432 research outputs found

    The Oxford Book of the American South: Testimony, Memory, and Fiction

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    Resonating with the testimony of slaves and slaveholders, the powerful and the powerless, women and men, black people and white, The Oxford Book of the American South combines the most telling fiction and nonfiction produced in the South from the late eighteenth century to the present. The first anthology to put short stories, novels, autobiographies, diaries, memoirs, and journalism together, this collection is a rich and varied record of life below the Mason Dixon line. We see the antebellum period both from the perspective of those who experienced it first-hand, such as Thomas Jefferson and Harriet Jacobs, as well as from authors who imagined the era later, including William Styron and Sherley Anne Williams. Likewise, we see the Civil War through eyewitness accounts such as Sarah Morgan\u27s, later writers\u27 analyses such as W.E.B Du Bois\u27s, and war-inspired fiction such as Margaret Mitchell\u27s. Classic authors of the 1920s and 30s Southern Renaissance are followed by figures including Martin Luther King, Jr., George Garrett, and Peter Taylor, whose works capture the dramatic years of the Civil Rights movement. The struggles, defeats, and triumphs chronicled in The Oxford Book of the American South speak not just to the South, but to all of the American experience.https://scholarship.richmond.edu/bookshelf/1255/thumbnail.jp

    Transcriptome-Wide Identification of the RNA-Binding Landscape of the Chromatin-Associated Protein PARP1 Reveals Functions in RNA Biogenesis

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    Recent studies implicate Poly (ADP-ribose) polymerase 1 (PARP1) in alternative splicing regulation, and PARP1 may be an RNA-binding protein. However, detailed knowledge of RNA targets and the RNA-binding region for PARP1 are unknown. Here we report the first global study of PARP1–RNA interactions using PAR–CLIP in HeLa cells. We identified a largely overlapping set of 22 142 PARP1–RNA-binding peaks mapping to mRNAs, with 20 484 sites located in intronic regions. PARP1 preferentially bound RNA containing GC-rich sequences. Using a Bayesian model, we determined positional effects of PARP1 on regulated exon-skipping events: PARP1 binding upstream and downstream of the skipped exons generally promotes exon inclusion, whereas binding within the exon of interest and intronic regions closer to the skipped exon promotes exon skipping. Using truncation mutants, we show that removal of the Zn1Zn2 domain switches PARP1 from a DNA binder to an RNA binder. This study represents a first step into understanding the role of PARP1–RNA interaction. Continued identification and characterization of the functional interplay between PARPs and RNA may provide important insights into the role of PARPs in RNA regulation

    Genome-wide profiling of PARP1 reveals an interplay with gene regulatory regions and DNA methylation

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    Poly (ADP-ribose) polymerase-1 (PARP1) is a nuclear enzyme involved in DNA repair, chromatin remodeling and gene expression. PARP1 interactions with chromatin architectural multi-protein complexes (i.e. nucleosomes) alter chromatin structure resulting in changes in gene expression. Chromatin structure impacts gene regulatory processes including transcription, splicing, DNA repair, replication and recombination. It is important to delineate whether PARP1 randomly associates with nucleosomes or is present at specific nucleosome regions throughout the cell genome. We performed genome-wide association studies in breast cancer cell lines to address these questions. Our studies show that PARP1 associates with epigenetic regulatory elements genome-wide, such as active histone marks, CTCF and DNase hypersensitive sites. Additionally, the binding of PARP1 to chromatin genome-wide is mutually exclusive with DNA methylation pattern suggesting a functional interplay between PARP1 and DNA methylation. Indeed, inhibition of PARylation results in genome-wide changes in DNA methylation patterns. Our results suggest that PARP1 controls the fidelity of gene transcription and marks actively transcribed gene regions by selectively binding to transcriptionally active chromatin. These studies provide a platform for developing our understanding of PARP1's role in gene regulation

    Involvement of PARP1 in the Regulation of Alternative Splicing

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    Specialized chromatin structures such as nucleosomes with specific histone modifications decorate exons in eukaryotic genomes, suggesting a functional connection between chromatin organization and the regulation of pre-mRNA splicing. Through profiling the functional location of Poly (ADP) ribose polymerase, we observed that it is associated with the nucleosomes at exon/intron boundaries of specific genes, suggestive of a role for this enzyme in alternative splicing. Poly (ADP) ribose polymerase has previously been implicated in the PARylation of splicing factors as well as regulation of the histone modification H3K4me3, a mark critical for co-transcriptional splicing. In light of these studies, we hypothesized that interaction of the chromatin-modifying factor, Poly (ADP) ribose polymerase with nucleosomal structures at exon–intron boundaries, might regulate pre-mRNA splicing. Using genome-wide approaches validated by gene-specific assays, we show that depletion of PARP1 or inhibition of its PARylation activity results in changes in alternative splicing of a specific subset of genes. Furthermore, we observed that PARP1 bound to RNA, splicing factors and chromatin, suggesting that Poly (ADP) ribose polymerase serves as a gene regulatory hub to facilitate co-transcriptional splicing. These studies add another function to the multi-functional protein, Poly (ADP) ribose polymerase, and provide a platform for further investigation of this protein’s function in organizing chromatin during gene regulatory processes

    Linker Histone H1 and H3K56 Acetylation are Antagonistic Regulators of Nucleosome Dynamics

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    H1 linker histones are highly abundant proteins that compact nucleosomes and chromatin to regulate DNA accessibility and transcription. However, the mechanisms that target H1 regulation to specific regions of eukaryotic genomes are unknown. Here we report fluorescence measurements of human H1 regulation of nucleosome dynamics and transcription factor (TF) binding within nucleosomes. H1 does not block TF binding, instead it suppresses nucleosome unwrapping to reduce DNA accessibility within H1-bound nucleosomes. We then investigated H1 regulation by H3K56 and H3K122 acetylation, two transcriptional activating histone post translational modifications (PTMs). Only H3K56 acetylation, which increases nucleosome unwrapping, abolishes H1.0 reduction of TF binding. These findings show that nucleosomes remain dynamic, while H1 is bound and H1 dissociation is not required for TF binding within the nucleosome. Furthermore, our H3K56 acetylation measurements suggest that a single-histone PTM can define regions of the genome that are not regulated by H1

    Bacterial Colony Counts During Vaginal Surgery

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    Objective: To describe the bacterial types and colony counts present before and during vaginal surgery. Methods: A descriptive study was undertaken of patients undergoing vaginal hysterectomy with or without reconstructive pelvic surgery. Aerobic and anaerobic bacterial cultures were obtained immediately before and throughout the surgical cases at preselected time intervals. Standard antimicrobial prophylaxis was administered in all cases. Mean total colony counts and mean anaerobic colony counts were determined by adding all colonies regardless of bacteria type. ‘Contamination’ was defined as ≥ 5000 colony-forming units/ml. Results: A total of 31 patients aged 26 to 82 years (mean age ± SD, 51 ± 15) were included. The highest total and anaerobic colony counts were found at the first intraoperative time interval. On the first set of cultures (30 minutes after the surgical scrub), 52% (16/31) of the surgical fields were contaminated, and at 90 minutes, 41% (12/29) were contaminated. A negligible number of subsequent cultures were contaminated. Conclusions: Any future interventions designed to minimize bacterial colony counts should focus on the first 30 to 90 minutes of surgery

    Biopsy confirmation of metastatic sites in breast cancer patients:clinical impact and future perspectives

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    Determination of hormone receptor (estrogen receptor and progesterone receptor) and human epidermal growth factor receptor 2 status in the primary tumor is clinically relevant to define breast cancer subtypes, clinical outcome,and the choice of therapy. Retrospective and prospective studies suggest that there is substantial discordance in receptor status between primary and recurrent breast cancer. Despite this evidence and current recommendations,the acquisition of tissue from metastatic deposits is not routine practice. As a consequence, therapeutic decisions for treatment in the metastatic setting are based on the features of the primary tumor. Reasons for this attitude include the invasiveness of the procedure and the unreliable outcome of biopsy, in particular for biopsies of lesions at complex visceral sites. Improvements in interventional radiology techniques mean that most metastatic sites are now accessible by minimally invasive methods, including surgery. In our opinion, since biopsies are diagnostic and changes in biological features between the primary and secondary tumors can occur, the routine biopsy of metastatic disease needs to be performed. In this review, we discuss the rationale for biopsy of suspected breast cancer metastases, review issues and caveats surrounding discordance of biomarker status between primary and metastatic tumors, and provide insights for deciding when to perform biopsy of suspected metastases and which one (s) to biopsy. We also speculate on the future translational implications for biopsy of suspected metastatic lesions in the context of clinical trials and the establishment of bio-banks of biopsy material taken from metastatic sites. We believe that such bio-banks will be important for exploring mechanisms of metastasis. In the future,advances in targeted therapy will depend on the availability of metastatic tissue

    Nutrition economics – characterising the economic and health impact of nutrition

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    There is a new merging of health economics and nutrition disciplines to assess the impact of diet on health and disease prevention and to characterise the health and economic aspects of specific changes in nutritional behaviour and nutrition recommendations. A rationale exists for developing the field of nutrition economics which could offer a better understanding of both nutrition, in the context of having a significant influence on health outcomes, and economics, in order to estimate the absolute and relative monetary impact of health measures. For this purpose, an expert meeting assessed questions aimed at clarifying the scope and identifying the key issues that should be taken into consideration in developing nutrition economics as a discipline that could potentially address important questions. We propose a first multidisciplinary outline for understanding the principles and particular characteristics of this emerging field. We summarise here the concepts and the observations of workshop participants and propose a basic setting for nutrition economics and health outcomes research as a novel discipline to support nutrition, health economics and health policy development in an evidence and health-benefit-based manner
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