The p53 tumor suppressor protein is an important molecule studied extensively in cancer research. In order to study the mechanism of tumor suppression by p53, structural knowledge is needed. Although the structure of the p53 DNA binding domain bound to DNA has been well elucidated, there is a lack of structural knowledge of the regulatory domain of p53 bound to the DNA. Structural knowledge of this domain bound to the DNA would contribute to the full understanding of the p53 tumor suppression mechanism. In order to solve this problem, X-ray crystallography was used to elucidate the p53 regulatory domain structure. In order to facilitate the crystallization of p53 regulatory domain with DNA, oligomerization of p53 with various DNAs was studied using the sedimentation velocity method. Functional aspects of p53 regulation were studied including acetylation and interaction with the MDM2 protein. It has been found that the p53 regulatory domain binds to both the consensus and non-consensus DNA as a tetramer, and the interaction of the p53 regulatory domain with MDM2 produces a novel MDM2 oligomerization state

The number of pet cats in South Korea has sharply increased since 2010. Problems have arisen with feral or stray cats, creating conflict among residents, to such an extent that the government provides some sites for people to offer feeding stations for the stray cats. This study investigated hypotheses on peoples attitudes toward feral cats in Seoul, South Korea: (i) dog and cat owners would show more positive attitudes than non-owners toward feral cats; (ii) females would have more positive attitudes toward feral cats than males; (iii) the number of Seoul-provided feeding stations by district would be correlated with peoples positive attitudes toward feral cats. Responses from 7,394 participants were used for the final analyses with 3,179 males, 3,607 females, and 599 others (includes decline to state). Cat owners reported more extremely positive attitudes toward feral cats than people who had no cats. Females more often had cats than males, and they were more extremely positive toward pet and feral cats than males, and strongly opposed to culling as a management strategy. The attitudes toward feral cats of people with only dogs were intermediate between people with cats and people without pets, more resembling those of people without pets. There was a correlation between the number of city-provided feeding stations and peoples attitudes toward feral cats, but only in the areas with at least 40 feeder stations; having many city-provided feeding stations was associated with very negative attitudes to feral cats. Whether the very large number of feeding stations were provided in the two neighborhoods due to a previously excessive number of feral cats in those neighborhoods, vs. those feeding stations attracting or provisioning an ever-growing number of feral cats, is unknown. These results show sharp differences in attitudes between cat owners and non-owners, and between males and females. Results resemble findings in other studies, perhaps with more extreme differences between sub-groups. The study revealed that attitudes toward pet and feral cats in Seoul were complex and varied with pet ownership, with sex, and with neighborhood context.

Fatty acid and fat synthesis in the liver is a highly regulated metabolic pathway that is important for very low-density lipoprotein (VLDL) production and thus energy distribution to other tissues. Having common features at their promoter regions, lipogenic genes are coordinately regulated at the transcriptional level. Transcription factors, such as upstream stimulatory factors (USFs), sterol regulatory element-binding protein 1C (SREBP1C), liver X receptors (LXRs) and carbohydrate-responsive element-binding protein (ChREBP) have crucial roles in this process. Recently, insights have been gained into the signalling pathways that regulate these transcription factors. After feeding, high blood glucose and insulin levels activate lipogenic genes through several pathways, including the DNA-dependent protein kinase (DNA-PK), atypical protein kinase C (aPKC) and AKT-mTOR pathways. These pathways control the post-translational modifications of transcription factors and co-regulators, such as phosphorylation, acetylation or ubiquitylation, that affect their function, stability and/or localization. Dysregulation of lipogenesis can contribute to hepatosteatosis, which is associated with obesity and insulin resistance.

Purpose

PPARγ plays a critical role in the maturation of immortalized human meibomian gland epithelial cells (hMGEC). To further understand the molecular changes associated with meibocyte differentiation, we analyzed transcriptome profiles from hMGEC after PPARγ activation.

Methods

Three sets of cultivated hMGEC with or without exposure to PPARγ agonist, rosiglitazone were used for RNA-seq analysis. RNA was isolated and processed to generate 6 libraries. The libraries were then sequenced and mapped to the human reference genome, and the expression results were gathered as reads per length of transcript in kilobases per million mapped reads (RPKM) values. Differential gene expression analyses were performed using DESeq2 and NOISeq. Gene ontology enrichment analysis (GOEA) was performed on gene sets that were upregulated or downregulated after rosiglitazone treatment. Five genes were selected for validation and differential expression was confirmed using quantitative PCR. The Differential expression of CK5 was evaluated using Western blotting.

Results

Expression data indicated that about 58,000 genes are expressed in hMGEC. DESeq2 and NOISeq indicated that 296 and 3436 genes were upregulated and 258 and 3592 genes were down regulated after rosiglitazone treatment, respectively. Of genes showing significant differences > 2 fold, GOEA indicated that cellular and metabolic processes were highly represented. Expression of ANGPTL4, PLIN2, SQSTM1, and DDIT3 were significantly upregulated and HHIP was downregulated by rosiglitazone. CK5 was downregulated by rosiglitazone.

Conclusions

The RNA-seq data suggested that PPARγ activation induced alterations in cell differentiation and metabolic process and affected multiple signaling pathways such as PPAR, autophagy, WNT, and Hedgehog.

A mathematical model was developed to investigate the performance limiting factors of Mg-ion battery with a Chevrel phase (MgxMo6S8) cathode and a Mg metal anode. The model was validated using experimental data from the literature [Cheng et al., Chem. Mater., 26, 4904 (2014)]. Two electrochemical reactions of the Chevrel phase with significantly different kinetics and solid diffusion were included in the porous electrode model, which captured the physics sufficiently well to generate charge curves of five rates (0.1C-2C) for two different particle sizes. Limitation analysis indicated that the solid diffusion and kinetics in the highervoltage plateau limit the capacity and increase the overpotential in the Cheng et al.'s thin (20-μm) electrodes. The model reveals that the performance of the cells with reasonable thickness would also be subject to electrolyte-phase limitations. The simulation also suggested that the polarization losses on discharge will be lower than that on charge, because of the differences in the kinetics and solid diffusion between the two reactions of the Chevrel phase.

Objectives

The aim of the study was to determine whether cats that exhibit aggression during veterinary visits are more likely to have behavior problems at home.

Methods

An online, anonymous, cross-sectional survey was developed and distributed to residents in the USA who were aged over 18 years and who were the primary owners of at least one cat. The survey collected information about cat and household factors, and utilized a validated questionnaire instrument for obtaining behavioral information of pet cats.

Results

Aggression at the veterinary clinic was reported in 42.6% of the cats. The frequency of aggression exhibited at the veterinary clinic was lower in cats that lived in multi-cat households. Most cats did not receive medications intended to reduce fear, anxiety and/or pain before veterinary visits. Aggression at the veterinary clinic was positively associated with behavior problems at home, including stranger-directed aggression, owner-directed aggression, resistance to restraint, familiar cat aggression, dog-directed aggression, house-soiling, separation-related behaviors and scratching claws on inappropriate surfaces indoors.

Conclusions and relevance

Cats that exhibit aggression at the veterinary clinic are more likely to exhibit aggression and anxiety-related behaviors at home. Veterinarians should screen cats that exhibit aggression at the veterinary clinic for behavior problems at home to institute prompt diagnosis and treatment.

DNA-binding motifs that are recognized by transcription factors (TFs) have been well studied; however, challenges remain in determining the in vivo architecture of TF-DNA complexes on a genome-scale. Here, we determined the in vivo architecture of Escherichia coli arginine repressor (ArgR)-DNA complexes using high-throughput sequencing of exonuclease-treated chromatin-immunoprecipitated DNA (ChIP-exo). The ChIP-exo has a unique peak-pair pattern indicating 5' and 3' ends of ArgR-binding region. We identified 62 ArgR-binding loci, which were classified into three groups, comprising single, double and triple peak-pairs. Each peak-pair has a unique 93 base pair (bp)-long (±2 bp) ArgR-binding sequence containing two ARG boxes (39 bp) and residual sequences. Moreover, the three ArgR-binding modes defined by the position of the two ARG boxes indicate that DNA bends centered between the pair of ARG boxes facilitate the non-specific contacts between ArgR subunits and the residual sequences. Additionally, our approach may also reveal other fundamental structural features of TF-DNA interactions that have implications for studying genome-scale transcriptional regulatory networks.

Classical cadherin cell-cell adhesion proteins are essential for the formation and maintenance of tissue structures; their primary function is to physically couple neighboring cells and withstand mechanical force. Cadherins from opposing cells bind in two distinct trans conformations: strand-swap dimers and X-dimers. As cadherins convert between these conformations, they form ideal bonds (i.e., adhesive interactions that are insensitive to force). However, the biophysical mechanism for ideal bond formation is unknown. Here, we integrate single-molecule force measurements with coarse-grained and atomistic simulations to resolve the mechanistic basis for cadherin ideal bond formation. Using simulations, we predict the energy landscape for cadherin adhesion, the transition pathways for interconversion between X-dimers and strand-swap dimers, and the cadherin structures that form ideal bonds. Based on these predictions, we engineer cadherin mutants that promote or inhibit ideal bond formation and measure their force-dependent kinetics using single-molecule force-clamp measurements with an atomic force microscope. Our data establish that cadherins adopt an intermediate conformation as they shuttle between X-dimers and strand-swap dimers; pulling on this conformation induces a torsional motion perpendicular to the pulling direction that unbinds the proteins and forms force-independent ideal bonds. Torsional motion is blocked when cadherins associate laterally in a cis orientation, suggesting that ideal bonds may play a role in mechanically regulating cadherin clustering on cell surfaces.

A patterning method termed "RIPPLE" (reactive interface patterning promoted by lithographic electrochemistry) is applied to the fabrication of arrays of dielectric and metallic optical elements. This method uses cyclic voltammetry to impart patterns onto the working electrode of a standard three-electrode electrochemical setup. Using this technique and a template stripping process, periodic arrays of Ag circular Bragg gratings are patterned in a high-throughput fashion over large substrate areas. By varying the scan rate of the cyclically applied voltage ramps, the periodicity of the gratings can be tuned in situ over micrometer and submicrometer length scales. Characterization of the periodic arrays of periodic gratings identified point-like and annular scattering modes at different planes above the structured surface. Facile, reliable, and rapid patterning techniques like RIPPLE may enable the high-throughput and low-cost fabrication of photonic elements and metasurfaces for energy conversion and sensing applications.

Hypoxic environment is known as one of the critical factors in various physiological/pathological processes. It is imperative to recapitulate oxygen level in microscale for human physiology/pathology induced by hypoxia. Herein, we propose an oxygen-regulating system that can be applied to in vitro tissue models. We fabricated a microdevice with a gas-permeable membrane, allowing oxygen diffusion without direct contact to cells. We verified the formation of oxygen level less than 2% O₂ concentration inside the device through computational simulation and experiments. H9c2 heart myoblasts were exposed to hypoxic condition in the device, and their cell viability were investigated. We anticipate that our system will be integrated with a platform to study hypoxia-induced human physiology and pathology as an efficient oxygen-regulating system.