Enhancers have critical functions in the precise, spatiotemporal control of transcription during development. It is thought that enhancer grammar, or the characteristics and arrangements of transcription factor binding sites, underlie the specific functions of developmental enhancers. In this study, we sought to identify grammatical constraints that direct enhancer activity in the naïve state of pluripotency, focusing on the enhancers for the naïve-state specific gene, Klf4.
View Article and Find Full Text PDFSupramolecular chemistry currently faces the challenge of controlling nonequilibrium dynamics such as the dynamic instability of microtubules. In this study, we explored the emergence of dynamic instability through the hybridization of peptide-type supramolecular nanofibers with surfactant micelles. Using real-time confocal imaging, we discovered that the addition of micelles to nanofibers induced the simultaneous but asynchronous growth and shrinkage of nanofibers during which the total number of fibers decreased monotonically.
View Article and Find Full Text PDFDectin-1 is a well-characterized C-type lectin receptor involved in anti-fungal immunity through the recognition of polysaccharides; however, molecular mechanisms and outcomes initiated through self-recognition have not been fully understood. Here, we purified a water-soluble fraction from mouse liver that acts as a Dectin-1 agonist. To address the physiological relevance of this recognition, we utilized sterile liver inflammation models.
View Article and Find Full Text PDFAspergillus fumigatus is a ubiquitous, yet potentially pathogenic, mold. The immune system employs innate receptors, such as dectin-1, to recognize fungal pathogens, but the immunological networks that afford protection are poorly explored. Here, we investigated the role of dectin-1 in anti-A.
View Article and Find Full Text PDFMycobacteria often cause chronic infection. To establish persistence in the host, mycobacteria need to evade host immune responses. However, the molecular mechanisms underlying the evasion strategy are not fully understood.
View Article and Find Full Text PDFThe fate of living cells often depends on their processing of temporally modulated information, such as the frequency and duration of various signals. Synthetic stimulus-responsive systems have been intensely studied for >50 years, but it is still challenging for chemists to create artificial systems that can decode dynamically oscillating stimuli and alter the systems' properties/functions because of the lack of sophisticated reaction networks that are comparable with biological signal transduction. Here, we report morphological differentiation of synthetic dipeptide-based coacervates in response to temporally distinct patterns of the light pulse.
View Article and Find Full Text PDFOur bodies are continuously assaulted by infection and tissue damage; most of these injurious insults are primarily sensed by immune receptors to maintain tissue homeostasis. Although immune recognition of proteins or nucleic acids has been well characterized, the molecular mechanisms by which immune receptors discriminate lipids to elicit suitable immune responses remain elusive. Recent studies have demonstrated that the C-type lectin receptor family functions as immune sensors for adjuvant lipids derived from pathogens and damaged tissues, thereby promoting innate/acquired immunity.
View Article and Find Full Text PDFAcPIM is a potential biosynthetic intermediate for phosphatidylinositol mannosides (PIMs) from Mycobacterium tuberculosis. We achieved the first synthesis of AcPIM by utilizing an allyl-type protecting group strategy and regioselective phosphorylation of inositol. A very potent agonist of an innate immune receptor DCAR, which is better than previously known agonists, is demonstrated.
View Article and Find Full Text PDFMulticomponent supramolecular hydrogels are promising scaffolds for applications in biosensors and controlled drug release due to their designer stimulus responsiveness. To achieve rational construction of multicomponent supramolecular hydrogel systems, their in-depth structural analysis is essential but still challenging. Confocal laser scanning microscopy (CLSM) has emerged as a powerful tool for structural analysis of multicomponent supramolecular hydrogels.
View Article and Find Full Text PDFTranscription factor (TF)-directed enhanceosome assembly constitutes a fundamental regulatory mechanism driving spatiotemporal gene expression programs during animal development. Despite decades of study, we know little about the dynamics or order of events animating TF assembly at -regulatory elements in living cells and the long-range molecular "dialog" between enhancers and promoters. Here, combining genetic, genomic, and imaging approaches, we characterize a complex long-range enhancer cluster governing () expression in naïve pluripotency.
View Article and Find Full Text PDFPhosphatidyl-inositol mannosides (PIM) are glycolipids unique to mycobacteria and other related bacteria that stimulate host immune responses and are implicated in mycobacteria pathogenicity. Here, we found that the FcRγ-coupled C-type lectin receptor DCAR (dendritic cell immunoactivating receptor; gene symbol Clec4b1) is a direct receptor for PIM. Mycobacteria activated reporter cells expressing DCAR, and delipidation of mycobacteria abolished this activity.
View Article and Find Full Text PDFThe amounts of the DNAs of human herpesviruses-6 (HHV-6) and -7 (HHV-7) in saliva samples were monitored during the acute and convalescent phases of exanthem subitum (ES) to elucidate the kinetics of virus shedding after ES. A total of 247 saliva samples were collected from 17 children (5 males and 12 females: 8-31 months old at onset). The monitoring period ranged from 152 to 721 days after onset, and in 15 children it was longer than 1 year.
View Article and Find Full Text PDFThe prokaryotic CRISPR (clustered regularly interspaced palindromic repeats)-associated protein, Cas9, has been widely adopted as a tool for editing, imaging, and regulating eukaryotic genomes. However, our understanding of how to select single-guide RNAs (sgRNAs) that mediate efficient Cas9 activity is incomplete, as we lack insight into how chromatin impacts Cas9 targeting. To address this gap, we analyzed large-scale genetic screens performed in human cell lines using either nuclease-active or nuclease-dead Cas9 (dCas9).
View Article and Find Full Text PDFChromatin comprises nucleosomes as well as nonnucleosomal histone-DNA particles. Prenucleosomes are rapidly formed histone-DNA particles that can be converted into canonical nucleosomes by a motor protein such as ACF. Here we show that the prenucleosome is a stable conformational isomer of the nucleosome.
View Article and Find Full Text PDFMycobacterium tuberculosis H37Ra produces a range of immunogenic β-gentiobiosyl diacylglycerides. We report the total synthesis of several candidate structures and show that these compounds signal weakly through mouse, but not human, Mincle. Structure-activity relationships reveal a striking dependence upon acyl chain length for gentiobiosyl diacylglyceride signalling through Mincle.
View Article and Find Full Text PDFAn enantioselective synthesis of (+)-corynomycolic acid, and its elaboration to esters of trehalose, glucose and glycerol, is described. Trehalose dicorynomycolate and trehalose monocorynomycolate activate human and mouse Mincle as effectively as trehalose dicorynomycolate (cord factor). Glucose monomycolate is revealed to be a potent activator of both mouse and human Mincle.
View Article and Find Full Text PDFWe describe differentiation of a spinal intramedullary lipoma from an intramedullary hematoma on magnetic resonance images (MRI) with fast spin-echo (FSE) sequences. A 60-year-old man with dysesthesia in the legs and gait disturbance, was suspected of having myelopathy at a middle thoracic lesion. MRI with FSE sequences revealed an intramedullary lesion at T7 to T8.
View Article and Find Full Text PDFChromatin assembly involves the combined action of ATP-dependent motor proteins and histone chaperones. Because motor proteins in chromatin assembly also function as chromatin remodeling factors, we investigated the relationship between ATP-driven chromatin assembly and chromatin remodeling in the generation of periodic nucleosome arrays. We found that chromatin remodeling-defective Chd1 motor proteins are able to catalyze ATP-dependent chromatin assembly.
View Article and Find Full Text PDFWe examined the efficacy and safety of inactivated influenza vaccine when the amount of HA influenza vaccination in children was increased to the dose recommended by the WHO. The purpose of this study was to obtain basic evidence to review the vaccination dose in Japanese children. HA influenza vaccine produced by the Research Foundation for Microbial Diseases of Osaka University (Biken) licenced in Japan was administered through vaccination at the international dose, and split HA influenza vaccine produced by Sanofi Pasteur corp.
View Article and Find Full Text PDFBackground: 5-Fluorouracil (5-FU) is widely used in the treatment of head and neck squamous cell carcinoma (HNSCC). However, development of drug resistance is one of the major causes of HNSCC treatment failure. The goal of this study was to investigate the mechanism of 5-FU resistance and to develop a novel combination therapy with another agent which sensitizes cells to 5-FU.
View Article and Find Full Text PDFChromatin assembly involves the combined action of histone chaperones and ATP-dependent motor proteins. Here, we investigate the mechanism of nucleosome assembly with a purified chromatin assembly system containing the histone chaperone NAP1 and the ATP-dependent motor protein ACF. These studies revealed the rapid formation of a stable nonnucleosomal histone-DNA intermediate that is converted into canonical nucleosomes by ACF.
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
November 2010
Stochastic resonance is numerically and analytically studied using a model wherein two coupled particles are exposed to noise of heterogeneous (i.e., particle-dependent) amplitude.
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