Biology subjects

Hirose, T.

Publications and source records attributed to Hirose, T..

At least 19 recordsLinked to original sources

bioRxiv2026

Antiglycation effects of imidazole dipeptides and 2-oxo-imidazole dipeptides on glyceraldehyde-induced intracellular protein glycation and neuronal cell death

Glyceraldehyde (GA) contributes to the development of various diseases, such as diabetes and Alzheimers disease via protein glycation and the formation of advanced glycation end products (AGEs); however, effective strategies for neutralizing GA are limited. Carnosine (Car), an imidazole dipeptide (IDP) that is abundant in meat, suppresses protein glycation by scavenging reactive aldehydes. There are only a few reports on the antiglycation activity of Car against GA. For other IDPs, such as anserine, balenine (Bal), and homocarnosine, there are almost no reports on their antiglycation activity. In this study, we demonstrated the antiglycation activity of four types of IDPs and 2-oxocarnosine (2-oxo-Car), an oxidized form of Car, against GA-induced intracellular protein glycation and neuronal cytotoxicity. Car and Bal exhibited significantly higher reactivity with GA compared with other IDPs and 2-oxo-Car. An in silico analysis suggested that the difference in reactivity is dependent upon intramolecular hydrogen bond formation and the conformation of each IDP. Although there were differences in reactivity with GA, LC-MS analysis revealed that all of the IDPs and 2-oxo-Car reacted with two molecules of GA to form adducts containing pyridinium rings. Car and Bal exhibited high reactivity with GA and markedly suppressed GA-induced cytotoxicity in SH-SY5Y cells. Western blot and qPCR analyses revealed that IDPs suppressed GA-induced protein glycation and the upregulation of endoplasmic reticulum and oxidative stress response genes. Our results indicate that IDPs represent a novel preventive approach to AGE-related diseases and provide a foundation for the development of strategies to treat GA-related neurotoxicity. Graphical abstractCarnosine and balenine, which are imidazole dipeptides (IDPs), scavenged two molecules of glyceraldehyde to form adducts containing pyridinium rings and suppressed intracellular protein glycation and neuronal cell death. The formation of intramolecular hydrogen bond of IDPs played a crucial role in the strength of antiglycation activity. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/734660v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@11d82dorg.highwire.dtl.DTLVardef@187aff0org.highwire.dtl.DTLVardef@12fe482org.highwire.dtl.DTLVardef@14327ee_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2026

Cohesin and NuRD Antagonistically Drive Alternative Neuronal Fates via PLZF Transcription Factors

Diverse genetic and epigenetic factors cooperate to specify cellular fates during development. Establishing these fates is especially critical in the nervous system, which comprises diverse neuronal cell types. How genomic architecture interfaces with epigenetic regulators to drive transcriptional programs underlying neuronal fates remains poorly understood. Here we show that cohesin, a protein complex that shapes genomic architecture, promotes GABAergic fate specification in a subset of neurons in the nematode Caenorhabditis elegans. This process is facilitated by EOR-1, a homolog of the human promyelocytic leukemia zinc finger (PLZF) transcription factor. The nucleosome remodeling and deacetylase (NuRD) complex and TRA-4, another PLZF homolog, promote tyraminergic fate in the normally GABAergic neurons when cohesin or EOR-1 function is lost, revealing an antagonistic mechanism determining alternative neuronal fates. These findings highlight a critical interplay among genome architecture, epigenetic remodeling and transcriptional regulation in neuronal fate specification and, given the evolutionary conservation of these factors, suggest a mechanism underlying neural development across species. TeaserGenomic architecture, epigenetic and genetic factors interact to determine specific neuronal fates during development.

developmental biology↗

bioRxiv2025

Cytoplasmic roles of HSATIII RNAs in RNA granule assembly and production of actin cytoskeleton-associated repeat-containing proteins

HSATIII architectural lncRNAs are nuclear short-tandem repeat ncRNAs induced upon thermal stress and serve as scaffolding molecules for nuclear stress bodies (nSBs), stress-induced membraneless organelles in the nucleus. We report that HSATIII lncRNAs are exported to the cytoplasm during stress recovery, where they form novel cytoplasmic bodies with nucleocytoplasmic RNA-binding proteins, including PURA, PURB, and m6A reader proteins. Recruitment of ALYREF to nSBs promotes HSATIII RNA export. These HSATIII-based granules, named HERALDs (Heat-removal-associated scaffolds), are transported along microtubules and accumulate at distal cellular regions. We further show that cytoplasmic HSATIII RNAs are translated into MEWNG-rich proteins, which interact with actin filaments and form complexes with HSPA8 and stress granule proteins such as ZC3HAV1 and ATXN2L. Together, these findings reveal previously unrecognized cytoplasmic roles of HSATIII RNAs, functioning both as lncRNAs to scaffold RNA granules and as mRNAs to produce proteins during the late phase of thermal stress recovery.

molecular biology↗

bioRxiv2025

Thermo-Sensing Mechanisms of Splicing Control by Nuclear Stress Bodies

Nuclear stress bodies (nSBs) are stress-inducible membraneless organelles formed on HSATIII lncRNAs and regulate pre-mRNA splicing during thermal stress recovery. During stress, dephosphorylated SRSFs accumulate in nSBs, whereas upon stress removal, their kinase CLK1 is recruited to rephosphorylate SRSFs, thereby promoting intron detention in specific transcripts. However, the mechanism underlying CLK1 localization to nSBs in response to stress removal has remained unclear. Here, we identify phosphorylation of CLK1 at Ser341 as a critical determinant of its nSB localization. Ser341 is phosphorylated under normal conditions, dephosphorylated by PP1 during stress, and rephosphorylated by RIOK2 during recovery, enabling CLK1 localization to nSBs specifically during recovery. We further identify PPP1R2, an entirely intrinsically disordered PP1 inhibitory subunit, as a reversible thermosensor that dissociates under stress to activate PP1. Together, our findings reveal multilayered thermosensing mechanisms that coordinate the temporally staged localization of SRSFs and CLK1 to nSBs, thereby regulating temperature-dependent pre-mRNA splicing.

molecular biology↗

bioRxiv2025

Reliable Detection of SGLT2 Protein through Knockout-based Antibody Characterization and Optimized Procedures

IntroductionSodium-glucose cotransporter 2 (SGLT2) is a key mediator of renal glucose reabsorption. Its pharmacological inhibition exerts cardio- and reno-protective benefits. Despite widespread clinical interest, reliable detection of SGLT2 protein remains challenging due to concerns regarding the specificity of available antibodies. MethodsThis study assessed the specificity of eight commercially available anti-SGLT2 antibodies by immunohistochemistry and Western blotting. Genetically engineered Sglt2-deficient mice and rats, generated via clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) technology, were employed as definitive negative controls. Additionally, human kidney tissues, including renal cell carcinoma samples, were analyzed. ResultsAmong the antibodies tested, few exhibited robust specificity, characterized by substantial immunostaining with minimal background in wild-type kidney tissues and complete absence of staining in Sglt2-deficient samples. In renal cell carcinoma samples, a validated antibody detected SGLT2 immunostaining in proximal tubules of non-tumor regions but not in tumor areas. Subcellular localization studies revealed that SGLT2 was enriched within proximal tubular microvilli, partially overlapping with its co-factor PDZK1IP1 (MAP17). LRP2 (megalin) and NHE3 were placed at the microvillar base and did not colocalize with SGLT2. Western blotting identified a specific SGLT2 band at approximately 55 kDa in kidney lysates using several antibodies under optimized procedures. This band was shifted to approximately 45 kDa after enzymatic removal of N-linked glycans. One antibody detected a weak band at the same molecular mass even in kidney lysates from Sglt2-deficient rodents. ConclusionsConsiderable variability exists in the specificity of commercially available anti-SGLT2 antibodies. Only a limited number of antibodies are suitable for reliable detection of SGLT2 in rodent and human samples. Rigorous antibody characterization, including the use of knockout controls and optimized experimental conditions, is essential to ensure reproducibility and prevent misinterpretation in studies investigating the biological and pathophysiological roles of SGLT2.

molecular biology↗

bioRxiv2025

Blocky proline/glutamine patterns in the SFPQ intrinsically disordered region dictate paraspeckle formation as a distinct membraneless organelle

Membraneless organelles (MLOs) formed through phase separation play crucial roles in various cellular processes. Many MLOs remain spatially compartmentalized, avoiding fusion or engulfment. MLOs are formed by dynamic multivalent interactions, often mediated by proteins with intrinsically disordered regions (IDRs). However, the molecular principles behind how IDRs maintain MLO independence remain poorly understood. Here, we investigated the proline/glutamine (P/Q)-rich IDR of SFPQ, a protein identified as a key factor in segregating paraspeckles from nuclear speckles. Paraspeckle segregation analyses, using SFPQ mutants tethered to NEAT1_2 long noncoding RNA, revealed that P/Q residues within the SFPQ IDR, conserved from humans to zebrafish, are crucial for its segregation activity. Beyond amino acid composition, the blocky patterns of P/Q residues are required for the segregation from nuclear speckles. Among human IDRs exhibiting PQ-block patterns, BRD4 IDR shows strong sequence similarity to the SFPQ IDR, and exhibits comparable segregation activity. Molecular dynamics simulation suggests that the PQ-blocky patterns required for the paraspeckle segregation do not correlate with the IDR characteristics necessary for self-assembly. Thus, these data suggest that the PQ-blocky patterns in IDRs represent a previously uncharacterized property that contributes to MLO independence, possibly through a mechanism distinct from the conventional phase separation-promoting function of IDRs.

molecular biology↗

bioRxiv2025

AGO1 interacts with NEAT1 lncRNA and impacts nuclear compartments

Argonaute 1 (AGO1), a central component of the RNA interference (RNAi) pathway, has recently been implicated in nuclear functions, particularly in chromatin organization and gene regulation. However, the role of AGO1 in lncRNA-driven nuclear compartmentalization remains elusive. In this study, we uncover a novel function for AGO1 in the regulation of nuclear architecture through its interaction with the long non-coding RNA (lncRNA) NEAT1. NEAT1 lncRNA is required for the formation of paraspeckles, nuclear substructures involved in multiple cellular processes. We show that AGO1 physically interacts with NEAT1 and other key paraspeckle proteins (PSPs) and co-localizes with paraspeckles in the nucleus. AGO1 depletion disrupts expression of both NEAT1 isoforms, reduces the interaction of essential PSPs with NEAT1 lncRNA, and leads to impaired paraspeckle formation. Furthermore, depletion of NEAT1 results in the mis-localization of AGO1 from paraspeckles and alters active chromatin compartments. Together, our findings establish a new functional relationship between AGO1 and NEAT1 in nuclear compartmentalization and chromatin architecture.

cell biology↗

bioRxiv2024

Harnessing the Biosynthetic Diversity of Actinomycetes: Discovery of Unique Natural Products through Comparative Genomic and Metabolic Analysis

Actinomycetes, rich in biosynthetic gene clusters (BGCs), are important sources of natural products (NPs). However, the rate of discovering novel NPs from actinomycetes has declined, indicating the need for a new strategy to obtain NPs. Herein, we present a strategy for the efficient discovery of novel NPs. First, we performed a comprehensive analysis of BGCs in actinomycetes, evaluating the average number and types of BGCs per genus to identify prolific NP producers. Our analysis revealed that certain actinomycetes strains, such as those in the family Pseudonocardiaceae, possess a greater number of BGCs than Streptomyces. In addition, these strains tend to possess strain-specific BGCs compared with others. To facilitate the identification of strain-specific compounds, we developed a comparative metabolic analysis method using molecular networking. Applying this method to eight Pseudonocardiaceae strains, we successfully discovered two novel peptides, lentindoles A (1) and B (2), featuring a 6/5/6 and 6/5/5 tricyclic ring system, respectively, along with their possible biosynthetic precursor, lentindole C (3). Our result demonstrates that the effectiveness of our developed strategy, which is expected to accelerate the discovery of novel NPs.

microbiology↗

bioRxiv2024

Huntingtin is an RNA-binding protein and participates in NEAT1-mediated paraspeckles

AbstractHuntingtin protein, mutated in Huntington disease, is implicated in nucleic acid- mediated processes, yet evidence for direct huntingtin-nucleic acid interaction is limited. Here we show wildtype and mutant huntingtin co-purify with nucleic acids, primarily RNA, and interact directly with G-rich RNAs in in vitro assays. Huntingtin RNA immunoprecipitation sequencing from patient-derived fibroblasts and neuronal progenitor cells expressing wildtype and mutant huntingtin revealed NEAT1 as a significantly enriched transcript. Altered NEAT1 levels were evident in Huntingtons disease cells and postmortem brain tissues, and huntingtin knockdown decreased NEAT1 levels. Huntingtin co-localized with NEAT1 in paraspeckles, and we identified a high-affinity RNA motif preferred by huntingtin. This study highlights NEAT1 as a novel huntingtin interactor, demonstrating huntingtins involvement in RNA-mediated functions and paraspeckle regulation. One-Sentence SummaryHTT is an RNA-binding protein that interacts with G-rich sequences, including those in the paraspeckle lncRNA NEAT1.

cell biology↗

bioRxiv2023

BET inhibition rescues ciliogenesis and ameliorates pancreatitis-driven phenotypic changes in mice with Par3 loss.

The apical-basal polarity of pancreatic acinar cells is essential for maintaining tissue architecture. However, the mechanisms by which polarity proteins regulate acinar pancreas tissue homeostasis are poorly understood. Here, we evaluate the role of Par3 in acinar pancreas injury and homeostasis. While Par3 loss in the mouse pancreas disrupts tight junctions, Par3 loss is dispensable for pancreatogenesis. However, with aging, Par3 loss results in low-grade inflammation, acinar degeneration, and pancreatic lipomatosis. Par3 loss also exacerbates pancreatitis-induced acinar cell loss, resulting in pronounced pancreatic lipomatosis and failure to regenerate. Moreover, Par3 loss in mice harboring mutant Kras causes extensive pancreatic intraepithelial neoplastic (PanIN) lesions and large pancreatic cysts. We also show that Par3 loss restricts injury-induced primary ciliogenesis. Significantly, targeting BET proteins enhances primary ciliogenesis during pancreatitis-induced injury and, in mice with Par3 loss, limits pancreatitis-induced acinar loss and facilitates acinar cell regeneration. Combined, this study demonstrates how Par3 restrains pancreatitis- and Kras-induced changes in the pancreas and identifies a potential role for BET inhibitors to attenuate pancreas injury and facilitate pancreas tissue regeneration.

pathology↗

bioRxiv2023

Neutralizing antibody responses and cellular responses against severe acute respiratory syndrome coronavirus 2 omicron subvariant BA.5 after an mRNA severe acute respiratory syndrome coronavirus 2 vaccine dose in kidney transplant recipients

We examined the anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein IgG antibody and neutralizing antibody titers and cellular immunity in 73 uninfected recipients and 17 uninfected healthy controls who received three doses of a coronavirus 2019 mRNA vaccine. Neutralizing antibody titers were evaluated using GFP-carrying recombinant SARS-CoV-2 with spike protein of B.1.1, omicron BA.1, or BA.5. For cellular immunity, peripheral blood mononuclear cells were stimulated with peptides corresponding to spike protein antigens of B.1.1, BA.1, and BA.5; spike-specific CD4/CD8 memory T cells were evaluated using intracellular cytokine staining. The median IgG antibody titers were 7.8 AU/mL in recipients and 143.0 AU/mL in healthy controls (p < 0.0001). Neutralizing antibody titers against all three viral variants were significantly lower in recipients (p < 0.0001). The number of spike-specific CD8 + memory T cells significantly decreased in recipients (p < 0.0001). Twenty recipients and seven healthy controls additionally received a bivalent omicron-containing booster vaccine, and IgG antibody and neutralizing antibody titers increased in both groups; however, the increase was significantly lower in recipients. Recipients did not gain sufficient immunity with a third dose of vaccine, suggesting a need to explore methods other than vaccines.

immunology↗

bioRxiv2023

Shell protein composition specified by NEAT1 domains dictates the formation of paraspeckles as distinct membraneless organelles

Many membraneless organelles (MLOs) formed through phase separation play crucial roles in various cellular processes. Although these MLOs co-exist in cells, how they maintain their independence without coalescence or engulfment remains largely unknown. Here, we investigated the molecular mechanism by which paraspeckles with core-shell architecture scaffolded by NEAT1_2 lncRNAs exist as distinct MLOs. We identified NEAT1 deletion mutants that assemble paraspeckles that are incorporated into nuclear speckles. Several paraspeckle proteins, including SFPQ, HNRNPF, and BRG1, prevent this incorporation and thus contribute to the segregation of paraspeckles from nuclear speckles. Shell localization of these proteins in the paraspeckles, which is determined by NEAT1_2 lncRNA domains, is required for this segregation process. Conversely, U2-related spliceosomal proteins are involved in internalizing the paraspeckles into nuclear speckles. This study shows that the paraspeckle shell composition dictates the independence of MLOs in the nucleus, providing insights into the importance of the shell in defining features and functions of MLOs.

cell biology↗

bioRxiv2023

Macrophage innate immune gene expression requires dynamic regulation of the nuclear paraspeckle

To ensure a robust immune response to pathogens without risking immunopathology, the kinetics and amplitude of inflammatory gene expression in macrophages needs to be exquisitely well-controlled. There is a growing appreciation for stress-responsive membraneless organelles (MLOs) regulating various steps of eukaryotic gene expression in response to extrinsic cues. Here, we implicate the nuclear paraspeckle, a highly ordered biomolecular condensate that nucleates on the Neat1 lncRNA, in tuning innate immune gene expression in murine macrophages. In response to a variety of innate agonists, macrophage paraspeckles rapidly aggregate (0.5 h post-stimulation) and disaggregate (2h post-stimulation). Paraspeckle maintenance and aggregation require active transcription and MAPK signaling whereas paraspeckle disaggregation requires degradation of Neat1 via the nuclear RNA exosome. Expression of a large cohort of cytokines, chemokines, and antimicrobial mediators is compromised in lipopolysaccharide-treated macrophages lacking Neat1, resulting in a failure to express a cohort of pro-inflammatory cytokines, chemokines, and antimicrobial mediators. Consequently, Neat1 KO macrophages cannot control replication of Salmonella enterica serovar Typhimurium or vesicular stomatitis virus. These findings highlight a prominent role for MLOs in orchestrating the macrophage response to pathogens and support a model whereby dynamic assembly and disassembly of paraspeckles reprograms the nuclear RNA binding protein landscape to enable inflammatory gene expression following innate stimuli. SIGNIFICANCE STATEMENTTo mount appropriate immune responses and fight infection, macrophages need to sense and respond to pathogen-associated signals with incredible precision. Membraneless organelles (MLOs) are complexes of RNAs and proteins that change in size, shape, and abundance in response to extracellular signals. We hypothesized that an MLO called the nuclear paraspeckle helps macrophages initiate and calibrate innate immune gene expression during infection. We found that paraspeckles rapidly aggregate and then dissolve in macrophages following pathogen sensing. Macrophages lacking paraspeckles cannot properly induce inflammatory genes, resulting in a failure to control replication of intracellular bacterial and viral pathogens. These data suggest that altered paraspeckle dynamics may dysregulate inflammatory gene expression in a variety of human diseases.

immunology↗

bioRxiv2022

Landscape of semi-extractable RNAs across five human cell lines

Phase-separated membraneless organelles often contain RNAs that exhibit unusual semi-extractability upon the conventional RNA extraction method, and can be efficiently retrieved by needle shearing or heating during RNA extraction. Semi-extractable RNAs are promising resources for understanding RNA-centric phase separation. However, limited assessments have been performed to systematically identify and characterize semi-extractable RNAs. In this study, 1,074 semi-extractable RNAs were identified across five human cell lines, including ASAP1, DANT2, EXT1, FTX, IGF1R, LIMS1, NEAT1, PHF21A, PVT1, SCMH1, STRG.3024.1, TBL1X, TCF7L2, TVP23C-CDRT4, UBE2E2, ZCCHC7, ZFAND3, and ZSWIM6, which exhibited consistent semi-extractability. By integrating publicly available datasets, we found that semi-extractable RNAs tend to be distributed in the nuclear compartments but are dissociated from the chromatin. Long and repeat-containing semi-extractable RNAs act as hubs to provide global RNA-RNA interactions. Semi-extractable RNAs were divided into four groups based on their k-mer content. The NEAT1 group preferred to interact with paraspeckle proteins, such as FUS and NONO, implying that RNAs in this group are potential candidates of architectural RNAs that constitute nuclear bodies.

bioinformatics↗

bioRxiv2022

Remarkable improvement in detection of readthrough downstream-of-gene transcripts by semi-extractable RNA-sequencing

The mammalian cell nucleus contains dozens of membrane-less nuclear bodies that play significant roles in various aspects of gene expression. Several nuclear bodies are nucleated by specific architectural noncoding RNAs (arcRNAs) acting as structural scaffolds. We have reported that a minor population of cellular RNAs exhibits an unusual semi-extractable feature upon using the conventional procedure of RNA preparation and that needle shearing or heating of cell lysates remarkably improves extraction of dozens of RNAs. Because semi-extractable RNAs, including known arcRNAs, commonly localize in nuclear bodies, this feature may be a hallmark of arcRNAs. Using the semi-extractability of RNA, we performed genome-wide screening of semi-extractable long non-coding RNAs to identify new candidate arcRNAs for arcRNA under hyperosmotic and heat stress conditions. After screening stress-inducible and semi-extractable RNAs, hundreds of readthrough downstream-of-gene (DoG) transcripts over several hundreds of kilobases, many of which were not detected among RNAs prepared by the conventional extraction procedure, were found to be stress-inducible and semi-extractable. We further characterized some of the abundant DoGs and found that stress-inducible transient extension of the 3-UTR made DoGs semi-extractable. Furthermore, they were localized in distinct nuclear foci that were sensitive to 1,6-hexanediol. These data suggest that semi-extractable DoGs exhibit arcRNA-like features and our semi-extractable RNA-seq is a powerful tool to extensively monitor DoGs that are induced under specific physiological conditions.

molecular biology↗

bioRxiv2021

Nascent ribosomal RNA acts as surfactant that suppresses growth of fibrillar centers in nucleolus

Liquid-liquid phase separation (LLPS) has been thought to be the biophysical principle governing the assembly of the multiphase structures of nucleoli, the site of ribosomal biogenesis. Condensates assembled through LLPS increase their sizes to minimize the surface energy as far as their components are available. However, multiple microphases, fibrillar centers (FCs), dispersed in a nucleolus are stable and their sizes do not grow unless the transcription of pre-ribosomal RNA (pre-rRNA) is inhibited. To understand the mechanism of the suppression of the FC growth, we here construct a minimal theoretical model by taking into account the nascent pre-rRNAs tethered to the FC surfaces by RNA polymerase I. Our theory predicts that nascent pre-rRNAs generate the lateral osmotic pressure that counteracts the surface tension of the FCs and this suppresses the growth of the FCs over the stable size. The stable FC size decreases with increasing the transcription rate and decreasing the RNA processing rate. This prediction is supported by our experiments showing that RNA polymerase inhibitors increase the FC size in a dose-dependent manner. This theory may provide insight into the general mechanism of the size control of nuclear bodies. Significance statementThe nucleolus, a site of pre-ribosomal RNA (pre-rRNA) production, has a characteristic multiphase structure, which has been thought to be assembled through liquid-liquid phase separation (LLPS). Although condensates assembled through LLPS grow by coarsening or coalescence as far as the components are available, the multiple inner phases, fibrillar centers (FCs), are dispersed in a nucleolus. To investigate the underlying mechanism, we constructed a minimal theoretical model by considering nascent pre-rRNAs tethered to RNA polymerase I at the FC surface. This model is supported by our experiments and explains previous experimental observations. This work shed light on the role of nascent RNAs to control the size of nuclear bodies.

biophysics↗

bioRxiv2021

The transcriptional corepressor CTBP-1 acts with the SOX family transcription factor EGL-13 to maintain AIA interneuron cell identity in C. elegans

Cell identity is characterized by a distinct combination of gene expression, cell morphology and cellular function established as progenitor cells divide and differentiate. Following establishment, cell identities can be unstable and require active and continuous maintenance throughout the remaining life of a cell. Mechanisms underlying the maintenance of cell identities are incompletely understood. Here we show that the gene ctbp-1, which encodes the transcriptional corepressor C-terminal binding protein-1 (CTBP-1), is essential for the maintenance of the identities of the two AIA interneurons in the nematode Caenorhabditis elegans. ctbp-1 is not required for the establishment of the AIA cell fate but rather functions cell-autonomously and can act in later larval stage and adult worms to maintain proper AIA gene expression, morphology and function. From a screen for suppressors of the ctbp-1 mutant phenotype, we identified the gene egl-13, which encodes a SOX family transcription factor. We found that egl-13 regulates AIA function and aspects of AIA gene expression, but not AIA morphology. We conclude that the CTBP-1 protein maintains AIA cell identity in part by utilizing EGL-13 to repress transcriptional activity in the AIAs. More generally, we propose that transcriptional corepressors like CTBP-1 might be critical factors in the maintenance of cell identities, harnessing the DNA-binding specificity of transcription factors like EGL-13 to selectively regulate gene expression in a cell-specific manner.

developmental biology↗

bioRxiv2021

Creation of X-linked Alport Syndrome Rat Model with Col4a5 Deficiency

Alport syndrome is an inherited chronic human kidney disease, characterized by glomerular basement membrane abnormalities. This disease is caused by mutations in COL4A3, COL4A4, or COL4A5 gene. The knockout mice for Col43, Col44, and Col45 are developed and well characterized for the study of Alport syndrome. However, disease progression and effects of pharmacological therapy depend on the genetic variability. This model is reliable only to mice. Therefore in this study, we created a novel Alport syndrome rat model utilizing rGONAD technology. Col45 deficient rats showed hematuria, proteinuria, high levels of BUN, Cre, and then died at 18 to 28 weeks of age (Hemizygous mutant males). Histological and ultrastructural analyses displayed the abnormalities including parietal cell hyperplasia, mesangial sclerosis, and interstitial fibrosis. Then, we demonstrated that 3/4/5 (IV) and 5/5/6 (IV) chains of type IV collagen disrupted in the Col45 deficient rats. Moreover, immunofluorescence analyses revealed that some glomeruli of Col45 mutant rats were found to be disrupted from postnatal day 0. Thus, Col45 mutant rat is a reliable candidate for Alport syndrome model for underlying the mechanism of renal diseases and further identifying potential therapeutic targets for human renal diseases.

bioengineering↗