductions in community stability. Together, these results show that long-term estuarine community stability emerges from the interplay of portfolio averaging, demographic variance scaling of dominant species, and the persistence of community composition, highlighting the central role of evenness in biodiversity-stability relationships.

ecology↗

bioRxiv2026

Inside insight: decoding how insight emerges from competing world models

When and how does insight emerge? We conceptualize insight as a sudden realization arising from restructuring a world model: an internal interpretation linking actions to outcomes. Yet these latent dynamics remain difficult to access, even with behavior and verbal report. Here we developed inside insight dynamics (IID), a machine-learning framework that estimates latent world-model dynamics from behavioral data. Using IID, we analyzed mouse behavior in indirect- and direct-rule tasks, each requiring a shift from an initial world model to a rule-consistent representation. IID inferred the "when" of insight-like shifts by estimating the timing of transitions between competing world models, and examined the "how" by comparing alternative learning processes underlying them. This analysis revealed distinct mechanisms of world-model learning: the indirect- and direct-rule tasks were better explained by gated learning and parallel learning, respectively. Thus, IID opens a route to quantifying latent insight dynamics from observable behavior alone.

neuroscience↗

bioRxiv2026

Community reorganization without collapse in a warming world: Habitat-contingent, trait-mediated biodiversity change within a conserved multi-scale structure

Biodiversity change under sustained environmental pressure is increasingly understood as a process of long-term reorganization across spatial scales rather than uniform loss or gain. Estuarine ecosystems, which experience strong environmental gradients and frequent short-term extreme disturbances, provide an ideal context for evaluating how local (), spatial ({beta}), and regional ({gamma}) diversity reorganize across habitat domains and functional guilds through time. Here, we examined four decades of fish and invertebrate community data from a coastwide, ecological monitoring program, spanning multiple estuarine systems along the Texas coast. We asked three main questions: whether habitat context modifies the direction of trait-mediated biodiversity responses across the full -{beta}-{gamma} structure; whether spatial homogenization is detectable through dominance-weighted {beta}-diversity metrics and how they relate to richness-based metrics; and whether the pace of reorganization has intensified over time. Functional traits related to dispersal capacity and thermal affinity structured the magnitude of biodiversity change within habitat domains, but habitat context determined its direction, the same guilds exhibited opposite diversity trajectories across gear-defined habitat domains despite broadly similar functional composition, demonstrating that trait-based forecasting frameworks will mispredict reorganization direction when habitat context is ignored. Spatial homogenization proceeded undetected by richness-based {beta}-diversity metrics but was revealed through dominance-weighted measures, indicating that dominance-weighted homogenization operates through two distinct habitat-dependent mechanisms: convergence on shared warm-adapted dominant taxa in shallow assemblages, and convergence toward impoverished assemblages as dominant taxa declined in deeper habitats, both processes invisible to richness-based metrics. Despite a measurable intensification in the pace of local and regional diversity change after approximately 2000, spatial turnover among bays remained stable and -{beta}-{gamma} scaling relationships were preserved across all diversity orders, demonstrating that rapid reorganization can proceed without destabilizing fundamental metacommunity structure. Across all findings, biodiversity change was persistent, directional, and strongly habitat dependent, following a chronic rather than episodic trajectory consistent with sustained environmental processes as the primary driver.

ecology↗

bioRxiv2026

A Predictability Framework for Conservation Strategy: Empirical Evidence from Estuarine Biodiversity Forecasting

Conservation biology increasingly relies on ecological forecasting, yet the biodiversity components most urgently targeted by conservation, such as rare species, local assemblages, and hotspot-defined communities, are often those whose dynamics are least predictable. Understanding how predictability varies across biodiversity is therefore essential for aligning management tools with their targets. This study tests whether predictability varies along three axes, how diversity is measured, the spatial scale of observation, and the temporal forecast horizon (which together govern the effective signal-to-noise ratio of ecological dynamics), and uses these patterns to inform conservation strategies. Using long-term monitoring data from seven estuaries along the Texas Gulf Coast, forecasting performance was evaluated for Hill diversity (q = 0, 1, 2) and population-level abundance of eight dominant taxa at local (bay) and regional (coastwide) scales across near-term (1-month) and long-term (12-month) horizons. Multiple time-series model classes were assessed within a rolling-origin cross-validation framework, with performance measured as improvement in root mean square error over a seasonal naive baseline. Forecasting performance increased consistently with Hill number order, reflecting reduced stochastic variation as dominant species are emphasized. The effects of spatial aggregation differed between systems. Aggregation generally improved performance for littoral assemblages but provided limited or no benefit for demersal assemblages, consistent with differences in how predictive signals are distributed across space. Forecast skill declined from 1-to 12-month horizons, with slower decay for dominance-weighted diversity and demersal assemblages than for rare-species-weighted richness and littoral assemblages. Environmental covariates provided limited near-term gains but became an increasingly important source of predictive information at longer horizons for a subset of demersal and crustacean targets. These results define a predictability landscape structured by diversity measurement, spatial scale, and forecast horizon. Three conservation domains, stochastic, transitional, and structured, emerge from this framework, each associated with distinct predictability regimes and management strategies. Aligning conservation approaches with the predictability properties of their targets provides a principled basis for determining when forecast-based management is informative and when precautionary approaches are more appropriate.

ecology↗

bioRxiv2026

A coordinated regeneration-selection strategy enables genetic transformation and rapid flowering in apple x pear intergeneric hybrids

Wide hybridization between related species and genera provides valuable opportunities for broadening genetic diversity and introducing desirable traits. In the tribe Maleae (Rosaceae), Malus (apple) and Pyrus (pear) are phylogenetically closely related, and apple x pear hybrids represent promising materials such as for disease-resistance breeding. However, the effective utilization of such hybrids in breeding programs is constrained by long juvenile period. In this study, we established a tissue culture-based regeneration and genetic transformation platform for apple x pear hybrids. Key stages affecting adventitious shoot regeneration were optimized, and appropriate ranges of antibiotic selection pressure and bacterial elimination conditions were systematically evaluated. Regeneration capacity was predominantly genotype-dependent and became further restricted under Agrobacterium infection, necessitating precise balancing between regeneration competence and selection pressure. Using the highly competence line and the established transformation system, MdFT1 gene was successfully introduced and over-expressed in intergeneric hybrids, resulting in transgenic plants exhibiting floral bud initiation approximately six months after infection under in vitro conditions. This study provides a practical and efficient regeneration-transformation framework for apple x pear hybrids and demonstrates its applicability for FT-mediated early flowering. The established system offers technical support for accelerated breeding strategies and facilitates the utilization of novel resources in genetic improvement of pome fruit.

plant biology↗

bioRxiv2025

Humoral immunity induced by LP.8.1 monovalent vaccines against a broad range of SARS-CoV-2 variants including XEC, NB.1.8.1, XFG, and BA.3.2

In the spring of 2025, multiple SARS-CoV-2 Omicron JN.1 subvariants were circulating, with LP.8.1 among the major variants. Pharmaceutical companies such as Pfizer/BioNTech, Moderna, and Novavax/Takeda adopted monovalent LP.8.1 for their 2025-2026 season vaccines, following recommendations issued by the WHO in May 2025. As of November 2025, SARS-CoV-2 variants including LP.8.1, XEC, NB.1.8.1, and XFG--all designated as variants under monitoring--were circulating. In terms of the spike gene, these recent variants as well as LP.8.1 are derived from JN.1. Moreover, BA.3.2, a BA.3 descendant with multiple mutations in the spike gene, has recently emerged and exhibits robust immune evasion. In Japan, the rollout of the LP.8.1-based vaccination has progressed since the end of September 2025. We previously reported the humoral immunity induced by the XBB.1.5-based monovalent vaccine in 2023 and the JN.1-based monovalent vaccine in 2024 in the Japanese population. Here, we investigated the efficiency of humoral immunity induced by two LP.8.1-based vaccines, the mRNA vaccine from Pfizer/BioNTech and the recombinant protein-based vaccine from Novavax/Takeda, in Japan. We performed neutralization assays using sera obtained from individuals who received the LP.8.1 mRNA vaccine from Pfizer/BioNTech (N=29) or the LP.8.1 recombinant protein vaccine from Novavax/Takeda (N=20) with pseudoviruses harboring spike proteins of B.1.1, BA.5, XBB.1.5, JN.1, LP.8.1, XEC, NB.1.8.1, XFG and BA.3.2. In both mRNA and protein-based vaccinee groups, the change in 50% neutralizing titer (NT50) against variants that were predominant before JN.1 (i.e., B.1.1, BA.5 and XBB.1.5) were smaller than those against JN.1 and its subvariants, including LP.8.1, XEC, NB.1.8.1 and XFG. Consistent with recent studies, neutralizing antibodies against BA.3.2 were induced by both vaccines. However, the induction fold change of BA.3.2 was smaller than those of JN.1 and its subvariants. Next, we tested humoral immune response of participants who received both JN.1-based vaccine in 2024 and LP.8.1-based vaccine in 2025 (N=15). Approximately a year after the JN.1-based vaccination, neutralization titer has waned against all variants tested. However, when we compare the NT50s of pre-vaccination sera between 2025 and 2024, those in 2025 against all variants except for B.1.1 were significantly higher than those last year. This suggests that the cross-neutralizing antibodies induced by JN.1-based vaccination were still maintained for a year. Furthermore, the neutralization abilities against the JN.1 sublineages tested and BA.3.2 were significantly reboosted after the LP.8.1-based vaccination. Our study shows immune boosting by the LP.8.1-based vaccine is effective in achieving cross-neutralization against a broad range of JN.1 sublineages in a JN.1-naive population and in recalling waning humoral immunity against these subvariants.

microbiology↗

bioRxiv2025

Gradual proactive regulation of body state by reinforcement learning of homeostasis

Living systems maintain physiological variables such as temperature, blood pressure, and glucose within narrow ranges--a process known as homeostasis. Homeostasis involves not only reactive feedback but also anticipatory adjustments shaped by experience. Prior homeostatic reinforcement learning (HRL) models have provided a computational account of anticipatory regulation under homeostatic challenges. However, existing formulations lack mechanisms for gradual, trial-by-trial adjustment and for extinction learning. To address this issue, we developed a continuous HRL framework that enables trial-wise tuning of anticipatory regulation. The model incorporates biologically informed components: asymmetric reinforcement, weighting negative outcomes more than positive outcomes; and a dual-unit, context-gated inhibitory mechanism. We applied the framework to thermoregulatory conditioning with ethanol-induced hypothermia and successfully reproduced cue-triggered compensation, gradual tolerance, and rapid reacquisition after extinction. We then extended the framework to multiple physiological variables influenced by shared neural or hormonal control signals, and found that when regulatory priorities across variables were uneven, a deviation in one variable propagated through shared control to others, yielding a cascading, system-wide failure to return to ideal state (non-recovery)--a pattern reminiscent of autonomic dysregulation (e.g., dysautonomia, ME/CFS). Overall, our framework provides a computational basis to advances a systems-level understanding of multi-organ homeostatic dysregulation in vivo.

neuroscience↗

bioRxiv2024

Biocontrol of bacterial wilt disease using plant-associated bacterial communities in tomato

Host-protective or disease-suppressive microorganisms are anticipated as sustainable controls for crop diseases, such as bacterial wilt. However, the efficacy of biocontrol strategies is often limited by a lack of resilience under varying environmental conditions and interactions with native microbial communities in the field. In this study, we assembled a bacterial wilt-suppressive synthetic community (SynCom) in tomato, consisting of bacterial isolates derived from co-cultured microbial complexes associated with the plant. This SynCom demonstrates significant disease-suppressive effects against Ralstonia solanacearum in tomato seedlings under both axenic and soil conditions. Additionally, our findings suggest the existence of an optimal level of SynCom colonization in plants, which is critical for effective disease control. Furthermore, the SynCom exhibits direct antibiotic activity and immunogenic properties that enhance the production of defense-related secondary metabolites, thereby influencing the plant-associated microbiome. Our results provide an effective approach to constructing SynComs that exert disease-suppressive effects within microbial community contexts.

plant biology↗

bioRxiv2024

Time-course analysis of the transcriptome of Arabidopsis thaliana leaves under high-concentration ammonium sulfate treatment

Nitrogen is essential for plant growth and is sourced primarily from nitrate and ammonium in the soil. Even though plants can take ammonium up for nutrition, it often results in toxic effects such as growth suppression and chlorosis. To elucidate the mechanism of ammonium toxicity, a time-course analysis of the transcriptome was performed on A. thaliana leaves treated with high concentrations of ammonium sulfate in the presence of sufficient nitrate. The expression of nitrate-inducible genes tended to be downregulated by the treatment. The expression of genes relating to abscisic acid, jasmonic acid (JA), salicylic acid (SA), and membrane trafficking was upregulated, whereas that of photosynthesis-, auxin-, and cytokinin-related genes involved in growth and development was downregulated. The induction of many osmotic stress-responsive genes suggests the involvement of osmotic stress in ammonium toxicity. Furthermore, the upregulation of nitric oxide (NO)-inducible genes and the simultaneous upregulation of genes involved in JA biosynthesis, glutathione metabolism, and SA response suggested the involvement of endogenous NO and protein S-nitrosylation in response to high concentrations of ammonium sulfate. This study provides a novel and comprehensive overview of transcriptional changes occurring in response to high ammonium sulfate concentrations and proposes possible mechanisms of ammonium toxicity that can be explored in future research.

plant biology↗

bioRxiv2023

Virtual screening of antimicrobial plant extracts by machine-learning classification of chemical compounds in semantic space

Plant extract is a mixture of diverse phytochemicals, and considered as an important resource for drug discovery. However, large-scale exploration of the bioactive extracts has been hindered by various obstacles until now. In this research, we have introduced and evaluated a new computational screening strategy that classifies bioactive compounds and plants in semantic space generated by word embedding algorithm. The classifier showed good performance in binary (presence/absence of bioactivity) classification for both compounds and plant genera. Furthermore, the strategy led to the discovery of antimicrobial activity of essential oils from Lindera triloba and Cinnamomum sieboldii against Staphylococcus aureus. The results of this study indicate that machine-learning classification in semantic space can be a highly efficient approach for exploring bioactive plant extracts.

bioinformatics↗

bioRxiv2022

Self-organization, quality control, and preclinical studies of human iPSC-derived retinal sheets for tissue-transplantation therapy

Three-dimensional retinal organoids (3D-retinas) are a promising graft source for transplantation therapy. We previously developed self-organizing culture for 3D-retina generation from human pluripotent stem cells (hPSCs). Here we present a quality control method and preclinical studies for tissue-sheet transplantation. Self-organizing hPSCs differentiated into both retinal and off-target tissues. Gene expression analyses identified the major off-target tissues as eye-related, cortex-like, and spinal cord-like tissues. For quality control, we developed a qPCR-based test in which each hPSC-derived neuroepithelium was dissected into two tissue-sheets: inner-central sheet for transplantation and outer-peripheral sheet for qPCR to ensure retinal tissue selection. During qPCR, tissue-sheets were stored for 3-4 days using a newly developed preservation method. In a rat tumorigenicity study, no transplant-related adverse events were observed. In retinal degeneration model rats, retinal transplants differentiated into mature photoreceptors and exhibited light responses in electrophysiology assays. These results demonstrate our rationale toward self-organizing retinal sheet transplantation therapy.

neuroscience↗

bioRxiv2021

Stromal-cell deletion of STAT3 protects mice from kidney fibrosis by inhibiting pericytes trans-differentiation and migration

Signal transducer and activator of transcription 3 (STAT3) is a key transcription factor implicated in the pathogenesis of kidney fibrosis. Although tubular Stat3 deletion in tubular epithelial cells is known to protect mice from kidney fibrosis, the exact function of STAT3 in stromal cells remains unknown. We utilized stromal-cell Stat3 knock-out (KO) mice, CRISPR and pharmacologic activators and inhibitors of STAT3 to investigate its function in pericyte-like cells. STAT3 is phosphorylated in tubular epithelial cells in acute kidney injury whereas its activation expanded to interstitial cells in chronic kidney disease in mice and humans. Stromal cell-specific deletion of Stat3 protects mice from folic acid- and aristolochic acid-induced kidney fibrosis. Mechanistically, STAT3 directly regulates the inflammatory pathway, differentiation of pericytes into myofibroblasts. Specifically, STAT3 activation leads to an increase in migration and profibrotic signaling in genome-edited pericyte-like cells, 10T1/2. Conversely, Stat3 KO or blocking STAT3 function inhibits detachment, spreading, migration, and profibrotic signaling. Furthermore, STAT3 binds to Collagen1a1 promoter of fibrotic mouse kidneys and in pericyte-like cells. Together, our study identifies a previously unknown function of STAT3 in stromal cells that promotes kidney fibrosis and may have therapeutic value in fibrotic kidney disease. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=73 SRC="FIGDIR/small/456872v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@35dcbforg.highwire.dtl.DTLVardef@2fc055org.highwire.dtl.DTLVardef@fc0d92org.highwire.dtl.DTLVardef@1def2e6_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2021

A mosaic adeno-associated virus vector as a versatile tool that exhibits high levels of transgene expression and neuron specificity in primate brain

Recent emphasis has been placed on gene transduction mediated through recombinant adeno-associated virus (AAV) vector to manipulate activity of neurons and their circuitry in the primate brain. In the present study, we created a novel AAV vector of which capsid was composed of capsid proteins derived from the serotypes 1 and 2 (AAV1 and AAV2). Following the injection into the frontal cortex of macaque monkeys, this mosaic vector, termed AAV2.1 vector, was found to exhibit the excellence in transgene expression (for the AAV1 vector) and neuron specificity (for the AAV2 vector) simultaneously. To explore its applicability to chemogenetic manipulation and in vivo calcium imaging, the AAV2.1 vector expressing excitatory DREADDs or GCaMP was injected into the striatum or the visual cortex of macaque monkeys, respectively. Our results have defined that such vectors secure intense and stable expression of the target proteins and yield conspicuous modulation and imaging of neuronal activity.

neuroscience↗

bioRxiv2021

Control of osteocyte dendrite formation by Sp7 and its target gene osteocrin

Osteocytes use an elaborate network of dendritic connections to control bone remodeling. Some osteoblasts embed within mineralized bone matrix, change shape, and become osteocytes. The molecular circuitry that drives dendrite formation during "osteocytogenesis" is poorly understood. Here we show that deletion of Sp7, a gene linked to rare and common skeletal disease, in mature osteoblasts and osteocytes causes severe defects in osteocyte dendrites. Unbiased profiling of Sp7 target genes and binding sites reveals unexpected repurposing of this transcription factor to drive dendrite formation. Osteocrin is a Sp7 target gene that promotes osteocyte dendrite formation and rescues phenotypic and molecular defects in Sp7-deficient mice. Single-cell RNA-sequencing demonstrates overt defects in osteocyte maturation in vivo in the absence of Sp7. Sp7-dependent gene networks enriched in developing osteocytes are associated with rare and common human skeletal traits. Moreover, humans homozygous for the osteogenesis imperfecta-causing SP7R316C mutation show dramatic defects in osteocyte morphology. Genes that mark osteocytes in vivo and that are regulated by Sp7 in vitro are highly enriched in neurons, highlighting shared features between osteocytic and neuronal connectivity. Taken together, these findings reveal a crucial role for Sp7 and its target gene Osteocrin in osteocytogenesis, demonstrating that pathways that control osteocyte development influence human bone diseases.

molecular biology↗

bioRxiv2020

Multiomics study of a heterotardigrade, Echinisicus testudo, suggests convergent evolution of anhydrobiosis-related proteins in Tardigrada

Many limno-terrestrial tardigrades can enter an ametabolic state upon desiccation, in which the animals can withstand extreme environments. To date, studies of the molecular mechanism have predominantly investigated the class Eutardigrada, and that in the Heterotardigrada, remains elusive. To this end, we report a multiomics study of the heterotardigrade Echiniscus testudo, which is one of the most desiccation-tolerant species. None of the previously identified tardigrade-specific anhydrobiosis-related genes was conserved, while the loss and expansion of existing pathways were partly shared. Furthermore, we identified two families of novel abundant heat-soluble proteins and the proteins exhibited structural changes from random coil to -helix as the water content decreased in vitro. These characteristics are analogous to those of anhydrobiosis-related protein in eutardigrades, while there is no conservation at the sequence level. Our results suggest that Heterotardigrada have partly shared but distinct anhydrobiosis machinery compared with Eutardigrada, possibly due to convergent evolution within Tardigrada.

genomics↗

bioRxiv2020

The Small GTPase OsRac1 forms two distinct immune receptor complexes containing the PRR OsCERK1 and the NLR Pit

Plants employ two different types of immune receptors, cell surface pattern recognition receptors (PRRs) and intracellular nucleotide-binding and Leucine-rich repeat-containing proteins (NLRs), to cope with pathogen invasion. Both immune receptors often share similar downstream components and responses but it remains unknown whether a PRR and an NLR assemble into the same protein complex or two distinct receptor complexes. We have previously found that the small GTPase OsRac1 plays key roles in the signaling of OsCERK1, a PRR for fungal chitin, and of Pit, an NLR for rice blast fungus, and associates directly and indirectly with both of these immune receptors. In this study, using biochemical and bioimaging approaches, we reveal that OsRac1 formed two distinct receptor complexes with OsCERK1 and with Pit. Supporting this result, OsCERK1 and Pit utilized different transport systems for anchorage to the plasma membrane. Activation of OsCERK1 and Pit led to OsRac1 activation and, concomitantly, OsRac1 shifted from a small to a large protein complex fraction. We also found that the chaperone Hsp90 contributed to the proper transport of Pit to the plasma membrane and the immune induction of Pit. These findings illuminate how the PRR OsCERK1 and the NLR Pit orchestrate rice immunity through the small GTPase OsRac1.Competing Interest StatementThe authors have declared no competing interest.View Full Text

plant biology↗

bioRxiv2019

Morphogenesis of giant telomeric nuclear bodies in cancer cells with alternative lengthening of telomeres

Some cancer cells lengthen their telomeres by alternative lengthening of telomeres (ALT); these are referred to as ALT cancer cells and do not express telomerase. The ALT mechanism involves the elongation of telomeric DNA repeats by homologous recombination. In interphase nuclei of ALT cancer cells, giant telomeres can be specifically observed by fluorescence in situ hybridization (FISH) to detect telomeric repeats, and they are co-localized with promyelocytic-leukemia nuclear-bodies (PML-NBs). However, it how large telomeres specific to ALT and how they form a structural relation with PML-NBs. We refer to giant telomeres specific to interphase ALT cancer cells giant-telomeric nuclear-bodies (GT-NBs). To quantitatively define GT-NBs, we performed telomeric FISH of both interphase nuclei and metaphase chromosomes and analyzed telomere sizes by integrated FISH signals. The distributions of telomere sizes in telomerase-positive cells were similar in interphase nuclei and chromosomes. However, the distribution of telomere sizes in ALT cancer cells differed between interphase nuclei and chromosomes. Giant telomeres that were larger than those at chromosomal ends were only observed in interphase nuclei of ALT cancer cells. Accordingly, GT-NBs could be quantitatively defined as larger than the maximum size of telomeres at chromosomal ends. Furthermore, ALT cancer cells demonstrated fewer telomeric signals in interphase nuclei than in chromosomes. These findings indicate that GT-NBs could be formed by the aggregation of two or more telomeres at chromosomal ends. Furthermore, super-resolution microscopy showed that GT-NBs contain one or two PML-NBs. GT-NBs are considered aggregates of telomeres and could contain multiple sites of homologous recombination accompanied by PML-NBs. These findings may contribute to the development of therapeutic approaches for ALT cancer. (251 words)

pathology↗