Real-time imaging of bHLH transcription factors reveals their dynamic control in the multipotency and fate choice of neural stem cells

The basic-helix-loop-helix (bHLH) transcription factors Ascl1/Mash1, Hes1, and Olig2 regulate the fate choice of neurons, astrocytes, and oligodendrocytes, respectively; however, these factors are coexpressed in self-renewing multipotent neural stem cells (NSCs) even before cell fate determination. This fact raises the possibility that these fate determination factors are differentially expressed between self-renewing and differentiating NSCs with unique expression dynamics. Real-time imaging analysis utilizing fluorescent proteins is a powerful strategy for monitoring expression dynamics. Fusion with fluorescent reporters makes it possible to analyze the dynamic behavior of specific proteins in living cells. However, it is technically challenging to conduct long-term imaging of proteins, particularly those with low expression levels, because a high-sensitivity and low-noise imaging system is required, and very often bleaching of fluorescent proteins and cell toxicity by prolonged laser exposure are problematic. Furthermore, to analyze the functional roles of the dynamic expression of cellular proteins, it is essential to image reporter fusion proteins that are expressed at comparable levels to their endogenous expression. In this review, we introduce our recent reports about the dynamic control of bHLH transcription factors in multipotency and fate choice of NSCs, focusing on real-time imaging of fluorescent reporters fused with bHLH transcription factors. Our imaging results indicate that bHLH transcription factors are expressed in an oscillatory manner by NSCs, and that one of them becomes dominant during fate choice. We propose that the multipotent state of NSCs correlates with the oscillatory expression of several bHLH transcription factors, whereas the differentiated state correlates with the sustained expression of a single bHLH transcription factor

Effectiveness of onomatopoeias on coping behaviors of Japanese preschool children undergoing medical procedures.

神奈川大

Carbonyl-Iron/Epoxy Composite Magnetic Core for Planar Power Inductor Used in Package-Level Power Grid

Our research objective is to realize the basic technology for a next generation package-level power grid (PLPG) for plural application large scale integrated circuits (LSIs). In this study, a carbonyl-iron powder (CIP)/epoxy composite magnetic core, for large-current power inductor used for the main dc-dc converter in the PLPG, has been fabricated and evaluated. 54 vol.%-CIP/epoxy composite core made by screen-printing had a relative permeability of 7.5 and loss tangent of about 0.03 at 100 MHz. The planar power inductor using composite core was fabricated and evaluated, which had a quasi closed magnetic circuit consisting of low permeability composite core and embedded 35-mu m-thick, two-turn copper spiral coil. The fabricated inductor with a 1-mm-square in size had 5.5 nH inductance, Q-factor of 15 at 100 MHz, and 18 m Omega dc coil resistance. Inductance was constant even when the superimposed dc current increased up to around 5.5 A.ArticleIEEE TRANSACTIONS ON MAGNETICS. 49(7):4172-4175 (2013)journal articl

Scientific Opinion on the safety and efficacy of disodium 5?-ribonucleotides, disodium 5?-guanylate, disodium 5?-inosinate for all animal species and categories

The flavours included in this assessment are widely present in nature as the building blocks of DNA and RNA. In the absence of any information on the microbial strains or substrates used for the production of the additives, and with little information on the manufacturing process, the FEEDAP Panel is unable to ascertain whether the manufacturing process introduces any safety concerns. Disodium 5′-guanylate and disodium 5′-inosinate and their mixture are considered to be safe for the target animals and the consumer. However, considering the lack of information on the production process, these conclusions apply only to the compounds ‘per se’ and their extrapolation to any feed additive containing these compounds is not possible. In the absence of any data related to hazard to the user, it would be prudent to regard disodium 5′-guanylate and disodium 5′-inosinate and their mixture as potentially hazardous to workers by skin or inhalation exposure. The compounds under assessment are naturally present in feed materials; therefore, no risk to the safety for the environment is foreseen. Since these compounds are used in food as flavourings, and their function in feed is essentially the same as that in food, no further demonstration of efficacy is necessary

Inductive asymmetric cell division: The WRM leads the way

C. elegans, with its invariant cell lineage, provides a powerful model system in which to study signaling-dependent asymmetric cell division. The C. elegans β-catenin-related protein, WRM-1, specifies endoderm at the 4-cell stage during the first cell signaling-induced asymmetric cell division of embryogenesis. During this interaction, Wnt signaling and the cell cycle regulator CDK-1 act together to induce the asymmetric cortical release of WRM-1 at prophase of the EMS cell cycle. Genetic studies suggest that release of WRM-1 unmasks a cortical site that drives EMS spindle rotation onto the polarized axis of the cell, simultaneously making WRM-1 available for nuclear translocation, and downstream signaling to specify endoderm. These studies suggest a general paradigm for how cortical factors like WRM-1 can function at the cell cortex to mask potentially confounding polarity cues, and when released with appropriate cell cycle timing, can also function downstream to define cell fate

Three-dimensional live imaging of Atoh1 reveals the dynamics of hair cell induction and organization in the developing cochlea

During cochlear development, hair cells (HCs) and supporting cells differentiate in the prosensory domain to form the organ of Corti, but how one row of inner HCs (IHCs) and three rows of outer HCs (OHCs) are organized is not well understood. Here, we investigated the process of HC induction by monitoring Atoh1 expression in cochlear explants of Atoh1-EGFP knock-in mouse embryos and showed that only the cells that express Atoh1 over a certain threshold are selected for HC fate determination. HC induction initially occurs at the medial edge of the prosensory domain to form IHCs and subsequently at the lateral edge to form OHCs, while Hedgehog signaling maintains a space between IHCs and OHCs, leading to formation of the tunnel of Corti. These results reveal dynamic Atoh1 expression in HC fate control and suggest that multi-directional signals regulate OHC induction, thereby organizing the prototype of the organ of Corti

The content of diacylglycerol, triacylglycerol and monoacylglycerol and a comparison of the structural and metabolic heterogeneity of diacylglycerols and phosphatidylcholine during rat lung development

The content of diacylglycerol in fetal rat lung is approx. 36% of the adult and rapidly increases to adult levels by 1 day after birth. Triacylglycerol content is also low (23%) and increases to adult levels between 1 and 2 days following birth. Monoacylglycerol content is relatively low at all stages of development. The analysis of the molecular species of diacylglycerols showed that the disaturated species accounted for 30-40% of the diacylglycerols and the monoene species 20-28%. Phosphatidylcholine contained 40-45% disaturated and approx. 30% monoene species. The overall pattern of molecular species of phosphatidylcholine was similar to the pattern for diacylglycerol. The in vivo incorporation of [2-3H]glycerol into molecular species of diacylglycerol and phosphatidylcholine in -1-day-fetal (i.e., 1 day before birth) lung showed that the disaturated species of diacylglycerol had the highest incorporation and appeared to have a higher rate of turnover. In contrast, [2-3H]glycerol was incorporated by fetal liver most actively in the monoenoic and dienoic species of diacylglycerol. The relative incorporation of radioactivity into disaturated, monoene and diene species of phosphatidylcholine in fetal lung was very similar to that for the corresponding diacylglycerol species. The rate of the reaction from the disaturated species of diacylglycerol to the disaturated species of phosphatidylcholine, calculated from the in vivo data, was one of the higher rates and indicated considerable potential for the synthesis of disaturated phosphatidylcholine via this route. The overall results suggests that de novo synthesis of disaturated phosphatidylcholine from the disaturated species of diacylglycerol can be a major route for the synthesis of dipalmitoylphosphatidylcholine in fetal lung.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24392/1/0000662.pd

The Antiviral RNA Interference Response Provides Resistance to Lethal Arbovirus Infection and Vertical Transmission in Caenorhabditis elegans

The recent discovery of the positive-sense single-stranded RNA (ssRNA) Orsay virus (OV) as a natural pathogen of the nematode Caenorhabditis elegans has stimulated interest in exploring virus-nematode interactions. However, OV infection is restricted to a small number of intestinal cells, even in nematodes defective in their antiviral RNA interference (RNAi) response, and is neither lethal nor vertically transmitted. Using a fluorescent reporter strain of the negative-sense ssRNA vesicular stomatitis virus (VSV), we show that microinjection of VSV particles leads to a dose-dependent, muscle tissue-tropic, lethal infection in C. elegans. Furthermore, we find nematodes deficient for components of the antiviral RNAi pathway, such as Dicer-related helicase 1 (DRH-1), to display hypersusceptibility to VSV infection as evidenced by elevated infection rates, virus replication in multiple tissue types, and earlier mortality. Strikingly, infection of oocytes and embryos could also be observed in drh-1 mutants. Our results suggest that the antiviral RNAi response not only inhibits vertical VSV transmission but also promotes transgenerational inheritance of antiviral immunity. Our study introduces a new, in vivo virus-host model system for exploring arbovirus pathogenesis and provides the first evidence for vertical pathogen transmission in C. elegans

Extracellular vesicles synchronize cellular phenotypes of differentiating cells

細胞外小胞が細胞の分化を同調させる現象の発見. 京都大学プレスリリース. 2021-10-01.Cells act in unison when next to each other. 京都大学プレスリリース. 2021-10-01.During embryonic development, cells differentiate in a coordinated manner, aligning their fate decisions and differentiation stages with those of surrounding cells. However, little is known about the mechanisms that regulate this synchrony. Here we show that cells in close proximity synchronize their differentiation stages and cellular phenotypes with each other via extracellular vesicle (EV)-mediated cellular communication. We previously established a mouse embryonic stem cell (ESC) line harbouring an inducible constitutively active protein kinase A (CA-PKA) gene and found that the ESCs rapidly differentiated into mesoderm after PKA activation. In the present study, we performed a co-culture of Control-ESCs and PKA-ESCs, finding that both ESC types rapidly differentiated in synchrony even when PKA was activated only in PKA-ESCs, a phenomenon we named ‘Phenotypic Synchrony of Cells (PSyC)’. We further demonstrated PSyC was mediated by EVs containing miR-132. PKA-ESC-derived EVs and miR-132-containing artificial nano-vesicles similarly enhanced mesoderm and cardiomyocyte differentiation in ESCs and ex vivo embryos, respectively. PSyC is a new form of cell-cell communication mediated by the EV regulation of neighbouring cells and could be broadly involved in tissue development and homeostasis