Affinity selection of DNA-binding protein complexes using mRNA display

Comprehensive analysis of DNA–protein interactions is important for mapping transcriptional regulatory networks on a genome-wide level. Here we present a new application of mRNA display for in vitro selection of DNA-binding protein heterodimeric complexes. Under improved selection conditions using a TPA-responsive element (TRE) as a bait DNA, known interactors c-fos and c-jun were simultaneously enriched about 100-fold from a model library (a 1:1:20 000 mixture of c-fos, c-jun and gst genes) after one round of selection. Furthermore, almost all kinds of the AP-1 family genes including c-jun, c-fos, junD, junB, atf2 and b-atf were successfully selected from an mRNA display library constructed from a mouse brain poly A(+) RNA after six rounds of selection. These results indicate that the mRNA display selection system can identify a variety of DNA-binding protein complexes in a single experiment. Since almost all transcription factors form heterooligomeric complexes to bind with their target DNA, this method should be most useful to search for DNA-binding transcription factor complexes

Activation of AMPK-Regulated CRH Neurons in the PVH is Sufficient and Necessary to Induce Dietary Preference for Carbohydrate over Fat

Food selection is essential for metabolic homeostasis and is influenced by nutritional state, food palatability, and social factors such as stress. However, the mechanism responsible for selection between a high-carbohydrate diet (HCD) and a high-fat diet (HFD) remains unknown. Here, we show that activation of a subset of corticotropin-releasing hormone (CRH)-positive neurons in the rostral region of the paraventricular hypothalamus (PVH) induces selection of an HCD over an HFD in mice during refeeding after fasting, resulting in a rapid recovery from the change in ketone metabolism. These neurons manifest activation of AMP-activated protein kinase (AMPK) during food deprivation, and this activation is necessary and sufficient for selection of an HCD over an HFD. Furthermore, this effect is mediated by carnitine palmitoyltransferase 1c (CPT1c). Thus, our results identify the specific neurons and intracellular signaling pathway responsible for regulation of the complex behavior of selection between an HCD and an HFD

Syntheses of rigid-rod but degradable biopolyamides from itaconic acid with aromatic diamines

Highly-thermostable but degradable polyamides have been synthesized by a polycondensation of bio-derived itaconic acid salts with aromatic diamines to form heterocyclic pyrrolidone ring in the polymer backbone. The molecular weight was greater than 33600 g/mol. Glass transition temperatures, T_g, and 10% weight loss temperatures, T_, ranged 156–242 °C and 370–400 °C, respectively, which were higher than those of conventional bio-based plastics. However their processability was too low to process the fiber as specimens of mechanical tests. We then incorporated an appropriate amount of aliphatic moiety into the aromatic backbones to prepare the high-performance and processable polyamides with T_g over 115 °C and T_ over 355 °C. The processed fibers showed tensile strength and Young's modulus ranged 20–58 MPa and 0.2–2.3 GPa, respectively. The degradation behaviors inside soil and under ultraviolet-irradiation in water were additionally found

Synthesis of well-defined hyperbranched polymers bio-based on multifunctional phenolic acids and their structure-thermal property relationships

A number of multifunctional ABx-type monomers exist in plant metabolites, and studies on the formation of hyperbranching polymers from ABx-type monomers are very significant in the development of bio-related polymeric materials. We established a method for the preparation of well-definedstructures in bio-based, hyperbranched (HB) polyarylates by the copolycondensation of caffeic acid (DHCA) as an AB_2-monomer and p-coumaric acid (4HCA) as an AB-monomer, using the highly efficient catalyst Na_2HPO_4 to regulate the polymerization speed. ^1H NMR analysis revealed the time course of the formation of the hyperbranching structures. which strongly affected the glass transition and degradation temperatures, as well as the molecular weight and composition

1H NMR and FT-IR dataset based structural investigation of poly(amic acid)s and polyimides from 4,4′-diaminostilbene

Structural investigation of polymers by various available analytical methods is important in order to correlate the structure with polymer properties for which understanding of polymer structure is very important factor. The data presented here in this article shows the 1H NMR spectra used for the characterization of prepared poly(amic acid)s (PAAs). It is often difficult to assigns the peak in NMR of polymers due to its complexity. Data presented here helps in assigning the proton peak in complex NMR of PAAs prepared from aromatic diamines. Further functionality in polymer chains can be confirmed by FT-IR spectra. Change in functionality during some reaction or process can be monitored by disappearance or appearance of peaks in FT-IR. The complete imidization of PAAs to Polyimides (PIs) is difficult to analyze because of the chemical stability i.e. insolubility of PIs in most of the solvent therefore the completion of imidization process was confirmed using FTIR