135 research outputs found

    Kafka’s Identity Crisis: Examining The Metamorphosis as a Response to Anti-Semitism and Assimilation in Turn-of-the-Century Europe

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    Franz Kafka’s The Metamorphosis chronicles the bizarre tale of Gregor Samsa’s transformation into an insect and the despairing isolation and personal quest for a meaningful existence that follows. A masterpiece of modern literature, it explores the universal concerns and struggles of Modernity, but also offers insight into the lives of assimilated Jews living in Prague at the turn-of-the-century. The acquisition of basic civil rights afforded European Jews opportunities in education, employment, and housing. Integration into Western society presented new challenges for the Jews as they carved out their new position in European society. The Jews’ difficult task of adapting to Western culture met further challenges from the ambivalent European society still unsure of integration. The new place for Jews as free citizens in Western society made them vulnerable to the pressures of assimilation. Western, most often interpreted as German, culture assisted as protection from anti-Semitism for the obtainment of European culture, in theory would serve as proof of the Jews’ loyalty to state culture. The literature of this time reflects both the anti-Semitic attitudes in politics and in the media and the Jews’ response to assimilation’s effects on their identity. Franz Kafka’s literature transcends the historical context in which it was written but The Metamorphosis reflects the anxiety that pervaded the psyche of assimilated Jews in turn- of-the-century Prague

    Interview with Half Century Club Inductees, Class of 1930

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    Oral history interview with Illinois State Normal University alumni, Class of 1930. The interview was conducted on May 10, 1980, by an unidentified interviewer. They discuss President Felmley, influential faculty, and racial discrimination experienced by students of color.https://ir.library.illinoisstate.edu/aoh/1002/thumbnail.jp

    High-Affinity Small Molecule Inhibitors of T Cell Costimulation: Compounds for Immunotherapy

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    SummaryCostimulatory molecules are important regulators of T cell activation and thus favored targets for therapeutic manipulation of immune responses. One of the key costimulatory receptors is CD80, which binds the T cell ligands, CD28, and CTLA-4. We describe a set of small compounds that bind with high specificity and low nanomolar affinity to CD80. The compounds have relatively slow off-rates and block both CD28 and CTLA-4 binding, implying that they occlude the shared ligand binding site. The compounds inhibit proinflammatory cytokine release in T cell assays with submicromolar potency, and as such, they represent promising leads for the development of novel therapeutics for immune-mediated inflammatory disease. Our results also suggest that other predominantly β proteins, such as those that dominate the cell surface, may also be accessible as potentially therapeutic targets

    Critical Role of the Rb Family in Myoblast Survival and Fusion

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    The tumor suppressor Rb is thought to control cell proliferation, survival and differentiation. We recently showed that differentiating Rb-deficient mouse myoblasts can fuse to form short myotubes that quickly collapse through a mechanism involving autophagy, and that autophagy inhibitors or hypoxia could rescue the defect leading to long, twitching myotubes. Here we determined the contribution of pRb relatives, p107 and p130, to this process. We show that chronic or acute inactivation of Rb plus p107 or p130 increased myoblast cell death and reduced myotube formation relative to Rb loss alone. Treatment with autophagy antagonists or hypoxia extended survival of double-knockout myotubes, which appeared indistinguishable from control fibers. In contrast, triple mutations in Rb, p107 and p130, led to substantial increase in myoblast death and to elongated bi-nuclear myocytes, which seem to derive from nuclear duplication, as opposed to cell fusion. Under hypoxia, some rare, abnormally thin triple knockout myotubes survived and twitched. Thus, mutation of p107 or p130 reduces survival of Rb-deficient myoblasts during differentiation but does not preclude myoblast fusion or necessitate myotube degeneration, whereas combined inactivation of the entire Rb family produces a distinct phenotype, with drastically impaired myoblast fusion and survival

    Cell cycle-dependent acetylation of Rb2/p130 in NIH3T3 cells

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    The retinoblastoma protein (pRb) and the pRb-related proteins, p130 and p107, form the ‘pocket protein' family of cell cycle regulatory factors. A well characterized function of these proteins is the cell cycle-dependent regulation of E2F-responsive genes. The biological activity of pocket proteins is regulated by phosphorylation and for the founding member pRb it has been shown that acetylation also has an important role in modulating its function during the cell cycle. Here, we show that hyperphosphorylated retinoblastoma 2 (Rb2)/p130 also exists in an acetylated form in NIH3T3 cells. Acetylated p130 is present in the nucleus but not in the cytoplasm. Acetylation is cell cycle dependent, starting in S-phase and persisting until late G2-period. Using recombinant p130 and truncated forms for in vitro acetylation by the acetyltransferase p300, we could identify K1079 in the C-terminal part as the major acetylation site by mass spectrometry. Minor acetylation sites were pinpointed to K1068 and K1111 in the C-terminus, and K128 and K130 in the N-terminus. The human papilloma virus 16 protein-E7 preferentially binds to acetylated p130 and significantly increases in vitro p130 acetylation by p300

    Transcriptional regulatory program in wild-type and retinoblastoma gene-deficient mouse embryonic fibroblasts during adipocyte differentiation

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    <p>Abstract</p> <p>Background</p> <p>Although many molecular regulators of adipogenesis have been identified a comprehensive catalogue of components is still missing. Recent studies showed that the retinoblastoma protein (pRb) was expressed in the cell cycle and late cellular differentiation phase during adipogenesis. To investigate this dual role of pRb in the early and late stages of adipogenesis we used microarrays to perform a comprehensive systems-level analysis of the common transcriptional program of the classic 3T3-L1 preadipocyte cell line, wild-type mouse embryonic fibroblasts (MEFs), and retinoblastoma gene-deficient MEFs (Rb-/- MEFs).</p> <p>Findings</p> <p>Comparative analysis of the expression profiles of 3T3-L1 cells and wild-type MEFs revealed genes involved specifically in early regulation of the adipocyte differentiation as well as secreted factors and signaling molecules regulating the later phase of differentiation. In an attempt to identify transcription factors regulating adipogenesis, bioinformatics analysis of the promoters of coordinately and highly expressed genes was performed. We were able to identify a number of high-confidence target genes for follow-up experimental studies. Additionally, combination of experimental data and computational analyses pinpointed a feedback-loop between Pparg and Foxo1.</p> <p>To analyze the effects of the retinoblastoma protein at the transcriptional level we chose a perturbated system (Rb-/- MEFs) for comparison to the transcriptional program of wild-type MEFs. Gene ontology analysis of 64 deregulated genes showed that the Rb-/- MEF model exhibits a brown(-like) adipocyte phenotype. Additionally, the analysis results indicate a different or additional role for pRb family member involvement in the lineage commitment.</p> <p>Conclusion</p> <p>In this study a number of commonly modulated genes during adipogenesis in 3T3-L1 cells and MEFs, potential transcriptional regulation mechanisms, and differentially regulated targets during adipocyte differentiation of Rb-/- MEFs could be identified. These data and the analysis provide a starting point for further experimental studies to identify target genes for pharmacological intervention and ultimately remodeling of white adipose tissue into brown adipose tissue.</p

    Tandem E2F Binding Sites in the Promoter of the p107 Cell Cycle Regulator Control p107 Expression and Its Cellular Functions

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    The retinoblastoma tumor suppressor (Rb) is a potent and ubiquitously expressed cell cycle regulator, but patients with a germline Rb mutation develop a very specific tumor spectrum. This surprising observation raises the possibility that mechanisms that compensate for loss of Rb function are present or activated in many cell types. In particular, p107, a protein related to Rb, has been shown to functionally overlap for loss of Rb in several cellular contexts. To investigate the mechanisms underlying this functional redundancy between Rb and p107 in vivo, we used gene targeting in embryonic stem cells to engineer point mutations in two consensus E2F binding sites in the endogenous p107 promoter. Analysis of normal and mutant cells by gene expression and chromatin immunoprecipitation assays showed that members of the Rb and E2F families directly bound these two sites. Furthermore, we found that these two E2F sites controlled both the repression of p107 in quiescent cells and also its activation in cycling cells, as well as in Rb mutant cells. Cell cycle assays further indicated that activation of p107 transcription during S phase through the two E2F binding sites was critical for controlled cell cycle progression, uncovering a specific role for p107 to slow proliferation in mammalian cells. Direct transcriptional repression of p107 by Rb and E2F family members provides a molecular mechanism for a critical negative feedback loop during cell cycle progression and tumorigenesis. These experiments also suggest novel therapeutic strategies to increase the p107 levels in tumor cells

    Partner in fat metabolism: role of KLFs in fat burning and reproductive behavior

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    The abnormalities caused by excess fat accumulation can result in pathological conditions which are linked to several interrelated diseases, such as cardiovascular disease and obesity. This set of conditions, known as metabolic syndrome, is a global pandemic of enormous medical, economic, and social concern affecting a significant portion of the world’s population. Although genetics, physiology and environmental components play a major role in the onset of disease caused by excessive fat accumulation, little is known about how or to what extent each of these factors contributes to it. The worm, Caenorhabditis elegans offers an opportunity to study disease related to metabolic disorder in a developmental system that provides anatomical and genomic simplicity relative to the vertebrate animals and is an excellent eukaryotic genetic model which enable us to answer the questions concerning fat accumulation which remain unresolved. The stored triglycerides (TG) provide the primary source of energy during periods of food deficiency. In nature, lipid stored as TGs are hydrolyzed into fatty acids which are broken down through β-oxidation to yield acetyl-CoA. Our recent study suggests that a member of C. elegans Krüppel-like factor, klf-3 regulates lipid metabolism by promoting FA β-oxidation and in parallel may contribute in normal reproduction and fecundity. Genetic and epigenetic factors that influence this pathway may have considerable impact on fat related diseases in human. Increasing number of studies suggest the role of mammalian KLFs in adipogenesis. This functional conservation should guide our further effort to explore C. elegans as a legitimate model system for studying the role of KLFs in many pathway components of lipid metabolism

    Claudin 13, a Member of the Claudin Family Regulated in Mouse Stress Induced Erythropoiesis

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    Mammals are able to rapidly produce red blood cells in response to stress. The molecular pathways used in this process are important in understanding responses to anaemia in multiple biological settings. Here we characterise the novel gene Claudin 13 (Cldn13), a member of the Claudin family of tight junction proteins using RNA expression, microarray and phylogenetic analysis. We present evidence that Cldn13 appears to be co-ordinately regulated as part of a stress induced erythropoiesis pathway and is a mouse-specific gene mainly expressed in tissues associated with haematopoietic function. CLDN13 phylogenetically groups with its genomic neighbour CLDN4, a conserved tight junction protein with a putative role in epithelial to mesenchymal transition, suggesting a recent duplication event. Mechanisms of mammalian stress erythropoiesis are of importance in anaemic responses and expression microarray analyses demonstrate that Cldn13 is the most abundant Claudin in spleen from mice infected with Trypanosoma congolense. In mice prone to anaemia (C57BL/6), its expression is reduced compared to strains which display a less severe anaemic response (A/J and BALB/c) and is differentially regulated in spleen during disease progression. Genes clustering with Cldn13 on microarrays are key regulators of erythropoiesis (Tal1, Trim10, E2f2), erythrocyte membrane proteins (Rhd and Gypa), associated with red cell volume (Tmcc2) and indirectly associated with erythropoietic pathways (Cdca8, Cdkn2d, Cenpk). Relationships between genes appearing co-ordinately regulated with Cldn13 post-infection suggest new insights into the molecular regulation and pathways involved in stress induced erythropoiesis and suggest a novel, previously unreported role for claudins in correct cell polarisation and protein partitioning prior to erythroblast enucleation

    Multiple molecular interactions redundantly contribute to RB-mediated cell cycle control

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    BACKGROUND: The G1-S phase transition is critical to maintaining proliferative control and preventing carcinogenesis. The retinoblastoma tumor suppressor is a key regulator of this step in the cell cycle. RESULTS: Here we use a structure–function approach to evaluate the contributions of multiple protein interaction surfaces on pRB towards cell cycle regulation. SAOS2 cell cycle arrest assays showed that disruption of three separate binding surfaces were necessary to inhibit pRB-mediated cell cycle control. Surprisingly, mutation of some interaction surfaces had no effect on their own. Rather, they only contributed to cell cycle arrest in the absence of other pRB dependent arrest functions. Specifically, our data shows that pRB–E2F interactions are competitive with pRB–CDH1 interactions, implying that interchangeable growth arrest functions underlie pRB’s ability to block proliferation. Additionally, disruption of similar cell cycle control mechanisms in genetically modified mutant mice results in ectopic DNA synthesis in the liver. CONCLUSIONS: Our work demonstrates that pRB utilizes a network of mechanisms to prevent cell cycle entry. This has important implications for the use of new CDK4/6 inhibitors that aim to activate this proliferative control network
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