Phase-contrast imaging using ultrafast x-rays in laser-shocked materials.

High-energy x-rays, >10 keV, can be efficiently produced from ultrafast laser target interactions with many applications to dense target materials in inertial confinement fusion and high-energy density physics. These same x-rays can also be applied to measurements of low-density materials inside high-density Hohlraum environments. In the experiments presented, high-energy x-ray images of laser-shocked polystyrene are produced through phase contrast imaging.

Scaling studies with the dual crystal spectrometer at the OMEGA-EP laser facility.

The dual crystal spectrometer (DCS) is an approved diagnostic at the OMEGA and the OMEGA-EP laser facilities for the measurement of high energy x-rays in the 11-90 keV energy range, e.g., for verification of the x-ray spectrum of backlighter targets of point projection radiography experiments.

Light at night increases body mass by shifting the time of food intake.

The global increase in the prevalence of obesity and metabolic disorders coincides with the increase of exposure to light at night (LAN) and shift work. Circadian regulation of energy homeostasis is controlled by an endogenous biological clock that is synchronized by light information. To promote optimal adaptive functioning, the circadian clock prepares individuals for predictable events such as food availability and sleep, and disruption of clock function causes circadian and metabolic disturbances.

Heterochromatin protein 1 (HP1) connects the FACT histone chaperone complex to the phosphorylated CTD of RNA polymerase II.

Heterochromatin protein 1 (HP1) is well known as a silencing protein found at pericentric heterochromatin. Most eukaryotes have at least three isoforms of HP1 that play differential roles in heterochromatin and euchromatin. In addition to its role in heterochromatin, HP1 proteins have been shown to function in transcription elongation.

Features of cryptic promoters and their varied reliance on bromodomain-containing factors.

The Set2-Rpd3S pathway is important for the control of transcription memory. Mutation of components of this pathway results in cryptic transcription initiation within the coding region of approximately 30% of yeast genes. Specifically, deletion of the Set2 histone methyltransferase or Rco1, a component of the Rpd3S histone deacetylase complex leads to hyperacetylation of certain open reading frames (ORFs).

Dairy reproductive management: assessing a comprehensive continuing education program for veterinary practitioners.

Comprehensive continuing veterinary medical education (CVME) programs are critical for veterinary practitioners to update their knowledge and improve their skills and services. CVME must offer an educational environment in which veterinarians can effectively rejuvenate their knowledge and skills and learn about new practices. The Ohio Dairy Health and Management Certificate Program is a comprehensive CVME program for practicing dairy veterinarians that was developed to provide advanced training on previously identified needs of the dairy industry.

The ATAC acetyltransferase complex coordinates MAP kinases to regulate JNK target genes.

In response to extracellular cues, signal transduction activates downstream transcription factors like c-Jun to induce expression of target genes. We demonstrate that the ATAC (Ada two A containing) histone acetyltransferase (HAT) complex serves as a transcriptional cofactor for c-Jun at the Jun N-terminal kinase (JNK) target genes Jra and chickadee. ATAC subunits are required for c-Jun occupancy of these genes and for H4K16 acetylation at the Jra enhancer, promoter, and transcribed sequences.

Potential animal models of seasonal affective disorder.

Seasonal affective disorder (SAD) is characterized by depressive episodes during winter that are alleviated during summer and by morning bright light treatment. Currently, there is no animal model of SAD. However, it may be possible to use rodents that respond to day length (photoperiod) to understand how photoperiod can shape the brain and behavior in humans.

The proteasome and its regulatory roles in gene expression.

Cumulative evidence indicates that the proteasome, which is mainly known as a protein-degrading machine, is very essential for gene expression. Destructive functions of the proteasome, i.e.

Phosphorylated Pol II CTD recruits multiple HDACs, including Rpd3C(S), for methylation-dependent deacetylation of ORF nucleosomes.

Methylation of histone H3 by Set1 and Set2 is required for deacetylation of nucleosomes in coding regions by histone deacetylase complexes (HDACs) Set3C and Rpd3C(S), respectively. We report that Set3C and Rpd3C(S) are cotranscriptionally recruited in the absence of Set1 and Set2, but in a manner stimulated by Pol II CTD kinase Cdk7/Kin28. Consistently, Rpd3C(S) and Set3C interact with Ser5-phosphorylated Pol II and histones in extracts, but only the histone interactions require H3 methylation.

Inducible gene expression: diverse regulatory mechanisms.

The rapid activation of gene expression in response to stimuli occurs largely through the regulation of RNA polymerase II-dependent transcription. In this Review, we discuss events that occur during the transcription cycle in eukaryotes that are important for the rapid and specific activation of gene expression in response to external stimuli. In addition to regulated recruitment of the transcription machinery to the promoter, it has now been shown that control steps can include chromatin remodelling and the release of paused polymerase.

Histone acetylation in heterochromatin assembly.

Histone acetylation is generally considered a mark involved in activating gene expression by making chromatin structures less compact. In the April 1, 2010, issue of Genes & Development, Xhemalce and Kouzarides (pp. 647-652) demonstrate that the acetylation of histone H3 at Lys 4 (H3K4) plays a role in the formation of repressive heterochromatin in Schizosaccharomyces pombe.

Rere controls retinoic acid signalling and somite bilateral symmetry.

One of the most notable features of the vertebrate body plan organization is its bilateral symmetry, evident at the level of vertebrae and skeletal muscles. Here we show that a mutation in Rere (also known as atrophin2) leads to the formation of asymmetrical somites in mouse embryos, similar to embryos deprived of retinoic acid. Furthermore, we also demonstrate that Rere controls retinoic acid signalling, which is required to maintain somite symmetry by interacting with Fgf8 in the left-right signalling pathway.

Deacetylase inhibitors dissociate the histone-targeting ING2 subunit from the Sin3 complex.

Histone deacetylase (HDAC) inhibitors are in clinical development for several diseases, including cancers and neurodegenerative disorders. HDACs 1 and 2 are among the targets of these inhibitors and are part of multisubunit protein complexes. HDAC inhibitors (HDACis) block the activity of HDACs by chelating a zinc molecule in their catalytic sites.

Environmental enrichment enhances delayed-type hypersensitivity in both short- and long-day Siberian hamsters.

Darwinian fitness reflects trade-offs between reproduction and survival. Mechanisms have evolved in small nontropical mammals and birds to maximize reproductive output during the summer when thermoregulatory demands are relatively low and food is abundant and to shunt energy to processes that presumably increase the odds of survival during the winter when thermoregulatory demands are high and food is scarce. In order to predict the onset of winter, many seasonally-breeding mammals use day length (photoperiod) information.

A novel histone fold domain-containing protein that replaces TAF6 in Drosophila SAGA is required for SAGA-dependent gene expression.

The histone acetyltransferase complex SAGA is well characterized as a coactivator complex in yeast. In this study of Drosophila SAGA (dSAGA), we describe three novel components that include an ortholog of Spt20, a potential ortholog of Sgf73/ATXN7, and a novel histone fold protein, SAF6 (SAGA factor-like TAF6). SAF6, which binds directly to TAF9, functions analogously in dSAGA to TAF6/TAF6L in the yeast and human SAGA complexes, respectively.

WD40 repeats arrange histone tails for spreading of silencing.

Direct binding of WD40 repeat of Embryonic Ectoderm Development (EED) in the Polycomb Repressor Complex 2 (PRC2) to the histone H3 tail regulates the H3K27 methyltrasnferase activity of PRC2. The binding activity is required for the methylation of H3K27 over long distance of a Drosophila chromosome from the UBX (Hox gene) promoter to the PBX upstream enhancer region, implying EED initiates propagation of this repressive mark.

Short day lengths skew prenatal sex ratios toward males in Siberian hamsters.

For decades, researchers have documented significant skews in the production of male versus female offspring in many species. Because males and females are differentially susceptible to environmental challenges and also represent different fitness benefits, it may be beneficial to exert control over the offspring sex ratio when environmental conditions become challenging. Some of the most dramatic environmental challenges occur on a seasonal basis.

Determining protein complex connectivity using a probabilistic deletion network derived from quantitative proteomics.

Protein complexes are key molecular machines executing a variety of essential cellular processes. Despite the availability of genome-wide protein-protein interaction studies, determining the connectivity between proteins within a complex remains a major challenge. Here we demonstrate a method that is able to predict the relationship of proteins within a stable protein complex.

Cse4 is part of an octameric nucleosome in budding yeast.

The budding yeast CenH3 histone variant Cse4 localizes to centromeric nucleosomes and is required for kinetochore assembly and chromosome segregation. The exact composition of centromeric Cse4-containing nucleosomes is a subject of debate. Using unbiased biochemical, cell-biological, and genetic approaches, we have tested the composition of Cse4-containing nucleosomes.

Anxious solitude and clinical disorder in middle childhood: bridging developmental and clinical approaches to childhood social anxiety.

It was hypothesized that children identified by their peers at school as anxious solitary would report more symptoms of social anxiety disorder on a self report questionnaire and, on the basis of child and parent clinical interviews, receive more diagnoses of social anxiety disorder and additional anxiety and mood disorders. Participants were 192 children drawn from a community sample of 688 children attending public elementary schools. Half of these children were selected because they were identified as anxious solitary by peers and the other half were demographically-matched controls.