Publications by authors named "Minesuke Yokoyama"

Article Synopsis
  • TDP-43 is a nuclear protein linked to the molecular development of amyotrophic lateral sclerosis (ALS), with its long C-terminal region (CTR) being critical for its stability and associated with ALS mutations.
  • Researchers created 12 mouse models lacking different sub-regions of the CTR to study their effects on TDP-43's protein stability and embryonic lethality.
  • They discovered that the Q/N-rich segment of the CTR significantly enhances TDP-43 stability, while the absence of the second GaroS segment does not impact protein stability or mouse development.
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Purpose: Our aim is to make an ideal embryo culture medium close to human oviduct fluid (HOF) components, and to evaluate the quality of this medium with embryo quality and clinical outcomes in assisted reproductive technology (ART) by a prospective randomized controlled trial (RCT).

Methods: Study I: HOF was collected laparoscopically from patients (= 28) with normal pelvic findings. According to HOF analysis results, the new medium "HiGROW OVIT" (OVIT) was designed.

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Sirh7/Ldoc1 [sushi-ichi retrotransposon homolog 7/leucine zipper, downregulated in cancer 1, also called mammalian retrotransposon-derived 7 (Mart7)] is one of the newly acquired genes from LTR retrotransposons in eutherian mammals. Interestingly, Sirh7/Ldoc1 knockout (KO) mice exhibited abnormal placental cell differentiation/maturation, leading to an overproduction of placental progesterone (P4) and placental lactogen 1 (PL1) from trophoblast giant cells (TGCs). The placenta is an organ that is essential for mammalian viviparity and plays a major endocrinological role during pregnancy in addition to providing nutrients and oxygen to the fetus.

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Although regulators of the Wnt/planar cell polarity (PCP) pathway are widely expressed in vertebrate nervous systems, their roles at synapses are unknown. Here, we show that Vangl2 is a postsynaptic factor crucial for synaptogenesis and that it coprecipitates with N-cadherin and PSD-95 from synapse-rich brain extracts. Vangl2 directly binds N-cadherin and enhances its internalization in a Rab5-dependent manner.

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Because genetic manipulation occasionally disrupts the expression of the neighboring genes, the chromosomal locus where the transgene has been integrated should be identified in the use of transgenic organisms. By using a new blend of thermostable DNA polymerase, we established a highly efficient method of inverse polymerase chain reaction for this purpose. By using this protocol, we successfully determined the vector integration sites of 2 mouse lines, NSE-tTA and tetO-Cre, the combination of which is a useful tool in neuroscience research.

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Extracellular factors that inhibit axon growth and intrinsic factors that promote it affect neural regeneration. Therapies targeting any single gene have not yet simultaneously optimized both types of factors. Chondroitin sulphate (CS), a glycosaminoglycan, is the most abundant extracellular inhibitor of axon growth.

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Syntaxin-1A is a t-SNARE that is involved in vesicle docking and vesicle fusion; it is important in presynaptic exocytosis in neurons because it interacts with many regulatory proteins. Previously, we found the following: 1) that autophosphorylated Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), an important modulator of neural plasticity, interacts with syntaxin-1A to regulate exocytosis, and 2) that a syntaxin missense mutation (R151G) attenuated this interaction. To determine more precisely the physiological importance of this interaction between CaMKII and syntaxin, we generated mice with a knock-in (KI) syntaxin-1A (R151G) mutation.

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Perlecan, a heparan sulfate proteoglycan, is enriched in the intercellular space of the enamel organ. To understand the role of perlecan in tooth morphogenesis, we used a keratin 5 promoter to generate transgenic (Tg) mice that over-express perlecan in epithelial cells, and examined their tooth germs at tissue and cellular levels. Immunohistochemistry showed that perlecan was more strongly expressed in the enamel organ cells of Tg mice than in wild-type mice.

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Synaptosomal-associated protein of 25 kDa (SNAP-25) is a presynaptic protein essential for neurotransmitter release. Previously, we demonstrate that protein kinase C (PKC) phosphorylates Ser(187) of SNAP-25, and enhances neurotransmitter release by recruiting secretory vesicles near to the plasma membrane. As PKC is abundant in the brain and SNAP-25 is essential for synaptic transmission, SNAP-25 phosphorylation is likely to play a crucial role in the central nervous system.

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We investigated whether the small litter size in the 129 inbred mouse strain results from a reduction in oocyte fertilizability. Sensitivity of the zona pellucida to α-chymotrypsin was examined for oocytes collected at 14 h (shortly after ovulation), 17 h, and 20 h after hCG injection. Passage of spermatozoa through the zona pellucida (using an in vitro fertilization (IVF) technique) and the density of cortical granules were examined for oocytes collected at 14 and 17 h after hCG injection.

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Background: The vesicular GABA transporter (VGAT) loads GABA and glycine from the neuronal cytoplasm into synaptic vesicles. To address functional importance of VGAT during embryonic development, we generated global VGAT knockout mice and analyzed them.

Results: VGAT knockouts at embryonic day (E) 18.

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Background: Neuregulin-1 (NRG1) is one of the susceptibility genes for schizophrenia and implicated in the neurotrophic regulation of GABAergic and dopaminergic neurons, myelination, and NMDA receptor function. Postmortem studies often indicate a pathologic association of increased NRG1 expression or signaling with this illness. However, the psychobehavioral implication of NRG1 signaling has mainly been investigated using hypomorphic mutant mice for individual NRG1 splice variants.

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We have previously shown that over-expression of the invariant Vα19-Jα33 TCR α transgene (Tg) using a natural TCR α promoter in mice induces the development of NK1.1(+) T cells (Vα19 NKT cells) in lymphoid organs, including the liver and intestine. These cells produce different spectra of immunoregulatory cytokines such as IL-4, IL-10, IL-17, and IFN-γ depending on the duration and intensity of the invariant TCR stimulation.

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CS (chondroitin sulfate) is a glycosaminoglycan species that is widely distributed in the extracellular matrix. To understand the physiological roles of enzymes involved in CS synthesis, we produced CSGalNAcT1 (CS N-acetylgalactosaminyltransferase 1)-null mice. CS production was reduced by approximately half in CSGalNAcT1-null mice, and the amount of short-chain CS was also reduced.

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Calponin h1 (CNh1) is an actin-binding protein originally isolated from vascular smooth muscle and has been reported to suppress bone formation. We are therefore curious how CNh1 is involved in bone loss that is caused by space flight in microgravity. We assessed the effects of tail suspension (TS) in C57BL/6J wild (CN+/+) and CNh1-deleted (CN-/-) mice to elucidate the role of CNh1 in bone loss under weightless conditions.

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Purpose: To characterize, in the setting of gamma-ray-induced atrophic thymus, probable prelymphoma cells showing clonal growth and changes in signaling, including DNA damage checkpoint.

Methods And Materials: A total of 111 and 45 mouse atrophic thymuses at 40 and 80 days, respectively, after gamma-irradiation were analyzed with polymerase chain reaction for D-J rearrangements at the TCRbeta locus, flow cytometry for cell cycle, and Western blotting for the activation of DNA damage checkpoints.

Results: Limited D-J rearrangement patterns distinct from normal thymus were detected at high frequencies (43 of 111 for 40-day thymus and 21 of 45 for 80-day thymus).

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A recent study has revealed that fear memory may be vulnerable following retrieval, and is then reconsolidated in a protein synthesis-dependent manner. However, little is known about the molecular mechanisms of these processes. Activin betaA, a member of the TGF-beta superfamily, is increased in activated neuronal circuits and regulates dendritic spine morphology.

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Purpose: 129 inbred mice show poor reproductive ability, as evidenced by small litters; however, the exact cause of this is unknown. In the present in vivo study we examined fertility and subsequent post-implantation development in an attempt to clarify the cause of small litter size in 129 mice.

Methods: 129 or C57BL/6J females that displayed vaginal plugs 1 day after mating with males of the same strain were examined for the presence of fertilized eggs.

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Cryopreservation of mouse sperm is useful for maintaining various strains. However, fertility generally decreases after freezing. In particular, the fertility of cryopreserved C57BL/6J sperm is very low.

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The beta-1,4-galactosyltransferase (beta-1,4-GalT) V whose human and mouse genes were cloned by us has been suggested to be involved in the biosynthesis of N-glycans and O-glycans, and lactosylceramide. To determine its biological function, beta-1,4-GalT V (B4galt5) mutant mice obtained by a gene trap method were analyzed. Analysis of pre- and post-implantation embryos revealed that the B4galt5(-/-) mice die by E10.

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Previously, we found that more than a half of the NK1.1(+) T cell lines prepared from CD1(-/-) livers expressed invariant Valpha19-Jalpha33 TCR alpha chains. Over-expression of the invariant Valpha19-Jalpha33 TCR alpha transgene (Tg) with a natural TCR alpha promoter and an enhancer in mice induced the development of NK1.

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Activin, a member of the transforming growth factor-beta superfamily, is an endocrine hormone that regulates differentiation and proliferation of a wide variety of cells. In the brain, activin protects neurons from ischemic damage. In this study, we demonstrate that activin modulates anxiety-related behavior by analyzing ACM4 and FSM transgenic mice in which activin and follistatin (which antagonizes the activin signal), respectively, were overexpressed in a forebrain-specific manner under the control of the alphaCaMKII promoter.

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Eutherian placenta, an organ that emerged in the course of mammalian evolution, provides essential architecture, the so-called feto-maternal interface, for fetal development by exchanging nutrition, gas and waste between fetal and maternal blood. Functional defects of the placenta cause several developmental disorders, such as intrauterine growth retardation in humans and mice. A series of new inventions and/or adaptations must have been necessary to form and maintain eutherian chorioallantoic placenta, which consists of capillary endothelial cells and a surrounding trophoblast cell layer(s).

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Article Synopsis
  • The study investigates the effectiveness of different saccharides as cryoprotectants for mouse sperm, comparing them to the commonly used combination of raffinose and skim milk.
  • Mouse sperm from various strains was frozen using different monosaccharides, disaccharides, and trisaccharides in various concentrations to find which provided the highest sperm motility post-thawing.
  • The results concluded that maltose, melezitose, and raffinose were the most effective cryoprotectants, particularly at optimal concentrations of 12% for disaccharides and 18% for trisaccharides.
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The proper regulation of microtubule (MT) structure is important for dendritic and neural circuit development. However, the relationship between the regulation of the MTs in dendrites and the formation of neural function is still unclear. Stathmin is a MT destabilizer, and we have previously reported that the expression and the activity of stathmin is downregulated during cerebellar Purkinje cell (PC) development.

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