Biology subjects

Ishikawa, T.

Publications and source records attributed to Ishikawa, T..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Rhizobial infection-specific accumulation ofphosphatidylinositol 4,5-bisphosphate inhibits the excessive infection of rhizobia in Lotus japonicus

O_LIDuring the symbiosis of legume with nitrogen-fixing bacteria, collectively called rhizobia, suppression of excessive rhizobial infection by host plants is important to maximize the benefits of symbiotic nitrogen fixation. However, it remains relatively poorly understood the molecular mechanism involved in the suppression. C_LIO_LIWe performed LC-MS and RNA-seq analysis using rhizobia-infected Lotus japonicus roots and investigated the role of phosphatidylinositol (PI) and phosphatidylinositol phosphates (PIPs) in the symbiosis. Phosphatidylinositol transfer protein (PITP)-like proteins 4 (PLP4), phosphatidylinositol 3-phosphate 5-kinase 4 (PIP5K4) and PIP5K6 mutants, which are involved in the vesicular transport of lipids and phosphorylation of PIPs, were used to show the involvement of the signaling of PI and PIPs. Accumulation of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] during rhizobial infection were examined by a fluorescent marker 1xTUBBY-C (TUBBY). C_LIO_LIWe found that PI signaling-related genes were upregulated, and the amount of PIP2 increased in L. japonicus roots during rhizobial infection. In the PLP4, PIP5K4 and PIP5K6 mutants, rhizobial infection increased and PIP2 accumulation was failed. Furthermore, the observation of PI(4,5)P2 in rhizobia-infected roots revealed that the ectopic accumulation was closely related to suppression of rhizobial infection. C_LIO_LIOur findings indicate that the accumulation of PI(4,5)P2, which is mediated by PLP and PIP5Ks, suppresses excessive rhizobial infection in the root epidermis and cortex, leading to the optimal number of nodules. C_LI

plant biology↗

bioRxiv2025

Simultaneous knockout of VITAMIN C DEFECTIVE 2 and 3 exacerbates ascorbate deficiency and light stress sensitivity

Light-dependent activation of ascorbate biosynthesis is essential for accumulating ascorbate to mitigate photooxidative stress. The VTC2 and VTC3 genes play key roles in this process: VTC2 encodes GDP-L-galactose phosphorylase (GGP), the rate-limiting enzyme in ascorbate biosynthesis, and VTC3 encodes a putative protein kinase/phosphatase with an unknown function. Here, we investigated their functional and genetic relationship. In vtc3 mutants, VTC2 transcription and GGP activity were slightly enhanced, suggesting that VTC3 is not required for VTC2 expression. Additionally, the vtc3 mutation had negligible effects on the transcriptome and the activity of enzymes involved in ascorbate redox cycle regulation, narrowing down the possible roles of VTC3 in ascorbate biosynthesis. Under low-light conditions, ascorbate levels were lower in vtc2 than in vtc3 mutants, but vtc2 retained the ability to increase ascorbate levels under high-light stress, unlike vtc3. The simultaneous knockout of VTC2 and VTC3 further reduced ascorbate levels compared to single mutants and severely impaired light stress-induced ascorbate accumulation, resulting in impaired non-photochemical quenching and enhanced photooxidative damage. These findings highlight the additive effects of VTC2 and VTC3 on ascorbate biosynthesis and stress tolerance. The vtc2 vtc3 double mutants provide a valuable model for further elucidating the physiological roles of ascorbate in plants.

plant biology↗

bioRxiv2025

Proteomic and structural comparison between cilia from primary ciliary dyskinesia patients with a DNAH5 defect

Primary ciliary dyskinesia (PCD) is a genetic disorder that affects the motile cilia in various organs, leading to recurrent respiratory infections, subfertility, and laterality abnormalities. Traditional diagnostic methods include high-speed video microscopy, immunofluorescence staining, electron microscopy, and genetic screening. However, how different disease-causing variants in the same PCD gene affect clinical presentation, as well as ciliary composition and structure, is not well understood. We investigated the effect of various mutations in DNAH5, an axonemal dynein heavy chain, using mass spectrometry and cryo-electron tomography. We demonstrated differences in the axonemal composition for patients with dnah5 mutations. Furthermore, we showed that reductions in some ciliary components are patient specific. Some of them, KIAA1430, CFAP97, and DTHD1, were not previously recognized as components of human respiratory motile cilia. Finally, we demonstrated that some differences in protein abundance between wild-type and PCD samples can be observed in the 96-nm repeated unit of the axoneme. Our results suggest that many axonemal components are affected in the DNAH5-defective samples. Additionally, our results highlight that disparate mutations have seemingly distinctive consequences for the axonemal composition.

cell biology↗

bioRxiv2025

High throughput protein serial crystallography using a grease matrix and a large-area support film

Serial femtosecond crystallography (SFX) using ultrashort pulses from X-ray free- electron lasers (XFELs) enables the determination of crystal structures at room temperature while minimizing radiation damage to the samples. This method involves irradiating numerous crystals one by one with XFEL pulses, allowing even the capture snapshots of dynamical structures in biological macromolecules. To achieve this, an efficient sample delivery system is essential for acquiring a large number of diffraction patterns. The most common approach uses a highly viscous grease matrix containing sample crystals, injected into the XFEL path from a narrow nozzle. However, the injection often suffers from clogging issues inside the injector nozzle, resulting in additional challenges such as the need for suitably sized crystals, increased sample consumption and unstable flow rates. Alternatively, a fixed-target approach, which scans a two-dimensional substrate with dispersed samples, can circumvent these issues. However, it must ensure the integrity of biological samples and provide sufficient surface area for efficient data collection. We here present an approach that utilizes a grease matrix and a large-area support film specially designed to address these requirements. This system offers a fast and reliable solution for protein SFX, enabling high-quality structure determination while significantly reducing sample consumption.

molecular biology↗

bioRxiv2024

LATE MERISTEM IDENTITY2 regulates cuticle formation on the seed surface and influences seed longevity

The seed coat protects the embryo from severe external environment. Like the aerial plant parts, the exterior surface of the seed coat is surrounded by a cuticle consisting of lipid polyesters and wax. However, the protective role of the cuticle in mature seeds has not been characterized. We herein study the transcriptional regulation of cuticle formation on the seed surface, which influences seed longevity. A chimeric repressor of Arabidopsis thaliana R2R3 MYB transcription factor gene LATE MERISTEM IDENTITY2 (LMI2) and a Torenia fournieri ortholog (TfMYBML3) was expressed in A. thaliana and T. fournieri, respectively. These lines and A. thaliana LMI2 T-DNA insertion lines were analyzed for cuticle deficiencies. A. thaliana LMI2 mutants and chimeric repressor lines exhibited a similar cuticle deficiency in immature seeds. Transmission electron microscopy observations, polyester composition analyses, and gene expression investigations revealed that LMI2 plays an essential role in cuticle development in the seed coat epidermis by regulating cutin biosynthesis. The lmi2-2 mutant exhibited shorter seed longevity than the wild-type controls in an accelerated aging test. These results indicate that LMI2 is a key regulator of cuticle formation in the seed coat, and is important for maintaining seed longevity. Significance statementCuticle is well known to have multiple important roles for surviving in the terrestrial environment, but their specific role on the seed coat and transcriptional regulation have not yet been elucidated. Here we show that LATE MERISTEM IDENTITY 2, encoding a transcription factor regulating floral meristem transition, is required for seed cuticle formation and maintaining seed longevity, providing evidence for a link between surface cuticle and seed longevity.

plant biology↗

bioRxiv2024

Identifying simultaneous inhibition of riboflavin metabolism and MEK as a novel therapeutic strategy for pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a formidable challenge with a survival rate of approximately 10%, largely due to the lack of diagnostic and therapeutic options. To identify novel therapeutic targets for PDAC, we previously developed a Drosophila melanogaster model, the 4-hit fly, which mimics the alterations in KRAS, TP53, CDKN2A, and SMAD4 genes observed in PDAC. Through whole-body genetic screening using the 4-hit model, we identified riboflavin (RF) metabolism as a novel potential therapeutic target for PDAC. Additionally, transcript levels of four out of five genes that are involved in RF metabolism were elevated in human PDAC compared to non-tumor tissues. Roseoflavin (RoF), an antimetabolite of RF, resulted in a variety range of metabolic changes, decreased mitochondrial respiratory chain activity, and suppressed proliferation in cultured PDAC cells. Furthermore, the combination of RoF with the MEK inhibitor drug trametinib significantly suppressed the growth of human PDAC xenografts compared to either treatment alone. These findings underscore that dual targeting of RF metabolism and MEK represents a novel therapeutic strategy for PDAC.

cancer biology↗

bioRxiv2024

Inhibitor of cardiolipin biosynthesis-related enzyme MoGep4 confers broad-spectrum anti-fungal activity

Plant pathogens cause devastating diseases, leading to serious losses to agriculture. Mechanistic understanding of pathogenesis of plant pathogens lays the foundation for the development of fungicides for disease control. Mitophagy, a specific form of autophagy, is important for fungal virulence. The role of cardiolipin, mitochondrial signature phospholipid, in mitophagy and pathogenesis is largely unknown in plant pathogenic fungi. The functions of enzymes involved in cardiolipin biosynthesis and relevant inhibitors were assessed using a set of assays, including genetic deletion, plant infection, lipidomics, chemical-protein interaction, chemical inhibition, and field trials. Our results showed that the cardiolipin biosynthesis-related gene MoGEP4 of the rice blast fungus Magnaporthe oryzae regulates growth, conidiation, cardiolipin biosynthesis, and virulence. Mechanistically, MoGep4 regulated mitophagy and Mps1-MAPK phosphorylation, which are required for virulence. Chemical alexidine dihydrochloride (AXD) inhibited the enzyme activity of MoGep4, cardiolipin biosynthesis and mitophagy. Importantly, AXD efficiently inhibited the growth of 10 plant pathogens and controlled rice blast and Fusarium head blight in the field. Our study demonstrated that MoGep4 regulates mitophagy, Mps1 phosphorylation and pathogenesis in M. oryzae. In addition, we found that the MoGep4 inhibitor, AXD, displays broad-spectrum antifungal activity and is a promising candidate for fungicide development.

microbiology↗

bioRxiv2024

Interaction between ciliary component proteins from Chlamydomonas revealed by CRISPR/CAS9, cryo-electron tomography and mass spectrometry

To understand molecular mechanism of ciliary beating motion, knowledge of location, interaction and dynamics of >400 component proteins are indispensable. While recent progress of structural biology revealed conformation and localization of >100 proteins, we still need to investigate their networking, art of their interaction and assembly mechanism. We applied CRISPR/CAS9 genome editing technique to the green algae Chlamydomonas to engineer a deletion mutant of a ciliary component, FAP263, located at the distal protrusion, and examined it structurally by cryo-electron tomography (cryo-ET) and mass spectrometry (MS). Cryo-ET and atomic model fitting demonstrated that the FAP263 deletion mutant lacks additional components, FAP78, and FAP184. Unassigned density near FAP263 in the cryo-ET map of WT cilia is likely FAP151, as suggested by cross-linking mass spectrometry. Based on the structure, we modeled how these four proteins might form a complex. Furthermore, it was shown that dynein f phosphorylation is inhibited in the FAP263 mutant, indicating an important role of this protein complex for dynein f phosphorylation. Our study demonstrates a novel approach to investigate protein networking inside cilia.

cell biology↗

bioRxiv2024

Assessing Target of Rapamycin (TOR) activity in the diatom Phaeodactylum tricornutum using commercially available materials

Target of rapamycin (TOR) is a conserved protein kinase that regulates the balance between catabolic and anabolic processes in response to nutrient availability. Although the central role of TOR kinase in nutrient stress responses is well-recognized, little is known about the molecular basis of TOR signaling in ecologically important secondary algae with plastids of red algal origin, such as diatoms, as assessing in vivo TOR kinase activity is a difficult task. To assess TOR kinase activity, the phosphorylation status of downstream components, such as ribosomal protein S6 (RPS6), must be measured. Unlike for model organisms, an antibody that detects phosphorylated (P-) RPS6 in diatoms is not commercially available. Therefore, we developed a convenient method in which P-RPS6 and non-P-RPS6 were detected via Phos-tag affinity electrophoresis and immunoblotting with a commercial antibody that cross-reacts with RPS6 (both P- and non-P-RPS6) in the diatom, Phaeodactylum tricornutum. Using this Phos-tag-based method, we observed a dose-dependent decrease in the P-RPS6/total RPS6 ratio in P. tricornutum cells treated with the TOR kinase inhibitor, AZD-8055. We also observed a reduction in the P-RPS6/total RPS6 ratio during the nitrogen-deficient culture of P. tricornutum, which indicated the inactivation of TOR kinase in response to nitrogen deficiency. Finally, we demonstrated the potential application of the Phos-tag-based method to other ecologically, evolutionarily, and industrially important secondary algae, such as Nannochloropsis oceanica (Stramenopiles), the haptophyte Tisochrysis lutea, and Euglena gracilis (Euglenid). As all experimental materials are commercially available, the Phos-tag-based method can be used to promote studies on TOR in diverse algae in different contexts.

biochemistry↗

bioRxiv2024

The Architecture of Sponge Choanocyte Chambers Maximizes Mechanical Pumping Efficiency

Sponges, the basalmost members of the animal kingdom, exhibit a range of complex architectures in which microfluidic channels connect multitudes of spherical chambers lined with choanocytes, flagellated filter-feeding cells. Choanocyte chambers can possess scores or even hundreds of such cells, which drive complex flows entering through porous walls and exiting into the sponge channels. One of the mysteries of the choanocyte chamber is its spherical shape, as it seems inappropriate for inducing directional transport since many choanocyte flagella beat in opposition to such a flow. Here we combine direct imaging of choanocyte chambers in living sponges with computational studies of many-flagella models to understand the connection between chamber architecture and directional flow. We find that those flagella that beat against the flow play a key role in raising the pressure inside the choanocyte chamber, with the result that the mechanical pumping efficiency, calculated from the pressure rise and flow rate, reaches a maximum at a small outlet opening angle. Comparison between experimental observations and the results of numerical simulations reveal that the chamber diameter, flagellar wave number and the outlet opening angle of the freshwater sponge E. muelleri, as well as several other species, are related in a manner that maximizes the mechanical pumping efficiency. These results indicate the subtle balances at play during morphogenesis of choanocyte chambers, and give insights into the physiology and body design of sponges.

biophysics↗

bioRxiv2023

Mitochondrial protein C15ORF48 is a stress-independent inducer of autophagy that regulates oxidative stress and autoimmunity

Autophagy is primarily activated by cellular stress, such as starvation or mitochondrial damage. However, stress-independent autophagy is activated by unknown mechanisms in several cell types, such as thymic epithelial cells (TECs). Here we report that the mitochondrial protein, C15ORF48, is a critical inducer of stress-independent autophagy. Mechanistically, C15ORF48 reduces the mitochondrial membrane potential and lowers intracellular ATP levels, thereby activating AMP-activated protein kinase and its downstream Unc-51-like kinase 1. Interestingly, C15ORF48 induction of autophagy upregulates intracellular glutathione levels, promoting cell survival by reducing oxidative stress. Mice deficient in C15orf48 showed a reduction in stress-independent autophagy in TECs, but not in typical starvation-induced autophagy in skeletal muscles. Moreover, C15orf48-/- mice developed autoimmunity, which is consistent with the fact that the stress-independent autophagy in TECs is crucial for the thymic self-tolerance. These results suggest that C15ORF48 induces stress-independent autophagy, thereby regulating oxidative stress and self-tolerance.

cell biology↗

bioRxiv2023

AtDREB2G is a novel regulator of riboflavin biosynthesis under low-temperature stress and abscisic acid treatment in Arabidopsis thaliana

Riboflavin (RF) serves as a precursor to FMN and FAD, crucial cofactors in various metabolic processes. Strict regulation of cellular flavin homeostasis is imperative, yet information regarding the factors governing this regulation remains largely elusive. In this study, we first examined the impact of external flavin treatment on the Arabidopsis transcriptome to identify novel regulators of cellular flavin levels. Our analysis revealed alterations in the expression of 49 putative transcription factors. Subsequent reverse genetic screening highlighted a member of the Dehydration-Responsive Element Binding (DREB) family, AtDREB2G, as a potential regulator of cellular flavin levels. Knockout mutants of AtDREB2G (dreb2g) exhibited reduced flavin levels and decreased expression of RF biosynthetic genes compared to wild-type plants. Conversely, conditional overexpression of AtDREB2G led to an increase in the expression of RF biosynthetic genes and elevated flavin levels. In wild-type plants, exposure to low temperatures and abscisic acid treatment stimulated enhanced flavin levels and upregulated the expression of RF biosynthetic genes, concomitant with the induction of AtDREB2G. Notably, these responses were significantly attenuated in dreb2g mutants. Our findings establish AtDREB2G as a novel positive regulator of flavin biosynthesis in Arabidopsis, particularly under conditions of low temperature and abscisic acid treatment.

plant biology↗

bioRxiv2023

The D-mannose/L-galactose pathway plays a predominant role in ascorbate biosynthesis in the liverwort Marchantia polymorpha but is not regulated by light and oxidative stress

Ascorbate plays an indispensable role in plants, functioning as both an antioxidant and a cellular redox buffer. It is widely acknowledged that the ascorbate biosynthesis in the photosynthetic tissues of land plants is governed by light-mediated regulation of the D-mannose/L-galactose (D-Man/L-Gal) pathway. At the core of this light-dependent regulation lies the VTC2 gene, encoding the rate-limiting enzyme GDP-L-Gal phosphorylase. The VTC2 expression is regulated by signals via the photosynthetic electron transport system. In this study, we directed our attention to the liverwort Marchantia polymorpha, representing one of the basal land plants, enabling us to conduct an in-depth analysis of its ascorbate biosynthesis. The M. polymorpha genome harbors a solitary gene for each enzyme involved in the D-Man/L-Gal pathway, including VTC2, along with three lactonase orthologs, which may be involved in the alternative ascorbate biosynthesis pathway. Through supplementation experiments with potential precursors, we observed that only L-Gal exhibited effectiveness in ascorbate biosynthesis. Furthermore, the generation of VTC2-deficient mutants through genome editing unveiled the inability of thallus regeneration in the absence of L-Gal supplementation, thereby revealing the importance of the D-Man/L-Gal pathway in ascorbate biosynthesis within M. polymorpha. Interestingly, gene expression analyses unveiled a distinct characteristic of M. polymorpha, where none of the genes associated with the D-Man/L-Gal pathway, including VTC2, showed upregulation in response to light, unlike other known land plants. This study sheds light on the exceptional nature of M. polymorpha as a land plant that has evolved distinctive mechanisms concerning ascorbate biosynthesis and its regulation.

plant biology↗

bioRxiv2023

Glucose stockpile in the intestinal apical brush border in C. elegans

Since understanding the mechanisms of glucose transport is a crucial approach for pathological diseases induced by glucose toxicities such as diabetes, numerous studies have unveiled molecular functions involved in glucose transport in the nematode Caenorhabditis elegans, a commonly used model organism. However, physicochemical behaviors of glucose in intestinal lumen-to-cell are still elusive. To address that, we here evaluated a diffusion coefficient of glucose in the intestinal apical brush border in C. elegans by fluorescence recovery after photobleaching (FRAP) with fluorescent glucose. Our results indicate that the fluorescent glucose is accumulated in the intestinal brush border, where the diffusion coefficient of glucose is [~]10-8 cm2/s, two orders of magnitude slower than that in bulk. Namely, the intestinal brush border is considered to be a highly viscous layer composed of intestinal microvilli and more dominantly glycocalyx. These findings imply that this high concentration of glucose in the viscous layer acts as a stockpile.

biophysics↗

bioRxiv2023

SPHINGOLIPIDS AND DELTA8-SPHINGOLIPID DESATURASE FROM THE PICOALGA O. TAURI AND INVOLVEMENT IN TEMPERATURE ACCLIMATION

Sphingolipids are crucial components of cell membranes. Sphingolipid {Delta}8-unsaturation is more specific to plants and is involved in the regulation of stress responses. The structure and functions of sphingolipids in microalgae are still poorly understood. Ostreococus tauri is a minimal microalga at the base of the green lineage, and is therefore a key organism for understanding lipid evolution. The present work reports the characterisation as well as the temperature regulation of sphingolipids and {Delta}8-sphingolipid desaturase from O. tauri. Complex sphingolipids are glycosylceramides with unique glycosyl moieties encompassing hexuronic acid residues, reminiscent of bacterial glucuronosylceramides, with up to three additional hexose residues. In contrast, the ceramide backbones show limited variety, with dihydroxylated C18/C18:1E{Delta}8 sphingoid bases and C16:0 fatty-acyl chain being the main compounds. The sphingolipid {Delta}8-desaturase from O. tauri, although phylogenetically related to plant homologues has a substrate preference similar to the diatom homologue. Both sphingolipid {Delta}8-desaturase transcripts and sphingolipid {Delta}8-unsaturation are regulated in a temperature- dependent manner being higher at 14{degrees}C than 24{degrees}C. Overexpressing the sphingolipid {Delta}8- desaturase in O. tauri at 24{degrees}C results in higher sphingolipid unsaturation and impairs the increase in cell size, structure and chlorophyll. In particular, the cell-size defect is not detected in cells acclimated to 14{degrees}C and is furthermore suppressed upon transfer from 24{degrees}C to 14{degrees}C. Our work provides the first functional evidence for the involvement of sphingolipid {Delta}8-unsaturation for temperature acclimation in microalgae, suggesting that this function is an ancestral feature in the green lineage.

biochemistry↗

bioRxiv2023

Pseudoirreversible inhibition elicits persistent efficacy of a sphigosine-1-phosphate receptor-1 antagonist

Sphingosine 1-phosphate receptor 1 (S1PR1), a G protein-coupled receptor, is required for lymphocyte trafficking, and is a promising therapeutic target in inflammatory diseases. We synthesized a competitive antagonist, KSI-6666, that persistently inhibits S1PR1 activity and effectively suppresses pathogenic inflammation. Metadynamics simulation proposed that the interaction of KSI-6666 with a methionine residue in the ligand-binding pocket of S1PR1 may inhibit the dissociation of KSI-6666 from S1PR1. Consistently, in vitro functional and mutational analyses revealed that KSI-6666 causes pseudoirreversible inhibition of S1PR1, dependent on the methionine residue of the protein and substituents on the distal benzene ring of KSI-6666. Moreover, in vivo study suggested that this pseudoirreversible inhibition is responsible for the persistent activity of KSI-6666. In this study, we discover that KSI-6666 is a potent S1PR1 antagonist, achieving pseudoirreversible inhibition of S1PR1 activity through interacting with a specific methionine residue.

pharmacology and toxicology↗

bioRxiv2023

Sexually dimorphic dynamics of the microtubule network in medaka (Oryzias latipes) germ cells

Oogenesis is the process through which ovarian germ cells enter meiosis and acquire essential characteristics of an egg, such as an increase in follicular size and deposition of maternal factors. In vertebrates, however, the pathways that initiate oogenic processes after germ cell sex determination remain elusive. Here we report a dome-shaped microtubule structure that is maintained during oogenesis. This structure is established in primordial germ cells and maintained in gonocytes and stem-type germ cells in a foxl3-independent manner. dmrt1 is required for disruption of the dome structure in differentiating spermatogonia. In addition, the dome structure accumulates mitochondria and Golgi apparatus, and is replaced by the Balbiani body, an oocyte-specific aggregate producing animal-vegetal polarity, suggesting a role for this structure in organelle transfer and oocyte polarization. Our findings show the presence of a pathway regulating a sexually dimorphic microtubule network independent of germ cell feminization by foxl3. Summary StatementA dome-shaped microtubule structure leading to oocyte polarity was identified in germ cells. Genetic pathways involved in the formation and destabilization of the structure during germ cell sex determination were clarified.

developmental biology↗

bioRxiv2023

Acute irradiation causes persistently altered heterogeneity among medullary thymic epithelial cells

The thymus has the ability to regenerate from acute injury caused by radiation, infection, and stressors. In addition to thymocytes, thymic epithelial cells in the medulla (mTECs), which are crucial for T cell self-tolerance by ectopically expressing and presenting thousands of tissue-specific antigens (TSAs), are damaged by these insults and recover thereafter. However, given recent discoveries on the high heterogeneity of mTECs, it remains to be determined whether the frequency and properties of mTEC subsets are restored during thymic recovery from radiation damage. Here we demonstrate that acute total body irradiation with a sublethal dose induces aftereffects on heterogeneity and gene expression of mTECs. Single-cell RNA-sequencing (scRNA-seq) analysis showed that irradiation reduces the frequency of mTECs expressing AIRE, which is a critical regulator of TSA expression, 15 days after irradiation. In contrast, transit-amplifying mTECs (TA-mTECs), which are progenitors of AIRE-expressing mTECs, and Ccl21a-expressing mTECs, were less affected. Interestingly, detailed analysis of scRNA-seq data suggested that the proportion of a unique mTEC cluster expressing Ccl25 and high level of TSAs was severely decreased by irradiation. Overall, we propose that acute irradiation disturbs the heterogeneity and properties of mTECs, and may thereby impair TSA expression for thymic T cell selection.

immunology↗