Biology subjects

Shindo, T.

Publications and source records attributed to Shindo, T..

5 recordsLinked to original sources

bioRxiv2024

Reconstruction of artificial nuclei with nuclear import activity in living mouse oocytes

The cell nucleus is a dynamic structure repeating disassembly and reformation during mitosis. Reformation of the nucleus is essential for cell proliferation, and therefore, the factors required for nuclear reformation are fundamental for eukaryotes. Although various factors have been identified in in vitro systems using frog egg extracts and in vivo imaging of somatic cells, little is known about the factors required for the formation of functional nuclear structures in living mouse eggs. To identify such factors, we used a reconstruction approach to construct an artificial nucleus around DNA in mouse eggs. T4 phage DNA (166 kbp) was microinjected into living mouse oocytes. Amounts of DNA injected and injection timing were examined to determine the conditions appropriate for the formation of functional nuclei. Microinjection of 100-500 ng/{micro}l DNA during metaphase through telophase of the second meiosis, but not the subsequent interphase, was important for the formation of artificial nucleus. This T4 DNA-derived artificial nucleus had the structure of nuclear lamina and nuclear pore complexes, and nuclear transport activity, similar to natural nuclei. These results suggest that exogenous DNA can form a functional nucleus in mouse oocytes, regardless of the sequence or the source of DNA.

cell biology↗

bioRxiv2024

Post-embryonic tail development through molting of the freshwater shrimp Neocaridina denticulata

BackgroundUnderstanding postembryonic morphogenesis through molting in arthropods has recently become a focus of developmental biology. The hierarchical mechanisms of epithelial sheet folds play a significant role in this process. Drosophila is a well-studied model for holometabolous insects, with extensive research on imaginal disc growth. While developmental processes in other arthropods have been described, live imaging of morphological changes is challenging due to the macroscopic movements and hard cuticles. Neocaridina denticulata, a crustacean, presents unique tail morphogenesis through molting, which makes it the potential model. This study investigated the development of the tail in Neocaridina denticulata through histological analysis and in vivo live imaging using fluorescent probes. This study also performed long-read sequencing of the whole genome for future genetic tools. ResultsThe tail of Neocaridina was found to undergo two major changes with the first ecdysis. Firstly, the branches of the uropods are cleared, and secondly, the telson undergoes convergent elongation. Cross-sectional analysis revealed that uropod and telson branching occurs immediately after hatching in the form of cuticle branching. The surface structure of the developmental tail suggested that telson elongation is achieved by the extension of anisotropic furrows in the cuticle during ecdysis. Anisotropy of cuticle furrows was associated with the epithelial cell shape, and the anisotropy of cell shape was found to occur during development from post-hatching. We also established an in vivo live imaging system with UV-LED resin and detected the changes of tail development over time. in vivo live imaging analysis revealed that telson contraction occurs gradually prior to ecdysis. Furthermore, we have also provided a draft genome of Neocaridina. ConclusionNeocaridina denticulata is a valuable model for studying morphogenesis in arthropods through molting. The tail undergoes complex changes involving cuticle branching, anisotropic furrows, and cellular dynamics. in vivo live imaging system provides insights into the developmental process, and the draft genome enhances the potential for genetic tools in future studies. This research contributes to the understanding of arthropod morphogenesis and provides a foundation for further developmental and cytological investigations in Neocaridina.

developmental biology↗

bioRxiv2023

Nuclear membrane protein Bqt4 maintains nuclear envelope integrity by recruiting phosphatidic acid

The nuclear envelope (NE) is a permeable barrier that maintains nuclear-cytoplasmic compartmentalization and ensures nuclear function; however, it ruptures in various situations such as mechanical stress and mitosis. Although the protein components for sealing a ruptured NE have been identified, the mechanism by which lipid components are involved in this process remains to be elucidated. Here, we found that an inner nuclear membrane (INM) protein Bqt4 directly interacts with phosphatidic acid (PA) and serves as a platform for NE maintenance in the fission yeast Schizosaccharomyces pombe. The intrinsically disordered region (IDR) of Bqt4, proximal to the transmembrane domain, binds to PA and forms a solid aggregate in vitro. Excessive accumulation of Bqt4 IDR in INM results in membrane overproliferation and lipid droplet formation in the nucleus, leading to centromere dissociation from the NE and chromosome missegregation. Our findings suggest that Bqt4 IDR controls nuclear membrane homeostasis by recruiting PA to the INM, thereby maintaining the structural integrity of the NE.

cell biology↗

bioRxiv2021

Novel System to Monitor In Vivo Neural Graft Activity After Spinal Cord Injury

Expectations for neural stem/progenitor cell (NS/PC) transplantation as a treatment for spinal cord injury (SCI) are increasing. However, whether and how grafted cells are incorporated into the host neural circuit and contribute to motor function recovery remain unknown. The aim of this project was to establish a novel non-invasive in vivo imaging system to visualize the activity of neural grafts by which we can simultaneously demonstrate the circuit-level integration between the graft and host, and the contribution of graft neuronal activity to host behaviour. We introduced Akaluc, a newly engineered luciferase, under control of a potent neuronal activity-dependent synthetic promoter, E-SARE, into NS/PCs and engrafted the cells into SCI model mice. Through the use of this system, we reveal that the activity of grafted cells was integrated with host behaviour and driven by host neural circuit inputs. This non-invasive system is expected to help elucidate the therapeutic mechanism of cell transplantation treatment for SCI and determine better therapy techniques that maximize the function of cells in the host circuit.

neuroscience↗

bioRxiv2019

Ferroptosis is programmed by the coordinated regulation of glutathione and iron metabolism by BACH1

Ferroptosis is an iron-dependent programmed cell death resulting from alterations of metabolic processes. However, its regulation and physiological significance remain to be elucidated. By analyzing transcriptional responses of murine embryonic fibroblasts exposed to the ferroptosis-inducer erastin, we found that a set of genes related to oxidative stress protection was induced upon ferroptosis. We further showed that the transcription factor BACH1 promoted ferroptosis by repressing the expression of a subset of erastin-inducible genes involved in the synthesis of glutathione or metabolism of intracellular labile iron, including Gclm, Gclc, Slc7a11, Hmox1, Fth1, Ftl1, and Slc40a1. Compared with wild-type mice, Bach1-/- mice showed resistance to myocardial infarction, the seriousness of which was palliated by the iron-chelator deferasirox, which suppressed ferroptosis. Our findings suggest that ferroptosis is programmed at the transcriptional level to induce genes combating labile-iron-induced oxidative stress and executed upon disruption of the balance between the transcriptional induction of protective genes and accumulation of iron-mediated damage. BACH1 is suggested to control the threshold of ferroptosis and to be a therapeutic target for palliating myocardial infarction.

cell biology↗