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CD4(+)CD25(+) regulatory T (Treg) cells are crucial mediators of autoimmune tolerance. The factors that regulate Treg cells, however, are largely unknown. Here, we show that deficiency in midkine (MK), a heparin-binding growth factor involved in oncogenesis, inflammation, and tissue repair, attenuated experimental autoimmune encephalomyelitis (EAE) because(More)
A wide variety of pyrimidines and purines were identified as products of a dilute frozen ammonium cyanide solution that had been held at -78 degrees C for 27 years. This demonstrates that both pyrimidines and purines could have been produced on the primitive earth in a short time by eutectic concentration of HCN, even though the concentration of HCN in the(More)
It has been suggested that hydrogen cyanide (HCN) would not have been present in sufficient concentration to polymerize in the primitive ocean to produce nucleic acid bases and amino acids. We have measured the hydrolysis rates of HCN and formamide over the range of 30-150 degrees C and pH 0-14, and estimated the steady state concentrations in the primitive(More)
Most models of the primitive atmosphere around the time life originated suggest that the atmosphere was dominated by carbon dioxide, largely based on the notion that the atmosphere was derived via volcanic outgassing, and that those gases were similar to those found in modern volcanic effluent. These models tend to downplay the possibility of a strongly(More)
Eukaryotic translation initiation factor 4G (eIF4G) plays a crucial multimodulatory role in mRNA translation and decay by interacting with other translation factors and mRNA-associated proteins. In this study, we isolated eight different RNA aptamers with high affinity to mammalian eIF4G by in vitro RNA selection amplification. Of these, three aptamers(More)
Potential applications for functional RNAs are rapidly expanding, not only to address functions based on primary nucleotide sequences, but also by RNA aptamer, which can suppress the activity of any target molecule. Aptamers are short DNA or RNA folded molecules that can be selected in vitro on the basis of their high affinity for a target molecule. Here,(More)
The possible role of catalysis in forming a limited number of RNAs from activated monomers is investigated by examining the sequence- and regioselectivity in the montmorillonite-catalyzed formation of RNA dimers and trimers. The reactivity of A was similar to that of G, and C was comparable in reactivity to U. Yet the reactivity of the purine nucleotides(More)
Aptamers are short single-stranded nucleic acids with high affinity to target molecules and are applicable to therapeutics and diagnostics. Regardless of an increasing number of reported aptamers, the structural basis of the interaction of RNA aptamer with proteins is poorly understood. Here, we determined the 2.15 Å crystal structure of the Fc fragment of(More)
Midkine is a heparin-binding growth factor highly expressed in various cancers, including neuroblastoma, the most common extracranial pediatric solid tumor. Prognosis of patients with neuroblastoma in which MYCN is amplified remains particularly poor. In this study, we used a MYCN transgenic model for neuroblastoma in which midkine is highly expressed in(More)
The origin of guanine has been unknown, though there are some reports concerning its abiotic synthesis. We show here that guanine, as well as uracil and cytosine, are synthesized from a 90%N2-10%CO-H2O gas mixture via a complex organic product produced with the high-temperature and rapid quenching technique. This result implies that a large amount of(More)