The transcription factor Sox9 is expressed in all chondroprogenitors and has an essential role in chondrogenesis. Sox9 is also expressed in other tissues, including central nervous system, neural crest, intestine, pancreas, testis, and endocardial cushions, and plays a crucial role in cell proliferation and differentiation in several of these tissues. To determine the cell fate of Sox9-expressing cells during mouse embryogenesis, we generated mice in which a Cre recombinase gene preceded by an internal ribosome entry site was inserted into the 3 untranslated region of the Sox9 gene (Sox9-Cre knock-in). In the developing skeleton, Sox9 was expressed before Runx2, an early osteoblast marker gene. Cell fate mapping by using Sox9-Cre;ROSA26 reporter (R26R) mice revealed that Sox9-expressing limb bud mesenchymal cells gave rise to both chondrocytes and osteoblasts. Furthermore, a mutant in which the Osterix gene was inactivated in Sox9-expressing cells exhibited a lack of endochondral and intramembranous ossification and a lack of mature osteoblasts comparable with Osterix-null mutants. In addition, Sox9-expressing limb bud mesenchymal cells also contributed to tendon and synovium formation. By using Sox9-Cre;R26R mice, we also were able to systematically follow Sox9-expressing cells from embryonic day 8.0 to 17.0. Our results showed that Sox9-expressing cells contributed to the formation of all cell types of the spinal cord, epithelium of the intestine, pancreas, and mesenchyme of the testis. Thus, our results strongly suggest that all osteo-chondroprogenitor cells, as well as progenitors in a variety of tissues, are derived from Sox9-expressing precursors during mouse embryogenesis.imb skeleton is formed as a cartilage model that undergoes endochondral bone formation. At the initiation of limb development, undifferentiated mesenchymal cells in the lateral plate mesoderm receive proliferation signals from the apical ectodermal ridge. These cells start to aggregate and form mesenchymal condensations, which are the primordia of the limb skeleton, then differentiate into chondrocytes and generate a cartilage skeleton. Cells surrounding the nascent cartilage form the perichondrium and periosteum, specialized structures consisting of thin layers of mesenchymal cells. The cells surrounding the zone of hypertrophic chondrocytes begin to differentiate into osteoblasts and, together with blood vessels and osteoclasts, invade the mineralized cartilage matrix and replace cartilage by bone.Specific transcription factors regulate the differentiation pathways of chondrocytes and osteoblasts. Sox9, a transcription factor with a high-mobility group DNA-binding domain, activates chondrocyte-specific marker genes, such as Col2a1, Col11a2, and Aggrecan (1-3). Sox9 is expressed in all chondroprogenitors and chondrocytes except hypertrophic chondrocytes (4, 5). Campomelic dysplasia, a human disease that is caused by heterozygous mutations in the Sox9 gene, is characterized by a general hypoplasia of endochondral bones (6, 7). We have re...

In oxides, the substitution of non-oxide anions (F(-),S(2-),N(3-) and so on) for oxide introduces many properties, but the least commonly encountered substitution is where the hydride anion (H(-)) replaces oxygen to form an oxyhydride. Only a handful of oxyhydrides have been reported, mainly with electropositive main group elements or as layered cobalt oxides with unusually low oxidation states. Here, we present an oxyhydride of the perhaps most well-known perovskite, BaTiO(3), as an O(2-)/H(-) solid solution with hydride concentrations up to 20% of the anion sites. BaTiO(3-x)H(x) is electronically conducting, and stable in air and water at ambient conditions. Furthermore, the hydride species is exchangeable with hydrogen gas at 400 °C. Such an exchange implies diffusion of hydride, and interesting diffusion mechanisms specific to hydrogen may be at play. Moreover, such a labile anion in an oxide framework should be useful in further expanding the mixed-anion chemistry of the solid state.

Iron arsenide superconductors based on the material LaFeAsO1-xFx are characterized by a two-dimensional Fermi surface (FS) consisting of hole and electron pockets yielding structural and antiferromagnetic transitions at x = 0. Electron doping by substituting O2- with F- suppresses these transitions and gives rise to superconductivity with a maximum Tc = 26 K at x = 0.1. However, the over-doped region cannot be accessed due to the poor solubility of F- above x = 0.2. Here we overcome this problem by doping LaFeAsO with hydrogen. We report the phase diagram of LaFeAsO1-xHx (x < 0.53) and, in addition to the conventional superconducting dome seen in LaFeAsO1-xFx, we find a second dome in the range 0.21 < x < 0.53, with a maximum Tc of 36 K at x = 0.3. Density functional theory calculations reveal that the three Fe 3d bands (xy, yz, zx) become degenerate at x = 0.36, whereas the FS nesting is weakened monotonically with x. These results imply that the band degeneracy has an important role to induce high Tc.Comment: 31 pages, 4 figures, 1 table and supplementary informatio

␤ig-h3 is a transforming growth factor-␤-inducible cell adhesion molecule that has four characteristic homologous repeated domains. We made recombinant ␤ig-h3 proteins, which were highly active in mediating human corneal epithelial (HCE) cell adhesion and spreading. The 2nd and the 4th repeated domains were sufficient to mediate HCE cell adhesion. A sequence analysis showed that aspartic acid (Asp) and isoleucine (Ile) of the 2nd and the 4th domains are highly conserved in many fasciclin 1 homologous (fas-1) domains. Substitution mutational study identified these two amino acids are essential for cell adhesion. Synthetic peptides containing Asp and Ile, NKDIL and EPDIM derived from the 2nd and the 4th domains, respectively, almost completely blocked cell adhesion mediated by not only wild type ␤ig-h3 but also each of the 2nd and the 4th domains. These peptides alone were fully active in mediating cell adhesion. In addition, we demonstrated the functional receptor for ␤ig-h3 is ␣ 3 ␤ 1 integrin. These results, therefore, establish the essential motifs within the 2nd and the 4th domains of ␤ig-h3, which interact with ␣ 3 ␤ 1 integrin to mediate HCE cell adhesion to ␤ig-h3 and suggest that other proteins containing Asp-Ile in their fas-1 domains could possibly function as cell adhesion molecules.␤ig-h3 is an extracellular matrix protein that can be induced by transforming growth factor-␤ in several cell types, including human melanoma cells, mammary epithelial cells, keratinocytes, and lung fibroblasts (1). Several studies suggest ␤ig-h3 is involved in cell growth (1), cell differentiation (2, 3), wound healing (4), and cell adhesion (5, 6), although the underlying mechanisms for these effects are still unclear. In addition, some ␤ig-h3 missense mutations were identified in families affected with human autosomal dominant corneal dystrophies (7). Yet the exact role of mutant ␤ig-h3 proteins in developing corneal dystrophies is unidentified.␤ig-h3 contains an RGD motif and four internal repeated domains, which have highly conserved sequences found in some secretory and membrane proteins of several species including mammals, insects, sea urchins, plants, yeast, and bacteria (8). These proteins include periostin, fasciclin I, sea urchin HLC-2, alga Algal-CAM, and mycobacterium MPB70. The homologous domain (designated fas-1) 1 of these proteins is 110 -140 amino acids long and is characterized by two highly conserved stretches of about 10 amino acids (H1 and H2). Some proteins including ␤ig-h3, periostin, and fasciclin I have four sets of fas-1, HLC-2 has two sets, and MPB70 contains only one set. Although their biological functions are poorly characterized, some of them have been reported to function as cell adhesion molecules. ␤ig-h3, periostin, and fasciclin I have been reported to mediate attachment of fibroblasts (5), osteoblasts (9), and neuronal cells (10), respectively. Algal-CAM is also known to be a cell adhesion molecule in embryos of the alga Volvox (11).According to a recent report (6), ␤ig-h3 enhanced the ...

␤ig-h3 is a TGF-␤-induced matrix protein known to mediate the adhesion of several cell types. In this study, we found that all four of the fas-1 domains in ␤ig-h3 mediate MRC-5 fibroblast adhesion and that this was specifically inhibited by a function-blocking monoclonal antibody specific for the ␣v␤5 integrin. Using deletion mutants of the fourth fas-1 domain revealed the MRC-5 cell adhesion motif (denoted the YH motif) is located in amino acids 548 -614. Experiments with substitution mutants showed that tyrosine 571, histidine 572, and their flanking leucine and isoleucine amino acids, which are all highly conserved in many fas-1 domains, are essential for mediating MRC-5 cell adhesion. A synthetic 18-amino acid peptide encompassing these conserved amino acids could effectively block MRC-5 cell adhesion to ␤ig-h3. Using HEK293 cells stably transfected with the ␤5 integrin cDNA, we confirmed that the ␣v␤5 integrin is a functional receptor for the YH motif. In conclusion, we have identified a new ␣v␤5 integrininteracting motif that is highly conserved in the fas-1 domains of many proteins. This suggests that fas-1 domain-containing proteins may perform their biological functions by interacting with integrins. ␤ig-h3 is an extracellular matrix protein whose expression in several cell types, including fibroblasts, is strongly induced by TGF-␤.1 The gene encoding ␤ig-h3 was first identified by Skonier et al. (1), who isolated it by screening a cDNA library made from a human lung adenocarcinoma cell line (A549) that had been treated with TGF-␤. The ␤ig-h3 protein comprises 683 amino acids containing four homologous internal repeat domains. These domains are homologous to similar motifs in the Drosophila protein fasciclin-I and thus are denoted fas-1 domains. The fas-1 domain has highly conserved sequences found in secretory and membrane proteins of several species, including mammals, insects, sea urchins, plants, yeast, and bacteria (2).Mutations in ␤ig-h3 have been shown to be responsible for 5q31-linked human autosomal dominant corneal dystrophies. It has a fibrillar structure and interacts with several extracellular matrix proteins such as fibronectin and collagen (3). In addition, ␤ig-h3 has been reported to be involved in cell growth and differentiation, wound healing, and cell adhesion (4 -9). ␤ig-h3 mediates the adhesion of many different cell types, including corneal epithelial cells, chondrocytes, and fibroblasts (8 -10). We reported previously that ␤ig-h3 mediates corneal epithelial cell adhesion by binding to ␣3␤1 integrin. Two motifs interacting with the ␣3␤1 integrin were located within the second and the fourth fas-1 domains of ␤ig-h3. Interestingly, however, we found that these two motifs are not involved in ␤ig-h3-mediated fibroblastic cell adhesion. Furthermore, all four fas-1 domains of ␤ig-h3 mediate fibroblastic cell adhesion, whereas corneal epithelial cell adhesion is supported by just the second and the fourth fas-1 domains. This suggests that ␤ig-h3 has additional motifs that can mediate the ...

Calcium (Ca(2+)) signals that are precisely modulated in space and time mediate a myriad of cellular processes, including contraction, excitation, growth, differentiation and apoptosis. However, study of Ca(2+) responses has been hampered by technological limitations of existing Ca(2+)-modulating tools. Here we present OptoSTIM1, an optogenetic tool for manipulating intracellular Ca(2+) levels through activation of Ca(2+)-selective endogenous Ca(2+) release-activated Ca(2+) (CRAC) channels. Using OptoSTIM1, which combines a plant photoreceptor and the CRAC channel regulator STIM1 (ref. 4), we quantitatively and qualitatively controlled intracellular Ca(2+) levels in various biological systems, including zebrafish embryos and human embryonic stem cells. We demonstrate that activating OptoSTIM1 in the CA1 hippocampal region of mice selectively reinforced contextual memory formation. The broad utility of OptoSTIM1 will expand our mechanistic understanding of numerous Ca(2+)-associated processes and facilitate screening for drug candidates that antagonize Ca(2+) signals.

The translation of polioviral mRNA occurs through an internal ribosomal entry site (IRES). Several RNA-binding proteins, such as polypyrimidine tract-binding protein (PTB) and poly(rC)-binding protein (PCBP), are required for the poliovirus IRES-dependent translation. Here we report that a poliovirus protein, 3C pro (and/or 3CD pro ), cleaves PTB isoforms (PTB1, PTB2, and PTB4). Three 3C pro target sites (one major target site and two minor target sites) exist in PTBs. PTB fragments generated by poliovirus infection are redistributed to the cytoplasm from the nucleus, where most of the intact PTBs are localized. Moreover, these PTB fragments inhibit polioviral IRES-dependent translation in a cell-based assay system. We speculate that the proteolytic cleavage of PTBs may contribute to the molecular switching from translation to replication of polioviral RNA.Picornaviruses are important pathogens of both humans (e.g., poliovirus, rhinovirus, and hepatitis A virus) and animals (e.g., foot-and-mouth disease virus [FMDV] and encephalomyocarditis virus [EMCV]) (75). Their genome consists of a positive-sense RNA that acts as a template for both translation and replication. On entering the host cell, the RNA directs the translation of a single polyprotein, which is cleaved during and after translation by virus-encoded proteases into functional proteins. In poliovirus, three virus-encoded proteases, 2A pro (specific to Tyr-Gly), 3Cpro (Gln-Gly), and 3CD pro (Gln-Gly), are involved in protein processing during virus replication (34, 50, 54, 60, 65-67, 80, 81). These proteases also play a role in host cell alteration; for example, it is well known that poliovirus 2A pro cleaves eIF4G, which results in shutting off the capdependent translation of host mRNAs (6,19,21,51). Recent studies suggest that 2A pro and 3C pro cleave poly(A)-binding protein (PABP), which augments the translation of the poly(A)-tailed mRNAs (42, 47). 3C pro induces morphological changes in host cells by cleaving microtubule-associated protein (MAP-4) (41). 3Cpro inhibits the transcription of host mRNAs by proteolytically cleaving transcription factors, such as TATA-binding protein (TBP), TFIIIC, Oct-1, and CREB (15,18,85,86). A recent report suggests that 3C pro cleaves La autoantigen and that this results in the redistribution of La in the cytoplasm, which results in the enhanced translation of viral mRNAs (77).After poliovirus RNA has been released into the cytoplasm of infected cells, translational initiation of the poliovirus RNA is initiated by the binding of ribosomes to a specialized region in the 5Ј nontranslated region (5ЈNTR), called the internal ribosomal entry site (IRES) (20,71,82). IRES-dependent translation of poliovirus requires IRES-specific cellular factors as well as canonical initiation factors for efficient translation (2, 10). Known cellular factors required for polioviral IRES include polypyrimidine tract-binding protein (PTB) (28,33,37,38), La protein (9, 17), and poly(rC) binding protein 2 (PCBP2) (12,25).PTB (also known as p...

Atopic dermatitis (AD) is a long-standing inflammatory skin disease that is highly prevalent worldwide. Multiple factors contribute to AD, with genetics as well as the environment affecting disease development. Although AD shows signs of skin barrier defect and immunological deviation, the mechanism underlying AD is not well understood, and AD treatment is often very difficult. There is substantial data that AD patients have a disturbed microbial composition and lack microbial diversity in their skin and gut compared to controls, which contributes to disease onset and atopic march. It is not clear whether microbial change in AD is an outcome of barrier defect or the cause of barrier dysfunction and inflammation. However, a cross-talk between commensals and the immune system is now noticed, and their alteration is believed to affect the maturation of innate and adaptive immunity during early life. The novel concept of modifying skin and gut microbiome by applying moisturizers that contain nonpathogenic biomass or probiotic supplementation during early years may be a preventive and therapeutic option in high risk groups, but currently lacks evidence. This review discusses the nature of the skin and gut flora in AD, possible mechanisms of skin–gut interaction, and the therapeutic implications of microbiome correction in AD.