Biology subjects

Kinoshita, M.

Publications and source records attributed to Kinoshita, M..

44 records · Page 3Linked to original sources

bioRxiv2020

Production of a tributyltin-binding protein 2 knockout mutant strain of Japanese medaka, Oryzias latipes

Tributyltin-binding proteins (TBT-bps), members of the lipocalin family, bind TBT in fish blood and are presumed to contribute to detoxification of TBT. Recent studies have shown that many fish species have TBT-bp genes, and that these genes are induced by stresses such as exposure to chemicals or fish pathogenic bacteria. However, the function of TBT-bps, and the mechanisms of their induction and detoxification activity are still unclear. Here, towards elucidating the functions of TBT-bp2, we produced a TBT-bp2 knockout (TBT-bp2-/-) strain of Japanese medaka, Oryzias latipes, by using the CRISPR/Cas9 system. Gene expression of the mutated TBT-bp2 was reduced, and the cDNA sequencing and predicted protein structure suggested possible loss of function. However, the fish could be grown under normal conditions. Exposure of the TBT-bp2-/- strain of medaka to various stresses in future experiments is expected to contribute to our understanding of this novel detoxification system in aquatic organisms.

pharmacology and toxicology↗

bioRxiv2019

Chr21 protein-protein interactions: enrichment in products involved in intellectual disabilities, autism and Late Onset Alzheimer Disease

Intellectual disability (ID) found in Down syndrome (DS), which is characterized by an extra copy of 234 genes on Chr21 is poorly understood. We first used two DS mouse models that either display an extra copy of the Dyrk1A gene or of the mouse Chr16 syntenic region. Exome sequencing of transcripts deregulated in embryonic hippocampus uncovers enrichment in genes involved in chromatin and synapse respectively. Using large-scale yeast two-hybrid screen (154 distinct screens) of human brain library containing at least 107 independent fragments, we identified 3,636 novel protein-protein interactions with an enrichment of direct interactors of both Chromosome 21(Hsa21) baits and rebounds in ID-related genes. Using proximity ligation assays, we identified that Hsa21-encoded proteins are located at the dendritic spine postsynaptic density in a protein network located at the dendritic spine post synapse. We located Hsa21 DYRK1A and DSCAM that confers a [~] 20-fold increase in Autism Spectrum Disorders (ASDs), in this postsynaptic network. We found that a DSCAM intracellular domain binds either DYRK1A or DLGs that are multimeric scaffolds for the clustering of receptors, ion channels, and associated signaling proteins. The DYRK1A-DSCAM interaction is conserved from drosophila to humans. The identified postsynaptic.network is enriched in ARC-related synaptic plasticity, ASDs and Late-Onset Alzheimer Disease. Altogether, these results emphasize links between DS and brain diseases with complex genetics.

neuroscience↗

bioRxiv2019

Epidemiological survey of serum titers from adults against various Gram-negative bacterial V-antigens

The V-antigen, a virulence-associated protein, was first identified in Yersinia pestis more than half a century ago. Since then, other V-antigen homologs and orthologs have been discovered and are now considered vital molecules for the toxic effects mediated by the type III secretion system in infections caused by various pathogenic Gram-negative bacteria. After purifying recombinant V-antigen proteins including PcrV from Pseudomonas aeruginosa, LcrV from Yersinia, LssV from Photorhabdus luminescens, AcrV from Aeromonas salmonicida, and VcrV from Vibrio parahaemolyticus, we developed an enzyme-linked immunoabsorbent assay to measure titers against each V-antigen in the sera collected from 186 adult volunteers. Different titer-specific correlation levels were determined for the five V-antigens. The anti-LcrV and anti-AcrV titers shared the highest correlation with each other, with a correlation coefficient of 0.84. The next highest correlation coefficient was between anti-AcrV and anti-VcrV titers at 0.79, while the lowest correlation was found between anti-LcrV and anti-VcrV titers, which were still higher than 0.7 Sera from mice immunized with one of the five recombinant V-antigens displayed cross-antigenicity with some of the other four V-antigens, supporting the results from the human sera. Thus, the serum anti-V-antigen titer measurement system could potentially be used for epidemiological investigations on various pathogenic Gram-negative bacteria.

immunology↗

bioRxiv2019

Neuropeptide B mediates female sexual receptivity in medaka fish, acting in a female-specific but reversible manner

Male and female animals display innate sex-specific mating behaviors. Among vertebrates, teleosts are unique in that altering the adult sex steroid milieu can reverse sex-typical mating behaviors, suggesting sexual lability of their brains. In the teleost medaka, neuropeptide B (NPB) is expressed female-specifically in the brain nuclei implicated in mating behavior. Here, we demonstrate that NPB is a direct mediator of estrogen action on female mating behavior, acting in a female-specific but reversible manner. Analysis of regulatory mechanisms revealed that the female-specific expression of NPB is dependent on direct transcriptional activation by estrogen via an estrogen-responsive element and is reversed in response to changes in the adult sex steroid milieu. Behavioral studies of NPB knockouts revealed that female-specific NBP mediates female receptivity to male courtship. The female-specific NPB signaling identified herein is presumably a critical element of the neural circuitry underlying sexual dimorphism and lability of mating behaviors in teleosts.

neuroscience↗

bioRxiv2018

Zinc Boosts EGCG’s hIAPP Amyloid Inhibition Both in Solution and Membrane

Amyloid aggregation of human islet amyloid polypeptide (hIAPP) is linked to insulin-producing islet cell death in type II diabetes. Previous studies have shown the amyloid inhibiting effects of zinc (Zn) and insulin that are co-present with hIAPP in islet cells, and the lipid membrane has been shown to significantly influence the aggregation kinetics. Increasing number of studies report the importance of developing small molecule inhibitors to suppress the hIAPPs toxicity. Particularly, the ability of epigallocatechin-gallate (EGCG) to inhibit amyloid aggregation of a variety of amyloid peptide/proteins including hIAPP initiated numerous studies including the development of compounds to potentially treat amyloid diseases. In this study, by using a combination of thioflavin-T fluorescence and transmission electron microscopy experiments, we demonstrate a significant enhancement in EGCGs efficiency, when mixed with Zn, to significantly suppress hIAPP amyloid aggregation both in presence and absence of lipid membrane. Circular dichroism experiments indicate the formation and stabilization of a helical structure of hIAPP in presence of EGCG:Zn complex. Our results also reveal the ability of EGCG or EGCG:Zn to suppress hIAPPs cellular toxicity and that the ability of EGCG to chelate with Zn suppresses zincs cellular toxicity. We suggest that the reported results would be useful to develop strategies to trap hIAPP intermediates for further biophysical and structural studies, and also to devise approaches to abolish amyloid aggregation and cellular toxicity.

biophysics↗

bioRxiv2018

MTA proteins act redundantly within the NuRD complex to ensure fidelity of ES cell lineage commitment

Multiprotein chromatin remodelling complexes show remarkable conservation of function amongst metazoans, even though components present in invertebrates are often present as multiple paralogous proteins in vertebrate complexes. In some cases these paralogues specify distinct biochemical and/or functional activities in vertebrate cells. Here we set out to define the biochemical and functional diversity encoded by one such group of proteins within the mammalian Nucleosome Remodelling and Deacetylation (NuRD) complex: Mta1, Mta2 and Mta3. We find that, in contrast to what has been described in somatic cells, MTA proteins are not mutually exclusive within ES cell NuRD and, despite subtle differences in chromatin binding and biochemical interactions, serve largely redundant functions. Nevertheless, ES cells lacking all three MTA proteins represent a complete NuRD null and are viable, allowing us to identify a previously undetected function for NuRD in maintaining differentiation trajectory during early stages of lineage commitment.

developmental biology↗

bioRxiv2018

Frequency and synchrony of actomyosin oscillation during PCP-dependent convergent extension

Oscillatory actomyosin flows play a key role in single cell migration and in collective cell movements that shape invertebrates embryos, but the role of such oscillations in vertebrate morphogenesis remains poorly defined. Here, data from mathematical modeling and in vivo 4D imaging of actomyosin in the Xenopus gastrula suggest that oscillatory actomyosin contractions are a general feature of convergent extension by junction shrinking. We show that synchronous intracellular flows link two spatially distinct populations of actomyosin within individual cells, but that oscillations are asynchronous between neighboring cells that share a shrinking cell-cell junction. We also show that the core PCP protein Prickle2 displays a parallel oscillatory behavior and is required for tuning the frequency of actomyosin contractions, indicating that PCP signaling controls not only the orientation of actomyosin contractions, but also their frequency. Together, these data provide new insights into the function and control of oscillatory actomyosin contractions in collective cell movement.

developmental biology↗

bioRxiv2017

A lncRNA/Lin28/Let7 Axis Coupled To DNA Methylation Fine Tunes The Dynamics Of A Cell State Transition

Execution of pluripotency requires progression from the naive status represented by mouse embryonic stem cells (ESCs) to a condition poised for lineage specification. This process is controlled at transcriptional, post-transcriptional and epigenetic levels and non-coding RNAs are contributors to this regulation complexity. Here we identify a molecular cascade initiated by a long non-coding RNA (lncRNA), Ephemeron (Epn), that modulates the dynamics of exit from naive pluripotency. Epn deletion delays the extinction of ESC identity, an effect mediated by perduring expression of the pivotal transcription factor Nanog. In the absence of Epn, Lin28a expression is reduced, resulting in an elevated level of Mirlet7g that suppresses de novo methyltransferases Dnmt3a/b. Dnmt3a/b deletion also retards exit from the ESC state, and is associated with delayed promoter methylation and slower down-regulation of Nanog. Altogether, our findings reveal a lncRNA/miRNA/DNA methylation axis that facilitates a timely stem cell state transition.

cell biology↗