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Sample records for polycomb group target

  1. Different Polycomb group complexes regulate common target genes in Arabidopsis.

    PubMed

    Makarevich, Grigory; Leroy, Olivier; Akinci, Umut; Schubert, Daniel; Clarenz, Oliver; Goodrich, Justin; Grossniklaus, Ueli; Köhler, Claudia

    2006-09-01

    Polycomb group (PcG) proteins convey epigenetic inheritance of repressed transcriptional states. Although the mechanism of the action of PcG is not completely understood, methylation of histone H3 lysine 27 (H3K27) is important in establishing PcG-mediated transcriptional repression. We show that the plant PcG target gene PHERES1 is regulated by histone trimethylation on H3K27 residues mediated by at least two different PcG complexes in plants, containing the SET domain proteins MEDEA or CURLY LEAF/SWINGER. Furthermore, we identify FUSCA3 as a potential PcG target gene and show that FUSCA3 is regulated by MEDEA and CURLY LEAF/SWINGER. We propose that different PcG complexes regulate a common set of target genes during the different stages of plant development.

  2. Polycomb Group Targeting through Different Binding Partners of RING1B C-Terminal Domain

    PubMed Central

    Wang, Renjing; Taylor, Alexander B.; Leal, Belinda Z.; Chadwell, Linda V.; Ilangovan, Udayar; Robinson, Angela K.; Schirf, Virgil; Hart, P. John; Lafer, Eileen M.; Demeler, Borries; Hinck, Andrew P.; McEwen, Donald G.; Kim, Chongwoo A.

    2015-01-01

    SUMMARY RING1B, a Polycomb Group (PcG) protein, binds methylated chromatin through its association with another PcG protein called Polycomb (Pc). However, RING1B can associate with nonmethylated chromatin suggesting an alternate mechanism for RING1B interaction with chromatin. Here, we demonstrate that two proteins with little sequence identity between them, the Pc cbox domain and RYBP, bind the same surface on the C-terminal domain of RING1B (C-RING1B). Pc cbox and RYBP each fold into a nearly identical, intermolecular beta sheet with C-RING1B and a loop structure which are completely different in the two proteins. Both the beta sheet and loop are required for stable binding and transcription repression. Further, a mutation engineered to disrupt binding on the Drosophila dRING1 protein prevents chromatin association and PcG function in vivo. These results suggest that PcG targeting to different chromatin locations relies, in part, on binding partners of C-RING1B that are diverse in sequence and structure. PMID:20696397

  3. Deregulated Expression of the Polycomb-Group Protein SUZ12 Target Genes Characterizes Mantle Cell Lymphoma

    PubMed Central

    Martín-Pérez, Daniel; Sánchez, Esther; Maestre, Lorena; Suela, Javier; Vargiu, Pierfrancesco; Di Lisio, Lorena; Martínez, Nerea; Alves, Javier; Piris, Miguel A.; Sánchez-Beato, Margarita

    2010-01-01

    Polycomb proteins are known to be of great importance in human cancer pathogenesis. SUZ12 is a component of the Polycomb PRC2 complex that, along with EZH2, is involved in embryonic stem cell differentiation. EZH2 plays an essential role in many cancer types, but an equivalent involvement of SUZ12 has not been as thoroughly demonstrated. Here we show that SUZ12 is anomalously expressed in human primary tumors, especially in mantle cell lymphoma (MCL), pulmonary carcinomas and melanoma, and is associated with gene locus amplification in some cases. Using MCL as a model, functional and genomic studies demonstrate that SUZ12 loss compromises cell viability, increases apoptosis, and targets genes involved in central oncogenic pathways associated with MCL pathogenesis. Our results support the hypothesis that the abnormal expression of SUZ12 accounts for some of the unexplained features of MCL, such as abnormal DNA repair and increased resistance to apoptosis. PMID:20558579

  4. Complementary Activities of TELOMERE REPEAT BINDING Proteins and Polycomb Group Complexes in Transcriptional Regulation of Target Genes[OPEN

    PubMed Central

    Hartwig, Benjamin; James, Geo Velikkakam

    2016-01-01

    In multicellular organisms, Polycomb Repressive Complex 1 (PRC1) and PRC2 repress target genes through histone modification and chromatin compaction. Arabidopsis thaliana mutants strongly compromised in the pathway cannot develop differentiated organs. LIKE HETEROCHROMATIN PROTEIN1 (LHP1) is so far the only known plant PRC1 component that directly binds to H3K27me3, the histone modification set by PRC2, and also associates genome-wide with trimethylation of lysine 27 of histone H3 (H3K27me3). Surprisingly, lhp1 mutants show relatively mild phenotypic alterations. To explain this paradox, we screened for genetic enhancers of lhp1 mutants to identify novel components repressing target genes together with, or in parallel to, LHP1. Two enhancing mutations were mapped to TELOMERE REPEAT BINDING PROTEIN1 (TRB1) and its paralog TRB3. We show that TRB1 binds to thousands of genomic sites containing telobox or related cis-elements with a significant increase of sites and strength of binding in the lhp1 background. Furthermore, in combination with lhp1, but not alone, trb1 mutants show increased transcription of LHP1 targets, such as floral meristem identity genes, which are more likely to be bound by TRB1 in the lhp1 background. By contrast, expression of a subset of LHP1-independent TRB1 target genes, many involved in primary metabolism, is decreased in the absence of TRB1 alone. Thus, TRB1 is a bivalent transcriptional modulator that maintains downregulation of Polycomb Group (PcG) target genes in lhp1 mutants, while it sustains high expression of targets that are regulated independently of PcG. PMID:26721861

  5. Drosophila Polycomb-group regulated chromatin inhibits the accessibility of a trans-activator to its target DNA.

    PubMed Central

    Zink, D; Paro, R

    1995-01-01

    The genes of the Polycomb-group (Pc-G) are responsible for maintaining the inactive expression state of homeotic genes. They act through specific cis-regulatory DNA elements termed PREs (Pc-G Response Elements). Multimeric complexes containing the Pc-G proteins are thought to induce heterochromatin-like structures, which stably and heritably inactivate transcription. We have tested the functional role of the FAB fragment, a PRE of the bithorax complex. We find that this element behaves as an orientation dependent silencer, capable of inducing mosaic gene expression on neighboring genes. Transgenic fly lines were constructed containing a PRE adjacent to a reporter gene inducible by the yeast GAL4 trans-activator. The competition between the activator and Pc-G-containing chromatin was visualized on polytene chromosomes using immunocytochemistry. The Pc-G protein Polycomb and GAL4 have mutually exclusive binding patterns, supporting the notion that Pc-G-induced chromatin structures can prevent activators from binding to their target sequences. However, this antagonistic function can be overcome by high doses of GAL4, even in the absence of DNA replication. Images PMID:8521823

  6. Transcriptional Silencing by Polycomb-Group Proteins

    PubMed Central

    Grossniklaus, Ueli; Paro, Renato

    2014-01-01

    Polycomb-group (PcG) genes encode chromatin proteins involved in stable and heritable transcriptional silencing. PcG proteins participate in distinct multimeric complexes that deposit, or bind to, specific histone modifications (e.g., H3K27me3 and H2AK119ub1) to prevent gene activation and maintain repressed chromatin domains. PcG proteins are evolutionary conserved and play a role in processes ranging from vernalization and seed development in plants, over X-chromosome inactivation in mammals, to the maintenance of stem cell identity. PcG silencing is medically relevant as it is often observed in human disorders, including cancer, and tissue regeneration, which involve the reprogramming of PcG-controlled target genes. PMID:25367972

  7. Selective Interactions between Vertebrate Polycomb Homologs and the SUV39H1 Histone Lysine Methyltransferase Suggest that Histone H3-K9 Methylation Contributes to Chromosomal Targeting of Polycomb Group Proteins

    PubMed Central

    Sewalt, Richard G. A. B.; Lachner, Monika; Vargas, Mark; Hamer, Karien M.; den Blaauwen, Jan L.; Hendrix, Thijs; Melcher, Martin; Schweizer, Dieter; Jenuwein, Thomas; Otte, Arie P.

    2002-01-01

    Polycomb group (PcG) proteins form multimeric chromatin-associated protein complexes that are involved in heritable repression of gene activity. Two distinct human PcG complexes have been characterized. The EED/EZH2 PcG complex utilizes histone deacetylation to repress gene activity. The HPC/HPH PcG complex contains the HPH, RING1, BMI1, and HPC proteins. Here we show that vertebrate Polycomb homologs HPC2 and XPc2, but not M33/MPc1, interact with the histone lysine methyltransferase (HMTase) SUV39H1 both in vitro and in vivo. We further find that overexpression of SUV39H1 induces selective nuclear relocalization of HPC/HPH PcG proteins but not of the EED/EZH2 PcG proteins. This SUV39H1-dependent relocalization concentrates the HPC/HPH PcG proteins to the large pericentromeric heterochromatin domains (1q12) on human chromosome 1. Within these PcG domains we observe increased H3-K9 methylation. Finally, we show that H3-K9 HMTase activity is associated with endogenous HPC2. Our findings suggest a role for the SUV39H1 HMTase and histone H3-K9 methylation in the targeting of human HPC/HPH PcG proteins to modified chromatin structures. PMID:12101246

  8. Selective interactions between vertebrate polycomb homologs and the SUV39H1 histone lysine methyltransferase suggest that histone H3-K9 methylation contributes to chromosomal targeting of Polycomb group proteins.

    PubMed

    Sewalt, Richard G A B; Lachner, Monika; Vargas, Mark; Hamer, Karien M; den Blaauwen, Jan L; Hendrix, Thijs; Melcher, Martin; Schweizer, Dieter; Jenuwein, Thomas; Otte, Arie P

    2002-08-01

    Polycomb group (PcG) proteins form multimeric chromatin-associated protein complexes that are involved in heritable repression of gene activity. Two distinct human PcG complexes have been characterized. The EED/EZH2 PcG complex utilizes histone deacetylation to repress gene activity. The HPC/HPH PcG complex contains the HPH, RING1, BMI1, and HPC proteins. Here we show that vertebrate Polycomb homologs HPC2 and XPc2, but not M33/MPc1, interact with the histone lysine methyltransferase (HMTase) SUV39H1 both in vitro and in vivo. We further find that overexpression of SUV39H1 induces selective nuclear relocalization of HPC/HPH PcG proteins but not of the EED/EZH2 PcG proteins. This SUV39H1-dependent relocalization concentrates the HPC/HPH PcG proteins to the large pericentromeric heterochromatin domains (1q12) on human chromosome 1. Within these PcG domains we observe increased H3-K9 methylation. Finally, we show that H3-K9 HMTase activity is associated with endogenous HPC2. Our findings suggest a role for the SUV39H1 HMTase and histone H3-K9 methylation in the targeting of human HPC/HPH PcG proteins to modified chromatin structures.

  9. Genome-wide analysis of Polycomb targets in Drosophila

    SciTech Connect

    Schwartz, Yuri B.; Kahn, Tatyana G.; Nix, David A.; Li,Xiao-Yong; Bourgon, Richard; Biggin, Mark; Pirrotta, Vincenzo

    2006-04-01

    Polycomb Group (PcG) complexes are multiprotein assemblages that bind to chromatin and establish chromatin states leading to epigenetic silencing. PcG proteins regulate homeotic genes in flies and vertebrates but little is known about other PcG targets and the role of the PcG in development, differentiation and disease. We have determined the distribution of the PcG proteins PC, E(Z) and PSC and of histone H3K27 trimethylation in the Drosophila genome. At more than 200 PcG target genes, binding sites for the three PcG proteins colocalize to presumptive Polycomb Response Elements (PREs). In contrast, H3 me3K27 forms broad domains including the entire transcription unit and regulatory regions. PcG targets are highly enriched in genes encoding transcription factors but receptors, signaling proteins, morphogens and regulators representing all major developmental pathways are also included.

  10. Biology of polycomb and trithorax group proteins.

    PubMed

    Breiling, Achim; Sessa, Luca; Orlando, Valerio

    2007-01-01

    Cellular phenotypes can be ascribed to different patterns of gene expression. Epigenetic mechanisms control the generation of different phenotypes from the same genotype. Thus differentiation is basically a process driven by changes in gene activity during development, often in response to transient factors or environmental stimuli. To keep the specific characteristics of cell types, tissue-specific gene expression patterns must be transmitted stably from one cell to the daughter cells, also in the absence of the early-acting determination factors. This heritability of patterns of active and inactive genes is enabled by epigenetic mechanisms that create a layer of information on top of the DNA sequence that ensures mitotic and sometimes also meiotic transmission of expression patterns. The proteins of the Polycomb and Trithorax group comprise such a cellular memory mechanism that preserves gene expression patterns through many rounds of cell division. This review provides an overview of the genetics and molecular biology of these maintenance proteins, concentrating mainly on mechanisms of Polycomb group-mediated repression.

  11. Combgap contributes to recruitment of Polycomb group proteins in Drosophila

    PubMed Central

    Ray, Payal; De, Sandip; Mitra, Apratim; Bezstarosti, Karel; Demmers, Jeroen A. A.; Pfeifer, Karl; Kassis, Judith A.

    2016-01-01

    Polycomb group (PcG) proteins are responsible for maintaining the silenced transcriptional state of many developmentally regulated genes. PcG proteins are organized into multiprotein complexes that are recruited to DNA via cis-acting elements known as “Polycomb response elements” (PREs). In Drosophila, PREs consist of binding sites for many different DNA-binding proteins, some known and others unknown. Identification of these DNA-binding proteins is crucial to understanding the mechanism of PcG recruitment to PREs. We report here the identification of Combgap (Cg), a sequence-specific DNA-binding protein that is involved in recruitment of PcG proteins. Cg can bind directly to PREs via GTGT motifs and colocalizes with the PcG proteins Pleiohomeotic (Pho) and Polyhomeotic (Ph) at the majority of PREs in the genome. In addition, Cg colocalizes with Ph at a number of targets independent of Pho. Loss of Cg leads to decreased recruitment of Ph at only a subset of sites; some of these sites are binding sites for other Polycomb repressive complex 1 (PRC1) components, others are not. Our data suggest that Cg can recruit Ph in the absence of PRC1 and illustrate the diversity and redundancy of PcG protein recruitment mechanisms. PMID:27001825

  12. Intergenic transcription through a polycomb group response element counteracts silencing.

    PubMed

    Schmitt, Sabine; Prestel, Matthias; Paro, Renato

    2005-03-15

    Polycomb group response elements (PREs) mediate the mitotic inheritance of gene expression programs and thus maintain determined cell fates. By default, PREs silence associated genes via the targeting of Polycomb group (PcG) complexes. Upon an activating signal, however, PREs recruit counteracting trithorax group (trxG) proteins, which in turn maintain target genes in a transcriptionally active state. Using a transgenic reporter system, we show that the switch from the silenced to the activated state of a PRE requires noncoding transcription. Continuous transcription through the PRE induced by an actin promoter prevents the establishment of PcG-mediated silencing. The maintenance of epigenetic activation requires transcription through the PRE to proceed at least until embryogenesis is completed. At the homeotic bithorax complex of Drosophila, intergenic PRE transcripts can be detected not only during embryogenesis, but also at late larval stages, suggesting that transcription through endogenous PREs is required continuously as an anti-silencing mechanism to prevent the access of repressive PcG complexes to the chromatin. Furthermore, all other PREs outside the homeotic complex we tested were found to be transcribed in the same tissue as the mRNA of the corresponding target gene, suggesting that anti-silencing by transcription is a fundamental aspect of the cellular memory system.

  13. Long-range repression by multiple polycomb group (PcG) proteins targeted by fusion to a defined DNA-binding domain in Drosophila.

    PubMed Central

    Roseman, R R; Morgan, K; Mallin, D R; Roberson, R; Parnell, T J; Bornemann, D J; Simon, J A; Geyer, P K

    2001-01-01

    A tethering assay was developed to study the effects of Polycomb group (PcG) proteins on gene expression in vivo. This system employed the Su(Hw) DNA-binding domain (ZnF) to direct PcG proteins to transposons that carried the white and yellow reporter genes. These reporters constituted naive sensors of PcG effects, as bona fide PcG response elements (PREs) were absent from the constructs. To assess the effects of different genomic environments, reporter transposons integrated at nearly 40 chromosomal sites were analyzed. Three PcG fusion proteins, ZnF-PC, ZnF-SCM, and ZnF-ESC, were studied, since biochemical analyses place these PcG proteins in distinct complexes. Tethered ZnF-PcG proteins repressed white and yellow expression at the majority of sites tested, with each fusion protein displaying a characteristic degree of silencing. Repression by ZnF-PC was stronger than ZnF-SCM, which was stronger than ZnF-ESC, as judged by the percentage of insertion lines affected and the magnitude of the conferred repression. ZnF-PcG repression was more effective at centric and telomeric reporter insertion sites, as compared to euchromatic sites. ZnF-PcG proteins tethered as far as 3.0 kb away from the target promoter produced silencing, indicating that these effects were long range. Repression by ZnF-SCM required a protein interaction domain, the SPM domain, which suggests that this domain is not primarily used to direct SCM to chromosomal loci. This targeting system is useful for studying protein domains and mechanisms involved in PcG repression in vivo. PMID:11333237

  14. Cooperativity, specificity, and evolutionary stability of Polycomb targeting in Drosophila.

    PubMed

    Schuettengruber, Bernd; Oded Elkayam, Noa; Sexton, Tom; Entrevan, Marianne; Stern, Shani; Thomas, Aubin; Yaffe, Eitan; Parrinello, Hugues; Tanay, Amos; Cavalli, Giacomo

    2014-10-09

    Metazoan genomes are partitioned into modular chromosomal domains containing active or repressive chromatin. In flies, Polycomb group (PcG) response elements (PREs) recruit PHO and other DNA-binding factors and act as nucleation sites for the formation of Polycomb repressive domains. The sequence specificity of PREs is not well understood. Here, we use comparative epigenomics and transgenic assays to show that Drosophila domain organization and PRE specification are evolutionarily conserved despite significant cis-element divergence within Polycomb domains, whereas cis-element evolution is strongly correlated with transcription factor binding divergence outside of Polycomb domains. Cooperative interactions of PcG complexes and their recruiting factor PHO stabilize PHO recruitment to low-specificity sequences. Consistently, PHO recruitment to sites within Polycomb domains is stabilized by PRC1. These data suggest that cooperative rather than hierarchical interactions among low-affinity sequences, DNA-binding factors, and the Polycomb machinery are giving rise to specific and strongly conserved 3D structures in Drosophila.

  15. miR-203 inhibits melanoma invasive and proliferative abilities by targeting the polycomb group gene BMI1

    SciTech Connect

    Chang, Xiao; Sun, Yong; Han, Siqi; Zhu, Wei; Zhang, Haiping; Lian, Shi

    2015-01-02

    Highlights: • First reported deregulation of miR-203 and up-regulation of BMI1 in metastatic melanoma. • miR-203 decreased BMI1 expression by directly binding to 3′UTR. • Further found miR-203 overexpression suppressed cell invasion and stemness. • Re-expression of BMI1 rescued miR-203-mediated suppression. • miR-203-BMI1 axis may be potential therapeutic targets of melanoma metastasis. - Abstract: Metastasis is the major problem in malignant melanoma, posing a therapeutic challenge to clinicians. The investigation of the underlying mechanism driving this progress remains a large unmet need. In this study, we revealed a miR-203-BMI1 axis that regulated melanoma metastasis. We found significantly deregulation of miR-203 and up-regulation of BMI1 in melanoma, particularly in metastatic melanoma. An inverse correlation between the levels of miR-203 and BMI1 was further observed in melanoma tissues and cell lines. We also identified BMI1 as a downstream target gene of miR-203, which bound to the 3′UTR of BMI1. Overexpression of miR-203 was associated with decreased BMI1 expression and impaired cell invasion and tumor sphere formation activities. Re-expression of BMI1 markedly rescued miR-203-mediated suppression of these events. Taken together, our results demonstrated that miR-203 regulated melanoma invasive and proliferative abilities in part by targeting BMI1, providing new insights into potential mechanisms of melanoma metastasis.

  16. Regulation by Polycomb and Trithorax Group Proteins in Arabidopsis

    PubMed Central

    Alvarez-Venegas, Raúl

    2010-01-01

    Polycomb group (PcG) and trithorax group (trxG) proteins are key regulators of homeotic genes and have crucial roles in cell proliferation, growth and development. PcG and trxG proteins form higher order protein complexes that contain SET domain proteins, with a histone methyltransferase (HMTase) activity, responsible for the different types of lysine methylation at the N-terminal tails of the core histone proteins. In recent years, genetic studies along with biochemical and cell biological analyses in Arabidopsis have enabled researchers to begin to understand how PcG and trxG proteins are recruited to chromatin and how they regulate their target genes and to elucidate their functions. This review focuses on the advances in our understanding of the biological roles of PcG and trxG proteins, their molecular mechanisms of action and further examines the role of histone marks in PcG and trxG regulation in Arabidopsis. PMID:22303254

  17. Polycomb Group (PcG) Proteins and Human Cancers: Multifaceted Functions and Therapeutic Implications

    PubMed Central

    Wang, Wei; Qin, Jiang-Jiang; Voruganti, Sukesh; Nag, Subhasree; Zhou, Jianwei; Zhang, Ruiwen

    2016-01-01

    Polycomb group (PcG) proteins are transcriptional repressors that regulate several crucial developmental and physiological processes in the cell. More recently, they have been found to play important roles in human carcinogenesis and cancer development and progression. The deregulation and dysfunction of PcG proteins often lead to blocking or inappropriate activation of developmental pathways, enhancing cellular proliferation, inhibiting apoptosis, and increasing the cancer stem cell population. Genetic and molecular investigations of PcG proteins have long been focused on their PcG functions. However, PcG proteins have recently been shown to exert non-polycomb functions, contributing to the regulation of diverse cellular functions. We and others have demonstrated that PcG proteins regulate the expression and function of several oncogenes and tumor suppressor genes in a PcG-independent manner, and PcG proteins are associated with the survival of patients with cancer. In this review, we summarize the recent advances in the research on PcG proteins, including both the polycomb-repressive and non-polycomb functions. We specifically focus on the mechanisms by which PcG proteins play roles in cancer initiation, development, and progression. Finally, we discuss the potential value of PcG proteins as molecular biomarkers for the diagnosis and prognosis of cancer, and as molecular targets for cancer therapy. PMID:26227500

  18. Dynamic regulation of Polycomb group activity during plant development.

    PubMed

    Bemer, Marian; Grossniklaus, Ueli

    2012-11-01

    Polycomb group (PcG) complexes play important roles in phase transitions and cell fate determination in plants and animals, by epigenetically repressing sets of genes that promote either proliferation or differentiation. The continuous differentiation of new organs in plants, such as leaves or flowers, requires a highly dynamic PcG function, which can be induced, modulated, or repressed when necessary. In this review, we discuss the recent advance in understanding PcG function in plants and focus on the diverse molecular mechanisms that have been described to regulate and counteract PcG activity in Arabidopsis.

  19. Interaction of Polycomb-group proteins controlling flowering in Arabidopsis.

    PubMed

    Chanvivattana, Yindee; Bishopp, Anthony; Schubert, Daniel; Stock, Christine; Moon, Yong-Hwan; Sung, Z Renee; Goodrich, Justin

    2004-11-01

    In Arabidopsis, the EMBYRONIC FLOWER2 (EMF2), VERNALISATION2 (VRN2) and FERTILISATION INDEPENDENT ENDOSPERM2 (FIS2) genes encode related Polycomb-group (Pc-G) proteins. Their homologues in animals act together with other Pc-G proteins as part of a multimeric complex, Polycomb Repressive Complex 2 (PRC2), which functions as a histone methyltransferase. Despite similarities between the fis2 mutant phenotype and those of some other plant Pc-G members, it has remained unclear how the FIS2/EMF2/VRN2 class Pc-G genes interact with the others. We have identified a weak emf2 allele that reveals a novel phenotype with striking similarity to that of severe mutations in another Pc-G gene, CURLY LEAF (CLF), suggesting that the two genes may act in a common pathway. Consistent with this, we demonstrate that EMF2 and CLF interact genetically and that this reflects interaction of their protein products through two conserved motifs, the VEFS domain and the C5 domain. We show that the full function of CLF is masked by partial redundancy with a closely related gene, SWINGER (SWN), so that null clf mutants have a much less severe phenotype than emf2 mutants. Analysis in yeast further indicates a potential for the CLF and SWN proteins to interact with the other VEFS domain proteins VRN2 and FIS2. The functions of individual Pc-G members may therefore be broader than single mutant phenotypes reveal. We suggest that plants have Pc-G protein complexes similar to the Polycomb Repressive Complex2 (PRC2) of animals, but the duplication and subsequent diversification of components has given rise to different complexes with partially discrete functions.

  20. Cell Reprogramming Requires Silencing of a Core Subset of Polycomb Targets

    PubMed Central

    Fragola, Giulia; Cuomo, Alessandro; Blasimme, Alessandro; Gross, Fridolin; Signaroldi, Elena; Bucci, Gabriele; Sommer, Cesar; Pruneri, Giancarlo; Mazzarol, Giovanni; Bonaldi, Tiziana; Mostoslavsky, Gustavo; Casola, Stefano; Testa, Giuseppe

    2013-01-01

    Transcription factor (TF)–induced reprogramming of somatic cells into induced pluripotent stem cells (iPSC) is associated with genome-wide changes in chromatin modifications. Polycomb-mediated histone H3 lysine-27 trimethylation (H3K27me3) has been proposed as a defining mark that distinguishes the somatic from the iPSC epigenome. Here, we dissected the functional role of H3K27me3 in TF–induced reprogramming through the inactivation of the H3K27 methylase EZH2 at the onset of reprogramming. Our results demonstrate that surprisingly the establishment of functional iPSC proceeds despite global loss of H3K27me3. iPSC lacking EZH2 efficiently silenced the somatic transcriptome and differentiated into tissues derived from the three germ layers. Remarkably, the genome-wide analysis of H3K27me3 in Ezh2 mutant iPSC cells revealed the retention of this mark on a highly selected group of Polycomb targets enriched for developmental regulators controlling the expression of lineage specific genes. Erasure of H3K27me3 from these targets led to a striking impairment in TF–induced reprogramming. These results indicate that PRC2-mediated H3K27 trimethylation is required on a highly selective core of Polycomb targets whose repression enables TF–dependent cell reprogramming. PMID:23468641

  1. Alternative epigenetic chromatin states of polycomb target genes.

    PubMed

    Schwartz, Yuri B; Kahn, Tatyana G; Stenberg, Per; Ohno, Katsuhito; Bourgon, Richard; Pirrotta, Vincenzo

    2010-01-01

    Polycomb (PcG) regulation has been thought to produce stable long-term gene silencing. Genomic analyses in Drosophila and mammals, however, have shown that it targets many genes, which can switch state during development. Genetic evidence indicates that critical for the active state of PcG target genes are the histone methyltransferases Trithorax (TRX) and ASH1. Here we analyze the repertoire of alternative states in which PcG target genes are found in different Drosophila cell lines and the role of PcG proteins TRX and ASH1 in controlling these states. Using extensive genome-wide chromatin immunoprecipitation analysis, RNAi knockdowns, and quantitative RT-PCR, we show that, in addition to the known repressed state, PcG targets can reside in a transcriptionally active state characterized by formation of an extended domain enriched in ASH1, the N-terminal, but not C-terminal moiety of TRX and H3K27ac. ASH1/TRX N-ter domains and transcription are not incompatible with repressive marks, sometimes resulting in a "balanced" state modulated by both repressors and activators. Often however, loss of PcG repression results instead in a "void" state, lacking transcription, H3K27ac, or binding of TRX or ASH1. We conclude that PcG repression is dynamic, not static, and that the propensity of a target gene to switch states depends on relative levels of PcG, TRX, and activators. N-ter TRX plays a remarkable role that antagonizes PcG repression and preempts H3K27 methylation by acetylation. This role is distinct from that usually attributed to TRX/MLL proteins at the promoter. These results have important implications for Polycomb gene regulation, the "bivalent" chromatin state of embryonic stem cells, and gene expression in development.

  2. Genome-wide identification of polycomb target genes reveals a functional association of Pho with Scm in Bombyx mori.

    PubMed

    Li, Zhiqing; Cheng, Daojun; Mon, Hiroaki; Tatsuke, Tsuneyuki; Zhu, Li; Xu, Jian; Lee, Jae Man; Xia, Qingyou; Kusakabe, Takahiro

    2012-01-01

    Polycomb group (PcG) proteins are evolutionarily conserved chromatin modifiers and act together in three multimeric complexes, Polycomb repressive complex 1 (PRC1), Polycomb repressive complex 2 (PRC2), and Pleiohomeotic repressive complex (PhoRC), to repress transcription of the target genes. Here, we identified Polycomb target genes in Bombyx mori with holocentric centromere using genome-wide expression screening based on the knockdown of BmSCE, BmESC, BmPHO, or BmSCM gene, which represent the distinct complexes. As a result, the expressions of 29 genes were up-regulated after knocking down 4 PcG genes. Particularly, there is a significant overlap between targets of BmPho (331 out of 524) and BmScm (331 out of 532), and among these, 190 genes function as regulator factors playing important roles in development. We also found that BmPho, as well as BmScm, can interact with other Polycomb components examined in this study. Further detailed analysis revealed that the C-terminus of BmPho containing zinc finger domain is involved in the interaction between BmPho and BmScm. Moreover, the zinc finger domain in BmPho contributes to its inhibitory function and ectopic overexpression of BmScm is able to promote transcriptional repression by Gal4-Pho fusions including BmScm-interacting domain. Loss of BmPho expression causes relocalization of BmScm into the cytoplasm. Collectively, we provide evidence of a functional link between BmPho and BmScm, and propose two Polycomb-related repression mechanisms requiring only BmPho associated with BmScm or a whole set of PcG complexes.

  3. Chromatin topology is coupled to Polycomb group protein subnuclear organization

    PubMed Central

    Wani, Ajazul H.; Boettiger, Alistair N.; Schorderet, Patrick; Ergun, Ayla; Münger, Christine; Sadreyev, Ruslan I.; Zhuang, Xiaowei; Kingston, Robert E.; Francis, Nicole J.

    2016-01-01

    The genomes of metazoa are organized at multiple scales. Many proteins that regulate genome architecture, including Polycomb group (PcG) proteins, form subnuclear structures. Deciphering mechanistic links between protein organization and chromatin architecture requires precise description and mechanistic perturbations of both. Using super-resolution microscopy, here we show that PcG proteins are organized into hundreds of nanoscale protein clusters. We manipulated PcG clusters by disrupting the polymerization activity of the sterile alpha motif (SAM) of the PcG protein Polyhomeotic (Ph) or by increasing Ph levels. Ph with mutant SAM disrupts clustering of endogenous PcG complexes and chromatin interactions while elevating Ph level increases cluster number and chromatin interactions. These effects can be captured by molecular simulations based on a previously described chromatin polymer model. Both perturbations also alter gene expression. Organization of PcG proteins into small, abundant clusters on chromatin through Ph SAM polymerization activity may shape genome architecture through chromatin interactions. PMID:26759081

  4. The Role of Polycomb Group Gene BMI-1 in the Development of Prostate Cancer

    DTIC Science & Technology

    2009-09-01

    0605 TITLE : The Role of Polycomb Group Gene Bmi-1 in the Development of Prostate Cancer PRINCIPAL INVESTIGATOR : Mohammad...NUMBER Prostate Cancer 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Mohammad Saleem Bhat 5d. PROJECT NUMBER 5e. TASK...investigate the role of Bmi-1 (a member of polycomb gene family) in human prostate cancer (CaP) development. Here, we present the work accomplished

  5. Genome-wide mapping of Polycomb target genes unravels their roles in cell fate transitions

    PubMed Central

    Bracken, Adrian P.; Dietrich, Nikolaj; Pasini, Diego; Hansen, Klaus H.; Helin, Kristian

    2006-01-01

    The Polycomb group (PcG) proteins form chromatin-modifying complexes that are essential for embryonic development and stem cell renewal and are commonly deregulated in cancer. Here, we identify their target genes using genome-wide location analysis in human embryonic fibroblasts. We find that Polycomb-Repressive Complex 1 (PRC1), PRC2, and tri-methylated histone H3K27 co-occupy >1000 silenced genes with a strong functional bias for embryonic development and cell fate decisions. We functionally identify 40 genes derepressed in human embryonic fibroblasts depleted of the PRC2 components (EZH2, EED, SUZ12) and the PRC1 component, BMI-1. Interestingly, several markers of osteogenesis, adipogenesis, and chrondrogenesis are among these genes, consistent with the mesenchymal origin of fibroblasts. Using a neuronal model of differentiation, we delineate two different mechanisms for regulating PcG target genes. For genes activated during differentiation, PcGs are displaced. However, for genes repressed during differentiation, we paradoxically find that they are already bound by the PcGs in nondifferentiated cells despite being actively transcribed. Our results are consistent with the hypothesis that PcGs are part of a preprogrammed memory system established during embryogenesis marking certain key genes for repressive signals during subsequent developmental and differentiation processes. PMID:16618801

  6. CHD3 proteins and polycomb group proteins antagonistically determine cell identity in Arabidopsis.

    PubMed

    Aichinger, Ernst; Villar, Corina B R; Farrona, Sara; Reyes, José C; Hennig, Lars; Köhler, Claudia

    2009-08-01

    Dynamic regulation of chromatin structure is of fundamental importance for modulating genomic activities in higher eukaryotes. The opposing activities of Polycomb group (PcG) and trithorax group (trxG) proteins are part of a chromatin-based cellular memory system ensuring the correct expression of specific transcriptional programs at defined developmental stages. The default silencing activity of PcG proteins is counteracted by trxG proteins that activate PcG target genes and prevent PcG mediated silencing activities. Therefore, the timely expression and regulation of PcG proteins and counteracting trxG proteins is likely to be of fundamental importance for establishing cell identity. Here, we report that the chromodomain/helicase/DNA-binding domain CHD3 proteins PICKLE (PKL) and PICKLE RELATED2 (PKR2) have trxG-like functions in plants and are required for the expression of many genes that are repressed by PcG proteins. The pkl mutant could partly suppress the leaf and flower phenotype of the PcG mutant curly leaf, supporting the idea that CHD3 proteins and PcG proteins antagonistically determine cell identity in plants. The direct targets of PKL in roots include the PcG genes SWINGER and EMBRYONIC FLOWER2 that encode subunits of Polycomb repressive complexes responsible for trimethylating histone H3 at lysine 27 (H3K27me3). Similar to mutants lacking PcG proteins, lack of PKL and PKR2 caused reduced H3K27me3 levels and, therefore, increased expression of a set of PcG protein target genes in roots. Thus, PKL and PKR2 are directly required for activation of PcG protein target genes and in roots are also indirectly required for repression of PcG protein target genes. Reduced PcG protein activity can lead to cell de-differentiation and callus-like tissue formation in pkl pkr2 mutants. Thus, in contrast to mammals, where PcG proteins are required to maintain pluripotency and to prevent cell differentiation, in plants PcG proteins are required to promote cell

  7. Targeting of Polycomb Repressive Complex 2 to RNA by Short Repeats of Consecutive Guanines.

    PubMed

    Wang, Xueyin; Goodrich, Karen J; Gooding, Anne R; Naeem, Haroon; Archer, Stuart; Paucek, Richard D; Youmans, Daniel T; Cech, Thomas R; Davidovich, Chen

    2017-03-16

    Polycomb repressive complex 2 (PRC2) is a histone methyltransferase that trimethylates H3K27, a mark of repressed chromatin. Mammalian PRC2 binds RNA promiscuously, with thousands of target transcripts in vivo. But what does PRC2 recognize in these RNAs? Here we show that purified human PRC2 recognizes G > C,U ≫ A in single-stranded RNA and has a high affinity for folded guanine quadruplex (G4) structures but little binding to duplex RNAs. Importantly, G-tract motifs are significantly enriched among PRC2-binding transcripts in vivo. DNA sequences coding for PRC2-binding RNA motifs are enriched at PRC2-binding sites on chromatin and H3K27me3-modified nucleosomes. Collectively, the abundance of PRC2-binding RNA motifs rationalizes the promiscuous RNA binding of PRC2, and their enrichment at Polycomb target genes provides a means for RNA-mediated regulation.

  8. Piwi maintains germline stem cells and oogenesis in Drosophila through negative regulation of Polycomb group proteins.

    PubMed

    Peng, Jamy C; Valouev, Anton; Liu, Na; Lin, Haifan

    2016-03-01

    The Drosophila melanogaster Piwi protein regulates both niche and intrinsic mechanisms to maintain germline stem cells, but its underlying mechanism remains unclear. Here we report that Piwi interacts with Polycomb group complexes PRC1 and PRC2 in niche and germline cells to regulate ovarian germline stem cells and oogenesis. Piwi physically interacts with the PRC2 subunits Su(z)12 and Esc in the ovary and in vitro. Chromatin coimmunoprecipitation of Piwi, the PRC2 enzymatic subunit E(z), histone H3 trimethylated at lysine 27 (H3K27me3) and RNA polymerase II in wild-type and piwi mutant ovaries demonstrates that Piwi binds a conserved DNA motif at ∼ 72 genomic sites and inhibits PRC2 binding to many non-Piwi-binding genomic targets and H3K27 trimethylation. Moreover, Piwi influences RNA polymerase II activities in Drosophila ovaries, likely via inhibiting PRC2. We hypothesize that Piwi negatively regulates PRC2 binding by sequestering PRC2 in the nucleoplasm, thus reducing PRC2 binding to many targets and influencing transcription during oogenesis.

  9. Kicking against the PRCs – A Domesticated Transposase Antagonises Silencing Mediated by Polycomb Group Proteins and Is an Accessory Component of Polycomb Repressive Complex 2

    PubMed Central

    Perera, Pumi; Mora-García, Santiago; de Leau, Erica; Thornton, Harry; de Alves, Flavia Lima; Rapsilber, Juri; Yang, Suxin; James, Geo Velikkakam; Schneeberger, Korbinian; Finnegan, E. Jean; Turck, Franziska; Goodrich, Justin

    2015-01-01

    The Polycomb group (PcG) and trithorax group (trxG) genes play crucial roles in development by regulating expression of homeotic and other genes controlling cell fate. Both groups catalyse modifications of chromatin, particularly histone methylation, leading to epigenetic changes that affect gene activity. The trxG antagonizes the function of PcG genes by activating PcG target genes, and consequently trxG mutants suppress PcG mutant phenotypes. We previously identified the ANTAGONIST OF LIKE HETEROCHROMATIN PROTEIN1 (ALP1) gene as a genetic suppressor of mutants in the Arabidopsis PcG gene LIKE HETEROCHROMATIN PROTEIN1 (LHP1). Here, we show that ALP1 interacts genetically with several other PcG and trxG components and that it antagonizes PcG silencing. Transcriptional profiling reveals that when PcG activity is compromised numerous target genes are hyper-activated in seedlings and that in most cases this requires ALP1. Furthermore, when PcG activity is present ALP1 is needed for full activation of several floral homeotic genes that are repressed by the PcG. Strikingly, ALP1 does not encode a known chromatin protein but rather a protein related to PIF/Harbinger class transposases. Phylogenetic analysis indicates that ALP1 is broadly conserved in land plants and likely lost transposase activity and acquired a novel function during angiosperm evolution. Consistent with this, immunoprecipitation and mass spectrometry (IP-MS) show that ALP1 associates, in vivo, with core components of POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), a widely conserved PcG protein complex which functions as a H3K27me3 histone methyltransferase. Furthermore, in reciprocal pulldowns using the histone methyltransferase CURLY LEAF (CLF), we identify not only ALP1 and the core PRC2 components but also plant-specific accessory components including EMBRYONIC FLOWER 1 (EMF1), a transcriptional repressor previously associated with PRC1-like complexes. Taken together our data suggest that ALP1 inhibits Pc

  10. A cellular chemical probe targeting the chromodomains of Polycomb Repressive Complex 1

    PubMed Central

    Stuckey, Jacob I; Dickson, Bradley M; Cheng, Nancy; Liu, Yanli; Norris, Jacqueline L; Cholensky, Stephanie H; Tempel, Wolfram; Qin, Su; Huber, Katherine G; Sagum, Cari; Black, Karynne; Li, Fengling; Huang, Xi-Ping; Roth, Bryan L; Baughman, Brandi M; Senisterra, Guillermo; Pattenden, Samantha G; Vedadi, Masoud; Brown, Peter J; Bedford, Mark T; Min, Jinrong; Arrowsmith, Cheryl H

    2015-01-01

    We report the design and characterization of UNC3866, a potent antagonist of the methyl-lysine (Kme) reading function of the Polycomb CBX and CDY families of chromodomains. Polycomb CBX proteins regulate gene expression by targeting Polycomb Repressive Complex 1 to sites of H3K27me3 via their chromodomains. UNC3866 binds the chromodomains of CBX4 and CBX7 most potently with a Kd of ∼100 nM for each, and is 6- to 18-fold selective versus seven other CBX and CDY chromodomains while being highly selective versus >250 other protein targets. X-ray crystallography revealed that UNC3866 closely mimics the interactions of the methylated H3 tail with these chromodomains. UNC4195, a biotinylated derivative of UNC3866, was used to demonstrate that UNC3866 engages intact PRC1 and that EED incorporation into PRC1 is isoform-dependent in PC3 prostate cancer cells. Finally, UNC3866 inhibits PC3 cell proliferation, a known CBX7 phenotype, while UNC4219, a methylated negative control compound, has negligible effects. PMID:26807715

  11. Programming off and on states in chromatin: mechanisms of Polycomb and trithorax group complexes.

    PubMed

    Simon, Jeffrey A; Tamkun, John W

    2002-04-01

    Polycomb and trithorax group proteins are evolutionarily conserved chromatin components that maintain stable states of gene expression. Recent studies have identified and characterized several multiprotein complexes containing these transcriptional regulators. Advances in understanding molecular activities of these complexes in vitro, and functional domains present in their subunits, suggest that they control transcription through multistep mechanisms that involve nucleosome modification, chromatin remodeling, and interaction with general transcription factors.

  12. Polycomb group proteins are required to couple seed coat initiation to fertilization

    PubMed Central

    Roszak, Pawel; Köhler, Claudia

    2011-01-01

    Seed development in flowering plants is initiated after a double fertilization event leading to the formation of zygotic embryo and endosperm tissues surrounded by the maternally derived seed coat. Although the seed coat does not take part in the fertilization process it develops immediately after fertilization, implicating a signaling mechanism from zygotic tissues to the surrounding maternal tissues. We addressed the question of the underlying mechanisms repressing seed coat development before fertilization and initiating seed coat development after fertilization by analyzing combinations of mutants that initiate seed development in the absence of fertilization. We discovered that seed coat development is actively repressed before fertilization by dosage-sensitive Polycomb group proteins acting in maternal tissues surrounding the female gametophyte. This repression is relieved after fertilization by a signal that is formed by the sexual endosperm. Fertilization is required for signal formation, as asexually formed endosperm fails to effectively initiate seed coat development in mutants with uncompromised maternal Polycomb group function. Mutants for the MADS-box transcription factor AGL62 initiate embryo and endosperm formation but fail to develop a seed coat, implicating AGL62 expression in the endosperm as a requirement for signal initiation. Together, our results provide evidence that fertilization of the central cell generates a signal that relieves Polycomb group-mediated repression in the surrounding maternal tissues to initiate seed coat formation. PMID:22143805

  13. A Polycomb Group Protein Is Retained at Specific Sites on Chromatin in Mitosis

    PubMed Central

    Follmer, Nicole E.; Wani, Ajazul H.; Francis, Nicole J.

    2012-01-01

    Epigenetic regulation of gene expression, including by Polycomb Group (PcG) proteins, may depend on heritable chromatin states, but how these states can be propagated through mitosis is unclear. Using immunofluorescence and biochemical fractionation, we find PcG proteins associated with mitotic chromosomes in Drosophila S2 cells. Genome-wide sequencing of chromatin immunoprecipitations (ChIP–SEQ) from mitotic cells indicates that Posterior Sex Combs (PSC) is not present at well-characterized PcG targets including Hox genes in mitosis, but does remain at a subset of interphase sites. Many of these persistent sites overlap with chromatin domain borders described by Sexton et al. (2012), which are genomic regions characterized by low levels of long range contacts. Persistent PSC binding sites flank both Hox gene clusters. We hypothesize that disruption of long-range chromatin contacts in mitosis contributes to PcG protein release from most sites, while persistent binding at sites with minimal long-range contacts may nucleate re-establishment of PcG binding and chromosome organization after mitosis. PMID:23284300

  14. Polycomb group protein gene silencing, non-coding RNA, stem cells, and cancer.

    PubMed

    Gieni, Randall S; Hendzel, Michael J

    2009-10-01

    Epigenetic programming is an important facet of biology, controlling gene expression patterns and the choice between developmental pathways. The Polycomb group proteins (PcGs) silence gene expression, allowing cells to both acquire and maintain identity. PcG silencing is important for stemness, X chromosome inactivation (XCI), genomic imprinting, and the abnormally silenced genes in cancers. Stem and cancer cells commonly share gene expression patterns, regulatory mechanisms, and signalling pathways. Many microRNA species have oncogenic or tumor suppressor activity, and disruptions in these networks are common in cancer; however, long non-coding (nc)RNA species are also important. Many of these directly guide PcG deposition and gene silencing at the HOX locus, during XCI, and in examples of genomic imprinting. Since inappropriate HOX expression and loss of genomic imprinting are hallmarks of cancer, disruption of long ncRNA-mediated PcG silencing likely has a role in oncogenesis. Aberrant silencing of coding and non-coding loci is critical for both the genesis and progression of cancers. In addition, PcGs are commonly abnormally overexpressed years prior to cancer pathology, making early PcG targeted therapy an option to reverse tumor formation, someday replacing the blunt instrument of eradication in the cancer therapy arsenal.

  15. Epigenetic regulation of cellular memory by the Polycomb and Trithorax group proteins.

    PubMed

    Ringrose, Leonie; Paro, Renato

    2004-01-01

    During the development of multicellular organisms, cells become different from one another by changing their genetic program in response to transient stimuli. Long after the stimulus is gone, "cellular memory" mechanisms enable cells to remember their chosen fate over many cell divisions. The Polycomb and Trithorax groups of proteins, respectively, work to maintain repressed or active transcription states of developmentally important genes through many rounds of cell division. Here we review current ideas on the protein and DNA components of this transcriptional memory system and how they interact dynamically with each other to orchestrate cellular memory for several hundred genes.

  16. A mosaic genetic screen reveals distinct roles for trithorax and polycomb group genes in Drosophila eye development.

    PubMed Central

    Janody, Florence; Lee, Jeffrey D; Jahren, Neal; Hazelett, Dennis J; Benlali, Aude; Miura, Grant I; Draskovic, Irena; Treisman, Jessica E

    2004-01-01

    The wave of differentiation that traverses the Drosophila eye disc requires rapid transitions in gene expression that are controlled by a number of signaling molecules also required in other developmental processes. We have used a mosaic genetic screen to systematically identify autosomal genes required for the normal pattern of photoreceptor differentiation, independent of their requirements for viability. In addition to genes known to be important for eye development and to known and novel components of the Hedgehog, Decapentaplegic, Wingless, Epidermal growth factor receptor, and Notch signaling pathways, we identified several members of the Polycomb and trithorax classes of genes encoding general transcriptional regulators. Mutations in these genes disrupt the transitions between zones along the anterior-posterior axis of the eye disc that express different combinations of transcription factors. Different trithorax group genes have very different mutant phenotypes, indicating that target genes differ in their requirements for chromatin remodeling, histone modification, and coactivation factors. PMID:15020417

  17. Architectural and Functional Diversity of Polycomb Group Response Elements in Drosophila

    PubMed Central

    Brown, J. Lesley; Kassis, Judith A.

    2013-01-01

    Polycomb group response elements (PREs) play an essential role in gene regulation by the Polycomb group (PcG) repressor proteins in Drosophila. PREs are required for the recruitment and maintenance of repression by the PcG proteins. PREs are made up of binding sites for multiple DNA-binding proteins, but it is still unclear what combination(s) of binding sites is required for PRE activity. Here we compare the binding sites and activities of two closely linked yet separable PREs of the Drosophila engrailed (en) gene, PRE1 and PRE2. Both PRE1 and PRE2 contain binding sites for multiple PRE–DNA-binding proteins, but the number, arrangement, and spacing of the sites differs between the two PREs. These differences have functional consequences. Both PRE1 and PRE2 mediate pairing-sensitive silencing of mini-white, a functional assay for PcG repression; however, PRE1 requires two binding sites for Pleiohomeotic (Pho), whereas PRE2 requires only one Pho-binding site for this activity. Furthermore, for full pairing-sensitive silencing activity, PRE1 requires an AT-rich region not found in PRE2. These two PREs behave differently in a PRE embryonic and larval reporter construct inserted at an identical location in the genome. Our data illustrate the diversity of architecture and function of PREs. PMID:23934890

  18. Comparative analysis of chromatin binding by Sex Comb on Midleg (SCM) and other polycomb group repressors at a Drosophila Hox gene.

    PubMed

    Wang, Liangjun; Jahren, Neal; Miller, Ellen L; Ketel, Carrie S; Mallin, Daniel R; Simon, Jeffrey A

    2010-06-01

    Sex Comb on Midleg (SCM) is a transcriptional repressor in the Polycomb group (PcG), but its molecular role in PcG silencing is not known. Although SCM can interact with Polycomb repressive complex 1 (PRC1) in vitro, biochemical studies have indicated that SCM is not a core constituent of PRC1 or PRC2. Nevertheless, SCM is just as critical for Drosophila Hox gene silencing as canonical subunits of these well-characterized PcG complexes. To address functional relationships between SCM and other PcG components, we have performed chromatin immunoprecipitation studies using cultured Drosophila Schneider line 2 (S2) cells and larval imaginal discs. We find that SCM associates with a Polycomb response element (PRE) upstream of the Ubx gene which also binds PRC1, PRC2, and the DNA-binding PcG protein Pleiohomeotic (PHO). However, SCM is retained at this Ubx PRE despite genetic disruption or knockdown of PHO, PRC1, or PRC2, suggesting that SCM chromatin targeting does not require prior association of these other PcG components. Chromatin immunoprecipitations (IPs) to test the consequences of SCM genetic disruption or knockdown revealed that PHO association is unaffected, but reduced levels of PRE-bound PRC2 and PRC1 were observed. We discuss these results in light of current models for recruitment of PcG complexes to chromatin targets.

  19. Requirement for sex comb on midleg protein interactions in Drosophila polycomb group repression.

    PubMed

    Peterson, Aidan J; Mallin, Daniel R; Francis, Nicole J; Ketel, Carrie S; Stamm, Joyce; Voeller, Rochus K; Kingston, Robert E; Simon, Jeffrey A

    2004-07-01

    The Drosophila Sex Comb on Midleg (SCM) protein is a transcriptional repressor of the Polycomb group (PcG). Although genetic studies establish SCM as a crucial PcG member, its molecular role is not known. To investigate how SCM might link to PcG complexes, we analyzed the in vivo role of a conserved protein interaction module, the SPM domain. This domain is found in SCM and in another PcG protein, Polyhomeotic (PH), which is a core component of Polycomb repressive complex 1 (PRC1). SCM-PH interactions in vitro are mediated by their respective SPM domains. Yeast two-hybrid and in vitro binding assays were used to isolate and characterize >30 missense mutations in the SPM domain of SCM. Genetic rescue assays showed that SCM repressor function in vivo is disrupted by mutations that impair SPM domain interactions in vitro. Furthermore, overexpression of an isolated, wild-type SPM domain produced PcG loss-of-function phenotypes in flies. Coassembly of SCM with a reconstituted PRC1 core complex shows that SCM can partner with PRC1. However, gel filtration chromatography showed that the bulk of SCM is biochemically separable from PH in embryo nuclear extracts. These results suggest that SCM, although not a core component of PRC1, interacts and functions with PRC1 in gene silencing.

  20. Requirement for sex comb on midleg protein interactions in Drosophila polycomb group repression.

    PubMed Central

    Peterson, Aidan J; Mallin, Daniel R; Francis, Nicole J; Ketel, Carrie S; Stamm, Joyce; Voeller, Rochus K; Kingston, Robert E; Simon, Jeffrey A

    2004-01-01

    The Drosophila Sex Comb on Midleg (SCM) protein is a transcriptional repressor of the Polycomb group (PcG). Although genetic studies establish SCM as a crucial PcG member, its molecular role is not known. To investigate how SCM might link to PcG complexes, we analyzed the in vivo role of a conserved protein interaction module, the SPM domain. This domain is found in SCM and in another PcG protein, Polyhomeotic (PH), which is a core component of Polycomb repressive complex 1 (PRC1). SCM-PH interactions in vitro are mediated by their respective SPM domains. Yeast two-hybrid and in vitro binding assays were used to isolate and characterize >30 missense mutations in the SPM domain of SCM. Genetic rescue assays showed that SCM repressor function in vivo is disrupted by mutations that impair SPM domain interactions in vitro. Furthermore, overexpression of an isolated, wild-type SPM domain produced PcG loss-of-function phenotypes in flies. Coassembly of SCM with a reconstituted PRC1 core complex shows that SCM can partner with PRC1. However, gel filtration chromatography showed that the bulk of SCM is biochemically separable from PH in embryo nuclear extracts. These results suggest that SCM, although not a core component of PRC1, interacts and functions with PRC1 in gene silencing. PMID:15280237

  1. Polycomb dysregulation in gliomagenesis targets a Zfp423-dependent differentiation network

    PubMed Central

    Signaroldi, Elena; Laise, Pasquale; Cristofanon, Silvia; Brancaccio, Arianna; Reisoli, Elisa; Atashpaz, Sina; Terreni, Maria Rosa; Doglioni, Claudio; Pruneri, Giancarlo; Malatesta, Paolo; Testa, Giuseppe

    2016-01-01

    Malignant gliomas constitute one of the most significant areas of unmet medical need, owing to the invariable failure of surgical eradication and their marked molecular heterogeneity. Accumulating evidence has revealed a critical contribution by the Polycomb axis of epigenetic repression. However, a coherent understanding of the regulatory networks affected by Polycomb during gliomagenesis is still lacking. Here we integrate transcriptomic and epigenomic analyses to define Polycomb-dependent networks that promote gliomagenesis, validating them both in two independent mouse models and in a large cohort of human samples. We find that Polycomb dysregulation in gliomagenesis affects transcriptional networks associated with invasiveness and de-differentiation. The dissection of these networks uncovers Zfp423 as a critical Polycomb-dependent transcription factor whose silencing negatively impacts survival. The anti-gliomagenic activity of Zfp423 requires interaction with the SMAD proteins within the BMP signalling pathway, pointing to a novel synergic circuit through which Polycomb inhibits BMP signalling. PMID:26923714

  2. Evidence of neofunctionalization after the duplication of the highly conserved Polycomb group gene Caf1-55 in the obscura group of Drosophila

    PubMed Central

    Calvo-Martín, Juan M.; Papaceit, Montserrat; Segarra, Carmen

    2017-01-01

    Drosophila CAF1-55 protein is a subunit of the Polycomb repressive complex PRC2 and other protein complexes. It is a multifunctional and evolutionarily conserved protein that participates in nucleosome assembly and remodelling, as well as in the epigenetic regulation of a large set of target genes. Here, we describe and analyze the duplication of Caf1-55 in the obscura group of Drosophila. Paralogs exhibited a strong asymmetry in evolutionary rates, which suggests that they have evolved according to a neofunctionalization process. During this process, the ancestral copy has been kept under steady purifying selection to retain the ancestral function and the derived copy (Caf1-55dup) that originated via a DNA-mediated duplication event ~18 Mya, has been under clear episodic selection. Different maximum likelihood approaches confirmed the action of positive selection, in contrast to relaxed selection, on Caf1-55dup after the duplication. This adaptive process has also taken place more recently during the divergence of D. subobscura and D. guanche. The possible association of this duplication with a previously detected acceleration in the evolutionary rate of three CAF1-55 partners in PRC2 complexes is discussed. Finally, the timing and functional consequences of the Caf1-55 duplication is compared to other duplications of Polycomb genes. PMID:28094282

  3. Identification of polycomb and trithorax group responsive elements in the regulatory region of the Drosophila homeotic gene Sex combs reduced

    SciTech Connect

    Gindhart, J.G. Jr.; Kaufman, T.C.

    1995-02-01

    The Drosophilia homeotic gene Sex combs reduced (Scr) is necessary for the establishment and maintenance of the morphological identity of the labial and prothoracic segments. In the early embryo, its expression pattern is established through the activity of several gap and segmentation gene products, as well as other transcription factors. Once established, the Polycomb group (Pc-G) and trithorax group (trx-G) gene products maintain the spatial pattern of Scr expression for the remainder of development. We report the identification of DNA fragments in the Scr regulatory region that may be important for its regulation by Polycomb and trithorax group gene products. When DNA fragments containing these regulatory sequences are subcloned into P-element vectors containing a white minigene, transformants containing these constructs exhibit mosaic patterns of pigmentation in the adult eye, indicating that white minigene expression is repressed in a clonally heritable manner. The size of pigmented and nonpigmented clones in the adult eye suggests that the event determining whether a cell in the eye anlagen will express white occurs at least as early as the first larval instar. The amount of white minigene repression is reduced in some Polycomb group mutants, whereas repression is enhanced in flies mutant for a subset of trithorax group loci. The repressor activity of one fragment, normally located in Scr Intron 2, is increased when it is able to homologously pair, a property consistent with genetic data suggesting that Scr exhibits transvection. Another Scr regulatory fragment, normally located 40 kb upstream of the Scr promoter, silences ectopic expression of an Scr-lacZ fusion gene in the embryo and does so in a Polycomb-dependent manner. We propose that the regulatory sequences located within these DNA fragments may normally mediate the regulation of Scr by proteins encoded by members of Polycomb and trithorax group loci. 98 refs., 6 figs., 4 tabs.

  4. Polycomb group protein ezh2 controls actin polymerization and cell signaling.

    PubMed

    Su, I-hsin; Dobenecker, Marc-Werner; Dickinson, Ephraim; Oser, Matthew; Basavaraj, Ashwin; Marqueron, Raphael; Viale, Agnes; Reinberg, Danny; Wülfing, Christoph; Tarakhovsky, Alexander

    2005-05-06

    Polycomb group protein Ezh2, one of the key regulators of development in organisms from flies to mice, exerts its epigenetic function through regulation of histone methylation. Here, we report the existence of the cytosolic Ezh2-containing methyltransferase complex and tie the function of this complex to regulation of actin polymerization in various cell types. Genetic evidence supports the essential role of cytosolic Ezh2 in actin polymerization-dependent processes such as antigen receptor signaling in T cells and PDGF-induced dorsal circular ruffle formation in fibroblasts. Revealed function of Ezh2 points to a broader usage of lysine methylation in regulation of both nuclear and extra-nuclear signaling processes.

  5. Trithorax and Polycomb group-dependent regulation: a tale of opposing activities.

    PubMed

    Geisler, Sarah J; Paro, Renato

    2015-09-01

    Intricate layers of regulation determine the unique gene expression profiles of a given cell and, therefore, underlie the immense phenotypic diversity observed among cell types. Understanding the mechanisms that govern which genes are expressed and which genes are silenced is a fundamental focus in biology. The Polycomb and Trithorax group chromatin proteins play important roles promoting the stable and heritable repression and activation of gene expression, respectively. These proteins, which are conserved across metazoans, modulate post-translational modifications on histone tails and regulate nucleosomal structures. Here, we review recent advances that have shed light on the mechanisms by which these two classes of proteins act to maintain epigenetic memory and allow dynamic switches in gene expression during development.

  6. Polycomb Group Protein Ezh2 Regulates Hepatic Progenitor Cell Proliferation and Differentiation in Murine Embryonic Liver

    PubMed Central

    Ueno, Yasuharu; Nakata, Susumu; Obana, Yuta; Sekine, Keisuke; Zheng, Yun-Wen; Takebe, Takanori; Isono, Kyoichi; Koseki, Haruhiko; Taniguchi, Hideki

    2014-01-01

    In embryonic liver, hepatic progenitor cells are actively proliferating and generate a fundamental cellular pool for establishing parenchymal components. However, the molecular basis for the expansion of the progenitors maintaining their immature state remains elusive. Polycomb group proteins regulate gene expression throughout the genome by modulating of chromatin structure and play crucial roles in development. Enhancer of zeste homolog 2 (Ezh2), a key component of polycomb group proteins, catalyzes tri-methylation of lysine 27 of histone H3 (H3K27me3), which trigger the gene suppression. In the present study, we investigated a role of Ezh2 in the regulation of the expanding hepatic progenitor population in vivo. We found that Ezh2 is highly expressed in the actively proliferating cells at the early developmental stage. Using a conditional knockout mouse model, we show that the deletion of the SET domain of Ezh2, which is responsible for catalytic induction of H3K27me3, results in significant reduction of the total liver size, absolute number of liver parenchymal cells, and hepatic progenitor cell population in size. A clonal colony assay in the hepatic progenitor cells directly isolated from in vivo fetal livers revealed that the bi-potent clonogenicity was significantly attenuated by the Ezh2 loss of function. Moreover, a marker expression based analysis and a global gene expression analysis showed that the knockout of Ezh2 inhibited differentiation to hepatocyte with reduced expression of a number of liver-function related genes. Taken together, our results indicate that Ezh2 is required for the hepatic progenitor expansion in vivo, which is essential for the functional maturation of embryonic liver, through its activity for catalyzing H3K27me3. PMID:25153170

  7. Polycombs and microRNA-223 regulate human granulopoiesis by transcriptional control of target gene expression.

    PubMed

    Zardo, Giuseppe; Ciolfi, Alberto; Vian, Laura; Starnes, Linda M; Billi, Monia; Racanicchi, Serena; Maresca, Carmen; Fazi, Francesco; Travaglini, Lorena; Noguera, Nelida; Mancini, Marco; Nanni, Mauro; Cimino, Giuseppe; Lo-Coco, Francesco; Grignani, Francesco; Nervi, Clara

    2012-04-26

    Epigenetic modifications regulate developmental genes involved in stem cell identity and lineage choice. NFI-A is a posttranscriptional microRNA-223 (miR-223) target directing human hematopoietic progenitor lineage decision: NFI-A induction or silencing boosts erythropoiesis or granulopoiesis, respectively. Here we show that NFI-A promoter silencing, which allows granulopoiesis, is guaranteed by epigenetic events, including the resolution of opposing chromatin "bivalent domains," hypermethylation, recruitment of polycomb (PcG)-RNAi complexes, and miR-223 promoter targeting activity. During granulopoiesis, miR-223 localizes inside the nucleus and targets the NFI-A promoter region containing PcGs binding sites and miR-223 complementary DNA sequences, evolutionarily conserved in mammalians. Remarkably, both the integrity of the PcGs-RNAi complex and DNA sequences matching the seed region of miR-223 are required to induce NFI-A transcriptional silencing. Moreover, ectopic miR-223 expression in human myeloid progenitors causes heterochromatic repression of NFI-A gene and channels granulopoiesis, whereas its stable knockdown produces the opposite effects. Our findings indicate that, besides the regulation of translation of mRNA targets, endogenous miRs can affect gene expression at the transcriptional level, functioning in a critical interface between chromatin remodeling complexes and the genome to direct fate lineage determination of hematopoietic progenitors.

  8. Polycomb Group Proteins Bind an engrailed PRE in Both the “ON” and “OFF” Transcriptional States of engrailed

    PubMed Central

    Langlais, Kristofor K.; Brown, J. Lesley; Kassis, Judith A.

    2012-01-01

    Polycomb group (PcG) and trithorax Group (trxG) proteins maintain the “OFF” and “ON” transcriptional states of HOX genes and other targets by modulation of chromatin structure. In Drosophila, PcG proteins are bound to DNA fragments called Polycomb group response elements (PREs). The prevalent model holds that PcG proteins bind PREs only in cells where the target gene is “OFF”. Another model posits that transcription through PREs disrupts associated PcG complexes, contributing to the establishment of the “ON” transcriptional state. We tested these two models at the PcG target gene engrailed. engrailed exists in a gene complex with invected, which together have 4 well-characterized PREs. Our data show that these PREs are not transcribed in embryos or larvae. We also examined whether PcG proteins are bound to an engrailed PRE in cells where engrailed is transcribed. By FLAG-tagging PcG proteins and expressing them specifically where engrailed is “ON” or “OFF”, we determined that components of three major PcG protein complexes are present at an engrailed PRE in both the “ON” and “OFF” transcriptional states in larval tissues. These results show that PcG binding per se does not determine the transcriptional state of engrailed. PMID:23139817

  9. Genome-Wide Ultrabithorax Binding Analysis Reveals Highly Targeted Genomic Loci at Developmental Regulators and a Potential Connection to Polycomb-Mediated Regulation

    PubMed Central

    Meireles-Filho, Antonio C. A.; Pagani, Michaela; Stark, Alexander

    2016-01-01

    Hox homeodomain transcription factors are key regulators of animal development. They specify the identity of segments along the anterior-posterior body axis in metazoans by controlling the expression of diverse downstream targets, including transcription factors and signaling pathway components. The Drosophila melanogaster Hox factor Ultrabithorax (Ubx) directs the development of thoracic and abdominal segments and appendages, and loss of Ubx function can lead for example to the transformation of third thoracic segment appendages (e.g. halters) into second thoracic segment appendages (e.g. wings), resulting in a characteristic four-wing phenotype. Here we present a Drosophila melanogaster strain with a V5-epitope tagged Ubx allele, which we employed to obtain a high quality genome-wide map of Ubx binding sites using ChIP-seq. We confirm the sensitivity of the V5 ChIP-seq by recovering 7/8 of well-studied Ubx-dependent cis-regulatory regions. Moreover, we show that Ubx binding is predictive of enhancer activity as suggested by comparison with a genome-scale resource of in vivo tested enhancer candidates. We observed densely clustered Ubx binding sites at 12 extended genomic loci that included ANTP-C, BX-C, Polycomb complex genes, and other regulators and the clustered binding sites were frequently active enhancers. Furthermore, Ubx binding was detected at known Polycomb response elements (PREs) and was associated with significant enrichments of Pc and Pho ChIP signals in contrast to binding sites of other developmental TFs. Together, our results show that Ubx targets developmental regulators via strongly clustered binding sites and allow us to hypothesize that regulation by Ubx might involve Polycomb group proteins to maintain specific regulatory states in cooperative or mutually exclusive fashion, an attractive model that combines two groups of proteins with prominent gene regulatory roles during animal development. PMID:27575958

  10. Loss of Polycomb Group Protein Pcgf1 Severely Compromises Proper Differentiation of Embryonic Stem Cells

    PubMed Central

    Yan, Yun; Zhao, Wukui; Huang, Yikai; Tong, Huan; Xia, Yin; Jiang, Qing; Qin, Jinzhong

    2017-01-01

    The Polycomb repressive complex 1 (PRC1) is essential for fate decisions of embryonic stem (ES) cells. Emerging evidence suggests that six major variants of PRC1 complex, defined by the mutually exclusive presence of Pcgf subunit, regulate distinct biological processes, yet very little is known about the mechanism by which each version of PRC1 instructs and maintains cell fate. Here, we disrupted the Pcgf1, also known as Nspc1 and one of six Pcgf paralogs, in mouse ES cells by the CRISPR/Cas9 technology. We showed that although these mutant cells were viable and retained normal self-renewal, they displayed severe defects in differentiation in vitro. To gain a better understanding of the role of Pcgf1 in transcriptional control of differentiation, we analysed mRNA profiles from Pcgf1 deficient cells using RNA-seq. Interestingly, we found that Pcgf1 positively regulated expression of essential transcription factors involved in ectoderm and mesoderm differentiation, revealing an unexpected function of Pcgf1 in gene activation during ES cell lineage specification. Chromatin immunoprecipitation experiments demonstrated that Pcgf1 deletion caused a decrease in Ring1B and its associated H2AK119ub1 mark binding to target genes. Altogether, our results suggested an unexpected function of Pcgf1 in gene activation during ES cell maintenance. PMID:28393894

  11. AGAMOUS Terminates Floral Stem Cell Maintenance in Arabidopsis by Directly Repressing WUSCHEL through Recruitment of Polycomb Group Proteins[W

    PubMed Central

    Liu, Xigang; Kim, Yun Ju; Müller, Ralf; Yumul, Rae Eden; Liu, Chunyan; Pan, Yanyun; Cao, Xiaofeng; Goodrich, Justin; Chen, Xuemei

    2011-01-01

    Floral stem cells produce a defined number of floral organs before ceasing to be maintained as stem cells. Therefore, floral stem cells offer an ideal model to study the temporal control of stem cell maintenance within a developmental context. AGAMOUS (AG), a MADS domain transcription factor essential for the termination of floral stem cell fate, has long been thought to repress the stem cell maintenance gene WUSCHEL (WUS) indirectly. Here, we uncover a role of Polycomb Group (PcG) genes in the temporally precise repression of WUS expression and termination of floral stem cell fate. We show that AG directly represses WUS expression by binding to the WUS locus and recruiting, directly or indirectly, PcG that methylates histone H3 Lys-27 at WUS. We also show that PcG acts downstream of AG and probably in parallel with the known AG target KNUCKLES to terminate floral stem cell fate. Our studies identify core components of the network governing the temporal program of floral stem cells. PMID:22028461

  12. The trithorax group proteins Kismet and ASH1 promote H3K36 dimethylation to counteract Polycomb group repression in Drosophila

    PubMed Central

    Dorighi, Kristel M.; Tamkun, John W.

    2013-01-01

    Members of the Polycomb group of repressors and trithorax group of activators maintain heritable states of transcription by modifying nucleosomal histones or remodeling chromatin. Although tremendous progress has been made toward defining the biochemical activities of Polycomb and trithorax group proteins, much remains to be learned about how they interact with each other and the general transcription machinery to maintain on or off states of gene expression. The trithorax group protein Kismet (KIS) is related to the SWI/SNF and CHD families of chromatin remodeling factors. KIS promotes transcription elongation, facilitates the binding of the trithorax group histone methyltransferases ASH1 and TRX to active genes, and counteracts repressive methylation of histone H3 on lysine 27 (H3K27) by Polycomb group proteins. Here, we sought to clarify the mechanism of action of KIS and how it interacts with ASH1 to antagonize H3K27 methylation in Drosophila. We present evidence that KIS promotes transcription elongation and counteracts Polycomb group repression via distinct mechanisms. A chemical inhibitor of transcription elongation, DRB, had no effect on ASH1 recruitment or H3K27 methylation. Conversely, loss of ASH1 function had no effect on transcription elongation. Mutations in kis cause a global reduction in the di- and tri-methylation of histone H3 on lysine 36 (H3K36) - modifications that antagonize H3K27 methylation in vitro. Furthermore, loss of ASH1 significantly decreases H3K36 dimethylation, providing further evidence that ASH1 is an H3K36 dimethylase in vivo. These and other findings suggest that KIS antagonizes Polycomb group repression by facilitating ASH1-dependent H3K36 dimethylation. PMID:24004944

  13. A Role of Polycomb Group Genes in the Regulation of Gap Gene Expression in Drosophila

    PubMed Central

    Pelegri, F.; Lehmann, R.

    1994-01-01

    Anteroposterior polarity of the Drosophila embryo is initiated by the localized activities of the maternal genes, bicoid and nanos, which establish a gradient of the hunchback (hb) morphogen. nanos determines the distribution of the maternal Hb protein by regulating its translation. To identify further components of this pathway we isolated suppressors of nanos. In the absence of nanos high levels of Hb protein repress the abdomen-specific genes knirps and giant. In suppressor-of-nanos mutants, knirps and giant are expressed in spite of high Hb levels. The suppressors are alleles of Enhancer of zeste (E(z)) a member of the Polycomb group (Pc-G) of genes. We show that E(z), and likely other Pc-G genes, are required for maintaining the expression domains of knirps and giant initiated by the maternal Hb protein gradient. We have identified a small region of the knirps promoter that mediates the regulation by E(z) and hb. Because Pc-G genes are thought to control gene expression by regulating chromatin, we propose that imprinting at the chromatin level underlies the determination of anteroposterior polarity in the early embryo. PMID:8013911

  14. A domain shared by the Polycomb group proteins Scm and ph mediates heterotypic and homotypic interactions.

    PubMed

    Peterson, A J; Kyba, M; Bornemann, D; Morgan, K; Brock, H W; Simon, J

    1997-11-01

    The Sex comb on midleg (Scm) and polyhomeotic (ph) proteins are members of the Polycomb group (PcG) of transcriptional repressors. PcG proteins maintain differential patterns of homeotic gene expression during development in Drosophila flies. The Scm and ph proteins share a homology domain with 38% identity over a length of 65 amino acids, termed the SPM domain, that is located at their respective C termini. Using the yeast two-hybrid system and in vitro protein-binding assays, we show that the SPM domain mediates direct interaction between Scm and ph. Binding studies with isolated SPM domains from Scm and ph show that the domain is sufficient for these protein interactions. These studies also show that the Scm-ph and Scm-Scm domain interactions are much stronger than the ph-ph domain interaction, indicating that the isolated domain has intrinsic binding specificity determinants. Analysis of site-directed point mutations identifies residues that are important for SPM domain function. These binding properties, predicted alpha-helical secondary structure, and conservation of hydrophobic residues prompt comparisons of the SPM domain to the helix-loop-helix and leucine zipper domains used for homotypic and heterotypic protein interactions in other transcriptional regulators. In addition to in vitro studies, we show colocalization of the Scm and ph proteins at polytene chromosome sites in vivo. We discuss the possible roles of the SPM domain in the assembly or function of molecular complexes of PcG proteins.

  15. Polycomb-group histone methyltransferase CLF is required for proper somatic recombination in Arabidopsis.

    PubMed

    Chen, Na; Zhou, Wang-Bin; Wang, Ying-Xiang; Dong, Ai-Wu; Yu, Yu

    2014-06-01

    Homologous recombination (HR) is a key process during meiosis in reproductive cells and the DNA damage repair process in somatic cells. Although chromatin structure is thought to be crucial for HR, only a small number of chromatin modifiers have been studied in HR regulation so far. Here, we investigated the function of CURLY LEAF (CLF), a Polycomb-group (PcG) gene responsible for histone3 lysine 27 trimethylation (H3K27me3), in somatic and meiotic HR in Arabidopsis thaliana. Although fluorescent protein reporter assays in pollen and seeds showed that the frequency of meiotic cross-over in the loss-of-function mutant clf-29 was not significantly different from that in wild type, there was a lower frequency of HR in clf-29 than in wild type under normal conditions and under bleomycin treatment. The DNA damage levels were comparable between clf-29 and wild type, even though several DNA damage repair genes (e.g. ATM, BRCA2a, RAD50, RAD51, RAD54, and PARP2) were expressed at lower levels in clf-29. Under bleomycin treatment, the expression levels of DNA repair genes were similar in clf-29 and wild type, thus CLF may also regulate HR via other mechanisms. These findings expand the current knowledge of PcG function and contribute to general interests of epigenetic regulation in genome stability regulation.

  16. Interaction of the Arabidopsis polycomb group proteins FIE and MEA mediates their common phenotypes.

    PubMed

    Spillane, C; MacDougall, C; Stock, C; Köhler, C; Vielle-Calzada, J P; Nunes, S M; Grossniklaus, U; Goodrich, J

    2000-11-30

    Genes of the FERTILISATION INDEPENDENT SEED (FIS) class regulate cell proliferation during reproductive development in Arabidopsis [1-5]. The FIS genes FERTILISATION INDEPENDENT ENDOSPERM (FIE) and MEDEA (MEA) encode homologs of animal Polycomb group (Pc-G) proteins, transcriptional regulators that modify chromatin structure and are thought to form multimeric complexes [3-11]. To test whether similarities in fis mutant phenotypes reflect interactions between their protein products, we characterised FIE RNA and protein localisation in vivo, and FIE protein interactions in yeast and in vitro. Expression of FIE mRNA overlaps with that of MEA during embryo sac and seed development and is unaffected in mea mutants. Results from the yeast two-hybrid system and an in vitro pull-down assay indicate that MEA and FIE proteins interact. The relevance of this interaction in vivo is supported by the finding that FIE and MEA co-localise in the nucleus in transfected plant cells. Interaction of MEA and FIE is mediated by the amino-terminal region of MEA. Despite sequence divergence in this domain, MEA can interact with its corresponding animal partner Extrasexcombs (ESC) in the yeast two-hybrid system. We conclude that FIE and MEA act together as part of a multimeric complex and that this accounts for the similarities in mutant phenotypes. We propose that an ancient mechanism for chromatin modification has been independently recruited to different developmental processes in the two kingdoms.

  17. Structure of a BMI-1-Ring1B Polycomb Group Ubiquitin Ligase Complex

    SciTech Connect

    Li,Z.; Cao, R.; Wang, M.; Myers, M.; Zhang, Y.; Xu, R.

    2006-01-01

    Polycomb group (PcG) proteins Bmi-1 and Ring1B are core subunits of the PRC1 complex which plays important roles in the regulation of Hox gene expression, X-chromosome inactivation, tumorigenesis and stem cell self-renewal. The RING finger protein Ring1B is an E3 ligase that participates in the ubiquitination of lysine 119 of histone H2A, and the binding of Bmi-1 stimulates the E3 ligase activity. We have mapped the regions of Bmi-1 and Ring1B required for efficient ubiquitin transfer and determined a 2.5 Angstroms structure of the Bmi-1-Ring1B core domain complex. The structure reveals that Ring1B 'hugs' Bmi-1 through extensive RING domain contacts and its N-terminal tail wraps around Bmi-1. The two regions of interaction have a synergistic effect on the E3 ligase activity. Our analyses suggest a model where the Bmi-1-Ring1B complex stabilizes the interaction between the E2 enzyme and the nucleosomal substrate to allow efficient ubiquitin transfer.

  18. A new transgenic mouse model for conditional overexpression of the Polycomb Group protein EZH2.

    PubMed

    Koppens, Martijn A J; Tanger, Ellen; Nacerddine, Karim; Westerman, Bart; Song, Ji-Ying; van Lohuizen, Maarten

    2017-04-01

    The Polycomb Group protein EZH2 is upregulated in most prostate cancers, and its overexpression is associated with poor prognosis. Most insights into the functional role of EZH2 in prostate cancer have been gained using cell lines and EZH2 inactivation studies. However, the question remains whether overexpression of EZH2 can initiate prostate tumourigenesis or drive tumour progression. Appropriate transgenic mouse models that are required to answer such questions are lacking. We developed one such transgenic mouse model for conditional overexpression of Ezh2. In this transgene, Ezh2 and Luciferase are transcribed from a single open reading frame. The latter gene enables intravital bioluminescent imaging of tissues expressing this transgene, allowing the detection of tumour outgrowth and potential metastatic progression over time. Prostate-specific Ezh2 overexpression by crossbreeding with Probasin-Cre mice led to neoplastic prostate lesions at low incidence and with a long latency. Compounding a previously described Bmi1-transgene and Pten-deficiency prostate cancer mouse model with the Ezh2 transgene did not enhance tumour progression or drive metastasis formation. In conclusion, we here report the generation of a wildtype Ezh2 overexpression mouse model that allows for intravital surveillance of tissues with activated transgene. This model will be an invaluable tool for further unravelling the role of EZH2 in cancer.

  19. Pluripotency Factors and Polycomb Group Proteins Repress Aryl Hydrocarbon Receptor Expression in Murine Embryonic Stem Cells

    PubMed Central

    Ko, Chia-I; Wang, Qin; Fan, Yunxia; Xia, Ying; Puga, Alvaro

    2013-01-01

    The aryl hydrocarbon receptor (AHR) is a transcription factor and environmental sensor that regulates expression of genes involved in drug-metabolism and cell cycle regulation. Chromatin immunoprecipitation analyses, Ahr ablation in mice and studies with orthologous genes in invertebrates suggest that AHR may also play a significant role in embryonic development. To address this hypothesis, we studied the regulation of Ahr expression in mouse embryonic stem cells and their differentiated progeny. In ES cells, interactions between OCT3/4, NANOG, SOX2 and Polycomb Group proteins at the Ahr promoter repress AHR expression, which can also be repressed by ectopic expression of reprogramming factors in hepatoma cells. In ES cells, unproductive RNA polymerase II binds at the Ahr transcription start site and drives the synthesis of short abortive transcripts. Activation of Ahr expression during differentiation follows from reversal of repressive marks in Ahr promoter chromatin, release of pluripotency factors and PcG proteins, binding of Sp factors, establishment of histone marks of open chromatin, and engagement of active RNAPII to drive full-length RNA transcript elongation. Our results suggest that reversible Ahr repression in ES cells holds the gene poised for expression and allows for a quick switch to activation during embryonic development. PMID:24316986

  20. Identification and characterization of Polycomb group genes in the silkworm, Bombyx mori.

    PubMed

    Li, Zhiqing; Tatsuke, Tsuneyuki; Sakashita, Kosuke; Zhu, Li; Xu, Jian; Mon, Hiroaki; Lee, Jae Man; Kusakabe, Takahiro

    2012-05-01

    Polycomb group (PcG) proteins are involved in chromatin modifications for maintaining gene repression that play important roles in the regulation of gene expression, tumorigenesis, chromosome X-inactivation, and genomic imprinting in Drosophila melanogaster, mammals, and even plants. To characterize the orthologs of PcG genes in the silkworm, Bombyx mori, 13 candidates were identified from the updated silkworm genome sequence by using the fruit fly PcG genes as queries. Comparison of the silkworm PcG proteins with those from other insect species revealed that the insect PcG proteins shared high sequence similarity. High-level expressions of all the silkworm PcG genes were maintained through day 2 to day 7 of embryogenesis, and tissue microarray data on day 3 of the fifth instar larvae showed that their expression levels were relatively low in somatic tissues, except for Enhancer of zeste (E(Z)). In addition, knockdown of each PRC2 component, such as E(Z), Extra sex combs (ESC), and Suppressor of zeste 12 (SU(Z)12), considerably decreased the global levels of H3K27me3 but not of H3K27me2. Taken together, these results suggest that insect PcG proteins are highly conserved during evolution and might play similar roles in embryogenesis.

  1. dBRWD3 Regulates Tissue Overgrowth and Ectopic Gene Expression Caused by Polycomb Group Mutations

    PubMed Central

    Shih, Hsueh-Tzu; Chen, Wei-Yu; Liu, Kwei-Yan; Shih, Zong-Siou; Chen, Yi-Jyun; Hsieh, Paul-Chen; Kuo, Kuan-Lin; Huang, Kuo-How; Hsu, Pang-Hung; Liu, Ya-Wen; Tsai, Yu-Chen; Wu, June-Tai

    2016-01-01

    To maintain a particular cell fate, a unique set of genes should be expressed while another set is repressed. One way to repress gene expression is through Polycomb group (PcG) proteins that compact chromatin into a silent configuration. In addition to cell fate maintenance, PcG proteins also maintain normal cell physiology, for example cell cycle. In the absence of PcG, ectopic activation of the PcG-repressed genes leads to developmental defects and malignant tumors. Little is known about the molecular nature of ectopic gene expression; especially what differentiates expression of a given gene in the orthotopic tissue (orthotopic expression) and the ectopic expression of the same gene due to PcG mutations. Here we present that ectopic gene expression in PcG mutant cells specifically requires dBRWD3, a negative regulator of HIRA/Yemanuclein (YEM)-mediated histone variant H3.3 deposition. dBRWD3 mutations suppress both the ectopic gene expression and aberrant tissue overgrowth in PcG mutants through a YEM-dependent mechanism. Our findings identified dBRWD3 as a critical regulator that is uniquely required for ectopic gene expression and aberrant tissue overgrowth caused by PcG mutations. PMID:27588417

  2. A bridging model for persistence of a polycomb group protein complex through DNA replication in vitro.

    PubMed

    Lo, Stanley M; Follmer, Nicole E; Lengsfeld, Bettina M; Madamba, Egbert V; Seong, Samuel; Grau, Daniel J; Francis, Nicole J

    2012-06-29

    Epigenetic regulation may involve heritable chromatin states, but how chromatin features can be inherited through DNA replication is incompletely understood. We address this question using cell-free replication of chromatin. Previously, we showed that a Polycomb group complex, PRC1, remains continuously associated with chromatin through DNA replication. Here we investigate the mechanism of persistence. We find that a single PRC1 subunit, Posterior sex combs (PSC), can reconstitute persistence through DNA replication. PSC binds nucleosomes and self-interacts, bridging nucleosomes into a stable, oligomeric structure. Within these structures, individual PSC-chromatin contacts are dynamic. Stable association of PSC with chromatin, including through DNA replication, depends on PSC-PSC interactions. Our data suggest that labile individual PSC-chromatin contacts allow passage of the DNA replication machinery while PSC-PSC interactions prevent PSC from dissociating, allowing it to rebind to replicated chromatin. This mechanism may allow inheritance of chromatin proteins including PRC1 through DNA replication to maintain chromatin states.

  3. Psip1/Ledgf p75 restrains Hox gene expression by recruiting both trithorax and polycomb group proteins

    PubMed Central

    Pradeepa, Madapura M.; Grimes, Graeme R.; Taylor, Gillian C.A.; Sutherland, Heidi G.; Bickmore, Wendy A.

    2014-01-01

    Trithorax and polycomb group proteins are generally thought to antagonize one another. The trithorax family member MLL (myeloid/lymphoid or mixed-lineage leukemia) is presumed to activate Hox expression, counteracting polycomb-mediated repression. PC4 and SF2 interacting protein 1 (PSIP1)/p75, also known as LEDGF, whose PWWP domain binds to H3K36me3, interacts with MLL and tethers MLL fusion proteins to HOXA9 in leukaemias. Here we show, unexpectedly, that Psip1/p75 regulates homeotic genes by recruiting not only MLL complexes, but also the polycomb group protein Bmi1. In Psip1−/− cells binding of Mll1/2, Bmi1 and the co-repressor Ctbp1 at Hox loci are all abrogated and Hoxa and Hoxd mRNA expression increased. Our data not only reveal a potential mechanism of action for Psip1 in the regulation of Hox genes but also suggest an unexpected interplay between proteins usually considered as transcriptional activators and repressors. PMID:25056311

  4. Structure of the polycomb group protein PCGF1 in complex with BCOR reveals basis for binding selectivity of PCGF homologs.

    PubMed

    Junco, Sarah E; Wang, Renjing; Gaipa, John C; Taylor, Alexander B; Schirf, Virgil; Gearhart, Micah D; Bardwell, Vivian J; Demeler, Borries; Hart, P John; Kim, Chongwoo A

    2013-04-02

    Polycomb-group RING finger homologs (PCGF1, PCGF2, PCGF3, PCGF4, PCGF5, and PCGF6) are critical components in the assembly of distinct Polycomb repression complex 1 (PRC1)-related complexes. Here, we identify a protein interaction domain in BCL6 corepressor, BCOR, which binds the RING finger- and WD40-associated ubiquitin-like (RAWUL) domain of PCGF1 (NSPC1) and PCGF3 but not of PCGF2 (MEL18) or PCGF4 (BMI1). Because of the selective binding, we have named this domain PCGF Ub-like fold discriminator (PUFD). The structure of BCOR PUFD bound to PCGF1 reveals that (1) PUFD binds to the same surfaces as observed for a different Polycomb group RAWUL domain and (2) the ability of PUFD to discriminate among RAWULs stems from the identity of specific residues within these interaction surfaces. These data show the molecular basis for determining the binding preference for a PCGF homolog, which ultimately helps determine the identity of the larger PRC1-like assembly.

  5. The impact of Polycomb group (PcG) and Trithorax group (TrxG) epigenetic factors in plant plasticity.

    PubMed

    de la Paz Sanchez, Maria; Aceves-García, Pamela; Petrone, Emilio; Steckenborn, Stefan; Vega-León, Rosario; Álvarez-Buylla, Elena R; Garay-Arroyo, Adriana; García-Ponce, Berenice

    2015-11-01

    Current advances indicate that epigenetic mechanisms play important roles in the regulatory networks involved in plant developmental responses to environmental conditions. Hence, understanding the role of such components becomes crucial to understanding the mechanisms underlying the plasticity and variability of plant traits, and thus the ecology and evolution of plant development. We now know that important components of phenotypic variation may result from heritable and reversible epigenetic mechanisms without genetic alterations. The epigenetic factors Polycomb group (PcG) and Trithorax group (TrxG) are involved in developmental processes that respond to environmental signals, playing important roles in plant plasticity. In this review, we discuss current knowledge of TrxG and PcG functions in different developmental processes in response to internal and environmental cues and we also integrate the emerging evidence concerning their function in plant plasticity. Many such plastic responses rely on meristematic cell behavior, including stem cell niche maintenance, cellular reprogramming, flowering and dormancy as well as stress memory. This information will help to determine how to integrate the role of epigenetic regulation into models of gene regulatory networks, which have mostly included transcriptional interactions underlying various aspects of plant development and its plastic response to environmental conditions.

  6. The Polycomb Group Protein Pcgf1 Is Dispensable in Zebrafish but Involved in Early Growth and Aging

    PubMed Central

    Le Bourhis, Xuefen; Angrand, Pierre-Olivier

    2016-01-01

    Polycomb Repressive Complex (PRC) 1 regulates the control of gene expression programs via chromatin structure reorganization. Through mutual exclusion, different PCGF members generate a variety of PRC1 complexes with potentially distinct cellular functions. In this context, the molecular function of each of the PCGF family members remains elusive. The study of PCGF family member expression in zebrafish development and during caudal fin regeneration reveals that the zebrafish pcgf genes are subjected to different regulations and that all PRC1 complexes in terms of Pcgf subunit composition are not always present in the same tissues. To unveil the function of Pcgf1 in zebrafish, a mutant line was generated using the TALEN technology. Mutant pcgf1-/- fish are viable and fertile, but the growth rate at early developmental stages is reduced in absence of pcgf1 gene function and a significant number of pcgf1-/- fish show signs of premature aging. This first vertebrate model lacking Pcgf1 function shows that this Polycomb Group protein is involved in cell proliferation during early embryogenesis and establishes a link between epigenetics and aging. PMID:27442247

  7. Partially redundant functions of two SET-domain polycomb-group proteins in controlling initiation of seed development in Arabidopsis.

    PubMed

    Wang, Dongfang; Tyson, Mark D; Jackson, Shawn S; Yadegari, Ramin

    2006-08-29

    In Arabidopsis, a complex of Polycomb-group (PcG) proteins functions in the female gametophyte to control the initiation of seed development. Mutations in the PcG genes, including MEDEA (MEA) and FERTILIZATION-INDEPENDENT SEED 2 (FIS2), produce autonomous seeds where endosperm proliferation occurs in the absence of fertilization. By using a yeast two-hybrid screen, we identified MEA and a related protein, SWINGER (SWN), as SET-domain partners of FIS2. Localization data indicated that all three proteins are present in the female gametophyte. Although single-mutant swn plants did not show any defects, swn mutations enhanced the mea mutant phenotype in producing autonomous seeds. Thus, MEA and SWN perform partially redundant functions in controlling the initiation of endosperm development before fertilization in Arabidopsis.

  8. Transcriptional Response of Polycomb Group Genes to Status Epilepticus in Mice is Modified by Prior Exposure to Epileptic Preconditioning.

    PubMed

    Reynolds, James P; Miller-Delaney, Suzanne F C; Jimenez-Mateos, Eva M; Sano, Takanori; McKiernan, Ross C; Simon, Roger P; Henshall, David C

    2015-01-01

    Exposure of the brain to brief, non-harmful seizures can activate protective mechanisms that temporarily generate a damage-refractory state. This process, termed epileptic tolerance, is associated with large-scale down-regulation of gene expression. Polycomb group (PcG) proteins are master controllers of gene silencing during development that are re-activated by injury to the brain. Here, we explored the transcriptional response of genes associated with polycomb repressive complex (PRC) 1 (Ring1A, Ring1B, and Bmi1) and PRC2 (Ezh1, Ezh2, and Suz12), as well as additional transcriptional regulators Sirt1, Yy1, and Yy2, in a mouse model of status epilepticus (SE). Findings were contrasted to changes after SE in mice previously given brief seizures to evoke tolerance. Real-time quantitative PCR showed SE prompted an early (1 h) increase in expression of several genes in PRC1 and PRC2 in the hippocampus, followed by down-regulation of many of the same genes at later times points (4, 8, and 24 h). Spatio-temporal differences were found among PRC2 genes in epileptic tolerance, including increased expression of Ezh2, Suz12, and Yy2 relative to the normal injury response to SE. In contrast, PRC1 complex genes including Ring 1B and Bmi1 displayed differential down-regulation in epileptic tolerance. The present study characterizes PcG gene expression following SE and shows prior seizure exposure produces select changes to PRC1 and PRC2 composition that may influence differential gene expression in epileptic tolerance.

  9. DNA Topoisomerase I Affects Polycomb Group Protein-Mediated Epigenetic Regulation and Plant Development by Altering Nucleosome Distribution in Arabidopsis[W

    PubMed Central

    Liu, Xigang; Gao, Lei; Dinh, Thanh Theresa; Shi, Ting; Li, Dongming; Wang, Ruozhong; Guo, Lin; Xiao, Langtao; Chen, Xuemei

    2014-01-01

    It has been perplexing that DNA topoisomerases, enzymes that release DNA supercoils, play specific roles in development. In this study, using a floral stem cell model in Arabidopsis thaliana, we uncovered a role for TOPOISOMERASE1α (TOP1α) in Polycomb Group (PcG) protein-mediated histone 3 lysine 27 trimethylation (H3K27me3) at, and transcriptional repression of, the stem cell maintenance gene WUSCHEL (WUS). We demonstrated that H3K27me3 deposition at other PcG targets also requires TOP1α. Intriguingly, the repression of some, as well as the expression of many, PcG target genes requires TOP1α. The mechanism that unifies the opposing effects of TOP1α appears to lie in its role in decreasing nucleosome density, which probably allows the binding of factors that either recruit PcG, as we demonstrated for AGAMOUS at the WUS locus, or counteract PcG-mediated regulation. Although TOP1α reduces nucleosome density at all genes, the lack of a 5′ nucleosome-free region is a feature that distinguishes PcG targets from nontargets and may condition the requirement for TOP1α for their expression. This study uncovers a connection between TOP1α and PcG, which explains the specific developmental functions of TOP1α. PMID:25070639

  10. Chronic Myelogenous Leukemia- Initiating Cells Require Polycomb Group Protein EZH2.

    PubMed

    Xie, Huafeng; Peng, Cong; Huang, Jialiang; Li, Bin E; Kim, Woojin; Smith, Elenoe C; Fujiwara, Yuko; Qi, Jun; Cheloni, Giulia; Das, Partha P; Nguyen, Minh; Li, Shaoguang; Bradner, James E; Orkin, Stuart H

    2016-11-01

    Tyrosine kinase inhibitors (TKI) have revolutionized chronic myelogenous leukemia (CML) management. Disease eradication, however, is hampered by innate resistance of leukemia-initiating cells (LIC) to TKI-induced killing, which also provides the basis for subsequent emergence of TKI-resistant mutants. We report that EZH2, the catalytic subunit of Polycomb Repressive Complex 2 (PRC2), is overexpressed in CML LICs and required for colony formation and survival and cell-cycle progression of CML cell lines. A critical role for EZH2 is supported by genetic studies in a mouse CML model. Inactivation of Ezh2 in conventional conditional mice and through CRISPR/Cas9-mediated gene editing prevents initiation and maintenance of disease and survival of LICs, irrespective of BCR-ABL1 mutational status, and extends survival. Expression of the EZH2 homolog EZH1 is reduced in EZH2-deficient CML LICs, creating a scenario resembling complete loss of PRC2. EZH2 dependence of CML LICs raises prospects for improved therapy of TKI-resistant CML and/or eradication of disease by addition of EZH2 inhibitors.

  11. Stuxnet Recruits the Proteasome to Take Down Polycomb.

    PubMed

    Karch, François

    2016-06-20

    In this issue of Developmental Cell, Du et al. (2016) describe a gene named stuxnet that regulates Polycomb protein stability, thereby influencing the activity of the Polycomb-group repressive chromatin complexes.

  12. Ago-RIP-Seq identifies Polycomb repressive complex I member CBX7 as a major target of miR-375 in prostate cancer progression

    PubMed Central

    Pickl, Julia M.A.; Tichy, Diana; Kuryshev, Vladimir Y.; Tolstov, Yanis; Falkenstein, Michael; Schüler, Julia; Reidenbach, Daniel; Hotz-Wagenblatt, Agnes; Kristiansen, Glen; Roth, Wilfried; Hadaschik, Boris; Hohenfellner, Markus; Duensing, Stefan; Heckmann, Doreen; Sültmann, Holger

    2016-01-01

    Prostate cancer is a heterogeneous disease. MiR-375 is a marker for prostate cancer progression, but its cellular function is not characterized. Here, we provide the first comprehensive investigation of miR-375 in prostate cancer. We show that miR-375 is enriched in prostate cancer compared to normal cells. Furthermore, miR-375 enhanced proliferation, migration and invasion in vitro and induced tumor growth and reduced survival in vivo showing that miR-375 has oncogenic properties in prostate cancer. On the molecular level, we provide the targetome and genome-wide transcriptional changes of miR-375 expression by applying a generalized linear model for Ago-RIP-Seq and RNA-Seq, and show that miR-375 is involved in tumorigenic networks and Polycomb regulation. Integration of tissue and gene ontology data prioritized miR-375 targets and identified the tumor suppressor gene CBX7, a member of Polycomb repressive complex 1, as a major miR-375 target. MiR-375-mediated repression of CBX7 was accompanied by increased expression of its homolog CBX8 and activated transcriptional programs linked to malignant progression in prostate cancer cells. Tissue analysis showed association of CBX7 loss with advanced prostate cancer. Our study indicates that miR-375 exerts its tumor-promoting role in prostate cancer by influencing the epigenetic regulation of transcriptional programs through its ability to directly target the Polycomb complex member CBX7. PMID:27449098

  13. Therapeutic targeting of polycomb and BET bromodomain proteins in diffuse intrinsic pontine gliomas.

    PubMed

    Piunti, Andrea; Hashizume, Rintaro; Morgan, Marc A; Bartom, Elizabeth T; Horbinski, Craig M; Marshall, Stacy A; Rendleman, Emily J; Ma, Quanhong; Takahashi, Yoh-Hei; Woodfin, Ashley R; Misharin, Alexander V; Abshiru, Nebiyu A; Lulla, Rishi R; Saratsis, Amanda M; Kelleher, Neil L; James, C David; Shilatifard, Ali

    2017-02-27

    Diffuse intrinsic pontine glioma (DIPG) is a highly aggressive pediatric brainstem tumor characterized by rapid and uniform patient demise. A heterozygous point mutation of histone H3 occurs in more than 80% of these tumors and results in a lysine-to-methionine substitution (H3K27M). Expression of this histone mutant is accompanied by a reduction in the levels of polycomb repressive complex 2 (PRC2)-mediated H3K27 trimethylation (H3K27me3), and this is hypothesized to be a driving event of DIPG oncogenesis. Despite a major loss of H3K27me3, PRC2 activity is still detected in DIPG cells positive for H3K27M. To investigate the functional roles of H3K27M and PRC2 in DIPG pathogenesis, we profiled the epigenome of H3K27M-mutant DIPG cells and found that H3K27M associates with increased H3K27 acetylation (H3K27ac). In accordance with previous biochemical data, the majority of the heterotypic H3K27M-K27ac nucleosomes colocalize with bromodomain proteins at the loci of actively transcribed genes, whereas PRC2 is excluded from these regions; this suggests that H3K27M does not sequester PRC2 on chromatin. Residual PRC2 activity is required to maintain DIPG proliferative potential, by repressing neuronal differentiation and function. Finally, to examine the therapeutic potential of blocking the recruitment of bromodomain proteins by heterotypic H3K27M-K27ac nucleosomes in DIPG cells, we performed treatments in vivo with BET bromodomain inhibitors and demonstrate that they efficiently inhibit tumor progression, thus identifying this class of compounds as potential therapeutics in DIPG.

  14. The CHD3 chromatin remodeler PICKLE and polycomb group proteins antagonistically regulate meristem activity in the Arabidopsis root.

    PubMed

    Aichinger, Ernst; Villar, Corina B R; Di Mambro, Riccardo; Sabatini, Sabrina; Köhler, Claudia

    2011-03-01

    The chromatin modifying Polycomb group (PcG) and trithorax group (trxG) proteins are central regulators of cell identity that maintain a tightly controlled balance between cell proliferation and cell differentiation. The opposing activities of PcG and trxG proteins ensure the correct expression of specific transcriptional programs at defined developmental stages. Here, we report that the chromatin remodeling factor PICKLE (PKL) and the PcG protein CURLY LEAF (CLF) antagonistically determine root meristem activity. Whereas loss of PKL function caused a decrease in meristematic activity, loss of CLF function increased meristematic activity. Alterations of meristematic activity in pkl and clf mutants were not connected with changes in auxin concentration but correlated with decreased or increased expression of root stem cell and meristem marker genes, respectively. Root stem cell and meristem marker genes are modified by the PcG-mediated trimethylation of histone H3 on lysine 27 (H3K27me3). Decreased expression levels of root stem cell and meristem marker genes in pkl correlated with increased levels of H3K27me3, indicating that root meristem activity is largely controlled by the antagonistic activity of PcG proteins and PKL.

  15. Polycomb proteins remain bound to chromatin and DNA during DNA replication in vitro

    PubMed Central

    Francis, Nicole J.; Follmer, Nicole E.; Simon, Matthew D.; Aghia, George; Butler, Jeffrey D.

    2009-01-01

    Summary The transcriptional status of a gene can be maintained through multiple rounds of cell division during development. This epigenetic effect is believed to reflect heritable changes in chromatin folding and histone modifications or variants at target genes, but little is known about how these chromatin features are inherited through cell division. A particular challenge for maintaining transcription states is DNA replication, which disrupts or dilutes chromatin associated proteins and histone modifications. PRC1-class Polycomb Group protein complexes are essential for development, and are thought to heritably silence transcription by altering chromatin folding and histone modifications. It is not known whether these complexes and their effects are maintained during DNA replication or subsequently re-established. We find that when PRC1-class Polycomb complex-bound chromatin or DNA is replicated in vitro, Polycomb complexes remain bound to replicated templates. Retention of Polycomb proteins through DNA replication may contribute to maintenance of transcriptional silencing through cell division. PMID:19303136

  16. Polycomb group complexes are recruited to reactivated FMR1 alleles in Fragile X syndrome in response to FMR1 transcription.

    PubMed

    Kumari, Daman; Usdin, Karen

    2014-12-15

    The FMR1 gene is subject to repeat mediated-gene silencing when the CGG-repeat tract in the 5' UTR exceeds 200 repeat units. This results in Fragile X syndrome, the most common heritable cause of intellectual disability and a major cause of autism spectrum disorders. The mechanism of gene silencing is not fully understood, and efforts to reverse this gene silencing have had limited success. Here, we show that the level of trimethylation of histone H3 on lysine 27, a hallmark of the activity of EZH2, a component of repressive Polycomb Group (PcG) complexes like PRC2, is increased on reactivation of the silenced allele by either the DNA demethylating agent 5-azadeoxycytidine or the SIRT1 inhibitor splitomicin. The level of H3K27me3 increases and decreases in parallel with the FMR1 mRNA level. Furthermore, reducing the levels of the FMR1 mRNA reduces the accumulation of H3K27me3. This suggests a model for FMR1 gene silencing in which the FMR1 mRNA generated from the reactivated allele acts in cis to repress its own transcription via the recruitment of PcG complexes to the FMR1 locus.

  17. Polycomb-Group Proteins and FLOWERING LOCUS T Maintain Commitment to Flowering in Arabidopsis thaliana[C][W][OPEN

    PubMed Central

    Müller-Xing, Ralf; Clarenz, Oliver; Pokorny, Lena; Goodrich, Justin; Schubert, Daniel

    2014-01-01

    The switch from vegetative to reproductive growth is extremely stable even if plants are only transiently exposed to environmental stimuli that trigger flowering. In the photoperiodic pathway, a mobile signal, florigen, encoded by FLOWERING LOCUS T (FT) in Arabidopsis thaliana, induces flowering. Because FT activity in leaves is not maintained after transient photoperiodic induction, the molecular basis for stable floral commitment is unclear. Here, we show that Polycomb-group (Pc-G) proteins, which mediate epigenetic gene regulation, maintain the identity of inflorescence and floral meristems after floral induction. Thus, plants with reduced Pc-G activity show a remarkable increase of cauline leaves under noninductive conditions and floral reversion when shifted from inductive to noninductive conditions. These phenotypes are almost completely suppressed by loss of FLOWERING LOCUS C (FLC) and SHORT VEGETATIVE PHASE, which both delay flowering and promote vegetative shoot identity. Upregulation of FLC in Pc-G mutants leads to a strong decrease of FT expression in inflorescences. We find that this activity of FT is needed to prevent floral reversion. Collectively, our results reveal that floral meristem identity is at least partially maintained by a daylength-independent role of FT whose expression is indirectly sustained by Pc-G activity. PMID:24920331

  18. The Polycomb group gene Bmi1 regulates antioxidant defenses in neurons by repressing p53 pro-oxidant activity

    PubMed Central

    Chatoo, Wassim; Abdouh, Mohamed; David, Jocelyn; Champagne, Marie-Pier; Ferreira, José; Rodier, Francis; Bernier, Gilbert

    2009-01-01

    Aging may be determined by a genetic program and/or by the accumulation rate of molecular damages. Reactive oxygen species (ROS) generated by the mitochondrial metabolism have been postulated to be the central source of molecular damages and imbalance between levels of intracellular ROS and antioxidant defenses is a characteristic of the aging brain. How aging modifies free radicals concentrations and increases the risk to develop most neurodegenerative diseases is poorly understood, however. Here we show that the Polycomb group and oncogene Bmi1 is required in neurons to suppress apoptosis and the induction of a premature aging-like program characterized by reduced antioxidant defenses. Before weaning, Bmi1−/− mice display a progeroid-like ocular and brain phenotype while Bmi1+/− mice, although apparently normal, have reduced lifespan. Bmi1 deficiency in neurons results in increased p19Arf/p53 levels, abnormally high ROS concentrations and hypersensitivity to neurotoxic agents. Most Bmi1 functions on neurons oxidative metabolism are genetically linked to repression of p53 pro-oxidant activity, which also operates in physiological conditions. In Bmi1−/− neurons, p53 and co-repressors accumulate at antioxidant gene promoters, correlating with a repressed chromatin state and antioxidant genes downregulation. These findings provide a molecular mechanism explaining how Bmi1 regulates free radical concentrations and reveal the biological impact of Bmi1 deficiency on neuronal survival and aging. PMID:19144853

  19. SUMO modification is required for in vivo Hox gene regulation by the Caenorhabditis elegans Polycomb group protein SOP-2.

    PubMed

    Zhang, Hong; Smolen, Gromoslaw A; Palmer, Rachel; Christoforou, Andrea; van den Heuvel, Sander; Haber, Daniel A

    2004-05-01

    Post-translational modification of proteins by the ubiquitin-like molecule SUMO (sumoylation) regulates their subcellular localization and affects their functional properties in vitro, but the physiological function of sumoylation in multicellular organisms is largely unknown. Here, we show that the C. elegans Polycomb group (PcG) protein SOP-2 interacts with the SUMO-conjugating enzyme UBC-9 through its evolutionarily conserved SAM domain. Sumoylation of SOP-2 is required for its localization to nuclear bodies in vivo and for its physiological repression of Hox genes. Global disruption of sumoylation phenocopies a sop-2 mutation by causing ectopic Hox gene expression and homeotic transformations. Chimeric constructs in which the SOP-2 SAM domain is replaced with that derived from fruit fly or mammalian PcG proteins, but not those in which the SOP-2 SAM domain is replaced with the SAM domains of non-PcG proteins, confer appropriate in vivo nuclear localization and Hox gene repression. These observations indicate that sumoylation of PcG proteins, modulated by their evolutionarily conserved SAM domain, is essential to their physiological repression of Hox genes.

  20. The Role of Polycomb Group Gene BMI-1 in the Development of Prostate Cancer

    DTIC Science & Technology

    2013-07-01

    cyclin D1 ( Wnt target) and Bcl-2 (Sonic Hedgehog-SHH target). The novel finding in presented in the 2nd annual report was that regulation of Bcl-2...chemotherapies. In this report, we show that targeting of BMI1 by gene-silencing improved the outcome of Sulindac ( Wnt - signaling inhibitor) therapy in animal...15. SUBJECT TERMS BMI1, Wnt Signaling, Bcl-2, TCF, Prostate Cancer 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER

  1. BMI1 Polycomb Group Protein Acts as a Master Switch for Growth and Death of Tumor Cells: Regulates TCF4-Transcriptional Factor-Induced BCL2 Signaling

    PubMed Central

    Siddique, Hifzur Rahman; Parray, Aijaz; Tarapore, Rohinton S.; Wang, Lei; Mukhtar, Hasan; Karnes, R. Jeffery; Deng, Yibin; Konety, Badrinath R.; Saleem, Mohammad

    2013-01-01

    For advanced prostate cancer (CaP), the progression of tumors to the state of chemoresistance and paucity of knowledge about the mechanism of chemoresistance are major stumbling blocks in the management of this disease. Here, we provide compelling evidence that BMI1 polycomb group protein and a stem cell factor plays a crucial role in determining the fate of tumors vis-à-vis chemotherapy. We show that progressive increase in the levels of BMI1 occurs during the progression of CaP disease in humans. We show that BMI1-rich tumor cells are non-responsive to chemotherapy whereas BMI1-silenced tumor cells are responsive to therapy. By employing microarray, ChIP, immunoblot and Luciferase reporter assays, we identified a unique mechanism through which BMI1 rescues tumor cells from chemotherapy. We found that BMI1 regulates (i) activity of TCF4 transcriptional factor and (ii) binding of TCF4 to the promoter region of anti-apoptotic BCL2 gene. Notably, an increased TCF4 occupancy on BCL2 gene was observed in prostatic tissues exhibiting high BMI1 levels. Using tumor cells other than CaP, we also showed that regulation of TCF4-mediated BCL2 by BMI1 is universal. It is noteworthy that forced expression of BMI1 was observed to drive normal cells to hyperproliferative mode. We show that targeting BMI1 improves the outcome of docetaxel therapy in animal models bearing chemoresistant prostatic tumors. We suggest that BMI1 could be exploited as a potential molecular target for therapeutics to treat chemoresistant tumors. PMID:23671559

  2. BMI1 polycomb group protein acts as a master switch for growth and death of tumor cells: regulates TCF4-transcriptional factor-induced BCL2 signaling.

    PubMed

    Siddique, Hifzur Rahman; Parray, Aijaz; Tarapore, Rohinton S; Wang, Lei; Mukhtar, Hasan; Karnes, R Jeffery; Deng, Yibin; Konety, Badrinath R; Saleem, Mohammad

    2013-01-01

    For advanced prostate cancer (CaP), the progression of tumors to the state of chemoresistance and paucity of knowledge about the mechanism of chemoresistance are major stumbling blocks in the management of this disease. Here, we provide compelling evidence that BMI1 polycomb group protein and a stem cell factor plays a crucial role in determining the fate of tumors vis-à-vis chemotherapy. We show that progressive increase in the levels of BMI1 occurs during the progression of CaP disease in humans. We show that BMI1-rich tumor cells are non-responsive to chemotherapy whereas BMI1-silenced tumor cells are responsive to therapy. By employing microarray, ChIP, immunoblot and Luciferase reporter assays, we identified a unique mechanism through which BMI1 rescues tumor cells from chemotherapy. We found that BMI1 regulates (i) activity of TCF4 transcriptional factor and (ii) binding of TCF4 to the promoter region of anti-apoptotic BCL2 gene. Notably, an increased TCF4 occupancy on BCL2 gene was observed in prostatic tissues exhibiting high BMI1 levels. Using tumor cells other than CaP, we also showed that regulation of TCF4-mediated BCL2 by BMI1 is universal. It is noteworthy that forced expression of BMI1 was observed to drive normal cells to hyperproliferative mode. We show that targeting BMI1 improves the outcome of docetaxel therapy in animal models bearing chemoresistant prostatic tumors. We suggest that BMI1 could be exploited as a potential molecular target for therapeutics to treat chemoresistant tumors.

  3. Short germ insects utilize both the ancestral and derived mode of Polycomb group-mediated epigenetic silencing of Hox genes.

    PubMed

    Matsuoka, Yuji; Bando, Tetsuya; Watanabe, Takahito; Ishimaru, Yoshiyasu; Noji, Sumihare; Popadić, Aleksandar; Mito, Taro

    2015-05-06

    In insect species that undergo long germ segmentation, such as Drosophila, all segments are specified simultaneously at the early blastoderm stage. As embryogenesis progresses, the expression boundaries of Hox genes are established by repression of gap genes, which is subsequently replaced by Polycomb group (PcG) silencing. At present, however, it is not known whether patterning occurs this way in a more ancestral (short germ) mode of embryogenesis, where segments are added gradually during posterior elongation. In this study, two members of the PcG family, Enhancer of zeste (E(z)) and Suppressor of zeste 12 (Su(z)12), were analyzed in the short germ cricket, Gryllus bimaculatus. Results suggest that although stepwise negative regulation by gap and PcG genes is present in anterior members of the Hox cluster, it does not account for regulation of two posterior Hox genes, abdominal-A (abd-A) and Abdominal-B (Abd-B). Instead, abd-A and Abd-B are predominantly regulated by PcG genes, which is the mode present in vertebrates. These findings suggest that an intriguing transition of the PcG-mediated silencing of Hox genes may have occurred during animal evolution. The ancestral bilaterian state may have resembled the current vertebrate mode of regulation, where PcG-mediated silencing of Hox genes occurs before their expression is initiated and is responsible for the establishment of individual expression domains. Then, during insect evolution, the repression by transcription factors may have been acquired in anterior Hox genes of short germ insects, while PcG silencing was maintained in posterior Hox genes.

  4. Short germ insects utilize both the ancestral and derived mode of Polycomb group-mediated epigenetic silencing of Hox genes

    PubMed Central

    Matsuoka, Yuji; Bando, Tetsuya; Watanabe, Takahito; Ishimaru, Yoshiyasu; Noji, Sumihare; Popadić, Aleksandar; Mito, Taro

    2015-01-01

    In insect species that undergo long germ segmentation, such as Drosophila, all segments are specified simultaneously at the early blastoderm stage. As embryogenesis progresses, the expression boundaries of Hox genes are established by repression of gap genes, which is subsequently replaced by Polycomb group (PcG) silencing. At present, however, it is not known whether patterning occurs this way in a more ancestral (short germ) mode of embryogenesis, where segments are added gradually during posterior elongation. In this study, two members of the PcG family, Enhancer of zeste (E(z)) and Suppressor of zeste 12 (Su(z)12), were analyzed in the short germ cricket, Gryllus bimaculatus. Results suggest that although stepwise negative regulation by gap and PcG genes is present in anterior members of the Hox cluster, it does not account for regulation of two posterior Hox genes, abdominal-A (abd-A) and Abdominal-B (Abd-B). Instead, abd-A and Abd-B are predominantly regulated by PcG genes, which is the mode present in vertebrates. These findings suggest that an intriguing transition of the PcG-mediated silencing of Hox genes may have occurred during animal evolution. The ancestral bilaterian state may have resembled the current vertebrate mode of regulation, where PcG-mediated silencing of Hox genes occurs before their expression is initiated and is responsible for the establishment of individual expression domains. Then, during insect evolution, the repression by transcription factors may have been acquired in anterior Hox genes of short germ insects, while PcG silencing was maintained in posterior Hox genes. PMID:25948756

  5. white+ transgene insertions presenting a dorsal/ventral pattern define a single cluster of homeobox genes that is silenced by the polycomb-group proteins in Drosophila melanogaster.

    PubMed Central

    Netter, S; Fauvarque, M O; Diez del Corral, R; Dura, J M; Coen, D

    1998-01-01

    We used the white gene as an enhancer trap and reporter of chromatin structure. We collected white+ transgene insertions presenting a peculiar pigmentation pattern in the eye: white expression is restricted to the dorsal half of the eye, with a clear-cut dorsal/ventral (D/V) border. This D/V pattern is stable and heritable, indicating that phenotypic expression of the white reporter reflects positional information in the developing eye. Localization of these transgenes led us to identify a unique genomic region encompassing 140 kb in 69D1-3 subject to this D/V effect. This region contains at least three closely related homeobox-containing genes that are constituents of the iroquois complex (IRO-C). IRO-C genes are coordinately regulated and implicated in similar developmental processes. Expression of these genes in the eye is regulated by the products of the Polycomb-group (Pc-G) and trithorax-group (trx-G) genes but is not modified by classical modifiers of position-effect variegation. Our results, together with the report of a Pc-G binding site in 69D, suggest that we have identified a novel cluster of target genes for the Pc-G and trx-G products. We thus propose that ventral silencing of the whole IRO-C in the eye occurs at the level of chromatin structure in a manner similar to that of the homeotic gene complexes, perhaps by local compaction of the region into a heterochromatin-like structure involving the Pc-G products. PMID:9584101

  6. Chromatin-Bound IκBα Regulates a Subset of Polycomb Target Genes in Differentiation and Cancer

    PubMed Central

    Mulero, María Carmen; Ferres-Marco, Dolors; Islam, Abul; Margalef, Pol; Pecoraro, Matteo; Toll, Agustí; Drechsel, Nils; Charneco, Cristina; Davis, Shelly; Bellora, Nicolás; Gallardo, Fernando; López-Arribillaga, Erika; Asensio-Juan, Elena; Rodilla, Verónica; González, Jessica; Iglesias, Mar; Shih, Vincent; Albà, M. Mar; Di Croce, Luciano; Hoffmann, Alexander; Miyamoto, Shigeki; Villà-Freixa, Jordi; López-Bigas, Nuria; Keyes, William M.; Domínguez, María; Bigas, Anna; Espinosa, Lluís

    2014-01-01

    Summary IκB proteins are the primary inhibitors of NF-κB. Here, we demonstrate that sumoylated and phosphorylated IκBα accumulates in the nucleus of keratinocytes and interacts with histones H2A and H4 at the regulatory region of HOX and IRX genes. Chromatin-bound IκBα modulates Polycomb recruitment and imparts their competence to be activated by TNFα. Mutations in the Drosophila IκBα gene cactus enhance the homeotic phenotype of Polycomb mutants, which is not counteracted by mutations in dorsal/NF-κB. Oncogenic transformation of keratinocytes results in cytoplasmic IκBα translocation associated with a massive activation of Hox. Accumulation of cytoplasmic IκBα was found in squamous cell carcinoma (SCC) associated with IKK activation and HOX upregulation. PMID:23850221

  7. Chromatin-bound IκBα regulates a subset of polycomb target genes in differentiation and cancer.

    PubMed

    Mulero, María Carmen; Ferres-Marco, Dolors; Islam, Abul; Margalef, Pol; Pecoraro, Matteo; Toll, Agustí; Drechsel, Nils; Charneco, Cristina; Davis, Shelly; Bellora, Nicolás; Gallardo, Fernando; López-Arribillaga, Erika; Asensio-Juan, Elena; Rodilla, Verónica; González, Jessica; Iglesias, Mar; Shih, Vincent; Mar Albà, M; Di Croce, Luciano; Hoffmann, Alexander; Miyamoto, Shigeki; Villà-Freixa, Jordi; López-Bigas, Nuria; Keyes, William M; Domínguez, María; Bigas, Anna; Espinosa, Lluís

    2013-08-12

    IκB proteins are the primary inhibitors of NF-κB. Here, we demonstrate that sumoylated and phosphorylated IκBα accumulates in the nucleus of keratinocytes and interacts with histones H2A and H4 at the regulatory region of HOX and IRX genes. Chromatin-bound IκBα modulates Polycomb recruitment and imparts their competence to be activated by TNFα. Mutations in the Drosophila IκBα gene cactus enhance the homeotic phenotype of Polycomb mutants, which is not counteracted by mutations in dorsal/NF-κB. Oncogenic transformation of keratinocytes results in cytoplasmic IκBα translocation associated with a massive activation of Hox. Accumulation of cytoplasmic IκBα was found in squamous cell carcinoma (SCC) associated with IKK activation and HOX upregulation.

  8. Adhesive pad differentiation in Drosophila melanogaster depends on the Polycomb group gene Su(z)2.

    PubMed

    Hüsken, Mirko; Hufnagel, Kim; Mende, Katharina; Appel, Esther; Meyer, Heiko; Peisker, Henrik; Tögel, Markus; Wang, Shuoshuo; Wolff, Jonas; Gorb, Stanislav N; Paululat, Achim

    2015-04-15

    The ability of many insects to walk on vertical smooth surfaces such as glass or even on the ceiling has fascinated biologists for a long time, and has led to the discovery of highly specialized adhesive organs located at the distal end of the animals' legs. So far, research has primarily focused on structural and ultrastructural investigations leading to a deeper understanding of adhesive organ functionality and to the development of new bioinspired materials. Genetic approaches, e.g. the analysis of mutants, to achieve a better understanding of adhesive organ differentiation have not been used so far. Here, we describe the first Drosophila melanogaster mutant that develops malformed adhesive organs, resulting in a complete loss of climbing ability on vertical smooth surfaces. Interestingly, these mutants fail to make close contact between the setal tips and the smooth surface, a crucial condition for wet adhesion mediated by capillary forces. Instead, these flies walk solely on their claws. Moreover, we were able to show that the mutation is caused by a P-element insertion into the Su(z)2 gene locus. Remobilization of the P-element restores climbing ability. Furthermore, we provide evidence that the P-element insertion results in an artificial Su(z)2 transcript, which most likely causes a gain-of-function mutation. We presume that this transcript causes deregulation of yet unknown target genes involved in pulvilli differentiation. Our results nicely demonstrate that the genetically treatable model organism Drosophila is highly suitable for future investigations on adhesive organ differentiation.

  9. Ectopic expression of DREF induces DNA synthesis, apoptosis, and unusual morphogenesis in the Drosophila eye imaginal disc: possible interaction with Polycomb and trithorax group proteins.

    PubMed

    Hirose, F; Ohshima, N; Shiraki, M; Inoue, Y H; Taguchi, O; Nishi, Y; Matsukage, A; Yamaguchi, M

    2001-11-01

    The promoters of Drosophila genes encoding DNA replication-related proteins contain transcription regulatory element DRE (5'-TATCGATA) in addition to E2F recognition sites. A specific DRE-binding factor, DREF, positively regulates DRE-containing genes. In addition, it has been reported that DREF can bind to a sequence in the hsp70 scs' chromatin boundary element that is also recognized by boundary element-associated factor, and thus DREF may participate in regulating insulator activity. To examine DREF function in vivo, we established transgenic flies in which ectopic expression of DREF was targeted to the eye imaginal discs. Adult flies expressing DREF exhibited a severe rough eye phenotype. Expression of DREF induced ectopic DNA synthesis in the cells behind the morphogenetic furrow, which are normally postmitotic, and abolished photoreceptor specifications of R1, R6, and R7. Furthermore, DREF expression caused apoptosis in the imaginal disc cells in the region where commitment to R1/R6 cells takes place, suggesting that failure of differentiation of R1/R6 photoreceptor cells might cause apoptosis. The DREF-induced rough eye phenotype was suppressed by a half-dose reduction of the E2F gene, one of the genes regulated by DREF, indicating that the DREF overexpression phenotype is useful to screen for modifiers of DREF activity. Among Polycomb/trithorax group genes, we found that a half-dose reduction of some of the trithorax group genes involved in determining chromatin structure or chromatin remodeling (brahma, moira, and osa) significantly suppressed and that reduction of Distal-less enhanced the DREF-induced rough eye phenotype. The results suggest a possibility that DREF activity might be regulated by protein complexes that play a role in modulating chromatin structure. Genetic crosses of transgenic flies expressing DREF to a collection of Drosophila deficiency stocks allowed us to identify several genomic regions, deletions of which caused enhancement or

  10. Live-cell single-molecule tracking reveals co-recognition of H3K27me3 and DNA targets polycomb Cbx7-PRC1 to chromatin

    PubMed Central

    Zhen, Chao Yu; Tatavosian, Roubina; Huynh, Thao Ngoc; Duc, Huy Nguyen; Das, Raibatak; Kokotovic, Marko; Grimm, Jonathan B; Lavis, Luke D; Lee, Jun; Mejia, Frances J; Li, Yang; Yao, Tingting; Ren, Xiaojun

    2016-01-01

    The Polycomb PRC1 plays essential roles in development and disease pathogenesis. Targeting of PRC1 to chromatin is thought to be mediated by the Cbx family proteins (Cbx2/4/6/7/8) binding to histone H3 with a K27me3 modification (H3K27me3). Despite this prevailing view, the molecular mechanisms of targeting remain poorly understood. Here, by combining live-cell single-molecule tracking (SMT) and genetic engineering, we reveal that H3K27me3 contributes significantly to the targeting of Cbx7 and Cbx8 to chromatin, but less to Cbx2, Cbx4, and Cbx6. Genetic disruption of the complex formation of PRC1 facilitates the targeting of Cbx7 to chromatin. Biochemical analyses uncover that the CD and AT-hook-like (ATL) motif of Cbx7 constitute a functional DNA-binding unit. Live-cell SMT of Cbx7 mutants demonstrates that Cbx7 is targeted to chromatin by co-recognizing of H3K27me3 and DNA. Our data suggest a novel hierarchical cooperation mechanism by which histone modifications and DNA coordinate to target chromatin regulatory complexes. DOI: http://dx.doi.org/10.7554/eLife.17667.001 PMID:27723458

  11. Polycomb Group-Dependent, Heterochromatin Protein 1-Independent, Chromatin Structures Silence Retrotransposons in Somatic Tissues Outside Ovaries

    PubMed Central

    Dufourt, J.; Brasset, E.; Desset, S.; Pouchin, P.; Vaury, C.

    2011-01-01

    Somatic cells are equipped with different silencing mechanisms that protect the genome against retrotransposons. In Drosophila melanogaster, a silencing pathway implicating the argonaute protein PIWI represses retrotransposons in cells surrounding the oocyte, whereas a PIWI-independent pathway is involved in other somatic tissues. Here, we show that these two silencing mechanisms result in distinct chromatin structures. Using sensor transgenes, we found that, in somatic tissues outside of the ovaries, these transgenes adopt a heterochromatic configuration implicating hypermethylation of H3K9 and K27. We identified the Polycomb repressive complexes (PRC1 and 2), but not heterochromatin protein 1 to be necessary factors for silencing. Once established, the compact structure is stably maintained through cell divisions. By contrast, in cells where the silencing is PIWI-dependent, the transgenes display an open and labile chromatin structure. Our data suggest that a post-transcriptional gene silencing (PTGS) mechanism is responsible for the repression in the ovarian somatic cells, whereas a mechanism that couples PTGS to transcriptional gene silencing operates to silence retrotransposons in the other somatic tissues. PMID:21908513

  12. Molecular architecture of polycomb repressive complexes

    PubMed Central

    Chittock, Emily C.; Latwiel, Sebastian; Miller, Thomas C.R.

    2017-01-01

    The polycomb group (PcG) proteins are a large and diverse family that epigenetically repress the transcription of key developmental genes. They form three broad groups of polycomb repressive complexes (PRCs) known as PRC1, PRC2 and Polycomb Repressive DeUBiquitinase, each of which modifies and/or remodels chromatin by distinct mechanisms that are tuned by having variable compositions of core and accessory subunits. Until recently, relatively little was known about how the various PcG proteins assemble to form the PRCs; however, studies by several groups have now allowed us to start piecing together the PcG puzzle. Here, we discuss some highlights of recent PcG structures and the insights they have given us into how these complexes regulate transcription through chromatin. PMID:28202673

  13. Arabidopsis Flower and Embryo Developmental Genes are Repressed in Seedlings by Different Combinations of Polycomb Group Proteins in Association with Distinct Sets of Cis-regulatory Elements

    PubMed Central

    Liu, Jian; Zhang, Lei; He, Chongsheng; Shen, Wen-Hui; Jin, Hong; Xu, Lin; Zhang, Yijing

    2016-01-01

    Polycomb repressive complexes (PRCs) play crucial roles in transcriptional repression and developmental regulation in both plants and animals. In plants, depletion of different members of PRCs causes both overlapping and unique phenotypic defects. However, the underlying molecular mechanism determining the target specificity and functional diversity is not sufficiently characterized. Here, we quantitatively compared changes of tri-methylation at H3K27 in Arabidopsis mutants deprived of various key PRC components. We show that CURLY LEAF (CLF), a major catalytic subunit of PRC2, coordinates with different members of PRC1 in suppression of distinct plant developmental programs. We found that expression of flower development genes is repressed in seedlings preferentially via non-redundant role of CLF, which specifically associated with LIKE HETEROCHROMATIN PROTEIN1 (LHP1). In contrast, expression of embryo development genes is repressed by PRC1-catalytic core subunits AtBMI1 and AtRING1 in common with PRC2-catalytic enzymes CLF or SWINGER (SWN). This context-dependent role of CLF corresponds well with the change in H3K27me3 profiles, and is remarkably associated with differential co-occupancy of binding motifs of transcription factors (TFs), including MADS box and ABA-related factors. We propose that different combinations of PRC members distinctively regulate different developmental programs, and their target specificity is modulated by specific TFs. PMID:26760036

  14. Arabidopsis Flower and Embryo Developmental Genes are Repressed in Seedlings by Different Combinations of Polycomb Group Proteins in Association with Distinct Sets of Cis-regulatory Elements.

    PubMed

    Wang, Hua; Liu, Chunmei; Cheng, Jingfei; Liu, Jian; Zhang, Lei; He, Chongsheng; Shen, Wen-Hui; Jin, Hong; Xu, Lin; Zhang, Yijing

    2016-01-01

    Polycomb repressive complexes (PRCs) play crucial roles in transcriptional repression and developmental regulation in both plants and animals. In plants, depletion of different members of PRCs causes both overlapping and unique phenotypic defects. However, the underlying molecular mechanism determining the target specificity and functional diversity is not sufficiently characterized. Here, we quantitatively compared changes of tri-methylation at H3K27 in Arabidopsis mutants deprived of various key PRC components. We show that CURLY LEAF (CLF), a major catalytic subunit of PRC2, coordinates with different members of PRC1 in suppression of distinct plant developmental programs. We found that expression of flower development genes is repressed in seedlings preferentially via non-redundant role of CLF, which specifically associated with LIKE HETEROCHROMATIN PROTEIN1 (LHP1). In contrast, expression of embryo development genes is repressed by PRC1-catalytic core subunits AtBMI1 and AtRING1 in common with PRC2-catalytic enzymes CLF or SWINGER (SWN). This context-dependent role of CLF corresponds well with the change in H3K27me3 profiles, and is remarkably associated with differential co-occupancy of binding motifs of transcription factors (TFs), including MADS box and ABA-related factors. We propose that different combinations of PRC members distinctively regulate different developmental programs, and their target specificity is modulated by specific TFs.

  15. RYBP stimulates PRC1 to shape chromatin-based communication between Polycomb repressive complexes

    PubMed Central

    Rose, Nathan R; King, Hamish W; Blackledge, Neil P; Fursova, Nadezda A; Ember, Katherine JI; Fischer, Roman; Kessler, Benedikt M; Klose, Robert J

    2016-01-01

    Polycomb group (PcG) proteins function as chromatin-based transcriptional repressors that are essential for normal gene regulation during development. However, how these systems function to achieve transcriptional regulation remains very poorly understood. Here, we discover that the histone H2AK119 E3 ubiquitin ligase activity of Polycomb repressive complex 1 (PRC1) is defined by the composition of its catalytic subunits and is highly regulated by RYBP/YAF2-dependent stimulation. In mouse embryonic stem cells, RYBP plays a central role in shaping H2AK119 mono-ubiquitylation at PcG targets and underpins an activity-based communication between PRC1 and Polycomb repressive complex 2 (PRC2) which is required for normal histone H3 lysine 27 trimethylation (H3K27me3). Without normal histone modification-dependent communication between PRC1 and PRC2, repressive Polycomb chromatin domains can erode, rendering target genes susceptible to inappropriate gene expression signals. This suggests that activity-based communication and histone modification-dependent thresholds create a localized form of epigenetic memory required for normal PcG chromatin domain function in gene regulation. DOI: http://dx.doi.org/10.7554/eLife.18591.001 PMID:27705745

  16. The Polycomb Group Protein L3mbtl2 Assembles an Atypical PRC1-Family Complex that Is Essential in Pluripotent Stem Cells and Early Development

    PubMed Central

    Qin, Jinzhong; Whyte, Warren A.; Anderssen, Endre; Apostolou, Effie; Chen, Hsu-Hsin; Akbarian, Schahram; Bronson, Roderick T.; Hochedlinger, Konrad; Ramaswamy, Sridhar; Young, Richard A.; Hock, Hanno

    2013-01-01

    SUMMARY L3mbtl2 has been implicated in transcriptional repression and chromatin compaction but its biological function has not been defined. Here we show that disruption of L3mbtl2 results in embryonic lethality with failure of gastrulation. This correlates with compromised proliferation and abnormal differentiation of L3mbtl2−/− embryonic stem (ES) cells. L3mbtl2 regulates genes by recruiting a Polycomb Repressive Complex1 (PRC1)-related complex, resembling the previously described E2F6-complex, and including G9A, Hdac1, and Ring1b. Presence of L3mbtl2 at target genes is associated with H3K9-dimethylation, low histone-acetylation, and H2AK119-ubiquitination, but the latter is neither dependent on L3mbtl2 nor sufficient for repression. Genome wide studies revealed that the L3mbtl2-dependent complex predominantly regulates genes not bound by canonical PRC1 and PRC2. However, some developmental regulators are repressed by the combined activity of all three complexes. Together, we have uncovered a highly selective, essential role for an atypical PRC1-family complex in ES cells and early development. PMID:22770845

  17. The Polycomb group protein RING1B is overexpressed in ductal breast carcinoma and is required to sustain FAK steady state levels in breast cancer epithelial cells

    PubMed Central

    Bosch, Almudena; Panoutsopoulou, Konstantina; Corominas, Josep Maria; Gimeno, Ramón; Moreno-Bueno, Gema; Martín-Caballero, Juan; Morales, Saleta; Lobato, Tania; Martínez-Romero, Carles; Farias, Eduardo F.; Mayol, Xavier; Cano, Amparo; Hernández-Muáoz, Inmaculada

    2014-01-01

    In early stages of metastasis malignant cells must acquire phenotypic changes to enhance their migratory behavior and their ability to breach the matrix surrounding tumors and blood vessel walls. Epigenetic regulation of gene expression allows the acquisition of these features that, once tumoral cells have escape from the primary tumor, can be reverted. Here we report that the expression of the Polycomb epigenetic repressor Ring1B is enhanced in tumoral cells that invade the stroma in human ductal breast carcinoma and its expression is coincident with that of Fak in these tumors. Ring1B knockdown in breast cancer cell lines revealed that Ring1B is required to sustain Fak expression in basal conditions as well as in Tgfβ-treated cells. Functionally, endogenous Ring1B is required for cell migration and invasion in vitro and for in vivo invasion of the mammary fat pad by tumoral cells. Finally we identify p63 as a target of Ring1B to regulate Fak expression: Ring1B depletion results in enhanced p63 expression, which in turns represses Fak expression. Importantly, Fak downregulation upon Ring1B depletion is dependent on p63 expression. Our findings provide new insights in the biology of the breast carcinoma and open new avenues for breast cancer prognosis and therapy. PMID:24742605

  18. The Polycomb group (PcG) protein EZH2 supports the survival of PAX3-FOXO1 alveolar rhabdomyosarcoma by repressing FBXO32 (Atrogin1/MAFbx).

    PubMed

    Ciarapica, R; De Salvo, M; Carcarino, E; Bracaglia, G; Adesso, L; Leoncini, P P; Dall'Agnese, A; Walters, Z S; Verginelli, F; De Sio, L; Boldrini, R; Inserra, A; Bisogno, G; Rosolen, A; Alaggio, R; Ferrari, A; Collini, P; Locatelli, M; Stifani, S; Screpanti, I; Rutella, S; Yu, Q; Marquez, V E; Shipley, J; Valente, S; Mai, A; Miele, L; Puri, P L; Locatelli, F; Palacios, D; Rota, R

    2014-08-07

    The Polycomb group (PcG) proteins regulate stem cell differentiation via the repression of gene transcription, and their deregulation has been widely implicated in cancer development. The PcG protein Enhancer of Zeste Homolog 2 (EZH2) works as a catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) by methylating lysine 27 on histone H3 (H3K27me3), a hallmark of PRC2-mediated gene repression. In skeletal muscle progenitors, EZH2 prevents an unscheduled differentiation by repressing muscle-specific gene expression and is downregulated during the course of differentiation. In rhabdomyosarcoma (RMS), a pediatric soft-tissue sarcoma thought to arise from myogenic precursors, EZH2 is abnormally expressed and its downregulation in vitro leads to muscle-like differentiation of RMS cells of the embryonal variant. However, the role of EZH2 in the clinically aggressive subgroup of alveolar RMS, characterized by the expression of PAX3-FOXO1 oncoprotein, remains unknown. We show here that EZH2 depletion in these cells leads to programmed cell death. Transcriptional derepression of F-box protein 32 (FBXO32) (Atrogin1/MAFbx), a gene associated with muscle homeostasis, was evidenced in PAX3-FOXO1 RMS cells silenced for EZH2. This phenomenon was associated with reduced EZH2 occupancy and H3K27me3 levels at the FBXO32 promoter. Simultaneous knockdown of FBXO32 and EZH2 in PAX3-FOXO1 RMS cells impaired the pro-apoptotic response, whereas the overexpression of FBXO32 facilitated programmed cell death in EZH2-depleted cells. Pharmacological inhibition of EZH2 by either 3-Deazaneplanocin A or a catalytic EZH2 inhibitor mirrored the phenotypic and molecular effects of EZH2 knockdown in vitro and prevented tumor growth in vivo. Collectively, these results indicate that EZH2 is a key factor in the proliferation and survival of PAX3-FOXO1 alveolar RMS cells working, at least in part, by repressing FBXO32. They also suggest that the reducing activity of EZH2 could represent a novel

  19. New peptides of the polycomb group protein enhancer of zeste homolog 2 with the potential to induce cancer-reactive cytotoxic T lymphocytes in human leukocyte antigen-A2+ prostate cancer patients.

    PubMed

    Itoh, Yukoh; Komohara, Yoshihiro; Komatsu, Nobukazu; Minami, Takafumi; Saito, Koujiro; Noguchi, Masanori; Itoh, Kyogo; Harada, Mamoru

    2007-11-01

    The polycomb group protein enhancer of zeste homolog 2 (EZH2) is linked to aggressive prostate cancer and could be an appropriate target in specific immunotherapy. In this study, we attempted to identify EZH2-derived peptides that have the potential to generate cancer-reactive cytotoxic T lymphocytes (CTLs) in human leukocyte antigen (HLA)-A2+ prostate cancer patients. Twelve EZH2-derived peptides were prepared based on the HLA-A2 binding motif. These peptide candidates were screened first by their ability to be recognized by immunoglobulin G (IgG), and then by their ability to induce peptide-specific cytotoxic T lymphocytes (CTLs). As a result, five EZH2 peptides recognized by IgG (EZH2 120-128, EZH2 165-174, EZH2 569-577, EZH2 665-674, and EZH2 699-708) were frequently detected in the plasma of prostate cancer patients. Among them, the EZH2 120-128 and EZH2 165-174 peptides effectively induced HLA-A2-restricted and cancer-reactive CTLs from prostate cancer patients. The cytotoxicity was mainly dependent on EZH2 peptide-specific and HLA-A2-restricted CD8+ T cells. These results indicate that these EZH2 120-128 and EZH2 165-174 peptides could be promising candidates in peptide-based immunotherapy for HLA-A2+ prostate cancer patients.

  20. Mammalian homologues of the Polycomb-group gene Enhancer of zeste mediate gene silencing in Drosophila heterochromatin and at S. cerevisiae telomeres.

    PubMed Central

    Laible, G; Wolf, A; Dorn, R; Reuter, G; Nislow, C; Lebersorger, A; Popkin, D; Pillus, L; Jenuwein, T

    1997-01-01

    Gene silencing is required to stably maintain distinct patterns of gene expression during eukaryotic development and has been correlated with the induction of chromatin domains that restrict gene activity. We describe the isolation of human (EZH2) and mouse (Ezh1) homologues of the Drosophila Polycomb-group (Pc-G) gene Enhancer of zeste [E(z)], a crucial regulator of homeotic gene expression implicated in the assembly of repressive protein complexes in chromatin. Mammalian homologues of E(z) are encoded by two distinct loci in mouse and man, and the two murine Ezh genes display complementary expression profiles during mouse development. The E(z) gene family reveals a striking functional conservation in mediating gene repression in eukaryotic chromatin: extra gene copies of human EZH2 or Drosophila E(z) in transgenic flies enhance position effect variegation of the heterochromatin-associated white gene, and expression of either human EZH2 or murine Ezh1 restores gene repression in Saccharomyces cerevisiae mutants that are impaired in telomeric silencing. Together, these data provide a functional link between Pc-G-dependent gene repression and inactive chromatin domains, and indicate that silencing mechanism(s) may be broadly conserved in eukaryotes. PMID:9214638

  1. Polycomb-group protein SlMSI1 represses the expression of fruit-ripening genes to prolong shelf life in tomato

    PubMed Central

    Liu, Dan-Dan; Zhou, Li-Jie; Fang, Mou-Jing; Dong, Qing-Long; An, Xiu-Hong; You, Chun-Xiang; Hao, Yu-Jin

    2016-01-01

    Polycomb-group (PcG) protein MULTICOPY SUPPRESSOR OF IRA1 (MSI1) protein is an evolutionarily conserved developmental suppressor and plays a crucial role in regulating epigenetic modulations. However, the potential role and function of MSI1 in fleshy fruits remain unknown. In this study, SlMSI1 was cloned and transformed into tomato to explore its function. The quantitative real-time PCR results showed that SlMSI1 was highly expressed in flowers and fruits and that its transcript and protein levels were significantly decreased in fruits after the breaker stage. Additionally, SlMSI1-overexpressing transgenic tomatoes displayed abnormal non-ripening fruit formation, whereas its suppression promoted fruit ripening in transgenic tomatoes. Quantitative real-time PCR assays also showed that RIN and its regulons were decreased in SlMSI1 overexpression transgenic tomato fruits. Furthermore, RNA-seq analysis demonstrated that SlMSI1 inhibits fruit ripening by negatively regulating a large set of fruit-ripening genes in addition to RIN and its regulons. Finally, genetic manipulation of SlMSI1 and RIN successfully prolonged the fruit shelf life by regulating the fruit-ripening genes in tomato. Our findings reveal a novel regulatory function of SlMSI1 in fruit ripening and provide a new regulator that may be useful for genetic engineering and modification of fruit shelf life. PMID:27558543

  2. Binding of the RING polycomb proteins to specific target genes in complex with the grainyhead-like family of developmental transcription factors.

    PubMed

    Tuckfield, Annabel; Clouston, David R; Wilanowski, Tomasz M; Zhao, Lin-Lin; Cunningham, John M; Jane, Stephen M

    2002-03-01

    The Polycomb group (PcG) of proteins represses homeotic gene expression through the assembly of multiprotein complexes on key regulatory elements. The mechanisms mediating complex assembly have remained enigmatic since most PcG proteins fail to bind DNA. We now demonstrate that the human PcG protein dinG interacts with CP2, a mammalian member of the grainyhead-like family of transcription factors, in vitro and in vivo. The functional consequence of this interaction is repression of CP2-dependent transcription. The CP2-dinG interaction is conserved in evolution with the Drosophila factor grainyhead binding to dring, the fly homologue of dinG. Electrophoretic mobility shift assays demonstrate that the grh-dring complex forms on regulatory elements of genes whose expression is repressed by grh but not on elements where grh plays an activator role. These observations reveal a novel mechanism by which PcG proteins may be anchored to specific regulatory elements in developmental genes.

  3. Zeste maintains repression of Ubx transgenes: Support for a new model of polycomb repression

    SciTech Connect

    Hur, Man-Wook; Laney, Jeffrey D.; Jeon, Sang-Hack; Ali, Janann; Biggin, Mark D.

    2001-09-01

    During late embryogenesis, the expression domains of homeotic genes are maintained by two groups of ubiquitously expressed regulators: the Polycomb repressors and the Trithorax activators. It is not known how the activities of the two maintenance systems are initially targeted to the correct genes. Zeste and GAGA are sequence specific DNA binding proteins previously shown to be Trithorax group activators of the homeotic gene Ultrabithorax (Ubx). Here we demonstrate that Zeste and GAGA DNA binding sites at the proximal promoter are also required to maintain, but not to initiate, repression of Ubx. Further, the repression mediated by Zeste DNA binding site is abolished in zeste null embryos. These data imply that Zeste and probably GAGA mediate Polycomb repression. We present a model in which the dual transcriptional activities of Zeste and GAGA are an essential component of the mechanism that chooses which maintenance system is to be targeted to a given promoter.

  4. The Polycomb group protein CLF emerges as a specific tri-methylase of H3K27 regulating gene expression and development in Physcomitrella patens.

    PubMed

    Pereman, Idan; Mosquna, Assaf; Katz, Aviva; Wiedemann, Gertrud; Lang, Daniel; Decker, Eva L; Tamada, Yosuke; Ishikawa, Takaaki; Nishiyama, Tomoaki; Hasebe, Mitsuyasu; Reski, Ralf; Ohad, Nir

    2016-07-01

    Packaging of eukaryotic DNA largely depends on histone modifications that affect the accessibility of DNA to transcriptional regulators, thus controlling gene expression. The Polycomb group (PcG) chromatin remodeling complex deposits a methyl group on lysine 27 of histone 3 leading to repressed gene expression. Plants encode homologs of the Enhancer of zeste (E(z)), a component of the PcG complex from Drosophila, one of which is a SET domain protein designated CURLY LEAF (CLF). Although this SET domain protein exhibits a strong correlation with the presence of the H3K27me3 mark in plants, the methyl-transferase activity and specificity of its SET domain have not been directly tested in-vivo. Using the evolutionary early-diverged land plant model species Physcomitrella patens we show that abolishment of a single copy gene PpCLF, as well as an additional member of the PcG complex, FERTILIZATION-INDEPENDENT ENDOSPERM (PpFIE), results in a specific loss of tri-methylation of H3K27. Using site-directed mutagenesis of key residues, we revealed that H3K27 tri-methylation is mediated by the SET domain of the CLF protein. Moreover, the abolishment of H3K27me3 led to enhanced expression of transcription factor genes. This in turn led to the development of fertilization-independent sporophyte-like structures, as observed in PpCLF and PpFIE null mutants. Overall, our results demonstrate the role of PpCLF as a SET protein in tri-methylation of H3K27 in-vivo and the importance of this modification in regulating the expression of transcription factor genes involved in developmental programs of P. patens.

  5. Mechanisms guiding Polycomb activities during gene silencing in Arabidopsis thaliana

    PubMed Central

    He, Chongsheng; Huang, Hai; Xu, Lin

    2013-01-01

    Polycomb group (PcG) proteins act in an evolutionarily conserved epigenetic pathway that regulates chromatin structures in plants and animals, repressing many developmentally important genes by modifying histones. PcG proteins can form at least two multiprotein complexes: Polycomb Repressive Complexes 1 and 2 (PRC1 and PRC2, respectively). The functions of Arabidopsis thaliana PRCs have been characterized in multiple stages of development and have diverse roles in response to environmental stimuli. Recently, the mechanism that precisely regulates Arabidopsis PcG activity was extensively studied. In this review, we summarize recent discoveries in the regulations of PcG at the three different layers: the recruitment of PRCs to specific target loci, the polyubiquitination and degradation of PRC2, and the antagonism of PRC2 activity by the Trithorax group proteins. Current knowledge indicates that the powerful activity of the PcG pathway is strictly controlled for specific silencing of target genes during plant development and in response to environmental stimuli. PMID:24312106

  6. Genome-wide profiling of histone H3 lysine 27 and lysine 4 trimethylation in multiple myeloma reveals the importance of Polycomb gene targeting and highlights EZH2 as a potential therapeutic target

    PubMed Central

    Párraga, Alba Atienza; Enroth, Stefan; Singh, Umashankar; Ungerstedt, Johanna; Österborg, Anders; Brown, Peter J.; Ma, Anqi; Jin, Jian; Nilsson, Kenneth; Öberg, Fredrik; Kalushkova, Antonia; Jernberg-Wiklund, Helena

    2016-01-01

    Multiple myeloma (MM) is a malignancy of the antibody-producing plasma cells. MM is a highly heterogeneous disease, which has hampered the identification of a common underlying mechanism for disease establishment as well as the development of targeted therapy. Here we present the first genome-wide profiling of histone H3 lysine 27 and lysine 4 trimethylation in MM patient samples, defining a common set of active H3K4me3-enriched genes and silent genes marked by H3K27me3 (H3K27me3 alone or bivalent) unique to primary MM cells, when compared to normal bone marrow plasma cells. Using this epigenome profile, we found increased silencing of H3K27me3 targets in MM patients at advanced stages of the disease, and the expression pattern of H3K27me3-marked genes correlated with poor patient survival. We also demonstrated that pharmacological inhibition of EZH2 had anti-myeloma effects in both MM cell lines and CD138+ MM patient cells. In addition, EZH2 inhibition decreased the global H3K27 methylation and induced apoptosis. Taken together, these data suggest an important role for the Polycomb repressive complex 2 (PRC2) in MM, and highlights the PRC2 component EZH2 as a potential therapeutic target in MM. PMID:26755663

  7. Polycomb Group Gene OsFIE2 Regulates Rice (Oryza sativa) Seed Development and Grain Filling via a Mechanism Distinct from Arabidopsis

    PubMed Central

    Nallamilli, Babi Ramesh Reddy; Zhang, Jian; Mujahid, Hana; Malone, Brandon M.; Bridges, Susan M.; Peng, Zhaohua

    2013-01-01

    Cereal endosperm represents 60% of the calories consumed by human beings worldwide. In addition, cereals also serve as the primary feedstock for livestock. However, the regulatory mechanism of cereal endosperm and seed development is largely unknown. Polycomb complex has been shown to play a key role in the regulation of endosperm development in Arabidopsis, but its role in cereal endosperm development remains obscure. Additionally, the enzyme activities of the polycomb complexes have not been demonstrated in plants. Here we purified the rice OsFIE2-polycomb complex using tandem affinity purification and demonstrated its specific H3 methyltransferase activity. We found that the OsFIE2 gene product was responsible for H3K27me3 production specifically in vivo. Genetic studies showed that a reduction of OsFIE2 expression led to smaller seeds, partially filled seeds, and partial loss of seed dormancy. Gene expression and proteomics analyses found that the starch synthesis rate limiting step enzyme and multiple storage proteins are down-regulated in OsFIE2 reduction lines. Genome wide ChIP–Seq data analysis shows that H3K27me3 is associated with many genes in the young seeds. The H3K27me3 modification and gene expression in a key helix-loop-helix transcription factor is shown to be regulated by OsFIE2. Our results suggest that OsFIE2-polycomb complex positively regulates rice endosperm development and grain filling via a mechanism highly different from that in Arabidopsis. PMID:23505380

  8. Polycomb group gene OsFIE2 regulates rice (Oryza sativa) seed development and grain filling via a mechanism distinct from Arabidopsis.

    PubMed

    Nallamilli, Babi Ramesh Reddy; Zhang, Jian; Mujahid, Hana; Malone, Brandon M; Bridges, Susan M; Peng, Zhaohua

    2013-01-01

    Cereal endosperm represents 60% of the calories consumed by human beings worldwide. In addition, cereals also serve as the primary feedstock for livestock. However, the regulatory mechanism of cereal endosperm and seed development is largely unknown. Polycomb complex has been shown to play a key role in the regulation of endosperm development in Arabidopsis, but its role in cereal endosperm development remains obscure. Additionally, the enzyme activities of the polycomb complexes have not been demonstrated in plants. Here we purified the rice OsFIE2-polycomb complex using tandem affinity purification and demonstrated its specific H3 methyltransferase activity. We found that the OsFIE2 gene product was responsible for H3K27me3 production specifically in vivo. Genetic studies showed that a reduction of OsFIE2 expression led to smaller seeds, partially filled seeds, and partial loss of seed dormancy. Gene expression and proteomics analyses found that the starch synthesis rate limiting step enzyme and multiple storage proteins are down-regulated in OsFIE2 reduction lines. Genome wide ChIP-Seq data analysis shows that H3K27me3 is associated with many genes in the young seeds. The H3K27me3 modification and gene expression in a key helix-loop-helix transcription factor is shown to be regulated by OsFIE2. Our results suggest that OsFIE2-polycomb complex positively regulates rice endosperm development and grain filling via a mechanism highly different from that in Arabidopsis.

  9. The Polycomb Group Protein EZH2 Impairs DNA Damage Repair Gene Expression in Human Uterine Fibroids1

    PubMed Central

    Yang, Qiwei; Nair, Sangeeta; Laknaur, Archana; Ismail, Nahed; Diamond, Michael P.; Al-Hendy, Ayman

    2016-01-01

    Uterine fibroids are benign, smooth muscle tumors that occur in approximately 70%–80% of women by age 50 yr. The cellular and molecular mechanism(s) by which uterine fibroids (UFs) develop are not fully understood. Accumulating evidence demonstrates that several genetic abnormalities, including deletions, rearrangements, translocations, as well as mutations, have been found in UFs. These genetic anomalies suggest that low DNA damage repair capacity may be involved in UF formation. The objective of this study was to determine whether expression levels of DNA damage repair-related genes were altered, and how they were regulated in the pathogenesis of UFs. Expression levels of DNA repair-related genes RAD51 and BRCA1 were deregulated in fibroid tissues as compared to adjacent myometrial tissues. Expression levels of chromatin protein enhancer of zeste homolog 2 (EZH2) were higher in a subset of fibroids as compared to adjacent myometrial tissues by both immunohistochemistry and Western blot analysis. Treatment with an inhibitor of EZH2 markedly increased expression levels of RAD51 and BRCA1 in fibroid cells and inhibited cell proliferation paired with cell cycle arrest. Restoring the expression of RAD51 and BRCA1 by treatment with EZH2 inhibitor was dependent on reducing the enrichment of trimethylation of histone 3 lysine 27 epigenetic mark in their promoter regions. This study reveals the important role of EZH2-regulated DNA damage-repair genes via histone methylation in fibroid biology, and may provide novel therapeutic targets for the medical treatment of women with symptomatic UFs. PMID:26888970

  10. Mammalian polycomb-like Pcl2/Mtf2 is a novel regulatory component of PRC2 that can differentially modulate polycomb activity both at the Hox gene cluster and at Cdkn2a genes.

    PubMed

    Li, Xiangzhi; Isono, Kyo-Ichi; Yamada, Daisuke; Endo, Takaho A; Endoh, Mitsuhiro; Shinga, Jun; Mizutani-Koseki, Yoko; Otte, Arie P; Casanova, Miguel; Kitamura, Hiroshi; Kamijo, Takehiko; Sharif, Jafar; Ohara, Osamu; Toyada, Tetsuro; Bernstein, Bradley E; Brockdorff, Neil; Koseki, Haruhiko

    2011-01-01

    The Polycomb group of proteins forms at least two distinct complexes designated the Polycomb repressive complex-1 (PRC1) and PRC2. These complexes cooperate to mediate transcriptional repression of their target genes, including the Hox gene cluster and the Cdkn2a genes. Mammalian Polycomb-like gene Pcl2/Mtf2 is expressed as four different isoforms, and the longest one contains a Tudor domain and two plant homeodomain (PHD) fingers. Pcl2 forms a complex with PRC2 and binds to Hox genes in a PRC2-dependent manner. We show that Pcl2 is a functional component of PRC2 and is required for PRC2-mediated Hox repression. Pcl2, however, exhibits a profound synergistic effect on PRC1-mediated Hox repression, which is not accompanied by major alterations in the local trimethylation of histone H3 at lysine 27 (H3K27me3) or PRC1 deposition. Pcl2 therefore functions in collaboration with both PRC2 and PRC1 to repress Hox gene expression during axial development. Paradoxically, in embryonic fibroblasts, Pcl2 is shown to activate the expression of Cdkn2a and promote cellular senescence, presumably by suppressing the catalytic activity of PRC2 locally. Taken together, we show that Pcl2 differentially regulates Polycomb-mediated repression of Hox and Cdkn2a genes. We therefore propose a novel role for Pcl2 to modify functional engagement of PRC2 and PRC1, which could be modulated by sensing cellular circumstances.

  11. Derepression of Polycomb targets during pancreatic organogenesis allows insulin-producing beta-cells to adopt a neural gene activity program

    PubMed Central

    van Arensbergen, Joris; García-Hurtado, Javier; Moran, Ignasi; Maestro, Miguel Angel; Xu, Xiaobo; Van de Casteele, Mark; Skoudy, Anouchka L.; Palassini, Matteo; Heimberg, Harry; Ferrer, Jorge

    2010-01-01

    The epigenome changes that underlie cellular differentiation in developing organisms are poorly understood. To gain insights into how pancreatic beta-cells are programmed, we profiled key histone methylations and transcripts in embryonic stem cells, multipotent progenitors of the nascent embryonic pancreas, purified beta-cells, and 10 differentiated tissues. We report that despite their endodermal origin, beta-cells show a transcriptional and active chromatin signature that is most similar to ectoderm-derived neural tissues. In contrast, the beta-cell signature of trimethylated H3K27, a mark of Polycomb-mediated repression, clusters with pancreatic progenitors, acinar cells and liver, consistent with the epigenetic transmission of this mark from endoderm progenitors to their differentiated cellular progeny. We also identified two H3K27 methylation events that arise in the beta-cell lineage after the pancreatic progenitor stage. One is a wave of cell-selective de novo H3K27 trimethylation in non-CpG island genes. Another is the loss of bivalent and H3K27me3-repressed chromatin in a core program of neural developmental regulators that enables a convergence of the gene activity state of beta-cells with that of neural cells. These findings reveal a dynamic regulation of Polycomb repression programs that shape the identity of differentiated beta-cells. PMID:20395405

  12. Polycomb silencing of the Drosophila 4E-BP gene regulates imaginal disc cell growth

    PubMed Central

    Mason-Suares, Heather; Tie, Feng; Yan, Christopher; Harte, Peter J.

    2015-01-01

    Polycomb group (PcG) proteins are best known for their role in maintaining stable, mitotically heritable silencing of the homeotic (HOX) genes during development. In addition to loss of homeotic gene silencing, some PcG mutants also have small imaginal discs. These include mutations in E(z), Su(z)12, esc and escl, which encode Polycomb Repressive Complex 2 (PRC2) subunits. The cause of this phenotype is not known, but the human homologs of PRC2 subunits have been shown to play a role in cell proliferation, are over-expressed in many tumors, and appear to be required for tumor proliferation. Here we show that the small imaginal disc phenotype arises, at least in part, from a cell growth defect. In homozygous E(z) mutants, imaginal disc cells are smaller than cells in normally proliferating discs. We show that the Thor gene, which encodes eIF4E-Binding Protein (4E-BP), the evolutionarily conserved inhibitor of cap-dependent translation and potent inhibitor of cell growth, is involved in the development of this phenotype. The Thor promoter region contains DNA binding motifs for transcription factors found in well-characterized Polycomb Response Elements (PREs), including PHO/PHOL, GAGA Factor, and others, suggesting that Thor may be a direct target of Polycomb silencing. We present chromatin immunoprecipitation evidence that PcG proteins are bound to the Thor 5’ region in vivo. The Thor gene is normally repressed in imaginal discs, but Thor mRNA and 4E-BP protein levels are elevated in imaginal discs of PRC2 subunit mutant larvae. Deletion of the Thor gene in E(z) mutants partially restores imaginal disc size toward wild-type and results in an increase in the fraction of larvae that pupariate. These results thus suggest that PcG proteins can directly modulate cell growth in Drosophila, in part by regulating Thor expression. PMID:23523430

  13. Group target tracking using game theory

    NASA Astrophysics Data System (ADS)

    Sadjadi, Firooz A.; Kober, Wolfgang

    2001-10-01

    The problem of tracking of a group of targets is considered in this paper. We will present an overview of an investigation into this problem by first using the targets velocity state vectors covariance matrix to establish target grouping and then by exploiting concepts derived from game theory, in particular the leader-follower techniques, and graph theory to represent and establish relationships that influence the tracking of objects that belong to a group formation.

  14. Polycomb-Mediated Gene Silencing in Arabidopsis thaliana

    PubMed Central

    Kim, Dong-Hwan; Sung, Sibum

    2014-01-01

    Polycomb group (PcG) proteins are conserved chromatin regulators involved in the control of key developmental programs in eukaryotes. They collectively provide the transcriptional memory unique to each cell identity by maintaining transcriptional states of developmental genes. PcG proteins form multi-protein complexes, known as Polycomb repressive complex 1 (PRC1) and Polycomb repressive complex 2 (PRC2). PRC1 and PRC2 contribute to the stable gene silencing in part through catalyzing covalent histone modifications. Components of PRC1 and PRC2 are well conserved from plants to animals. PcG-mediated gene silencing has been extensively investigated in efforts to understand molecular mechanisms underlying developmental programs in eukaryotes. Here, we describe our current knowledge on PcG-mediated gene repression which dictates developmental programs by dynamic layers of regulatory activities, with an emphasis given to the model plant Arabidopsis thaliana. PMID:25410906

  15. DNMT1 and DNMT3B modulate distinct polycomb-mediated histone modifications in colon cancer.

    PubMed

    Jin, Bilian; Yao, Bing; Li, Jian-Liang; Fields, C Robert; Delmas, Amber L; Liu, Chen; Robertson, Keith D

    2009-09-15

    DNA methylation patterns are established and maintained by three DNA methyltransferases (DNMT): DNMT1, DNMT3A, and DNMT3B. Although essential for development, methylation patterns are frequently disrupted in cancer and contribute directly to carcinogenesis. Recent studies linking polycomb group repression complexes (PRC1 and PRC2) to the DNMTs have begun to shed light on how methylation is targeted. We identified previously a panel of genes regulated by DNMT3B. Here, we compare these with known polycomb group targets to show that approximately 47% of DNMT3B regulated genes are also bound by PRC1 or PRC2. We chose 44 genes coregulated by DNMT3B and PRC1/PRC2 to test whether these criteria would accurately identify novel targets of epigenetic silencing in colon cancer. Using reverse transcription-PCR, bisulfite genomic sequencing, and pyrosequencing, we show that the majority of these genes are frequently silenced in colorectal cancer cell lines and primary tumors. Some of these, including HAND1, HMX2, and SIX3, repressed cell growth. Finally, we analyzed the histone code, DNMT1, DNMT3B, and PRC2 binding by chromatin immunoprecipitation at epigenetically silenced genes to reveal a novel link between DNMT3B and the mark mediated by PRC1. Taken together, these studies suggest that patterns of epigenetic modifiers and the histone code influence the propensity of a gene to become hypermethylated in cancer and that DNMT3B plays an important role in regulating PRC1 function.

  16. Interdependence of PRC1 and PRC2 for recruitment to Polycomb Response Elements

    PubMed Central

    Kahn, Tatyana G.; Dorafshan, Eshagh; Schultheis, Dorothea; Zare, Aman; Stenberg, Per; Reim, Ingolf; Pirrotta, Vincenzo; Schwartz, Yuri B.

    2016-01-01

    Polycomb Group (PcG) proteins are epigenetic repressors essential for control of development and cell differentiation. They form multiple complexes of which PRC1 and PRC2 are evolutionary conserved and obligatory for repression. The targeting of PRC1 and PRC2 is poorly understood and was proposed to be hierarchical and involve tri-methylation of histone H3 (H3K27me3) and/or monoubiquitylation of histone H2A (H2AK118ub). Here, we present a strict test of this hypothesis using the Drosophila model. We discover that neither H3K27me3 nor H2AK118ub is required for targeting PRC complexes to Polycomb Response Elements (PREs). We find that PRC1 can bind PREs in the absence of PRC2 but at many PREs PRC2 requires PRC1 to be targeted. We show that one role of H3K27me3 is to allow PcG complexes anchored at PREs to interact with surrounding chromatin. In contrast, the bulk of H2AK118ub is unrelated to PcG repression. These findings radically change our view of how PcG repression is targeted and suggest that PRC1 and PRC2 can communicate independently of histone modifications. PMID:27557709

  17. Polycomb enables primitive endoderm lineage priming in embryonic stem cells

    PubMed Central

    Illingworth, Robert S; Hölzenspies, Jurriaan J; Roske, Fabian V; Bickmore, Wendy A; Brickman, Joshua M

    2016-01-01

    Mouse embryonic stem cells (ESCs), like the blastocyst from which they are derived, contain precursors of the epiblast (Epi) and primitive endoderm (PrEn) lineages. While transient in vivo, these precursor populations readily interconvert in vitro. We show that altered transcription is the driver of these coordinated changes, known as lineage priming, in a process that exploits novel polycomb activities. We find that intragenic levels of the polycomb mark H3K27me3 anti-correlate with changes in transcription, irrespective of the gene’s developmental trajectory or identity as a polycomb target. In contrast, promoter proximal H3K27me3 is markedly higher for PrEn priming genes. Consequently, depletion of this modification stimulates the degree to which ESCs are primed towards PrEn when challenged to differentiate, but has little effect on gene expression in self-renewing ESC culture. These observations link polycomb with dynamic changes in transcription and stalled lineage commitment, allowing cells to explore alternative choices prior to a definitive decision. DOI: http://dx.doi.org/10.7554/eLife.14926.001 PMID:27723457

  18. Stuxnet Facilitates the Degradation of Polycomb Protein during Development.

    PubMed

    Du, Juan; Zhang, Junzheng; He, Tao; Li, Yajuan; Su, Ying; Tie, Feng; Liu, Min; Harte, Peter J; Zhu, Alan Jian

    2016-06-20

    Polycomb-group (PcG) proteins function to ensure correct deployment of developmental programs by epigenetically repressing target gene expression. Despite the importance, few studies have been focused on the regulation of PcG activity itself. Here, we report a Drosophila gene, stuxnet (stx), that controls Pc protein stability. We find that heightened stx activity leads to homeotic transformation, reduced Pc activity, and de-repression of PcG targets. Conversely, stx mutants, which can be rescued by decreased Pc expression, display developmental defects resembling hyperactivation of Pc. Our biochemical analyses provide a mechanistic basis for the interaction between stx and Pc; Stx facilitates Pc degradation in the proteasome, independent of ubiquitin modification. Furthermore, this mode of regulation is conserved in vertebrates. Mouse stx promotes degradation of Cbx4, an orthologous Pc protein, in vertebrate cells and induces homeotic transformation in Drosophila. Our results highlight an evolutionarily conserved mechanism of regulated protein degradation on PcG homeostasis and epigenetic activity.

  19. Contribution of Polycomb Homologues Bmi-1 and Mel-18 to Medulloblastoma Pathogenesis▿ †

    PubMed Central

    Wiederschain, Dmitri; Chen, Lin; Johnson, Brett; Bettano, Kimberly; Jackson, Dowdy; Taraszka, John; Wang, Y. Karen; Jones, Michael D.; Morrissey, Michael; Deeds, James; Mosher, Rebecca; Fordjour, Paul; Lengauer, Christoph; Benson, John D.

    2007-01-01

    Bmi-1 and Mel-18 are structural homologues that belong to the Polycomb group of transcriptional regulators and are believed to stably maintain repression of gene expression by altering the state of chromatin at specific promoters. While a number of clinical and experimental observations have implicated Bmi-1 in human tumorigenesis, the role of Mel-18 in cancer cell growth has not been investigated. We report here that short hairpin RNA-mediated knockdown of either Bmi-1 or Mel-18 in human medulloblastoma DAOY cells results in the inhibition of proliferation, loss of clonogenic survival, anchorage-independent growth, and suppression of tumor formation in nude mice. Furthermore, overexpression of both Bmi-1 and Mel-18 significantly increases the clonogenic survival of Rat1 fibroblasts. In contrast, stable downregulation of Bmi-1 or Mel-18 alone does not affect the growth of normal human WI38 fibroblasts. Proteomics-based characterization of Bmi-1 and Mel-18 protein complexes isolated from cancer cells revealed substantial similarities in their respective compositions. Finally, gene expression analysis identified a number of cancer-relevant pathways that may be controlled by Bmi-1 and Mel-18 and also showed that these Polycomb proteins regulate a set of common gene targets. Taken together, these results suggest that Bmi-1 and Mel-18 may have overlapping functions in cancer cell growth. PMID:17452456

  20. A High-Density Map for Navigating the Human Polycomb Complexome.

    PubMed

    Hauri, Simon; Comoglio, Federico; Seimiya, Makiko; Gerstung, Moritz; Glatter, Timo; Hansen, Klaus; Aebersold, Ruedi; Paro, Renato; Gstaiger, Matthias; Beisel, Christian

    2016-10-04

    Polycomb group (PcG) proteins are major determinants of gene silencing and epigenetic memory in higher eukaryotes. Here, we systematically mapped the human PcG complexome using a robust affinity purification mass spectrometry approach. Our high-density protein interaction network uncovered a diverse range of PcG complexes. Moreover, our analysis identified PcG interactors linking them to the PcG system, thus providing insight into the molecular function of PcG complexes and mechanisms of recruitment to target genes. We identified two human PRC2 complexes and two PR-DUB deubiquitination complexes, which contain the O-linked N-acetylglucosamine transferase OGT1 and several transcription factors. Finally, genome-wide profiling of PR-DUB components indicated that the human PR-DUB and PRC1 complexes bind distinct sets of target genes, suggesting differential impact on cellular processes in mammals.

  1. Formation of a Polycomb-Domain in the Absence of Strong Polycomb Response Elements

    PubMed Central

    De, Sandip; Mitra, Apratim; Cheng, Yuzhong; Pfeifer, Karl; Kassis, Judith A.

    2016-01-01

    Polycomb group response elements (PREs) in Drosophila are DNA-elements that recruit Polycomb proteins (PcG) to chromatin and regulate gene expression. PREs are easily recognizable in the Drosophila genome as strong peaks of PcG-protein binding over discrete DNA fragments; many small but statistically significant PcG peaks are also observed in PcG domains. Surprisingly, in vivo deletion of the four characterized strong PREs from the PcG regulated invected-engrailed (inv-en) gene complex did not disrupt the formation of the H3K27me3 domain and did not affect inv-en expression in embryos or larvae suggesting the presence of redundant PcG recruitment mechanism. Further, the 3D-structure of the inv-en domain was only minimally altered by the deletion of the strong PREs. A reporter construct containing a 7.5kb en fragment that contains three weak peaks but no large PcG peaks forms an H3K27me3 domain and is PcG-regulated. Our data suggests a model for the recruitment of PcG-complexes to Drosophila genes via interactions with multiple, weak PREs spread throughout an H3K27me3 domain. PMID:27466807

  2. Premarital counseling: view of the target group.

    PubMed

    Mitwally, H H; Abd El-Rahman, D A; Mohamed, N I

    2000-01-01

    Premarital counseling is one of the most important strategies for prevention of genetic disorders, congenital anomalies and several medical, psychosocial marital problems. Nursing students as a target group are in a unique position to provide prospective couples with information and guidance regarding premarital counseling. The aim of this study is to assess knowledge and attitude of secondary technical nursing school students towards premarital counseling in Alexandria. The study was conducted at four secondary technical nursing schools. 200 students from the chosen schools participated in the study. Questionnaire sheet was developed to assess student's knowledge and a 3-point Likert-like scale was used to assess the student's attitude. The results revealed that 46.5% of the study sample had an average score in knowledge, while 65.5% of the students had a positive attitude towards premarital counseling. The recommendations focused on dissemination of information through formal and informal education and media publicity.

  3. Coordinated regulation of transcriptional repression by the RBP2 H3K4 demethylase and Polycomb-Repressive Complex 2

    PubMed Central

    Pasini, Diego; Hansen, Klaus H.; Christensen, Jesper; Agger, Karl; Cloos, Paul A.C.; Helin, Kristian

    2008-01-01

    Polycomb group (PcG) proteins regulate important cellular processes such as embryogenesis, cell proliferation, and stem cell self-renewal through the transcriptional repression of genes determining cell fate decisions. The Polycomb-Repressive Complex 2 (PRC2) is highly conserved during evolution, and its intrinsic histone H3 Lys 27 (K27) trimethylation (me3) activity is essential for PcG-mediated transcriptional repression. Here, we show a functional interplay between the PRC2 complex and the H3K4me3 demethylase Rbp2 (Jarid1a) in mouse embryonic stem (ES) cells. By genome-wide location analysis we found that Rbp2 is associated with a large number of PcG target genes in mouse ES cells. We show that the PRC2 complex recruits Rbp2 to its target genes, and that this interaction is required for PRC2-mediated repressive activity during ES cell differentiation. Taken together, these results demonstrate an elegant mechanism for repression of developmental genes by the coordinated regulation of epigenetic marks involved in repression and activation of transcription. PMID:18483221

  4. CBP-mediated acetylation of histone H3 lysine 27 antagonizes Drosophila Polycomb silencing

    PubMed Central

    Tie, Feng; Banerjee, Rakhee; Stratton, Carl A.; Prasad-Sinha, Jayashree; Stepanik, Vincent; Zlobin, Andrei; Diaz, Manuel O.; Scacheri, Peter C.; Harte, Peter J.

    2009-01-01

    Summary Trimethylation of histone H3 lysine 27 (H3K27me3) by Polycomb repressive complex 2 (PRC2) is essential for transcriptional silencing of Polycomb target genes, whereas acetylation of H3K27 (H3K27ac) has recently been shown to be associated with many active mammalian genes. The Trithorax protein (TRX), which associates with the histone acetyltransferase CBP, is required for maintenance of transcriptionally active states and antagonizes Polycomb silencing, although the mechanism underlying this antagonism is unknown. Here we show that H3K27 is specifically acetylated by Drosophila CBP and its deacetylation involves RPD3. H3K27ac is present at high levels in early embryos and declines after 4 hours as H3K27me3 increases. Knockdown of E(Z) decreases H3K27me3 and increases H3K27ac in bulk histones and at the promoter of the repressed Polycomb target gene abd-A, suggesting that these indeed constitute alternative modifications at some H3K27 sites. Moderate overexpression of CBP in vivo causes a global increase in H3K27ac and a decrease in H3K27me3, and strongly enhances Polycomb mutant phenotypes. We also show that TRX is required for H3K27 acetylation. TRX overexpression also causes an increase in H3K27ac and a concomitant decrease in H3K27me3 and leads to defects in Polycomb silencing. Chromatin immunoprecipitation coupled with DNA microarray (ChIP-chip) analysis reveals that H3K27ac and H3K27me3 are mutually exclusive and that H3K27ac and H3K4me3 signals coincide at most sites. We propose that TRX-dependent acetylation of H3K27 by CBP prevents H3K27me3 at Polycomb target genes and constitutes a key part of the molecular mechanism by which TRX antagonizes or prevents Polycomb silencing. PMID:19700617

  5. A Long ncRNA Links Copy Number Variation to a Polycomb/Trithorax Epigenetic Switch in FSHD Muscular Dystrophy

    PubMed Central

    Cabianca, Daphne S.; Casa, Valentina; Bodega, Beatrice; Xynos, Alexandros; Ginelli, Enrico; Tanaka, Yujiro; Gabellini, Davide

    2012-01-01

    Summary Repetitive sequences account for more than 50% of the human genome. Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant disease associated with reduction in the copy number of the D4Z4 repeat mapping to 4q35. By an unknown mechanism, D4Z4 deletion causes an epigenetic switch leading to de-repression of 4q35 genes. Here we show that the Polycomb group of epigenetic repressors targets D4Z4 in healthy subjects and that D4Z4 deletion is associated with reduced Polycomb silencing in FSHD patients. We identify DBE-T, a chromatin-associated noncoding RNA produced selectively in FSHD patients that coordinates de-repression of 4q35 genes. DBE-T recruits the Trithorax group protein Ash1L to the FSHD locus, driving histone H3 lysine 36 dimethylation, chromatin remodeling, and 4q35 gene transcription. This study provides insights into the biological function of repetitive sequences in regulating gene expression and shows how mutations of such elements can influence the progression of a human genetic disease. PMID:22541069

  6. Timing mechanism dependent on cell division is invoked by Polycomb eviction in plant stem cells.

    PubMed

    Sun, Bo; Looi, Liang-Sheng; Guo, Siyi; He, Zemiao; Gan, Eng-Seng; Huang, Jiangbo; Xu, Yifeng; Wee, Wan-Yi; Ito, Toshiro

    2014-01-31

    Plant floral stem cells divide a limited number of times before they stop and terminally differentiate, but the mechanisms that control this timing remain unclear. The precise temporal induction of the Arabidopsis zinc finger repressor KNUCKLES (KNU) is essential for the coordinated growth and differentiation of floral stem cells. We identify an epigenetic mechanism in which the floral homeotic protein AGAMOUS (AG) induces KNU at ~2 days of delay. AG binding sites colocalize with a Polycomb response element in the KNU upstream region. AG binding to the KNU promoter causes the eviction of the Polycomb group proteins from the locus, leading to cell division-dependent induction. These analyses demonstrate that floral stem cells measure developmental timing by a division-dependent epigenetic timer triggered by Polycomb eviction.

  7. Corepressor Protein CDYL Functions as a Molecular Bridge between Polycomb Repressor Complex 2 and Repressive Chromatin Mark Trimethylated Histone Lysine 27*

    PubMed Central

    Zhang, Yu; Yang, Xiaohan; Gui, Bin; Xie, Guojia; Zhang, Di; Shang, Yongfeng; Liang, Jing

    2011-01-01

    Polycomb group proteins play essential roles in transcriptional regulation of multiple gene families involved in various pathophysiological processes. It is believed that Polycomb Repressive Complex 2 (PRC2) is targeted to chromatin by the EED subunit to methylate histone H3 lysine 27 (H3K27), leading to a repressive chromatin state that inhibits gene expression. Here we report that the chromodomain-containing protein CDYL specifically recognizes di- and tri-methylated H3K27 (H3K27me2 and H3K27me3) and directly interacts with EZH2, the catalytic subunit of PRC2. We show that CDYL dramatically enhances the methyltransferase activity of PRC2 toward oligonucleosome substrates in vitro. Genome-wide analysis of CDYL targets by ChIP sequencing revealed that CDYL and PRC2 share a number of genomic targets. CDYL is required for chromatin targeting and maximal enzymatic activity of PRC2 at their common target sites. Our experiments indicate that CDYL functions as a molecular bridge between PRC2 and the repressive chromatin mark H3K27me3, forming a positive feedback loop to facilitate the establishment and propagation of H3K27me3 modifications along the chromatin. PMID:22009739

  8. Animal Rights Groups Target High School Dissection.

    ERIC Educational Resources Information Center

    Trotter, Andrew

    1992-01-01

    Two groups leading the charge against dissection are People for the Ethical Treatment of Animals (PETA) and the Student Action Corps for Animals (SACA). Protests by student and community members remain the movement's strongest weapon. (MLF)

  9. Functional analysis of AEBP2, a PRC2 Polycomb protein, reveals a Trithorax phenotype in embryonic development and in ESCs

    PubMed Central

    Grijzenhout, Anne; Godwin, Jonathan; Koseki, Haruhiko; Gdula, Michal Ryszard; Szumska, Dorota; McGouran, Joanna F.; Bhattacharya, Shoumo; Kessler, Benedikt M.; Brockdorff, Neil

    2016-01-01

    The Polycomb repressive complexes PRC1 and PRC2 are key mediators of heritable gene silencing in multicellular organisms. Here, we characterise AEBP2, a known PRC2 co-factor which, in vitro, has been shown to stimulate PRC2 activity. We show that AEBP2 localises specifically to PRC2 target loci, including the inactive X chromosome. Proteomic analysis confirms that AEBP2 associates exclusively with PRC2 complexes. However, analysis of embryos homozygous for a targeted mutation of Aebp2 unexpectedly revealed a Trithorax phenotype, normally linked to antagonism of Polycomb function. Consistent with this, we observe elevated levels of PRC2-mediated histone H3K27 methylation at target loci in Aebp2 mutant embryonic stem cells (ESCs). We further demonstrate that mutant ESCs assemble atypical hybrid PRC2 subcomplexes, potentially accounting for enhancement of Polycomb activity, and suggesting that AEBP2 normally plays a role in defining the mutually exclusive composition of PRC2 subcomplexes. PMID:27317809

  10. New Group Targets Political Bias on Campus.

    ERIC Educational Resources Information Center

    Marshall, Eliot

    1985-01-01

    "Accuracy in Academia" (AIA) is a new lobby organized for recruiting student volunteers to monitor university courses and expose anti-American teaching. Hard science and journalism courses will be omitted from scrutiny with emphasis on political science, economics, history, and sociology courses. University groups feel that AIA's tactics threaten…

  11. Promiscuous RNA binding by Polycomb Repressive Complex 2

    PubMed Central

    Davidovich, Chen; Zheng, Leon; Goodrich, Karen J.; Cech, Thomas R.

    2013-01-01

    Polycomb repressive complex-2 (PRC2) is a histone methyltransferase required for epigenetic silencing during development and cancer. Long non-coding RNAs (lncRNAs) recruit PRC2 to chromatin, but the general role of RNA in maintaining repressed chromatin is unknown. Here we measure the binding constant of human PRC2 to various RNAs and find comparable affinity for human lncRNAs targeted by PRC2 and irrelevant transcripts from ciliates and bacteria. PRC2 binding is size-dependent, with lower affinity for shorter RNAs. In vivo, PRC2 predominantly occupies repressed genes; PRC2 is also associated with active genes, but most of these are not regulated by PRC2. These findings support a model in which promiscuous binding of PRC2 to RNA transcripts allows it to scan for target genes that have escaped repression, leading to maintenance of the repressed state. Such RNAs may also provide a decoy for PRC2. PMID:24077223

  12. Tracking group targets using hypergraph matching in data association

    NASA Astrophysics Data System (ADS)

    Wu, Shunguang; Xiao, Jiangjiang

    2011-09-01

    Group moving targets are number of targets independently moving in a physical space but keeping their relative order or pattern invariant. The up to date state-of-the-art multi-target tracking (MTT) data association methods (GNN,JPDA,MHT) are easily fail on group targets tracking problems, since the tracker-to-observation ambiguity cannot be resolved if only using the individual track to observation information. A hypergraph G is represented by G = {V,E}, where V is a set of elements called nodes or vertices, E is a set of non-empty subsets containing d-tuple of vertices called hyperedges. It can be used as a new mathematic tool to represent a group of moving targets if we let each target be a vertex and a d-target subset be an hyperedge. Under this representation, this paper reformulates the traditional MTT data association problem as an hypergraph matching one between the hypergraphs formed from tracks and observations, and shows that the traditional approach (only uses the vertex-to-vertex information) which is a special case under the proposed framework. In addition to the vertex-to-vertex information, since the hyperedge-to-hyperegde information is also used in building the assignment matrix, the hypergraph matching based algorithms give better performance than that from the traditional methods in group target tracking problems. We demonstrate the declaration from simulations as well as video based geotracking examples.

  13. Epigenetic balance of gene expression by Polycomb and COMPASS families.

    PubMed

    Piunti, Andrea; Shilatifard, Ali

    2016-06-03

    Epigenetic regulation of gene expression in metazoans is central for establishing cellular diversity, and its deregulation can result in pathological conditions. Although transcription factors are essential for implementing gene expression programs, they do not function in isolation and require the recruitment of various chromatin-modifying and -remodeling machineries. A classic example of developmental chromatin regulation is the balanced activities of the Polycomb group (PcG) proteins within the PRC1 and PRC2 complexes, and the Trithorax group (TrxG) proteins within the COMPASS family, which are highly mutated in a large number of human diseases. In this review, we will discuss the latest findings regarding the properties of the PcG and COMPASS families and the insight they provide into the epigenetic control of transcription under physiological and pathological settings.

  14. The Arabidopsis GAGA-Binding Factor BASIC PENTACYSTEINE6 Recruits the POLYCOMB-REPRESSIVE COMPLEX1 Component LIKE HETEROCHROMATIN PROTEIN1 to GAGA DNA Motifs1

    PubMed Central

    Hecker, Andreas; Brand, Luise H.; Peter, Sébastien; Simoncello, Nathalie; Kilian, Joachim; Gaudin, Valérie

    2015-01-01

    Polycomb-repressive complexes (PRCs) play key roles in development by repressing a large number of genes involved in various functions. Much, however, remains to be discovered about PRC-silencing mechanisms as well as their targeting to specific genomic regions. Besides other mechanisms, GAGA-binding factors in animals can guide PRC members in a sequence-specific manner to Polycomb-responsive DNA elements. Here, we show that the Arabidopsis (Arabidopsis thaliana) GAGA-motif binding factor protein BASIC PENTACYSTEINE6 (BPC6) interacts with LIKE HETEROCHROMATIN PROTEIN1 (LHP1), a PRC1 component, and associates with VERNALIZATION2 (VRN2), a PRC2 component, in vivo. By using a modified DNA-protein interaction enzyme-linked immunosorbant assay, we could show that BPC6 was required and sufficient to recruit LHP1 to GAGA motif-containing DNA probes in vitro. We also found that LHP1 interacts with VRN2 and, therefore, can function as a possible scaffold between BPC6 and VRN2. The lhp1-4 bpc4 bpc6 triple mutant displayed a pleiotropic phenotype, extreme dwarfism and early flowering, which disclosed synergistic functions of LHP1 and group II plant BPC members. Transcriptome analyses supported this synergy and suggested a possible function in the concerted repression of homeotic genes, probably through histone H3 lysine-27 trimethylation. Hence, our findings suggest striking similarities between animal and plant GAGA-binding factors in the recruitment of PRC1 and PRC2 components to Polycomb-responsive DNA element-like GAGA motifs, which must have evolved through convergent evolution. PMID:26025051

  15. Timing matters: sonar call groups facilitate target localization in bats.

    PubMed

    Kothari, Ninad B; Wohlgemuth, Melville J; Hulgard, Katrine; Surlykke, Annemarie; Moss, Cynthia F

    2014-01-01

    To successfully negotiate a cluttered environment, an echolocating bat must control the timing of motor behaviors in response to dynamic sensory information. Here we detail the big brown bat's adaptive temporal control over sonar call production for tracking prey, moving predictably or unpredictably, under different experimental conditions. We studied the adaptive control of vocal-motor behaviors in free-flying big brown bats, Eptesicus fuscus, as they captured tethered and free-flying insects, in open and cluttered environments. We also studied adaptive sonar behavior in bats trained to track moving targets from a resting position. In each of these experiments, bats adjusted the features of their calls to separate target and clutter. Under many task conditions, flying bats produced prominent sonar sound groups identified as clusters of echolocation pulses with relatively stable intervals, surrounded by longer pulse intervals. In experiments where bats tracked approaching targets from a resting position, bats also produced sonar sound groups, and the prevalence of these sonar sound groups increased when motion of the target was unpredictable. We hypothesize that sonar sound groups produced during flight, and the sonar call doublets produced by a bat tracking a target from a resting position, help the animal resolve dynamic target location and represent the echo scene in greater detail. Collectively, our data reveal adaptive temporal control over sonar call production that allows the bat to negotiate a complex and dynamic environment.

  16. Timing matters: sonar call groups facilitate target localization in bats

    PubMed Central

    Kothari, Ninad B.; Wohlgemuth, Melville J.; Hulgard, Katrine; Surlykke, Annemarie; Moss, Cynthia F.

    2014-01-01

    To successfully negotiate a cluttered environment, an echolocating bat must control the timing of motor behaviors in response to dynamic sensory information. Here we detail the big brown bat's adaptive temporal control over sonar call production for tracking prey, moving predictably or unpredictably, under different experimental conditions. We studied the adaptive control of vocal-motor behaviors in free-flying big brown bats, Eptesicus fuscus, as they captured tethered and free-flying insects, in open and cluttered environments. We also studied adaptive sonar behavior in bats trained to track moving targets from a resting position. In each of these experiments, bats adjusted the features of their calls to separate target and clutter. Under many task conditions, flying bats produced prominent sonar sound groups identified as clusters of echolocation pulses with relatively stable intervals, surrounded by longer pulse intervals. In experiments where bats tracked approaching targets from a resting position, bats also produced sonar sound groups, and the prevalence of these sonar sound groups increased when motion of the target was unpredictable. We hypothesize that sonar sound groups produced during flight, and the sonar call doublets produced by a bat tracking a target from a resting position, help the animal resolve dynamic target location and represent the echo scene in greater detail. Collectively, our data reveal adaptive temporal control over sonar call production that allows the bat to negotiate a complex and dynamic environment. PMID:24860509

  17. Polycomb repressive complex 2 contributes to DNA double-strand break repair

    PubMed Central

    Campbell, Stuart; Ismail, Ismail Hassan; Young, Leah C; Poirier, Guy G; Hendzel, Michael J

    2013-01-01

    Polycomb protein histone methyltransferase, enhancer of Zeste homolog 2 (EZH2), is frequently overexpressed in human malignancy and is implicated in cancer cell proliferation and invasion. However, it is largely unknown whether EZH2 has a role in modulating the DNA damage response. Here, we show that polycomb repressive complex 2 (PRC2) is recruited to sites of DNA damage. This recruitment is independent of histone 2A variant X (H2AX) and the PI-3-related kinases ATM and DNA-PKcs. We establish that PARP activity is required for retaining PRC2 at sites of DNA damage. Furthermore, depletion of EZH2 in cells decreases the efficiency of DSB repair and increases sensitivity of cells to gamma-irradiation. These data unravel a crucial role of PRC2 in determining cancer cellular sensitivity following DNA damage and suggest that therapeutic targeting of EZH2 activity might serve as a strategy for improving conventional chemotherapy in a given malignancy. PMID:23907130

  18. A functionally conserved Polycomb response element from mouse HoxD complex responds to heterochromatin factors

    NASA Astrophysics Data System (ADS)

    Vasanthi, Dasari; Nagabhushan, A.; Matharu, Navneet Kaur; Mishra, Rakesh K.

    2013-10-01

    Anterior-posterior body axis in all bilaterians is determined by the Hox gene clusters that are activated in a spatio-temporal order. This expression pattern of Hox genes is established and maintained by regulatory mechanisms that involve higher order chromatin structure and Polycomb group (PcG) and trithorax group (trxG) proteins. We identified earlier a Polycomb response element (PRE) in the mouse HoxD complex that is functionally conserved in flies. We analyzed the molecular and genetic interactions of mouse PRE using Drosophila melanogaster and vertebrate cell culture as the model systems. We demonstrate that the repressive activity of this PRE depends on PcG/trxG genes as well as the heterochromatin components. Our findings indicate that a wide range of factors interact with the HoxD PRE that can contribute to establishing the expression pattern of homeotic genes in the complex early during development and maintain that pattern at subsequent stages.

  19. A polycomb-mediated epigenetic field defect precedes invasive cervical carcinoma

    PubMed Central

    Wijetunga, Neil Ari; Ben-Dayan, Miriam; Tozour, Jessica; Burk, Robert D.; Schlecht, Nicolas F.; Einstein, Mark H.; Greally, John M.

    2016-01-01

    Human papillomavirus (HPV)-associated cervical carcinoma is preceded by stages of cervical intra-epithelial neoplasia (CIN) that can variably progress to malignancy. Understanding the different molecular processes involved in the progression of pre-malignant CIN is critical to the development of improved predictive and interventional capabilities. We tested the role of regulators of transcription in both the development and the progression of HPV-associated CIN, performing the most comprehensive genomic survey to date of DNA methylation in HPV-associated cervical neoplasia, testing ~2 million loci throughout the human genome in biopsies from 78 HPV+ women, identifying changes starting in early CIN and maintained through carcinogenesis. We identified loci at which DNA methylation is consistently altered, beginning early in the course of neoplastic disease and progressing with disease advancement. While the loss of DNA methylation occurs mostly at intergenic regions, acquisition of DNA methylation is at sites involved in transcriptional regulation, with strong enrichment for targets of polycomb repression. Using an independent cohort from The Cancer Genome Atlas, we validated the loci with increased DNA methylation and found that these regulatory changes were associated with locally decreased gene expression. Secondary validation using immunohistochemistry showed that the progression of neoplasia was associated with increasing polycomb protein expression specifically in the cervical epithelium. We find that perturbations of genomic regulatory processes occur early and persist in cervical carcinoma. The results indicate a polycomb-mediated epigenetic field defect in cervical neoplasia that may represent a target for early, topical interventions using polycomb inhibitors. PMID:27557505

  20. Genome-wide co-localization of Polycomb orthologs and their effects on gene expression in human fibroblasts

    PubMed Central

    2014-01-01

    Background Polycomb group proteins form multicomponent complexes that are important for establishing lineage-specific patterns of gene expression. Mammalian cells encode multiple permutations of the prototypic Polycomb repressive complex 1 (PRC1) with little evidence for functional specialization. An aim of this study is to determine whether the multiple orthologs that are co-expressed in human fibroblasts act on different target genes and whether their genomic location changes during cellular senescence. Results Deep sequencing of chromatin immunoprecipitated with antibodies against CBX6, CBX7, CBX8, RING1 and RING2 reveals that the orthologs co-localize at multiple sites. PCR-based validation at representative loci suggests that a further six PRC1 proteins have similar binding patterns. Importantly, sequential chromatin immunoprecipitation with antibodies against different orthologs implies that multiple variants of PRC1 associate with the same DNA. At many loci, the binding profiles have a distinctive architecture that is preserved in two different types of fibroblast. Conversely, there are several hundred loci at which PRC1 binding is cell type-specific and, contrary to expectations, the presence of PRC1 does not necessarily equate with transcriptional silencing. Interestingly, the PRC1 binding profiles are preserved in senescent cells despite changes in gene expression. Conclusions The multiple permutations of PRC1 in human fibroblasts congregate at common rather than specific sites in the genome and with overlapping but distinctive binding profiles in different fibroblasts. The data imply that the effects of PRC1 complexes on gene expression are more subtle than simply repressing the loci at which they bind. PMID:24485159

  1. A positive role for polycomb in transcriptional regulation via H4K20me1.

    PubMed

    Lv, Xiangdong; Han, Zhijun; Chen, Hao; Yang, Bo; Yang, Xiaofeng; Xia, Yuanxin; Pan, Chenyu; Fu, Lin; Zhang, Shuo; Han, Hui; Wu, Min; Zhou, Zhaocai; Zhang, Lei; Li, Lin; Wei, Gang; Zhao, Yun

    2016-05-01

    The highly conserved polycomb group (PcG) proteins maintain heritable transcription repression of the genes essential for development from fly to mammals. However, sporadic reports imply a potential role of PcGs in positive regulation of gene transcription, although systematic investigation of such function and the underlying mechanism has rarely been reported. Here, we report a Pc-mediated, H3K27me3-dependent positive transcriptional regulation of Senseless (Sens), a key transcription factor required for development. Mechanistic studies show that Pc regulates Sens expression by promoting H4K20me1 at the Sens locus. Further bioinformatic analysis at genome-wide level indicates that the existence of H4K20me1 acts as a selective mark for positive transcriptional regulation by Pc/H3K27me3. Both the intensities and specific patterns of Pc and H3K27me3 are important for the fates of target gene transcription. Moreover, binding of transcription factor Broad (Br), which physically interacts with Pc and positively regulates the transcription of Sens, is observed in Pc(+)H3K27me3(+)H4K20me1(+) genes, but not in Pc(+)H3K27me3(+)H4K20me1(-) genes. Taken together, our study reveals that, coupling with the transcription factor Br, Pc positively regulates transcription of Pc(+)H3K27me3(+)H4K20me1(+) genes in developing Drosophila wing disc.

  2. Polycomb repression in the regulation of growth and development in Arabidopsis.

    PubMed

    Xiao, Jun; Wagner, Doris

    2015-02-01

    Chromatin state is critical for cell identity and development in multicellular eukaryotes. Among the regulators of chromatin state, Polycomb group (PcG) proteins stand out because of their role in both establishment and maintenance of cell identity. PcG proteins act in two major complexes in metazoans and plants. These complexes function to epigenetically-in a mitotically heritable manner-prevent expression of important developmental regulators at the wrong stage of development or in the wrong tissue. In Arabidopsis, PcG function is required throughout the life cycle from seed germination to embryo formation. Recent studies have expanded our knowledge regarding the biological roles and the regulation of the activity of PcG complexes. In this review, we discuss novel functions of Polycomb repression in plant development as well as advances in understanding PcG complex recruitment, activity regulation and removal in Arabidopsis and other plant species.

  3. A PHD-polycomb repressive complex 2 triggers the epigenetic silencing of FLC during vernalization.

    PubMed

    De Lucia, Filomena; Crevillen, Pedro; Jones, Alexandra M E; Greb, Thomas; Dean, Caroline

    2008-11-04

    Vernalization, the acceleration of flowering by winter, involves cold-induced epigenetic silencing of Arabidopsis FLC. This process has been shown to require conserved Polycomb Repressive Complex 2 (PRC2) components including the Su(z)12 homologue, VRN2, and two plant homeodomain (PHD) finger proteins, VRN5 and VIN3. However, the sequence of events leading to FLC repression was unclear. Here we show that, contrary to expectations, VRN2 associates throughout the FLC locus independently of cold. The vernalization-induced silencing is triggered by the cold-dependent association of the PHD finger protein VRN5 to a specific domain in FLC intron 1, and this association is dependent on the cold-induced PHD protein VIN3. In plants returned to warm conditions, VRN5 distribution changes, and it associates more broadly over FLC, coincident with significant increases in H3K27me3. Biochemical purification of a VRN5 complex showed that during prolonged cold a PHD-PRC2 complex forms composed of core PRC2 components (VRN2, SWINGER [an E(Z) HMTase homologue], FIE [an ESC homologue], MSI1 [p55 homologue]), and three related PHD finger proteins, VRN5, VIN3, and VEL1. The PHD-PRC2 activity increases H3K27me3 throughout the locus to levels sufficient for stable silencing. Arabidopsis PHD-PRC2 thus seems to act similarly to Pcl-PRC2 of Drosophila and PHF1-PRC2 of mammals. These data show FLC silencing involves changed composition and dynamic redistribution of Polycomb complexes at different stages of the vernalization process, a mechanism with greater parallels to Polycomb silencing of certain mammalian loci than the classic Drosophila Polycomb targets.

  4. Targeted inactivation of francisella tularensis genes by group II introns.

    PubMed

    Rodriguez, Stephen A; Yu, Jieh-Juen; Davis, Greg; Arulanandam, Bernard P; Klose, Karl E

    2008-05-01

    Studies of the molecular mechanisms of pathogenesis of Francisella tularensis, the causative agent of tularemia, have been hampered by a lack of genetic techniques for rapid targeted gene disruption in the most virulent subspecies. Here we describe efficient targeted gene disruption in F. tularensis utilizing mobile group II introns (targetrons) specifically optimized for F. tularensis. Utilizing a targetron targeted to blaB, which encodes ampicillin resistance, we showed that the system works at high efficiency in three different subspecies: F. tularensis subsp. tularensis, F. tularensis subsp. holarctica, and "F. tularensis subsp. novicida." A targetron was also utilized to inactivate F. tularensis subsp. holarctica iglC, a gene required for virulence. The iglC gene is located within the Francisella pathogenicity island (FPI), which has been duplicated in the most virulent subspecies. Importantly, the iglC targetron targeted both copies simultaneously, resulting in a strain mutated in both iglC genes in a single step. This system will help illuminate the contributions of specific genes, and especially those within the FPI, to the pathogenesis of this poorly studied organism.

  5. Targeted gene disruption in Francisella tularensis by group II introns.

    PubMed

    Rodriguez, Stephen A; Davis, Greg; Klose, Karl E

    2009-11-01

    Francisella tularensis is a highly infectious Gram-negative bacterium that is the causative agent of tularemia. Very little is known about the molecular mechanisms responsible for F. tularensis virulence, in part due to the paucity of genetic tools available for the study of F. tularensis. We have developed a gene knockout system for F. tularensis that utilizes retargeted mobile group II introns, or "targetrons". These targetrons disrupt both single and duplicated target genes at high efficiency in three different F. tularensis subspecies. Here we describe in detail the targetron-based method for insertional mutagenesis of F. tularensis genes, which should facilitate a better understanding of F. tularensis pathogenesis. Group II introns can be adapted to inactivate genes in bacteria for which few genetic tools exist, thus providing a powerful tool to study the genetic basis of bacterial pathogenesis.

  6. Inheritance of Polycomb-dependent chromosomal interactions in Drosophila

    PubMed Central

    Bantignies, Frédéric; Grimaud, Charlotte; Lavrov, Sergey; Gabut, Mathieu; Cavalli, Giacomo

    2003-01-01

    Maintenance of cell identity is a complex task that involves multiple layers of regulation, acting at all levels of chromatin packaging, from nucleosomes to folding of chromosomal domains in the cell nucleus. Polycomb-group (PcG) and trithorax-group (trxG) proteins maintain memory of chromatin states through binding at cis-regulatory elements named PcG response elements or cellular memory modules. Fab-7 is a well-defined cellular memory module involved in regulation of the homeotic gene Abdominal-B (Abd-B). In addition to its action in cis, we show here by three-dimensional FISH that the Fab-7 element leads to association of transgenes with each other or with the endogenous Fab-7, even when inserted in different chromosomes. These long-distance interactions enhance PcG-mediated silencing. They depend on PcG proteins, on DNA sequence homology, and on developmental progression. Once long-distance pairing is abolished by removal of the endogenous Fab-7, the derepressed chromatin state induced at the transgene locus can be transmitted through meiosis into a large fraction of the progeny, even after reintroduction of the endogenous Fab-7. Strikingly, meiotic inheritance of the derepressed state involves loss of pairing between endogenous and transgenic Fab-7. This suggests that transmission of nuclear architecture through cell division might contribute to inheritance of chromatin states in eukaryotes. PMID:14522946

  7. Cohort Profile: The Applied Research Group for Kids (TARGet Kids!).

    PubMed

    Carsley, Sarah; Borkhoff, Cornelia M; Maguire, Jonathon L; Birken, Catherine S; Khovratovich, Marina; McCrindle, Brian; Macarthur, Colin; Parkin, Patricia C

    2015-06-01

    The Applied Research Group for Kids (TARGet Kids!) is an ongoing open longitudinal cohort study enrolling healthy children (from birth to 5 years of age) and following them into adolescence. The aim of the TARGet Kids! cohort is to link early life exposures to health problems including obesity, micronutrient deficiencies and developmental problems. The overarching goal is to improve the health of Canadians by optimizing growth and developmental trajectories through preventive interventions in early childhood. TARGet Kids!, the only child health research network embedded in primary care practices in Canada, leverages the unique relationship between children and families and their trusted primary care practitioners, with whom they have at least seven health supervision visits in the first 5 years of life. Children are enrolled during regularly scheduled well-child visits. To date, we have enrolled 5062 children. In addition to demographic information, we collect physical measurements (e.g. height, weight), lifestyle factors (nutrition, screen time and physical activity), child behaviour and developmental screening and a blood sample (providing measures of cardiometabolic, iron and vitamin D status, and trace metals). All data are collected at each well-child visit: twice a year until age 2 and every year until age 10. Information can be found at: http://www.targetkids.ca/contact-us/.

  8. Conserved roles for Polycomb Repressive Complex 2 in the regulation of lateral organ development in Aquilegia x coerulea ‘Origami’

    PubMed Central

    2013-01-01

    Background Epigenetic regulation is necessary for maintaining gene expression patterns in multicellular organisms. The Polycomb Group (PcG) proteins form several complexes with important and deeply conserved epigenetic functions in both the plant and animal kingdoms. One such complex, the Polycomb Repressive Complex 2 (PRC2), is critical to many developmental processes in plants including the regulation of major developmental transitions. In addition, PRC2 restricts the expression domain of various transcription factor families in Arabidopsis, including the class I KNOX genes and several of the ABCE class MADS box genes. While the functions of these transcription factors are known to be deeply conserved, whether or not their regulation by PRC2 is similarly conserved remains an open question. Results Here we use virus-induced gene silencing (VIGS) to characterize the function of the PRC2 complex in lateral organ development of Aquilegia x coerulea ‘Origami’, a member of the lower eudicot order Ranunculales. Leaves with PRC2 down-regulation displayed a range of phenotypes including ruffled or curled laminae, additional lobing, and an increased frequency of higher order branching. Sepals and petals were also affected, being narrowed, distorted, or, in the case of the sepals, exhibiting partial homeotic transformation. Many of the petal limbs also had a particularly intense yellow coloration due to an accumulation of carotenoid pigments. We show that the A. x coerulea floral MADS box genes AGAMOUS1 (AqAG1), APETALA3-3 (AqAP3-3) and SEPALLATA3 (AqSEP3) are up-regulated in many tissues, while expression of the class I KNOX genes and several candidate genes involved in carotenoid production or degradation are largely unaffected. Conclusions PRC2 targeting of several floral MADS box genes may be conserved in dicots, but other known targets do not appear to be. In the case of the type I KNOX genes, this may reflect a regulatory shift associated with the evolution of

  9. A positive role for polycomb in transcriptional regulation via H4K20me1

    PubMed Central

    Lv, Xiangdong; Han, Zhijun; Chen, Hao; Yang, Bo; Yang, Xiaofeng; Xia, Yuanxin; Pan, Chenyu; Fu, Lin; Zhang, Shuo; Han, Hui; Wu, Min; Zhou, Zhaocai; Zhang, Lei; Li, Lin; Wei, Gang; Zhao, Yun

    2016-01-01

    The highly conserved polycomb group (PcG) proteins maintain heritable transcription repression of the genes essential for development from fly to mammals. However, sporadic reports imply a potential role of PcGs in positive regulation of gene transcription, although systematic investigation of such function and the underlying mechanism has rarely been reported. Here, we report a Pc-mediated, H3K27me3-dependent positive transcriptional regulation of Senseless (Sens), a key transcription factor required for development. Mechanistic studies show that Pc regulates Sens expression by promoting H4K20me1 at the Sens locus. Further bioinformatic analysis at genome-wide level indicates that the existence of H4K20me1 acts as a selective mark for positive transcriptional regulation by Pc/H3K27me3. Both the intensities and specific patterns of Pc and H3K27me3 are important for the fates of target gene transcription. Moreover, binding of transcription factor Broad (Br), which physically interacts with Pc and positively regulates the transcription of Sens, is observed in Pc+H3K27me3+H4K20me1+ genes, but not in Pc+H3K27me3+H4K20me1− genes. Taken together, our study reveals that, coupling with the transcription factor Br, Pc positively regulates transcription of Pc+H3K27me3+H4K20me1+ genes in developing Drosophila wing disc. PMID:27002220

  10. The ASYMMETRIC LEAVES complex maintains repression of KNOX homeobox genes via direct recruitment of Polycomb-repressive complex2

    PubMed Central

    Lodha, Mukesh; Marco, Cristina F.; Timmermans, Marja C.P.

    2013-01-01

    Polycomb-repressive complexes (PRCs) ensure the correct spatiotemporal expression of numerous key developmental regulators. Despite their pivotal role, how PRCs are recruited to specific targets remains largely unsolved, particularly in plants. Here we show that the Arabidopsis ASYMMETRIC LEAVES complex physically interacts with PRC2 and recruits this complex to the homeobox genes BREVIPEDICELLUS and KNAT2 to stably silence these stem cell regulators in differentiating leaves. The recruitment mechanism resembles the Polycomb response element-based recruitment of PRC2 originally defined in flies and provides the first such example in plants. Combined with recent studies in mammals, our findings reveal a conserved paradigm to epigenetically regulate homeobox gene expression during development. PMID:23468429

  11. Checks and balances between cohesin and polycomb in gene silencing and transcription.

    PubMed

    Dorsett, Dale; Kassis, Judith A

    2014-06-02

    The cohesin protein complex was discovered for its roles in sister chromatid cohesion and segregation, and the Polycomb group (PcG) proteins for their roles in epigenetic gene silencing during development. Cohesin also controls gene transcription via multiple mechanisms. Genetic and molecular evidence from Drosophila argue that cohesin and the PRC1 PcG complex interact to control transcription of many active genes that are critical for development, and that via these interactions cohesin also controls the availability of PRC1 for gene silencing.

  12. Polycomb/Trithorax response elements and epigenetic memory of cell identity.

    PubMed

    Ringrose, Leonie; Paro, Renato

    2007-01-01

    Polycomb/Trithorax group response elements (PRE/TREs) are fascinating chromosomal pieces. Just a few hundred base pairs long, these elements can remember and maintain the active or silent transcriptional state of their associated genes for many cell generations, long after the initial determining activators and repressors have disappeared. Recently, substantial progress has been made towards understanding the nuts and bolts of PRE/TRE function at the molecular level and in experimentally mapping PRE/TRE sites across whole genomes. Here we examine the insights, controversies and new questions that have been generated by this recent flood of data.

  13. Wilms Tumor Suppressor, WT1, Cooperates with MicroRNA-26a and MicroRNA-101 to Suppress Translation of the Polycomb Protein, EZH2, in Mesenchymal Stem Cells*

    PubMed Central

    Akpa, Murielle M.; Iglesias, Diana; Chu, LeeLee; Thiébaut, Antonin; Jentoft, Ida; Hammond, Leah; Torban, Elena; Goodyer, Paul R.

    2016-01-01

    Hereditary forms of Wilms arise from developmentally arrested clones of renal progenitor cells with biallelic mutations of WT1; recently, it has been found that Wilms tumors may also be associated with biallelic mutations in DICER1 or DROSHA, crucial for miRNA biogenesis. We have previously shown that a critical role for WT1 during normal nephrogenesis is to suppress transcription of the Polycomb group protein, EZH2, thereby de-repressing genes in the differentiation cascade. Here we show that WT1 also suppresses translation of EZH2. All major WT1 isoforms induce an array of miRNAs, which target the 3′ UTR of EZH2 and other Polycomb-associated transcripts. We show that the WT1(+KTS) isoform binds to the 5′ UTR of EZH2 and interacts directly with the miRNA-containing RISC to enhance post-transcriptional inhibition. These observations suggest a novel mechanism through which WT1 regulates the transition from resting stem cell to activated progenitor cell during nephrogenesis. Our findings also offer a plausible explanation for the fact that Wilms tumors can arise either from loss of WT1 or loss of miRNA processing enzymes. PMID:26655220

  14. Polycomb genes interact with the tumor suppressor genes hippo and warts in the maintenance of Drosophila sensory neuron dendrites

    PubMed Central

    Parrish, Jay Z.; Emoto, Kazuo; Jan, Lily Yeh; Jan, Yuh Nung

    2007-01-01

    Dendritic fields are important determinants of neuronal function. However, how neurons establish and then maintain their dendritic fields is not well understood. Here we show that Polycomb group (PcG) genes are required for maintenance of complete and nonoverlapping dendritic coverage of the larval body wall by Drosophila class IV dendrite arborization (da) neurons. In esc, Su(z)12, or Pc mutants, dendritic fields are established normally, but class IV neurons display a gradual loss of dendritic coverage, while axons remain normal in appearance, demonstrating that PcG genes are specifically required for dendrite maintenance. Both multiprotein Polycomb repressor complexes (PRCs) involved in transcriptional silencing are implicated in regulation of dendrite arborization in class IV da neurons, likely through regulation of homeobox (Hox) transcription factors. We further show genetic interactions and association between PcG proteins and the tumor suppressor kinase Warts (Wts), providing evidence for their cooperation in multiple developmental processes including dendrite maintenance. PMID:17437999

  15. The Arabidopsis thaliana vernalization response requires a polycomb-like protein complex that also includes VERNALIZATION INSENSITIVE 3.

    PubMed

    Wood, Craig C; Robertson, Masumi; Tanner, Greg; Peacock, W James; Dennis, Elizabeth S; Helliwell, Chris A

    2006-09-26

    In Arabidopsis thaliana, the promotion of flowering by cold temperatures, vernalization, is regulated via a floral-repressive MADS box transcription factor, FLOWERING LOCUS C (FLC). Vernalization leads to the epigenetic repression of FLC expression, a process that requires the polycomb group (PcG) protein VERNALIZATION 2 (VRN2) and the plant homeodomain protein VERNALIZATION INSENSITIVE 3 (VIN3). We demonstrate that the repression of FLC by vernalization requires homologues of other Polycomb Repressive Complex 2 proteins and VRN2. We show in planta that VRN2 and VIN3 are part of a large protein complex that can include the PcG proteins FERTILIZATION INDEPENDENT ENDOSPERM, CURLY LEAF, and SWINGER. These findings suggest a single protein complex is responsible for histone deacetylation at FLC and histone methylation at FLC in vernalized plants. The abundance of the complex increases during vernalization and declines after plants are returned to higher temperatures, consistent with the complex having a role in establishing FLC repression.

  16. Polycomb- and REST-associated histone deacetylases are independent pathways toward a mature neuronal phenotype

    PubMed Central

    McGann, James C; Oyer, Jon A; Garg, Saurabh; Yao, Huilan; Liu, Jun; Feng, Xin; Liao, Lujian; Yates, John R; Mandel, Gail

    2014-01-01

    The bivalent hypothesis posits that genes encoding developmental regulators required for early lineage decisions are poised in stem/progenitor cells by the balance between a repressor histone modification (H3K27me3), mediated by the Polycomb Repressor Complex 2 (PRC2), and an activator modification (H3K4me3). In this study, we test whether this mechanism applies equally to genes that are not required until terminal differentiation. We focus on the RE1 Silencing Transcription Factor (REST) because it is expressed highly in stem cells and is an established global repressor of terminal neuronal genes. Elucidation of the REST complex, and comparison of chromatin marks and gene expression levels in control and REST-deficient stem cells, shows that REST target genes are poised by a mechanism independent of Polycomb, even at promoters which bear the H3K27me3 mark. Specifically, genes under REST control are actively repressed in stem cells by a balance of the H3K4me3 mark and a repressor complex that relies on histone deacetylase activity. Thus, chromatin distinctions between pro-neural and terminal neuronal genes are established at the embryonic stem cell stage by two parallel, but distinct, repressor pathways. DOI: http://dx.doi.org/10.7554/eLife.04235.001 PMID:25250711

  17. Polycomb recruitment attenuates retinoic acid-induced transcription of the bivalent NR2F1 gene.

    PubMed

    Laursen, Kristian B; Mongan, Nigel P; Zhuang, Yong; Ng, Mary M; Benoit, Yannick D; Gudas, Lorraine J

    2013-07-01

    Polycomb proteins play key roles in mediating epigenetic modifications that occur during cell differentiation. The Polycomb repressive complex 2 (PRC2) mediates the tri-methylation of histone H3 lysine 27 (H3K27me3). In this study, we identify a distinguishing feature of two classes of PRC2 target genes, represented by the Nr2F1 (Coup-TF1) and the Hoxa5 gene, respectively. Both genes are transcriptionally activated by all-trans retinoic acid (RA) and display increased levels of the permissive H3K9/K14ac and tri-methylated histone H3 lysine 4 epigenetic marks in response to RA. However, while in response to RA the PRC2 and H3K27me3 marks are greatly decreased at the Hoxa5 promoter, these marks are initially increased at the Nr2F1 promoter. Functional depletion of the essential PRC2 protein Suz12 by short hairpin RNA (shRNA) technology enhanced the RA-associated transcription of Nr2F1, Nr2F2, Meis1, Sox9 and BMP2, but had no effect on the Hoxa5, Hoxa1, Cyp26a1, Cyp26b1 and RARβ2 transcript levels in wild-type embryonic stem cells. We propose that PRC2 recruitment attenuates the RA-associated transcriptional activation of a subset of genes. Such a mechanism would permit the fine-tuning of transcriptional networks during differentiation.

  18. Polycomb RING1A- and RING1B-dependent histone H2A monoubiquitylation at pericentromeric regions promotes S-phase progression.

    PubMed

    Bravo, Mónica; Nicolini, Fabio; Starowicz, Katarzyna; Barroso, Sonia; Calés, Carmela; Aguilera, Andrés; Vidal, Miguel

    2015-10-01

    The functions of polycomb products extend beyond their well-known activity as transcriptional regulators to include genome duplication processes. Polycomb activities during DNA replication and DNA damage repair are unclear, particularly without induced replicative stress. We have used a cellular model of conditionally inactive polycomb E3 ligases (RING1A and RING1B), which monoubiquitylate lysine 119 of histone H2A (H2AK119Ub), to examine DNA replication in unperturbed cells. We identify slow elongation and fork stalling during DNA replication that is associated with the accumulation of mid and late S-phase cells. Signs of replicative stress and colocalisation of double-strand breaks with chromocenters, the sites of coalesced pericentromeric heterocromatic (PCH) domains, were enriched in cells at mid S-phase, the stage at which PCH is replicated. Altered replication was rescued by targeted monoubiquitylation of PCH through methyl-CpG binding domain protein 1. The acute senescence associated with the depletion of RING1 proteins, which is mediated by p21 (also known as CDKN1A) upregulation, could be uncoupled from a response to DNA damage. These findings link cell proliferation and the polycomb proteins RING1A and RING1B to S-phase progression through a specific function in PCH replication.

  19. Potential Cysteine Redox Regulation of the Polycomb Group

    DTIC Science & Technology

    2010-08-01

    study, Ph isolated from Drosophila embryos show little interaction with Scm. However, when recombinant proteins are co-expressed in Sf9 cells, Scm co...would be expected that they would have lower concentrations of reactive oxygen species9 compared to Sf9 cells which are derived from ovarian tissues of

  20. Swarm Robots Search for Multiple Targets Based on an Improved Grouping Strategy.

    PubMed

    Tang, Qirong; Ding, Lu; Yu, Fangchao; Zhang, Yuan; Li, Yinghao; Tu, Haibo

    2017-03-14

    Swarm robots search for multiple targets in collaboration in unknown environments has been addressed in this paper. An improved grouping strategy based on constriction factors Particle Swarm Optimization is proposed. Robots are grouped under this strategy after several iterations of stochastic movements, which considers the influence range of targets and environmental information they have sensed. The group structure may change dynamically and each group focuses on searching one target. All targets are supposed to be found finally. Obstacle avoidance is considered during the search process. Simulation compared with previous method demonstrates the adaptability, accuracy and efficiency of the proposed strategy in multiple targets searching.

  1. Polycomb complex PRC1 as gatekeeper of intestinal stem cell identity

    PubMed Central

    Léveillé, Nicolas

    2016-01-01

    Intestinal stem cells (ISCs) are adult multipotent cells essential for the maintenance of intestinal epithelial homeostasis. Wnt signaling activity ensures that the pool of ISCs at the basis of the intestinal crypts is preserved. Dysregulation of the Wnt pathway is often observed in cancer and supports malignant progression. Chiacchiera and colleagues recently demonstrated the implication of the polycomb complex PRC1 in the regulation of the Wnt pathway in adult ISCs. The authors show that PRC1 maintains intestinal homeostasis by repressing the expression of ZICs, a family of transcription factors inactivating the β-catenin/TCF complex. Importantly, interfering with PRC1 activity completely inhibits the formation of Wnt-dependent tumors. These findings reveal a new layer of epigenetic regulation of the Wnt pathway and open novel opportunities for cancer stem cell targeted therapy. PMID:27488310

  2. Trithorax monomethylates histone H3K4 and interacts directly with CBP to promote H3K27 acetylation and antagonize Polycomb silencing.

    PubMed

    Tie, Feng; Banerjee, Rakhee; Saiakhova, Alina R; Howard, Benny; Monteith, Kelsey E; Scacheri, Peter C; Cosgrove, Michael S; Harte, Peter J

    2014-03-01

    Trithorax (TRX) antagonizes epigenetic silencing by Polycomb group (PcG) proteins, stimulates enhancer-dependent transcription, and establishes a 'cellular memory' of active transcription of PcG-regulated genes. The mechanisms underlying these TRX functions remain largely unknown, but are presumed to involve its histone H3K4 methyltransferase activity. We report that the SET domains of TRX and TRX-related (TRR) have robust histone H3K4 monomethyltransferase activity in vitro and that Tyr3701 of TRX and Tyr2404 of TRR prevent them from being trimethyltransferases. The trx(Z11) missense mutation (G3601S), which abolishes H3K4 methyltransferase activity in vitro, reduces the H3K4me1 but not the H3K4me3 level in vivo. trx(Z11) also suppresses the impaired silencing phenotypes of the Pc(3) mutant, suggesting that H3K4me1 is involved in antagonizing Polycomb silencing. Polycomb silencing is also antagonized by TRX-dependent H3K27 acetylation by CREB-binding protein (CBP). We show that perturbation of Polycomb silencing by TRX overexpression requires CBP. We also show that TRX and TRR are each physically associated with CBP in vivo, that TRX binds directly to the CBP KIX domain, and that the chromatin binding patterns of TRX and TRR are highly correlated with CBP and H3K4me1 genome-wide. In vitro acetylation of H3K27 by CBP is enhanced on K4me1-containing H3 substrates, and independently altering the H3K4me1 level in vivo, via the H3K4 demethylase LSD1, produces concordant changes in H3K27ac. These data indicate that the catalytic activities of TRX and CBP are physically coupled and suggest that both activities play roles in antagonizing Polycomb silencing, stimulating enhancer activity and cellular memory.

  3. Bivalve molluscs as a unique target group for nanoparticle toxicity.

    PubMed

    Canesi, Laura; Ciacci, Caterina; Fabbri, Rita; Marcomini, Antonio; Pojana, Giulio; Gallo, Gabriella

    2012-05-01

    Due to the continuous development and production of manufactured nanomaterials or nanoparticles (NPs), their uptake and effects in the aquatic biota represent a major concern. Estuarine and coastal environments are expected to represent the ultimate sink for NPs, where their chemical behavior (aggregation/agglomeration) and consequent fate may be critical in determining the biological impact. Bivalve mollusks are abundant from freshwater to marine ecosystems, where they are widely utilized in biomonitoring of environmental perturbations. As suspension-feeders, they have highly developed processes for cellular internalization of nano- and micro-scale particles (endo- and phagocytosis), integral to key physiological functions such as intra-cellular digestion and cellular immunity. Here we will summarise available information on the effects of different types of NPs in different bivalve species, in particular Mytilus spp. Data on the effects and modes of action of different NPs on mussel hemocytes in vitro demonstrate that cell-mediated immunity represents a significant target for NPs. Moreover, in vivo exposure to NPs indicates that, due to the physiological mechanisms involved in the feeding process, NP agglomerates/aggregates taken up by the gills are directed to the digestive gland, where intra-cellular uptake of nanosized materials induces lysosomal perturbations and oxidative stress. Overall, bivalves represent a particularly suitable model for investigating the effects and mechanisms of action underlying the potential toxicity of NPs in marine invertebrates.

  4. 7 CFR 761.208 - Target participation rates for socially disadvantaged groups.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... disadvantaged groups. (a) General. (1) The Agency establishes target participation rates for providing FO and OL... percent of rural population in the county who are members of such socially disadvantaged groups. (c) OL loans based on ethnicity or race. The OL loan target participation rate based on ethnicity or race...

  5. Novel motifs distinguish multiple homologues of Polycomb in vertebrates: expansion and diversification of the epigenetic toolkit

    PubMed Central

    2009-01-01

    Background Polycomb group (PcG) proteins maintain expression pattern of genes set early during development. Although originally isolated as regulators of homeotic genes, PcG members play a key role in epigenetic mechanism that maintains the expression state of a large number of genes. Polycomb (PC) is conserved during evolution and while invertebrates have one PC gene, vertebrates have five or more homologues. It remains unclear if different vertebrate PC homologues have distinct or overlapping functions. We have identified and compared the sequence of PC homologues in various organisms to analyze similarities and differences that shaped the evolutionary history of this key regulatory protein. Results All PC homologues have an N-terminal chromodomain and a C-terminal Polycomb Repressor box. We searched the protein and genome sequence database of various organisms for these signatures and identified ~100 PC homologues. Comparative analysis of these sequences led to the identification of a novel insect specific motif and several novel and signature motifs in the vertebrate homologue: two in CBX2 (Cx2.1 and Cx2.2), four in CBX4 (Cx4.1, Cx4.2, Cx4.3 and Cx4.4), three in CBX6 (Cx6.1, Cx6.2 and Cx6.3) and one in CBX8 (Cx8.1). Additionally, adjacent to the chromodomain, all the vertebrate homologues have a DNA binding motif - AT-Hook in case of CBX2, which was known earlier, and 'AT-Hook Like' motif, from this study, in other PC homologues. Conclusion Our analysis shows that PC is an ancient gene dating back to pre bilaterian origin that has not only been conserved but has also expanded during the evolution of complexity. Unique motifs acquired by each homologue have been maintained for more than 500 millions years indicating their functional relevance in boosting the epigenetic 'tool kit'. We report the presence of a DNA interaction motif adjacent to chromodomain in all vertebrate PC homologues and suggest a three-way 'PC-histoneH3-DNA' interaction that can restrict

  6. Collaboration of MLLT1/ENL, Polycomb and ATM for transcription and genome integrity.

    PubMed

    Ui, Ayako; Yasui, Akira

    2016-04-25

    Polycomb group (PcG) repress, whereas Trithorax group (TrxG) activate transcription for tissue development and cellular proliferation, and misregulation of these factors is often associated with cancer. ENL (MLLT1) and AF9 (MLLT3) are fusion partners of Mixed Lineage Leukemia (MLL), TrxG proteins, and are factors in Super Elongation Complex (SEC). SEC controls transcriptional elongation to release RNA polymerase II, paused around transcription start site. In MLL rearranged leukemia, several components of SEC have been found as MLL-fusion partners and the control of transcriptional elongation is misregulated leading to tumorigenesis in MLL-SEC fused Leukemia. It has been suggested that unexpected collaboration of ENL/AF9-MLL and PcG are involved in tumorigenesis in leukemia. Recently, we found that the collaboration of ENL/AF9 and PcG led to a novel mechanism of transcriptional switch from elongation to repression under ATM-signaling for genome integrity. Activated ATM phosphorylates ENL/AF9 in SEC, and the phosphorylated ENL/AF9 binds BMI1 and RING1B, a heterodimeric E3-ubiquitin-ligase complex in Polycomb Repressive complex 1 (PRC1), and recruits PRC1 at transcriptional elongation sites to rapidly repress transcription. The ENL/AF9 in SEC- and PcG-mediated transcriptional repression promotes DSB repair near transcription sites. The implication of this is that the collaboration of ENL/AF9 in SEC and PcG ensures a rapid response of transcriptional switching from elongation to repression to neighboring genotoxic stresses for DSB repair. Therefore, these results suggested that the collaboration of ENL/AF9 and PcG in transcriptional control is required to maintain genome integrity and may be link to the MLL-ENL/AF9 leukemia.

  7. Global Comparison of Warring Groups in 2002–2007: Fatalities from Targeting Civilians vs. Fighting Battles

    PubMed Central

    Hicks, Madelyn Hsiao-Rei; Lee, Uih Ran; Sundberg, Ralph; Spagat, Michael

    2011-01-01

    Background Warring groups that compete to dominate a civilian population confront contending behavioral options: target civilians or battle the enemy. We aimed to describe degrees to which combatant groups concentrated lethal behavior into intentionally targeting civilians as opposed to engaging in battle with opponents in contemporary armed conflict. Methodology/Principal Findings We identified all 226 formally organized state and non-state groups (i.e. actors) that engaged in lethal armed conflict during 2002–2007: 43 state and 183 non-state. We summed civilians killed by an actor's intentional targeting with civilians and combatants killed in battles in which the actor was involved for total fatalities associated with each actor, indicating overall scale of armed conflict. We used a Civilian Targeting Index (CTI), defined as the proportion of total fatalities caused by intentional targeting of civilians, to measure the concentration of lethal behavior into civilian targeting. We report actor-specific findings and four significant trends: 1.) 61% of all 226 actors (95% CI 55% to 67%) refrained from targeting civilians. 2.) Logistic regression showed actors were more likely to have targeted civilians if conflict duration was three or more years rather than one year. 3.) In the 88 actors that targeted civilians, multiple regressions showed an inverse correlation between CTI values and the total number of fatalities. Conflict duration of three or more years was associated with lower CTI values than conflict duration of one year. 4.) When conflict scale and duration were accounted for, state and non-state actors did not differ. We describe civilian targeting by actors in prolonged conflict. We discuss comparable patterns found in nature and interdisciplinary research. Conclusions/Significance Most warring groups in 2002–2007 did not target civilians. Warring groups that targeted civilians in small-scale, brief conflict concentrated more lethal behavior into

  8. 48 CFR 952.226-73 - Energy Policy Act target group certification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Energy Policy Act target... ENERGY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 952.226-73 Energy Policy Act target group certification. As prescribed in 926.7007(d), insert...

  9. 48 CFR 952.226-73 - Energy Policy Act target group certification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Energy Policy Act target... ENERGY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 952.226-73 Energy Policy Act target group certification. As prescribed in 926.7007(d), insert...

  10. 48 CFR 952.226-73 - Energy Policy Act target group certification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Energy Policy Act target... ENERGY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 952.226-73 Energy Policy Act target group certification. As prescribed in 926.7007(d), insert...

  11. 48 CFR 952.226-73 - Energy Policy Act target group certification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Energy Policy Act target... ENERGY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 952.226-73 Energy Policy Act target group certification. As prescribed in 926.7007(d), insert...

  12. A two-step similarity-based method for prediction of drug's target group.

    PubMed

    Chen, Lei; Zeng, Wei-Ming

    2013-03-01

    Determination of drug's target protein is very important for studying drug-target interaction network, while drug-target interaction network is a key area in the drug discovery pipeline. Thus correct prediction of drug's target protein is very helpful to promote the development of drug discovery. In this study, we developed a two-step similarity-based method to predict drug's target group. In each step, a similarity score (obtained by graph representation in the first step, and chemical functional group representation in the second step) was employed to make prediction. Since some drugs can target proteins distributing in more than one group of proteins, the method provided a series of candidate target groups for each drug. As a result, the first-order prediction accuracy on training set and test set were 79.01% and 76.43%, respectively, which were much higher than the success rate of a random guess. The results show that using graph representation to encode drug is a good choice in this area. We expect that this contribution will provide some help to understand drug-target interaction network.

  13. Involvement of endometrial membrane sulphydryl groups in blastocyst implantation: sulphydryl groups as a potential target for contraceptive research.

    PubMed

    Nivsarkar, M; Sethi, A; Bapu, C; Patel, M; Padh, H

    2001-10-01

    The role of membrane sulphydryl groups in blastocyst implantation was studied by masking the membrane sulphydryl groups in the endometrium of Swiss albino mice, Mus musculus, using 10(-5) M cobalt chloride and 0.05 mM as well as 0.005 mM n-ethylmaleimide. Here we show that the blocking of sulphydryl groups with cobalt resulted in a decrease in superoxide radical surge and an increase in superoxide dismutase levels at the time of implantation. We hypothesize that it may be due to either a decrease in membrane fluidity or the unavailability of sulphydryl groups of endometrial membrane, thus preventing blastocyst implantation. These sulphydryl groups can be targeted for future contraceptive research.

  14. [Family Caregivers as a Target Group for Health Promotion and Prevention].

    PubMed

    Budnick, A; Dräger, D; Blüher, S; Kummer, K

    2015-09-01

    Family caregivers are a target group for health promotion, due to the various burdens. Against this background an assessment (ARR) was developed, implemented, and validated in the project "Health Promotion for Elderly Family Caregiver". On the basis of the ARR, family caregivers received an individual, need-oriented, and specific offer for health promotion. In order to reach the target group optimally, a national health insurance company was used.

  15. Jarid2 binds mono-ubiquitylated H2A lysine 119 to mediate crosstalk between Polycomb complexes PRC1 and PRC2

    PubMed Central

    Cooper, Sarah; Grijzenhout, Anne; Underwood, Elizabeth; Ancelin, Katia; Zhang, Tianyi; Nesterova, Tatyana B.; Anil-Kirmizitas, Burcu; Bassett, Andrew; Kooistra, Susanne M.; Agger, Karl; Helin, Kristian; Heard, Edith; Brockdorff, Neil

    2016-01-01

    The Polycomb repressive complexes PRC1 and PRC2 play a central role in developmental gene regulation in multicellular organisms. PRC1 and PRC2 modify chromatin by catalysing histone H2A lysine 119 ubiquitylation (H2AK119u1), and H3 lysine 27 methylation (H3K27me3), respectively. Reciprocal crosstalk between these modifications is critical for the formation of stable Polycomb domains at target gene loci. While the molecular mechanism for recognition of H3K27me3 by PRC1 is well defined, the interaction of PRC2 with H2AK119u1 is poorly understood. Here we demonstrate a critical role for the PRC2 cofactor Jarid2 in mediating the interaction of PRC2 with H2AK119u1. We identify a ubiquitin interaction motif at the amino-terminus of Jarid2, and demonstrate that this domain facilitates PRC2 localization to H2AK119u1 both in vivo and in vitro. Our findings ascribe a critical function to Jarid2 and define a key mechanism that links PRC1 and PRC2 in the establishment of Polycomb domains. PMID:27892467

  16. Loss of the polycomb mark from bivalent promoters leads to activation of cancer-promoting genes in colorectal tumors.

    PubMed

    Hahn, Maria A; Li, Arthur X; Wu, Xiwei; Yang, Richard; Drew, David A; Rosenberg, Daniel W; Pfeifer, Gerd P

    2014-07-01

    In colon tumors, the transcription of many genes becomes deregulated by poorly defined epigenetic mechanisms that have been studied mainly in established cell lines. In this study, we used frozen human colon tissues to analyze patterns of histone modification and DNA cytosine methylation in cancer and matched normal mucosa specimens. DNA methylation is strongly targeted to bivalent H3K4me3- and H3K27me3-associated promoters, which lose both histone marks and acquire DNA methylation. However, we found that loss of the Polycomb mark H3K27me3 from bivalent promoters was accompanied often by activation of genes associated with cancer progression, including numerous stem cell regulators, oncogenes, and proliferation-associated genes. Indeed, we found many of these same genes were also activated in patients with ulcerative colitis where chronic inflammation predisposes them to colon cancer. Based on our findings, we propose that a loss of Polycomb repression at bivalent genes combined with an ensuing selection for tumor-driving events plays a major role in cancer progression.

  17. A target group tracking algorithm for wireless sensor networks using azimuthal angle of arrival information

    NASA Astrophysics Data System (ADS)

    Zhang, Chun; Fei, Shu-Min; Zhou, Xing-Peng

    2012-12-01

    In this paper, we explore the technology of tracking a group of targets with correlated motions in a wireless sensor network. Since a group of targets moves collectively and is restricted within a limited region, it is not worth consuming scarce resources of sensors in computing the trajectory of each single target. Hence, in this paper, the problem is modeled as tracking a geographical continuous region covered by all targets. A tracking algorithm is proposed to estimate the region covered by the target group in each sampling period. Based on the locations of sensors and the azimuthal angle of arrival (AOA) information, the estimated region covering all the group members is obtained. Algorithm analysis provides the fundamental limits to the accuracy of localizing a target group. Simulation results show that the proposed algorithm is superior to the existing hull algorithm due to the reduction in estimation error, which is between 10% and 40% of the hull algorithm, with a similar density of sensors. And when the density of sensors increases, the localization accuracy of the proposed algorithm improves dramatically.

  18. Clustering of mammalian Hox genes with other H3K27me3 targets within an active nuclear domain.

    PubMed

    Vieux-Rochas, Maxence; Fabre, Pierre J; Leleu, Marion; Duboule, Denis; Noordermeer, Daan

    2015-04-14

    Embryogenesis requires the precise activation and repression of many transcriptional regulators. The Polycomb group proteins and the associated H3K27me3 histone mark are essential to maintain the inactive state of many of these genes. Mammalian Hox genes are targets of Polycomb proteins and form local 3D clusters centered on the H3K27me3 mark. More distal contacts have also been described, yet their selectivity, dynamics, and relation to other layers of chromatin organization remained elusive. We report that repressed Hox genes form mutual intra- and interchromosomal interactions with other genes located in strong domains labeled by H3K27me3. These interactions occur in a central and active nuclear environment that consists of the HiC compartment A, away from peripheral lamina-associated domains. Interactions are independent of nearby H3K27me3-marked loci and determined by chromosomal distance and cell-type-specific scaling factors, thus inducing a moderate reorganization during embryogenesis. These results provide a simplified view of nuclear organization whereby Polycomb proteins may have evolved to repress genes located in gene-dense regions whose position is restricted to central, active, nuclear environments.

  19. Appropriately Targeting Group Interventions for Academic Success Adopting the Clinical Model and PAR Profiles

    ERIC Educational Resources Information Center

    Johnson, Craig W.; Johnson, Ronald; Steigman, Michael; Odo, Chioma; Vijayan, Suvendra; Tata, Devadatta V.

    2016-01-01

    Prevalence of academic risk (PAR) group profiles provide data enabling empirically based group-specialized prescriptions for targeted academic success interventions to increase student retention, completion, and graduation rates, while improving allocation of institutional resources. Postsecondary student attrition engenders student debt,…

  20. Acting Diverse: Target Group Orientation as Key Competence in Engineering Education

    ERIC Educational Resources Information Center

    Ihsen, S.; Buschmeyer, A.

    2007-01-01

    International companies are recognised by equity between men and women as well as between other different groups (Diversity) as an economic factor and incorporate it into their company visions. Mixed teams are set up to design target group-oriented products, for example in automotive engineering. Therefore they need employees who represent the…

  1. Cooperative enclosing control for multiple moving targets by a group of agents

    NASA Astrophysics Data System (ADS)

    Shi, Y. J.; Li, R.; Teo, K. L.

    2015-01-01

    In this paper, the enclosing control problem of second-order multi-agent systems is considered, where the targets can be either stationary or moving. The objective is to achieve an equidistant circular formation for a group of agents to enclose a team of targets. In order to do so, we first introduce a formal definition explaining certain basic properties of the exploring relation between the agents and the targets. We then construct the estimator of the centre of the targets, which is used to build the control protocol to achieve equidistant circular enclosing. Using a Lyapunov function and Lasalle's Invariance Principle, the convergency of the estimator and control protocol are, respectively, established. We then construct a smooth function to approximate the discontinuous term in the estimator. Finally, the simulations for stationary targets and moving targets are given to verify the validity of the results obtained.

  2. The iab-7 Polycomb Response Element Maps to a Nucleosome-Free Region of Chromatin and Requires Both GAGA and Pleiohomeotic for Silencing Activity

    PubMed Central

    Mishra, Rakesh K.; Mihaly, Jozsef; Barges, Stéphane; Spierer, Annick; Karch, François; Hagstrom, Kirsten; Schweinsberg, Susan E.; Schedl, Paul

    2001-01-01

    In the work reported here we have undertaken a functional dissection of a Polycomb response element (PRE) from the iab-7 cis-regulatory domain of the Drosophila melanogaster bithorax complex (BX-C). Previous studies mapped the iab-7 PRE to an 860-bp fragment located just distal to the Fab-7 boundary. Located within this fragment is an ∼230-bp chromatin-specific nuclease-hypersensitive region called HS3. We have shown that HS3 is capable of functioning as a Polycomb-dependent silencer in vivo, inducing pairing-dependent silencing of a mini-white reporter. The HS3 sequence contains consensus binding sites for the GAGA factor, a protein implicated in the formation of nucleosome-free regions of chromatin, and Pleiohomeotic (Pho), a Polycomb group protein that is related to the mammalian transcription factor YY1. We show that GAGA and Pho interact with these sequences in vitro and that the consensus binding sites for the two proteins are critical for the silencing activity of the iab-7 PRE in vivo. PMID:11158316

  3. Identification of alsterpaullone as a novel small molecule inhibitor to target group 3 medulloblastoma.

    PubMed

    Faria, Claudia C; Agnihotri, Sameer; Mack, Stephen C; Golbourn, Brian J; Diaz, Roberto J; Olsen, Samantha; Bryant, Melissa; Bebenek, Matthew; Wang, Xin; Bertrand, Kelsey C; Kushida, Michelle; Head, Renee; Clark, Ian; Dirks, Peter; Smith, Christian A; Taylor, Michael D; Rutka, James T

    2015-08-28

    Advances in the molecular biology of medulloblastoma revealed four genetically and clinically distinct subgroups. Group 3 medulloblastomas are characterized by frequent amplifications of the oncogene MYC, a high incidence of metastasis, and poor prognosis despite aggressive therapy. We investigated several potential small molecule inhibitors to target Group 3 medulloblastomas based on gene expression data using an in silico drug screen. The Connectivity Map (C-MAP) analysis identified piperlongumine as the top candidate drug for non-WNT medulloblastomas and the cyclin-dependent kinase (CDK) inhibitor alsterpaullone as the compound predicted to have specific antitumor activity against Group 3 medulloblastomas. To validate our findings we used these inhibitors against established Group 3 medulloblastoma cell lines. The C-MAP predicted drugs reduced cell proliferation in vitro and increased survival in Group 3 medulloblastoma xenografts. Alsterpaullone had the highest efficacy in Group 3 medulloblastoma cells. Genomic profiling of Group 3 medulloblastoma cells treated with alsterpaullone confirmed inhibition of cell cycle-related genes, and down-regulation of MYC. Our results demonstrate the preclinical efficacy of using a targeted therapy approach for Group 3 medulloblastomas. Specifically, we provide rationale for advancing alsterpaullone as a targeted therapy in Group 3 medulloblastoma.

  4. Epigenetics of T cells regulated by Polycomb/Trithorax molecules.

    PubMed

    Onodera, Atsushi; Nakayama, Toshinori

    2015-05-01

    Epigenetics provides a bridge between genetic and environmental factors, and can change the transcriptional outcome of a gene without changing the genomic sequence. Allergies and autoimmune diseases are caused by both of these factors, and dynamic changes in epigenetic marks have been reported in T cells, which are key players in the pathogenesis of immune-mediated diseases. Advances in technology, including gene knockout systems and high-throughput sequencing, have significantly enhanced the understanding of the lifespan of T cells, including maturation, differentiation and memory formation. In this review, we focus on Polycomb and Trithorax proteins, well-characterized epigenetic modulators, and discuss their role in the epigenetic regulation of T cell differentiation and function.

  5. Deciphering the Role of POLYCOMB REPRESSIVE COMPLEX1 Variants in Regulating the Acquisition of Flowering Competence in Arabidopsis.

    PubMed

    Picó, Sara; Ortiz-Marchena, M Isabel; Merini, Wiam; Calonje, Myriam

    2015-08-01

    Polycomb group (PcG) proteins play important roles in regulating developmental phase transitions in plants; however, little is known about the role of the PcG machinery in regulating the transition from juvenile to adult phase. Here, we show that Arabidopsis (Arabidopsis thaliana) B lymphoma Moloney murine leukemia virus insertion region1 homolog (BMI1) POLYCOMB REPRESSIVE COMPLEX1 (PRC1) components participate in the repression of microRNA156 (miR156). Loss of AtBMI1 function leads to the up-regulation of the primary transcript of MIR156A and MIR156C at the time the levels of miR156 should decline, resulting in an extended juvenile phase and delayed flowering. Conversely, the PRC1 component EMBRYONIC FLOWER (EMF1) participates in the regulation of SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE and MIR172 genes. Accordingly, plants impaired in EMF1 function displayed misexpression of these genes early in development, which contributes to a CONSTANS-independent up-regulation of FLOWERING LOCUS T (FT) leading to the earliest flowering phenotype described in Arabidopsis. Our findings show how the different regulatory roles of two functional PRC1 variants coordinate the acquisition of flowering competence and help to reach the threshold of FT necessary to flower. Furthermore, we show how two central regulatory mechanisms, such as PcG and microRNA, assemble to achieve a developmental outcome.

  6. Polycomb protein SCML2 regulates the cell cycle by binding and modulating CDK/CYCLIN/p21 complexes.

    PubMed

    Lecona, Emilio; Rojas, Luis Alejandro; Bonasio, Roberto; Johnston, Andrew; Fernández-Capetillo, Oscar; Reinberg, Danny

    2013-12-01

    Polycomb group (PcG) proteins are transcriptional repressors of genes involved in development and differentiation, and also maintain repression of key genes involved in the cell cycle, indirectly regulating cell proliferation. The human SCML2 gene, a mammalian homologue of the Drosophila PcG protein SCM, encodes two protein isoforms: SCML2A that is bound to chromatin and SCML2B that is predominantly nucleoplasmic. Here, we purified SCML2B and found that it forms a stable complex with CDK/CYCLIN/p21 and p27, enhancing the inhibitory effect of p21/p27. SCML2B participates in the G1/S checkpoint by stabilizing p21 and favoring its interaction with CDK2/CYCE, resulting in decreased kinase activity and inhibited progression through G1. In turn, CDK/CYCLIN complexes phosphorylate SCML2, and the interaction of SCML2B with CDK2 is regulated through the cell cycle. These findings highlight a direct crosstalk between the Polycomb system of cellular memory and the cell-cycle machinery in mammals.

  7. A distal intergenic region controls pancreatic endocrine differentiation by acting as a transcriptional enhancer and as a polycomb response element.

    PubMed

    van Arensbergen, Joris; Dussaud, Sebastien; Pardanaud-Glavieux, Corinne; García-Hurtado, Javier; Sauty, Claire; Guerci, Aline; Ferrer, Jorge; Ravassard, Philippe

    2017-01-01

    Lineage-selective expression of developmental genes is dependent on the interplay between activating and repressive mechanisms. Gene activation is dependent on cell-specific transcription factors that recognize transcriptional enhancer sequences. Gene repression often depends on the recruitment of Polycomb group (PcG) proteins, although the sequences that underlie the recruitment of PcG proteins, also known as Polycomb response elements (PREs), remain poorly understood in vertebrates. While distal PREs have been identified in mammals, a role for positive-acting enhancers in PcG-mediated repression has not been described. Here we have used a highly efficient procedure based on lentiviral-mediated transgenesis to carry out in vivo fine-mapping of, cis-regulatory sequences that control lineage-specific activation of Neurog3, a master regulator of pancreatic endocrine differentiation. Our findings reveal an enhancer region that is sufficient to drive correct spacio-temporal expression of Neurog3 and demonstrate that this same region serves as a PRE in alternative lineages where Neurog3 is inactive.

  8. Deciphering the Role of POLYCOMB REPRESSIVE COMPLEX1 Variants in Regulating the Acquisition of Flowering Competence in Arabidopsis1

    PubMed Central

    Picó, Sara; Merini, Wiam

    2015-01-01

    Polycomb group (PcG) proteins play important roles in regulating developmental phase transitions in plants; however, little is known about the role of the PcG machinery in regulating the transition from juvenile to adult phase. Here, we show that Arabidopsis (Arabidopsis thaliana) B lymphoma Moloney murine leukemia virus insertion region1 homolog (BMI1) POLYCOMB REPRESSIVE COMPLEX1 (PRC1) components participate in the repression of microRNA156 (miR156). Loss of AtBMI1 function leads to the up-regulation of the primary transcript of MIR156A and MIR156C at the time the levels of miR156 should decline, resulting in an extended juvenile phase and delayed flowering. Conversely, the PRC1 component EMBRYONIC FLOWER (EMF1) participates in the regulation of SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE and MIR172 genes. Accordingly, plants impaired in EMF1 function displayed misexpression of these genes early in development, which contributes to a CONSTANS-independent up-regulation of FLOWERING LOCUS T (FT) leading to the earliest flowering phenotype described in Arabidopsis. Our findings show how the different regulatory roles of two functional PRC1 variants coordinate the acquisition of flowering competence and help to reach the threshold of FT necessary to flower. Furthermore, we show how two central regulatory mechanisms, such as PcG and microRNA, assemble to achieve a developmental outcome. PMID:25897002

  9. A distal intergenic region controls pancreatic endocrine differentiation by acting as a transcriptional enhancer and as a polycomb response element

    PubMed Central

    Pardanaud-Glavieux, Corinne; García-Hurtado, Javier; Sauty, Claire; Guerci, Aline; Ferrer, Jorge

    2017-01-01

    Lineage-selective expression of developmental genes is dependent on the interplay between activating and repressive mechanisms. Gene activation is dependent on cell-specific transcription factors that recognize transcriptional enhancer sequences. Gene repression often depends on the recruitment of Polycomb group (PcG) proteins, although the sequences that underlie the recruitment of PcG proteins, also known as Polycomb response elements (PREs), remain poorly understood in vertebrates. While distal PREs have been identified in mammals, a role for positive-acting enhancers in PcG-mediated repression has not been described. Here we have used a highly efficient procedure based on lentiviral-mediated transgenesis to carry out in vivo fine-mapping of, cis-regulatory sequences that control lineage-specific activation of Neurog3, a master regulator of pancreatic endocrine differentiation. Our findings reveal an enhancer region that is sufficient to drive correct spacio-temporal expression of Neurog3 and demonstrate that this same region serves as a PRE in alternative lineages where Neurog3 is inactive. PMID:28225770

  10. Group II p21-activated kinases as therapeutic targets in gastrointestinal cancer

    PubMed Central

    Shao, Yang-Guang; Ning, Ke; Li, Feng

    2016-01-01

    P21-activated kinases (PAKs) are central players in various oncogenic signaling pathways. The six PAK family members are classified into group I (PAK1-3) and group II (PAK4-6). Focus is currently shifting from group I PAKs to group II PAKs. Group II PAKs play important roles in many fundamental cellular processes, some of which have particular significance in the development and progression of cancer. Because of their important functions, group II PAKs have become popular potential drug target candidates. However, few group II PAKs inhibitors have been reported, and most do not exhibit satisfactory kinase selectivity and “drug-like” properties. Isoform- and kinase-selective PAK inhibitors remain to be developed. This review describes the biological activities of group II PAKs, the importance of group II PAKs in the development and progression of gastrointestinal cancer, and small-molecule inhibitors of group II PAKs for the treatment of cancer. PMID:26811660

  11. ZRF1 Chromatin Regulators Have Polycomb Silencing and Independent Roles in Development1[OPEN

    PubMed Central

    Chen, Donghong; Berr, Alexandre

    2016-01-01

    Histone H2A monoubiquitination (H2Aub1), catalyzed by Polycomb-Repressive Complex1 (PRC1), is a key epigenetic mark in Polycomb silencing. However, little is known about how H2Aub1 is read to exert downstream physiological functions. The animal ZUOTIN-RELATED FACTOR1 (ZRF1) has been reported to bind H2Aub1 to promote or repress the expression of varied target genes. Here, we show that the Arabidopsis (Arabidopsis thaliana) ZRF1 homologs, AtZRF1a and AtZRF1b, are key regulators of multiple processes during plant growth and development. Loss of function of both AtZRF1a and AtZRF1b in atzrf1a atzrf1b mutants causes seed germination delay, small plant size, abnormal meristem activity, abnormal flower development, as well as gametophyte transmission and embryogenesis defects. Some of these defects overlap with those described previously in the PRC1-defective mutants atbmi1a atbmi1b and atring1a atring1b, but others are specific to atzrf1a atzrf1b. In line with this, 4,519 genes (representing more than 14% of all genes) within the Arabidopsis genome are found differentially expressed in atzrf1a atzrf1b seedlings, and among them, 114 genes are commonly up-regulated in atring1a atring1b and atbmi1a atbmi1b. Finally, we show that in both atzrf1a atzrf1b and atbmi1a atbmi1b seedlings, the seed developmental genes ABSCISIC ACID INSENSITIVE3, CRUCIFERIN3, and CHOTTO1 are derepressed, in association with the reduced levels of H2Aub1 and histone H3 lysine-27 trimethylation (H3K27me3). Collectively, our results indicate that AtZRF1a/b play both PRC1-related and PRC1-unrelated functions in regulating plant growth and development and that AtZRF1a/b promote H2Aub1 and H3K27me3 deposition in gene suppression. Our work provides novel insight into the mechanisms of function of this family of evolutionarily conserved chromatin regulators. PMID:27630184

  12. Polycomb protein EZH2 regulates cancer cell fate decision in response to DNA damage.

    PubMed

    Wu, Z; Lee, S T; Qiao, Y; Li, Z; Lee, P L; Lee, Y J; Jiang, X; Tan, J; Aau, M; Lim, C Z H; Yu, Q

    2011-11-01

    Polycomb protein histone methyltransferase enhancer of Zeste homologe 2 (EZH2) is frequently overexpressed in human malignancy and is implicated in cancer cell proliferation and invasion. However, it is largely unknown whether EZH2 has a role in modulating DNA damage response. Here, we show that EZH2 is an important determinant of cell fate decision in response to genotoxic stress. EZH2 depletion results in abrogation of both cell cycle G1 and G2/M checkpoints, directing DNA damage response toward predominant apoptosis in both p53-proficient and p53-deficient cancer cells, but not in normal cells. Mechanistically, EZH2 regulates DNA damage response in p53 wild-type cells mainly through transcriptional repression of FBXO32, which binds to and directs p21 for proteasome-mediated degradation, whereas it affects p53-deficient cells through regulating Chk1 activation by a distinct mechanism. Furthermore, pharmacological depletion of EZH2 phenocopies the effects of EZH2 knockdown on cell cycle checkpoints and apoptosis. These data unravel a crucial role of EZH2 in determining the cancer cell outcome following DNA damage and suggest that therapeutic targeting oncogenic EZH2 might serve as a strategy for improving conventional chemotherapy in a given malignancy.

  13. Experiential Learning Methods, Simulation Complexity and Their Effects on Different Target Groups

    ERIC Educational Resources Information Center

    Kluge, Annette

    2007-01-01

    This article empirically supports the thesis that there is no clear and unequivocal argument in favor of simulations and experiential learning. Instead the effectiveness of simulation-based learning methods depends strongly on the target group's characteristics. Two methods of supporting experiential learning are compared in two different complex…

  14. Lysis of typhus-group rickettsia-infected targets by lymphokine activated killers

    SciTech Connect

    Carl, M.; Dasch, G.A.

    1986-03-01

    The authors recently described a subset of OKT8, OKT3-positive lymphocytes from typhus-group rickettsia immune individuals which were capable of lysing autologous PHA-blasts or Epstein-Barr virus transformed B cells (LCL) infected with typhus-group rickettsiae. In order to determine if killing by these effectors was HLA-restricted, they stimulated peripheral blood mononuclear cells (PBMC) from typhus-group rickettsia immune individuals in vitro with typhus-group rickettsia-derived antigen for one week and then measured lysis of autologous LCL or HLA-mismatched LCL in a 4-6 hour Cr/sup 51/-release assay. There was significant lysis of both the autologous and the HLA-mismatched infected targets as compared to the corresponding uninfected targets. Since this suggested that the effectors were lymphokine activated killers (LAK) rather than cytotoxic T lymphocytes, they then tested this hypothesis by stimulating PBMC from both immune and non-immune individuals in vitro for one week with purified interleukin 2 and measuring lysis of infected, autologous LCL. PBMC thus treated, from both immune and non-immune individuals, were capable of significantly lysing autologous, infected LCL as compared to the non-infected control. They therefore conclude that targets infected with typhus-group rickettsiae are susceptible to lysis to LAK.

  15. The Arabidopsis SWI2/SNF2 Chromatin Remodeler BRAHMA Regulates Polycomb Function during Vegetative Development and Directly Activates the Flowering Repressor Gene SVP

    PubMed Central

    Li, Chenlong; Chen, Chen; Gao, Lei; Yang, Songguang; Nguyen, Vi; Shi, Xuejiang; Siminovitch, Katherine; Kohalmi, Susanne E.; Huang, Shangzhi; Wu, Keqiang; Chen, Xuemei; Cui, Yuhai

    2015-01-01

    The chromatin remodeler BRAHMA (BRM) is a Trithorax Group (TrxG) protein that antagonizes the functions of Polycomb Group (PcG) proteins in fly and mammals. Recent studies also implicate such a role for Arabidopsis (Arabidopsis thaliana) BRM but the molecular mechanisms underlying the antagonism are unclear. To understand the interplay between BRM and PcG during plant development, we performed a genome-wide analysis of trimethylated histone H3 lysine 27 (H3K27me3) in brm mutant seedlings by chromatin immunoprecipitation followed by next generation sequencing (ChIP-seq). Increased H3K27me3 deposition at several hundred genes was observed in brm mutants and this increase was partially supressed by removal of the H3K27 methyltransferase CURLY LEAF (CLF) or SWINGER (SWN). ChIP experiments demonstrated that BRM directly binds to a subset of the genes and prevents the inappropriate association and/or activity of PcG proteins at these loci. Together, these results indicate a crucial role of BRM in restricting the inappropriate activity of PcG during plant development. The key flowering repressor gene SHORT VEGETATIVE PHASE (SVP) is such a BRM target. In brm mutants, elevated PcG occupancy at SVP accompanies a dramatic increase in H3K27me3 levels at this locus and a concomitant reduction of SVP expression. Further, our gain- and loss-of-function genetic evidence establishes that BRM controls flowering time by directly activating SVP expression. This work reveals a genome-wide functional interplay between BRM and PcG and provides new insights into the impacts of these proteins in plant growth and development. PMID:25615622

  16. The Arabidopsis SWI2/SNF2 chromatin Remodeler BRAHMA regulates polycomb function during vegetative development and directly activates the flowering repressor gene SVP.

    PubMed

    Li, Chenlong; Chen, Chen; Gao, Lei; Yang, Songguang; Nguyen, Vi; Shi, Xuejiang; Siminovitch, Katherine; Kohalmi, Susanne E; Huang, Shangzhi; Wu, Keqiang; Chen, Xuemei; Cui, Yuhai

    2015-01-01

    The chromatin remodeler BRAHMA (BRM) is a Trithorax Group (TrxG) protein that antagonizes the functions of Polycomb Group (PcG) proteins in fly and mammals. Recent studies also implicate such a role for Arabidopsis (Arabidopsis thaliana) BRM but the molecular mechanisms underlying the antagonism are unclear. To understand the interplay between BRM and PcG during plant development, we performed a genome-wide analysis of trimethylated histone H3 lysine 27 (H3K27me3) in brm mutant seedlings by chromatin immunoprecipitation followed by next generation sequencing (ChIP-seq). Increased H3K27me3 deposition at several hundred genes was observed in brm mutants and this increase was partially supressed by removal of the H3K27 methyltransferase CURLY LEAF (CLF) or SWINGER (SWN). ChIP experiments demonstrated that BRM directly binds to a subset of the genes and prevents the inappropriate association and/or activity of PcG proteins at these loci. Together, these results indicate a crucial role of BRM in restricting the inappropriate activity of PcG during plant development. The key flowering repressor gene SHORT VEGETATIVE PHASE (SVP) is such a BRM target. In brm mutants, elevated PcG occupancy at SVP accompanies a dramatic increase in H3K27me3 levels at this locus and a concomitant reduction of SVP expression. Further, our gain- and loss-of-function genetic evidence establishes that BRM controls flowering time by directly activating SVP expression. This work reveals a genome-wide functional interplay between BRM and PcG and provides new insights into the impacts of these proteins in plant growth and development.

  17. Unique Polycomb Gene Expression Pattern in Hodgkin’s Lymphoma and Hodgkin’s Lymphoma-Derived Cell Lines

    PubMed Central

    Dukers, Danny F.; van Galen, Joost C.; Giroth, Cindy; Jansen, Patty; Sewalt, Richard G.A.B.; Otte, Arie P.; Kluin-Nelemans, Hanneke C.; Meijer, Chris J.L.M.; Raaphorst, Frank M.

    2004-01-01

    Human Polycomb-group (PcG) genes play a crucial role in the regulation of embryonic development and regulation of the cell cycle and hematopoiesis. PcG genes encode proteins that form two distinct PcG complexes, involved in maintenance of cell identity and gene silencing patterns. We recently showed that expression of the BMI-1 and EZH2 PcG genes is separated during normal B-cell development in germinal centers, whereas Hodgkin/Reed-Sternberg (H/RS) cells co-express BMI-1 and EZH2. In the current study, we used immunohistochemistry and immunofluorescence to determine whether the binding partners of these PcG proteins are also present in H/RS cells and H/RS-derived cell lines. PcG expression profiles were analyzed in combination with expression of the cell cycle inhibitor p16INK4a, because experimental model systems indicate that p16 is a downstream target of Bmi-1. We found that H/RS cells and HL-derived cell lines co-express all core proteins of the two known PcG complexes, including BMI-1, MEL-18, RING1, HPH1, HPC1, and -2, EED, EZH2, YY1, and the HPC2 binding partner, CtBP. Expression of HPC1 has not been found in normal mature B cells and other malignant lymphomas of B-cell origin, suggesting that the PcG expression profile of H/RS is unique. In contrast to Bmi-1 transgenic mice where p16INK4a is down-regulated, 27 of 52 BMI-1POS cases of HL revealed strong nuclear expression of p16INK4a. We propose that abnormal expression of BMI-1 and its binding partners in H/RS cells contributes to development of HL. However, abnormal expression of BMI-1 in HL is not necessarily associated with down-regulation of p16INK4a. PMID:14982841

  18. A New Strategy to Reduce Influenza Escape: Detecting Therapeutic Targets Constituted of Invariance Groups.

    PubMed

    Lao, Julie; Vanet, Anne

    2017-03-02

    The pathogenicity of the different flu species is a real public health problem worldwide. To combat this scourge, we established a method to detect drug targets, reducing the possibility of escape. Besides being able to attach a drug candidate, these targets should have the main characteristic of being part of an essential viral function. The invariance groups that are sets of residues bearing an essential function can be detected genetically. They consist of invariant and synthetic lethal residues (interdependent residues not varying or slightly varying when together). We analyzed an alignment of more than 10,000 hemagglutinin sequences of influenza to detect six invariance groups, close in space, and on the protein surface. In parallel we identified five potential pockets on the surface of hemagglutinin. By combining these results, three potential binding sites were determined that are composed of invariance groups located respectively in the vestigial esterase domain, in the bottom of the stem and in the fusion area. The latter target is constituted of residues involved in the spring-loaded mechanism, an essential step in the fusion process. We propose a model describing how this potential target could block the reorganization of the hemagglutinin HA2 secondary structure and prevent viral entry into the host cell.

  19. A New Strategy to Reduce Influenza Escape: Detecting Therapeutic Targets Constituted of Invariance Groups

    PubMed Central

    Lao, Julie; Vanet, Anne

    2017-01-01

    The pathogenicity of the different flu species is a real public health problem worldwide. To combat this scourge, we established a method to detect drug targets, reducing the possibility of escape. Besides being able to attach a drug candidate, these targets should have the main characteristic of being part of an essential viral function. The invariance groups that are sets of residues bearing an essential function can be detected genetically. They consist of invariant and synthetic lethal residues (interdependent residues not varying or slightly varying when together). We analyzed an alignment of more than 10,000 hemagglutinin sequences of influenza to detect six invariance groups, close in space, and on the protein surface. In parallel we identified five potential pockets on the surface of hemagglutinin. By combining these results, three potential binding sites were determined that are composed of invariance groups located respectively in the vestigial esterase domain, in the bottom of the stem and in the fusion area. The latter target is constituted of residues involved in the spring-loaded mechanism, an essential step in the fusion process. We propose a model describing how this potential target could block the reorganization of the hemagglutinin HA2 secondary structure and prevent viral entry into the host cell. PMID:28257108

  20. Target selection and comparison of mission design for space debris removal by DLR's advanced study group

    NASA Astrophysics Data System (ADS)

    van der Pas, Niels; Lousada, Joao; Terhes, Claudia; Bernabeu, Marc; Bauer, Waldemar

    2014-09-01

    Space debris is a growing problem. Models show that the Kessler syndrome, the exponential growth of debris due to collisions, has become unavoidable unless an active debris removal program is initiated. The debris population in LEO with inclination between 60° and 95° is considered as the most critical zone. In order to stabilize the debris population in orbit, especially in LEO, 5 to 10 objects will need to be removed every year. The unique circumstances of such a mission could require that several objects are removed with a single launch. This will require a mission to rendezvous with a multitude of objects orbiting on different altitudes, inclinations and planes. Removal models have assumed that the top priority targets will be removed first. However this will lead to a suboptimal mission design and increase the ΔV-budget. Since there is a multitude of targets to choose from, the targets can be selected for an optimal mission design. In order to select a group of targets for a removal mission the orbital parameters and political constraints should also be taken into account. Within this paper a number of the target selection criteria are presented. The possible mission targets and their order of retrieval is dependent on the mission architecture. A comparison between several global mission architectures is given. Under consideration are 3 global missions of which a number of parameters are varied. The first mission launches multiple separate deorbit kits. The second launches a mother craft with deorbit kits. The third launches an orbital tug which pulls the debris in a lower orbit, after which a deorbit kit performs the final deorbit burn. A RoM mass and cost comparison is presented. The research described in this paper has been conducted as part of an active debris removal study by the Advanced Study Group (ASG). The ASG is an interdisciplinary student group working at the DLR, analyzing existing technologies and developing new ideas into preliminary

  1. Polycomb Repressive Complex 2 Controls the Embryo-to-Seedling Phase Transition

    PubMed Central

    Bouyer, Daniel; Roudier, Francois; Heese, Maren; Andersen, Ellen D.; Gey, Delphine; Nowack, Moritz K.; Goodrich, Justin; Renou, Jean-Pierre; Grini, Paul E.; Colot, Vincent; Schnittger, Arp

    2011-01-01

    Polycomb repressive complex 2 (PRC2) is a key regulator of epigenetic states catalyzing histone H3 lysine 27 trimethylation (H3K27me3), a repressive chromatin mark. PRC2 composition is conserved from humans to plants, but the function of PRC2 during the early stage of plant life is unclear beyond the fact that it is required for the development of endosperm, a nutritive tissue that supports embryo growth. Circumventing the requirement of PRC2 in endosperm allowed us to generate viable homozygous null mutants for FERTILIZATION INDEPENDENT ENDOSPERM (FIE), which is the single Arabidopsis homolog of Extra Sex Combs, an indispensable component of Drosophila and mammalian PRC2. Here we show that H3K27me3 deposition is abolished genome-wide in fie mutants demonstrating the essential function of PRC2 in placing this mark in plants as in animals. In contrast to animals, we find that PRC2 function is not required for initial body plan formation in Arabidopsis. Rather, our results show that fie mutant seeds exhibit enhanced dormancy and germination defects, indicating a deficiency in terminating the embryonic phase. After germination, fie mutant seedlings switch to generative development that is not sustained, giving rise to neoplastic, callus-like structures. Further genome-wide studies showed that only a fraction of PRC2 targets are transcriptionally activated in fie seedlings and that this activation is accompanied in only a few cases with deposition of H3K4me3, a mark associated with gene activity and considered to act antagonistically to H3K27me3. Up-regulated PRC2 target genes were found to act at different hierarchical levels from transcriptional master regulators to a wide range of downstream targets. Collectively, our findings demonstrate that PRC2-mediated regulation represents a robust system controlling developmental phase transitions, not only from vegetative phase to flowering but also especially from embryonic phase to the seedling stage. PMID:21423668

  2. Bounded openness: The effect of openness to experience on intolerance is moderated by target group conventionality.

    PubMed

    Brandt, Mark J; Chambers, John R; Crawford, Jarret T; Wetherell, Geoffrey; Reyna, Christine

    2015-09-01

    Openness to experience is consistently associated with tolerance. We suggest that tests of the association between openness to experience and tolerance have heretofore been incomplete because they have primarily focused on prejudice toward unconventional target groups. We test (a) the individual difference perspective, which predicts that because people who are high in openness are more open to diverse and dissimilar people and ideas, they will express more tolerance than people who are low in openness and (b) the worldview conflict perspective, which predicts that people high and low in openness will both be intolerant toward those with different worldviews. Four studies, using both conventional and unconventional target groups, find support for an integrative perspective. People high in openness do appear more tolerant of diverse worldviews compared with people low in openness; however, at the same time, people both high and low in openness are more intolerant of groups whose worldviews conflict with their own. These findings highlight the need to consider how individual difference variables and features of the target groups may interact in important ways to influence the expression of prejudice.

  3. A Polycomb and Gaga Dependent Silencer Adjoins the Fab-7 Boundary in the Drosophila Bithorax Complex

    PubMed Central

    Hagstrom, K.; Muller, M.; Schedl, P.

    1997-01-01

    The homeotic genes of the Drosophila bithorax complex are controlled by a large cis-regulatory region that ensures their segmentally restricted pattern of expression. A deletion that removes the Frontabdominal-7 cis-regulatory region (Fab-7(1)) dominantly transforms parasegment 11 into parasegment 12. Previous studies suggested that removal of a domain boundary element on the proximal side of Fab-7(1) is responsible for this gain-of-function phenotype. In this article we demonstrate that the Fab-7(1) deletion also removes a silencer element, the iab-7 PRE, which maps to a different DNA segment and plays a different role in regulating parasegment-specific expression patterns of the Abd-B gene. The iab-7 PRE mediates pairing-sensitive silencing of mini-white, and can maintain the segmentally restricted expression pattern of a BXD, Ubx/lacZ reporter transgene. Both silencing activities depend upon Polycomb Group proteins. Pairing-sensitive silencing is relieved by removing the transvection protein Zeste, but is enhanced in a novel pairing-independent manner by the zeste(1) allele. The iab-7 PRE silencer is contained within a 0.8-kb fragment that spans a nuclease hypersensitive site, and silencing appears to depend on the chromatin remodeling protein, the GAGA factor. PMID:9258680

  4. Polycomb silencing: from linear chromatin domains to 3D chromosome folding.

    PubMed

    Cheutin, Thierry; Cavalli, Giacomo

    2014-04-01

    Polycomb group (PcG) proteins are conserved chromatin factors that regulate key developmental genes. Genome wide studies have shown that PcG proteins and their associated H3K27me3 histone mark cover long genomic domains. PcG proteins and H3K27me3 accumulate in Pc nuclear foci, which are the cellular counterparts of genomic domains silenced by PcG proteins. One explanation for how large genomic domains form nuclear foci may rely on loops occurring between specific elements located within domains. However, recent improvement of the chromosome conformation capture (3C) technology, which allowed monitoring genome wide contacts depicts a more complex picture in which chromosomes are composed of many topologically associating domains (TADs). Chromatin regions marked with H3K27me3 correspond to one class of TADs and PcG proteins participate in long-range interactions of H3K27me3 TADs, whereas insulator proteins seem to be important for separating TADs and may also participate in the regulation of intra TAD architecture. Recent data converge to suggest that this hierarchical organization of chromosome domains plays an important role in genome function during cell proliferation and differentiation.

  5. The C. elegans Polycomb gene SOP-2 encodes an RNA binding protein.

    PubMed

    Zhang, Hong; Christoforou, Andrea; Aravind, L; Emmons, Scott W; van den Heuvel, Sander; Haber, Daniel A

    2004-06-18

    Epigenetic silencing of Hox cluster genes by Polycomb group (PcG) proteins is thought to involve the formation of a stably inherited repressive chromatin structure. Here we show that the C. elegans-specific PcG protein SOP-2 directly binds to RNA through three nonoverlapping regions, each of which is essential for its localization to characteristic nuclear bodies and for its in vivo function in the repression of Hox genes. Functional studies indicate that the RNA involved in SOP-2 binding is distinct from either siRNA or microRNA. Remarkably, the vertebrate PcG protein Rae28, which is functionally and structurally related to SOP-2, also binds to RNA through an FCS finger domain. Substitution of the Rae28 FCS finger for the essential RNA binding region of SOP-2 partially restores localization to nuclear bodies. These observations suggest that direct binding to RNA is an evolutionarily conserved and potentially important property of PcG proteins.

  6. LATS2 Positively Regulates Polycomb Repressive Complex 2

    PubMed Central

    Torigata, Kosuke; Daisuke, Okuzaki; Mukai, Satomi; Hatanaka, Akira; Ohka, Fumiharu; Motooka, Daisuke; Nakamura, Shota; Ohkawa, Yasuyuki; Yabuta, Norikazu; Kondo, Yutaka; Nojima, Hiroshi

    2016-01-01

    LATS2, a pivotal Ser/Thr kinase of the Hippo pathway, plays important roles in many biological processes. LATS2 also function in Hippo-independent pathway, including mitosis, DNA damage response and epithelial to mesenchymal transition. However, the physiological relevance and molecular basis of these LATS2 functions remain obscure. To understand novel functions of LATS2, we constructed a LATS2 knockout HeLa-S3 cell line using TAL-effector nuclease (TALEN). Integrated omics profiling of this cell line revealed that LATS2 knockout caused genome-wide downregulation of Polycomb repressive complex 2 (PRC2) and H3K27me3. Cell-cycle analysis revealed that downregulation of PRC2 was not due to cell cycle aberrations caused by LATS2 knockout. Not LATS1, a homolog of LATS2, but LATS2 bound PRC2 on chromatin and phosphorylated it. LATS2 positively regulates histone methyltransferase activity of PRC2 and their expression at both the mRNA and protein levels. Our findings reveal a novel signal upstream of PRC2, and provide insight into the crucial role of LATS2 in coordinating the epigenome through regulation of PRC2. PMID:27434182

  7. Possible roles for polycomb repressive complex 2 in cereal endosperm

    PubMed Central

    Tonosaki, Kaoru; Kinoshita, Tetsu

    2015-01-01

    The polycomb repressive complex 2 (PRC2) is an evolutionarily conserved multimeric protein complex in both plants and animals. In contrast to animals, plants have evolved a range of different components of PRC2 and form diverse complexes that act in the control of key regulatory genes at many stages of development during the life cycle. A number of studies, particularly in the model species Arabidopsis thaliana, have highlighted the role of PRC2 and of epigenetic controls via parent-of-origin specific gene expression for endosperm development. However, recent research in cereal plants has revealed that although some components of PRC2 show evolutionary conservation with respect to parent-of-origin specific gene expression patterns, the identity of the imprinted genes encoding PRC2 components is not conserved. This disparity may reflect the facts that cereal plant genomes have undergone different patterns of duplication during evolution compared to A. thaliana and that the endosperm development program is not identical in monocots and eudicots. In this context, we focus this review on the expression of imprinted PRC2 genes and their roles in endosperm development in cereals. PMID:25814998

  8. Chatters on the Internet: a special target group for HIV prevention.

    PubMed

    Hospers, H J; Harterink, P; Van Den Hoek, K; Veenstra, J

    2002-08-01

    This study examined characteristics of men who use gay chat boxes on the Internet, including dating behaviour and sexual risk-taking with sex partners who were initially met through chatting. Men on chat boxes were asked to complete a brief questionnaire on the Internet. The questionnaire contained questions on demographics, chatting-related variables, and dating and risk-taking sexual behaviour. The results show that a large majority of the 190 respondents reported actual encounters as well as sex with men who were initially met through chatting. Almost 30% of the respondents who engaged in sex with chat dates reported inconsistent safe sexual behaviour. The level of unprotected sex increased as the number of sex partners who were met through chatting increased. These results suggest that chatters on the Internet may be a new target group for HIV prevention. Further study is needed to gain insight into the feasibility of prevention efforts for this target group.

  9. The effect of target group size on risk judgments and comparative optimism: the more, the riskier.

    PubMed

    Price, Paul C; Smith, Andrew R; Lench, Heather C

    2006-03-01

    In 5 experiments, college students exhibited a group size effect on risk judgments. As the number of individuals in a target group increased, so did participants' judgments of the risk of the average member of the group for a variety of negative life events. This happened regardless of whether the stimuli consisted of photographs of real peers or stick-figure representations of peers. As a result, the degree to which participants exhibited comparative optimism (i.e., judged themselves to be at lower risk than their peers) also increased as the size of the comparison group increased. These results suggest that the typical comparative optimism effect reported so often in the literature might be, at least in part, a group size effect. Additional results include a group size effect on judgments of the likelihood that the average group member will experience positive and neutral events and a group size effect on perceptual judgments of the heights of stick figures. These latter results, in particular, support the existence of a simple, general cognitive mechanism that integrates stimulus numerosity into quantitative judgments about that stimulus.

  10. UAHuntsville-NASA MSFC Heliophysics REU: A Model for Recruiting Targeted Groups

    NASA Astrophysics Data System (ADS)

    Farid, S.; Heerikhuisen, J.; Winebarger, A. R.

    2014-12-01

    In 2011, researchers from the University of Alabama-Huntsville Center for Space Plasma and Aeronomic Research Center (CSPAR) and NASA Marshall Space Fight Center (MSFC) received a 3-year NSF award to create a REU site specifically designed to increase the participation of underrepresented groups in the Geo-sciences, specifically Heliophysics, and to reduce the attrition rate of sophomores by engaging them in research. This program has been highly successful. In three years of operation, we have increased in the diversity of applicant pool and selected participants, increased the number of inexperienced participants and made measurable impacts on the students' perceptions of graduate school and Heliophysics careers, and produced research with significant scientific merit. We attribute the success of the program to our proactive recruitment of first and second year students, underrepresented groups, and students from small universities. Key factors in our efforts include: 1) In person school visits of targeted schools 2.) Establishing relationships with faculty at targeted schools. 3.) An inclusive selection process that considers the availability of research at the students home institution 4.) A reduced focus on GPA and more focus on recommendation letters as indicators of success 5.) A successful cohort of experienced and inexperienced students 6.) The unique learning environment fostered by UAH-CSPAR and NASA-MSFC scientists. In this presentation, we review our strategies and suggest techniques to recruit targeted groups to similar REU programs.

  11. Polycomb Repressive Complex 2 Confers BRG1 Dependency on the CIITA Locus.

    PubMed

    Abou El Hassan, Mohamed; Yu, Tao; Song, Lan; Bremner, Rod

    2015-05-15

    CIITA (or MHC2TA) coordinates constitutive and IFN-γ-induced expression of MHC class II genes. IFN-γ responsiveness of CIITA requires BRG1 (SMARCA4), the ATPase engine of the chromatin remodeling SWI/SNF complex (also called BAF). SWI/SNF is defective in many human cancers, providing a mechanism to explain IFN-γ resistance. BRG1 dependency is mediated through remote elements. Short CIITA reporters lacking these elements respond to IFN-γ, even in BRG1-deficient cells, suggesting that BRG1 counters a remote repressive influence. The nature of this distal repressor is unknown, but it would represent a valuable therapeutic target to reactivate IFN-γ responsiveness in cancer. In this article, we show that the polycomb repressive complex 2 (PRC2) components EZH2 and SUZ12, as well as the associated histone mark H3K27me3, are codetected at interenhancer regions across the CIITA locus. IFN-γ caused a BRG1-dependent reduction in H3K27me3, associated with nucleosome displacement. SUZ12 knockdown restored IFN-γ responsiveness in BRG1-null cells, and it mimicked the ability of BRG1 to induce active histone modifications (H3K27ac, H3K4me) at the -50-kb enhancer. Thus, PRC2 confers BRG1 dependency on the CIITA locus. Our data suggest that, in addition to its known roles in promoting stemness and proliferation, PRC2 may inhibit immune surveillance, and it could be targeted to reactivate CIITA expression in SWI/SNF deficient cancers.

  12. Arabidopsis Polycomb Repressive Complex 2 binding sites contain putative GAGA factor binding motifs within coding regions of genes

    PubMed Central

    2013-01-01

    Background Polycomb Repressive Complex 2 (PRC2) is an essential regulator of gene expression that maintains genes in a repressed state by marking chromatin with trimethylated Histone H3 lysine 27 (H3K27me3). In Arabidopsis, loss of PRC2 function leads to pleiotropic effects on growth and development thought to be due to ectopic expression of seed and embryo-specific genes. While there is some understanding of the mechanisms by which specific genes are targeted by PRC2 in animal systems, it is still not clear how PRC2 is recruited to specific regions of plant genomes. Results We used ChIP-seq to determine the genome-wide distribution of hemagglutinin (HA)-tagged FERTLIZATION INDEPENDENT ENDOSPERM (FIE-HA), the Extra Sex Combs homolog protein present in all Arabidopsis PRC2 complexes. We found that the FIE-HA binding sites co-locate with a subset of the H3K27me3 sites in the genome and that the associated genes were more likely to be de-repressed in mutants of PRC2 components. The FIE-HA binding sites are enriched for three sequence motifs including a putative GAGA factor binding site that is also found in Drosophila Polycomb Response Elements (PREs). Conclusions Our results suggest that PRC2 binding sites in plant genomes share some sequence features with Drosophila PREs. However, unlike Drosophila PREs which are located in promoters and devoid of H3K27me3, Arabidopsis FIE binding sites tend to be in gene coding regions and co-localize with H3K27me3. PMID:24001316

  13. Group IIC Intron with an Unusual Target of Integration in Enterobacter cloacae

    PubMed Central

    Rodríguez-Martínez, José-Manuel; Poirel, Laurent

    2012-01-01

    A potential role of group IIC-attC introns in integron gene cassette formation, that is, the way in which they could provide the attC sequence essential for recombination, has been proposed. Group IIC introns usually target the attC site of gene cassettes and more specifically their inverse core. Here we characterized a novel group IIC intron targeting the core site of the aadA1 gene cassette attC site (aadA1-qacEΔ1 gene cassette junction) from enterobacterial isolates. Intron mobility (retrohoming) was analyzed using a two-plasmid assay performed in Escherichia coli. Intron mobility assays confirmed the mobilization-integration of the group II intron into the core site of the aadA2, blaVIM-2, blaCARB-2, aac(6′)-Ib, dfrXVb, arr2, cmlA4, and aadB gene cassettes but not into the attI site. This mobility was dependent on maturase activity. Reverse transcriptase PCR showed that this intron was transcriptionally active, and an intermediate circular form was detected by inverse PCR. This element was linked to the blaVEB-1 extended-spectrum β-lactamase gene in a high number of enterobacterial isolates. A phylogenetic tree showed that the identified element was located in a branch separate from group IIC-attC introns, being an IIC intron possessing the ability to integrate using the core site of the attC sites as target. PMID:22020643

  14. Spy: a new group of eukaryotic DNA transposons without target site duplications.

    PubMed

    Han, Min-Jin; Xu, Hong-En; Zhang, Hua-Hao; Feschotte, Cédric; Zhang, Ze

    2014-06-24

    Class 2 or DNA transposons populate the genomes of most eukaryotes and like other mobile genetic elements have a profound impact on genome evolution. Most DNA transposons belong to the cut-and-paste types, which are relatively simple elements characterized by terminal-inverted repeats (TIRs) flanking a single gene encoding a transposase. All eukaryotic cut-and-paste transposons so far described are also characterized by target site duplications (TSDs) of host DNA generated upon chromosomal insertion. Here, we report a new group of evolutionarily related DNA transposons called Spy, which also include TIRs and DDE motif-containing transposase but surprisingly do not create TSDs upon insertion. Instead, Spy transposons appear to transpose precisely between 5'-AAA and TTT-3' host nucleotides, without duplication or modification of the AAATTT target sites. Spy transposons were identified in the genomes of diverse invertebrate species based on transposase homology searches and structure-based approaches. Phylogenetic analyses indicate that Spy transposases are distantly related to IS5, ISL2EU, and PIF/Harbinger transposases. However, Spy transposons are distinct from these and other DNA transposon superfamilies by their lack of TSD and their target site preference. Our findings expand the known diversity of DNA transposons and reveal a new group of eukaryotic DDE transposases with unusual catalytic properties.

  15. Polycomb recruitment at the Class II transactivator gene.

    PubMed

    Boyd, Nathaniel H; Morgan, Julie E; Greer, Susanna F

    2015-10-01

    The Class II Transactivator (CIITA) is the master regulator of Major Histocompatibility Class II (MHC II) genes. Transcription of CIITA through the IFN-γ inducible CIITA promoter IV (CIITA pIV) during activation is characterized by a decrease in trimethylation of histone H3 lysine 27 (H3K27me3), catalyzed by the histone methyltransferase Enhancer of Zeste Homolog 2 (EZH2). While EZH2 is the known catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) and is present at the inactive CIITA pIV, the mechanism of PRC2 recruitment to mammalian promoters remains unknown. Here we identify two DNA-binding proteins, which interact with and regulate PRC2 recruitment to CIITA pIV. We demonstrate Yin Yang 1 (YY1) and Jumonji domain containing protein 2 (JARID2) are binding partners along with EZH2 in mammalian cells. Upon IFN-γ stimulation, YY1 dissociates from CIITA pIV while JARID2 binding to CIITA pIV increases, suggesting novel roles for these proteins in regulating expression of CIITA pIV. Knockdown of YY1 and JARID2 yields decreased binding of EZH2 and H3K27me3 at CIITA pIV, suggesting important roles for YY1 and JARID2 at CIITA pIV. JARID2 knockdown also results in significantly elevated levels of CIITA mRNA upon IFN-γ stimulation. This study is the first to identify novel roles of YY1 and JARID2 in the epigenetic regulation of the CIITA pIV by recruitment of PRC2. Our observations indicate the importance of JARID2 in CIITA pIV silencing, and also provide a novel YY1-JARID2-PRC2 regulatory complex as a possible explanation of differential PRC2 recruitment at inducible versus permanently silenced genes.

  16. Crystallization of the Focal Adhesion Kinase Targeting (FAT) Domain in a Primitive Orthorhombic Space Group

    SciTech Connect

    Magis,A.; Bailey, K.; Kurenova, E.; Hernandez Prada, J.; Cance, W.; Ostrov, D.

    2008-01-01

    X-ray diffraction data from the targeting (FAT) domain of focal adhesion kinase (FAK) were collected from a single crystal that diffracted to 1.99 Angstroms resolution and reduced to the primitive orthorhombic lattice. A single molecule was predicted to be present in the asymmetric unit based on the Matthews coefficient. The data were phased using molecular-replacement methods using an existing model of the FAK FAT domain. All structures of human focal adhesion kinase FAT domains solved to date have been solved in a C-centered orthorhombic space group.

  17. NCCN Work Group Report: Designing Clinical Trials in the Era of Multiple Biomarkers and Targeted Therapies

    PubMed Central

    Venook, Alan P.; Arcila, Maria E.; Benson, Al B.; Berry, Donald A.; Camidge, David Ross; Carlson, Robert W.; Choueiri, Toni K.; Guild, Valerie; Kalemkerian, Gregory P.; Kurzrock, Razelle; Lovly, Christine M.; McKee, Amy E.; Morgan, Robert J.; Olszanski, Anthony J.; Redman, Mary W.; Stearns, Vered; McClure, Joan; Birkeland, Marian L.

    2016-01-01

    Defining treatment susceptible or resistant populations of cancer patients through the use of genetically defined biomarkers has revolutionized cancer care in recent years for some disease/patient groups. Research continues to show that histologically defined diseases are diverse in their expression of unique mutations or other genetic alterations, however, which presents both opportunities for the development of personalized cancer treatments, but increased difficulty in testing these therapies because potential patient populations are divided into ever-smaller numbers. To address some of the growing challenges in biomarker development and clinical trial design, NCCN assembled a group of experts across specialties and solid tumor disease types to begin to define the problems and to consider alternate ways of designing clinical trials in the era of multiple biomarkers and targeted therapies. Results from that discussion are presented, focusing on issues of clinical trial design from the perspective of statisticians, clinical researchers, regulators, pathologists and information developers. PMID:25361808

  18. The structure of ethnic attitudes: the effects of target group, region, gender, and national identity.

    PubMed

    Verkuyten, M

    1997-08-01

    The present study was an assessment of attitudes of 410 ethnically Dutch adolescents toward three ethnic minority groups living in the Netherlands. Stereotypes, symbolic beliefs, affective associations, and the evaluation of possible interactions were used to predict the global evaluation of ethnic outgroups and accounted for much of the variance in ethnic attitudes. The relative importance of the four predictors varied by target group and location. Gender differences were found in the structure of attitudes; symbolic beliefs played a greater role in the attitudes of boys, whereas emotions played a more central role in the attitudes of girls. The evaluation of Dutch identity was related to the favorability of ethnic attitudes and also to the underlying structure. Respondents with a positive national identity had less favorable ethnic attitudes, and emotions were more predictive of their attitudes, whereas symbolic beliefs were most predictive among respondents with a less positive national identity.

  19. Activity targets for nanostructured platinum-group-metal-free catalysts in hydroxide exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Setzler, Brian P.; Zhuang, Zhongbin; Wittkopf, Jarrid A.; Yan, Yushan

    2016-12-01

    Fuel cells are the zero-emission automotive power source that best preserves the advantages of gasoline automobiles: low upfront cost, long driving range and fast refuelling. To make fuel-cell cars a reality, the US Department of Energy has set a fuel cell system cost target of US$30 kW-1 in the long-term, which equates to US$2,400 per vehicle, excluding several major powertrain components (in comparison, a basic, but complete, internal combustion engine system costs approximately US$3,000). To date, most research for automotive applications has focused on proton exchange membrane fuel cells (PEMFCs), because these systems have demonstrated the highest power density. Recently, however, an alternative technology, hydroxide exchange membrane fuel cells (HEMFCs), has gained significant attention, because of the possibility to use stable platinum-group-metal-free catalysts, with inherent, long-term cost advantages. In this Perspective, we discuss the cost profile of PEMFCs and the advantages offered by HEMFCs. In particular, we discuss catalyst development needs for HEMFCs and set catalyst activity targets to achieve performance parity with state-of-the-art automotive PEMFCs. Meeting these targets requires careful optimization of nanostructures to pack high surface areas into a small volume, while maintaining high area-specific activity and favourable pore-transport properties.

  20. Activity targets for nanostructured platinum-group-metal-free catalysts in hydroxide exchange membrane fuel cells.

    PubMed

    Setzler, Brian P; Zhuang, Zhongbin; Wittkopf, Jarrid A; Yan, Yushan

    2016-12-06

    Fuel cells are the zero-emission automotive power source that best preserves the advantages of gasoline automobiles: low upfront cost, long driving range and fast refuelling. To make fuel-cell cars a reality, the US Department of Energy has set a fuel cell system cost target of US$30 kW(-1) in the long-term, which equates to US$2,400 per vehicle, excluding several major powertrain components (in comparison, a basic, but complete, internal combustion engine system costs approximately US$3,000). To date, most research for automotive applications has focused on proton exchange membrane fuel cells (PEMFCs), because these systems have demonstrated the highest power density. Recently, however, an alternative technology, hydroxide exchange membrane fuel cells (HEMFCs), has gained significant attention, because of the possibility to use stable platinum-group-metal-free catalysts, with inherent, long-term cost advantages. In this Perspective, we discuss the cost profile of PEMFCs and the advantages offered by HEMFCs. In particular, we discuss catalyst development needs for HEMFCs and set catalyst activity targets to achieve performance parity with state-of-the-art automotive PEMFCs. Meeting these targets requires careful optimization of nanostructures to pack high surface areas into a small volume, while maintaining high area-specific activity and favourable pore-transport properties.

  1. Over-the-counter hearing aids: electroacoustic characteristics and possible target client groups.

    PubMed

    Cheng, C M; McPherson, B

    2000-01-01

    Over-the-counter hearing aids (OTCs) are those directly purchased from retail outlets, without the benefit of prior professional hearing health care. They are particularly common in developing countries. This study examined the amplification characteristics of a selected sample of OTCs to determine if any target client group or groups were suitable for the OTCs. The electroacoustical performance of 10 OTCs was measured. The measurements included saturated sound pressure level curve, high-frequency average full-on gain, frequency response, total harmonic distortion, equivalent input noise level, and input-output curve. The full-on gain curve of each hearing aid was used to estimate the hypothetical hearing loss of target clients for each aid as it would be calculated by four hearing aid prescription formulae. Real-ear probe tube measurements were also performed on 10 adult subjects to determine the amplification that could be achieved by the OTCs before audible feedback occurred. The OTC hearing aids were not able to meet the prescription gain requirements of the majority of elderly clients who usually purchased them.

  2. Group II Metabotropic Glutamate Receptors as Targets for Novel Antipsychotic Drugs

    PubMed Central

    Muguruza, Carolina; Meana, J. Javier; Callado, Luis F.

    2016-01-01

    Schizophrenia is a chronic psychiatric disorder which substantially impairs patients’ quality of life. Despite the extensive research in this field, the pathophysiology and etiology of schizophrenia remain unknown. Different neurotransmitter systems and functional networks have been found to be affected in the brain of patients with schizophrenia. In this context, postmortem brain studies as well as genetic assays have suggested alterations in Group II metabotropic glutamate receptors (mGluRs) in schizophrenia. Despite many years of drug research, several needs in the treatment of schizophrenia have not been addressed sufficiently. In fact, only 5–10% of patients with schizophrenia successfully achieve a full recovery after treatment. In recent years mGluRs have turned up as novel targets for the design of new antipsychotic medications for schizophrenia. Concretely, Group II mGluRs are of particular interest due to their regulatory role in neurotransmission modulating glutamatergic activity in brain synapses. Preclinical studies have demonstrated that orthosteric Group II mGluR agonists exhibit antipsychotic-like properties in animal models of schizophrenia. However, when these compounds have been tested in human clinical studies with schizophrenic patients results have been inconclusive. Nevertheless, it has been recently suggested that this apparent lack of efficacy in schizophrenic patients may be related to previous exposure to atypical antipsychotics. Moreover, the role of the functional heterocomplex formed by 5-HT2A and mGlu2 receptors in the clinical response to Group II mGluR agonists is currently under study. PMID:27242534

  3. Incidence Rate of Prediabetes Progression to Diabetes: Modeling an Optimum Target Group for Intervention.

    PubMed

    DeJesus, Ramona S; Radecki Breitkopf, Carmen; Rutten, Lila J; Jacobson, Debra J; Wilson, Patrick M; St Sauver, Jennifer

    2016-09-30

    Thirty-seven percent of US adults have prediabetes. Various interventions can delay diabetes progression; however, the optimum target group for risk reduction is uncertain. This study estimated rate of progression to diabetes at 1 and 5 years among a cohort of patients from 3 primary care clinics and modeled the potential magnitude in diabetes incidence risk reduction of an intervention program among specific subgroups. Records of 106,821 empaneled patients in 2005 were reviewed. Generalized population attributable risk (PAR) statistics were calculated to estimate the impact of reducing fasting blood glucose on diabetes progression. Multiple intervention effects (varying levels of glucose reduction along with multiple adherence rates) were examined for those with baseline glucose from 110 to 119 mg/dL and ≥120 mg/dL. Ten percent of patients (n = 10,796) met criteria for prediabetes. The 1- and 5-year diabetes incidence rate was 38.6 and 40.24 per 1000 person-years, respectively. Age and obesity were independent predictors of increased progression rate. The generalized PAR for a 10-point reduction in the 110-119 mg/dL subgroup with 25% adherence was 7.6%. The generalized PAR for similar percent reduction and adherence level in patients with baseline glucose of ≥120 mg/dL was only 3.0%. Rate of progression to diabetes increased over time and with associated independent risk factors. Greater risk reduction in diabetes progression within the target population can be achieved when the intervention is successful in those with baseline glucose of 110-119 mg/dL. Modeling an optimum target group for a diabetes prevention intervention offers a novel and useful guide to planning and allocating resources in population health management.

  4. Polycomb Protein OsFIE2 Affects Plant Height and Grain Yield in Rice

    PubMed Central

    Sheng, Zhonghua; Jiao, Guiai; Tang, Shaoqing; Luo, Ju; Hu, Peisong

    2016-01-01

    Polycomb group (PcG) proteins have been shown to affect growth and development in plants. To further elucidate their role in these processes in rice, we isolated and characterized a rice mutant which exhibits dwarfism, reduced seed setting rate, defective floral organ, and small grains. Map-based cloning revealed that abnormal phenotypes were attributed to a mutation of the Fertilization Independent Endosperm 2 (OsFIE2) protein, which belongs to the PcG protein family. So we named the mutant as osfie2-1. Histological analysis revealed that the number of longitudinal cells in the internodes decreased in osfie2-1, and that lateral cell layer of the internodes was markedly thinner than wild-type. In addition, compared to wild-type, the number of large and small vascular bundles decreased in osfie2-1, as well as cell number and cell size in spikelet hulls. OsFIE2 is expressed in most tissues and the coded protein localizes in both nucleus and cytoplasm. Yeast two-hybrid and bimolecular fluorescence complementation assays demonstrated that OsFIE2 interacts with OsiEZ1 which encodes an enhancer of zeste protein previously identified as a histone methylation enzyme. RNA sequencing-based transcriptome profiling and qRT-PCR analysis revealed that some homeotic genes and genes involved in endosperm starch synthesis, cell division/expansion and hormone synthesis and signaling are differentially expressed between osfie2-1 and wild-type. In addition, the contents of IAA, GA3, ABA, JA and SA in osfie2-1 are significantly different from those in wild-type. Taken together, these results indicate that OsFIE2 plays an important role in the regulation of plant height and grain yield in rice. PMID:27764161

  5. Targeting the Psychosexual Challenges Faced by Couples with Breast Cancer: Can Couples Group Psychotherapy Help?

    PubMed Central

    Lagana, Luciana; Fobair, Patricia; Spiegel, David

    2016-01-01

    The need for the psychosexual rehabilitation of breast cancer survivors and their intimate partners is underscored by the high prevalence of multiple psychosexual difficulties encountered by this patient population. Concerns about health, sexuality, and emotional distress are common among women with breast cancer and are often related to the side effects of cancer treatment. Additionally, both intimate relationship problems and partners’ distress are likely to influence patients’ psychosexual health. A clearer understanding of these complex clinical issues is needed in order to implement effective psychosexual rehabilitation interventions. In this article, we extended the use of the manualized and empirically validated Supportive-Expressive Group Therapy (SEGT) model to target the specific psychosexual needs of couples with breast (as well as other types of) cancer. In view of the pertinent literature in this area and based on our clinical experience utilizing this group therapy model with different patient populations, we have discussed how clinicians involved in the psychosexual care of oncology patients could apply such a model within a couples group therapy format. PMID:27239398

  6. Target Group Segmentation in the Horse Buyers' Market against the Background of Equestrian Experience.

    PubMed

    Gille, Claudia; Kayser, Maike; Spiller, Achim

    2010-01-01

    Whereas in former times horses were reserved primarily for people involved in agriculture, elite equestrians or the military, nowadays equestrian sport has become an activity for people with a wide variety of backgrounds. However, as more and more people become involved with equestrian sport today, the knowledge concerning animal husbandry in general is diminishing due to an alienation from agricultural themes in modern societies. As a consequence, this development affects both riding ability and the appraisal of horses, especially with respect to the purchase of horses. In order to analyse which factors influence purchase decisions in the horse market in conjunction with equestrian experience, 739 horse riders were surveyed on their purchase behaviour in this study. Using cluster analysis, a typology was generated that provides a differentiated picture of the preferences of the various rider groups. Three clusters were distinguished: the "amateurs", the "experienced" and the "experts". Taking personal horse riding proficiency into account, it could be concluded that especially the "amateur" group required objective criteria for the evaluation of a horse they are considering purchasing. Alongside "measureable" qualities, such as previous showing success or the level of training of the horse, also other attributes such as the simple handling of the horse should be taken into consideration. As particularly the "amateur" group in equestrian sport is increasing in numbers, it is therefore advisable when preparing a horse for sale to align oneself to the needs of this customer segment in order to ensure an effective and targeted marketing of horses.

  7. European Commission project: European Guideline for Target Group-Oriented Psychosocial Aftercare-Implementation.

    PubMed

    Vymetal, Stepan; Deistler, Albert; Bering, Robert; Schedlich, Claudia; Rooze, Magda; Orengo, Francisco; Zurek, Gisela; Krtickova, Michaela

    2011-06-01

    After disasters, the individual health and well-being of first responders and affected population are affected for years. Therefore, psychosocial help is needed. Although most victims recover on their own, a minority of survivors, members of rescue teams, or relatives develop long-term, disaster-related psychic disorders, such as post-traumatic stress disorder (PTSD). This subgroup especially should receive timely and appropriate psychosocial help. Many European countries offer post-disaster psychosocial care from a variety of caregivers (i.e., professionals and volunteers, non-governmental organizations, church or commercial organizations). Therefore, European standards for providing post-disaster psychosocial support currently is required. This article describes the project European Guideline for Target Group-Oriented Psychosocial Aftercare-Implementation, supported by the European Commission.

  8. Assertive outreach in Slovenia; identification of target group and goals of treatment in a new program.

    PubMed

    Furlan, Mirjana

    2009-09-01

    A team from the Rehabilitation unit of Ljubljana psychiatric clinic attended a course on community care in London in October and November 2005. Because we decided that the methods presented to us could be of great use in Slovenia where the Health system is lacking such services we decided to implement them after our return. Immediately after we returned we started to carry out our plan. We designated our target group which were patients who poorly participated in treatment or had multiple and severe difficulties functioning and retaining their progress after discharge. Our goals were to improve patient participation in treatment before and after discharge, less and shorter hospitalizations and better integration of patients into society. Initial results are very positive, which leaves me much hope for further implementation of assertive outreach and community care in Slovenia.

  9. AGS SUPER NEUTRINO BEAM FACILITY ACCELERATOR AND TARGET SYSTEM DESIGN (NEUTRINO WORKING GROUP REPORT-II).

    SciTech Connect

    DIWAN,M.; MARCIANO,W.; WENG,W.; RAPARIA,D.

    2003-04-21

    This document describes the design of the accelerator and target systems for the AGS Super Neutrino Beam Facility. Under the direction of the Associate Laboratory Director Tom Kirk, BNL has established a Neutrino Working Group to explore the scientific case and facility requirements for a very long baseline neutrino experiment. Results of a study of the physics merit and detector performance was published in BNL-69395 in October 2002, where it was shown that a wide-band neutrino beam generated by a 1 MW proton beam from the AGS, coupled with a half megaton water Cerenkov detector located deep underground in the former Homestake mine in South Dakota would be able to measure the complete set of neutrino oscillation parameters: (1) precise determination of the oscillation parameters {Delta}m{sub 32}{sup 2} and sin{sup 2} 2{theta}{sub 32}; (2) detection of the oscillation of {nu}{sub {mu}}-{nu}{sub e} and measurement of sin{sup 2} 2{theta}{sub 13}; (3) measurement of {Delta}m{sub 21}{sup 2} sin 2{theta}{sub 12} in a {nu}{sub {mu}} {yields} {nu}{sub e} appearance mode, independent of the value of {theta}{sub 13}; (4) verification of matter enhancement and the sign of {Delta}m{sub 32}{sup 2}; and (5) determination of the CP-violation parameter {delta}{sub CP} in the neutrino sector. This report details the performance requirements and conceptual design of the accelerator and the target systems for the production of a neutrino beam by a 1.0 MW proton beam from the AGS. The major components of this facility include a new 1.2 GeV superconducting linac, ramping the AGS at 2.5 Hz, and the new target station for 1.0 MW beam. It also calls for moderate increase, about 30%, of the AGS intensity per pulse. Special care is taken to account for all sources of proton beam loss plus shielding and collimation of stray beam halo particles to ensure equipment reliability and personal safety. A preliminary cost estimate and schedule for the accelerator upgrade and target system are also

  10. BMI-1, a promising therapeutic target for human cancer

    PubMed Central

    WANG, MIN-CONG; LI, CHUN-LI; CUI, JIE; JIAO, MIN; WU, TAO; JING, LI; NAN, KE-JUN

    2015-01-01

    BMI-1 oncogene is a member of the polycomb-group gene family and a transcriptional repressor. Overexpression of BMI-1 has been identified in various human cancer tissues and is known to be involved in cancer cell proliferation, cell invasion, distant metastasis, chemosensitivity and patient survival. Accumulating evidence has revealed that BMI-1 is also involved in the regulation of self-renewal, differentiation and tumor initiation of cancer stem cells (CSCs). However, the molecular mechanisms underlying these biological processes remain unclear. The present review summarized the function of BMI-1 in different human cancer types and CSCs, and discussed the signaling pathways in which BMI-1 is potentially involved. In conclusion, BMI-1 may represent a promising target for the prevention and therapy of various cancer types. PMID:26622537

  11. Target Group Segmentation in the Horse Buyers’ Market against the Background of Equestrian Experience

    PubMed Central

    GILLE, Claudia; KAYSER, Maike; SPILLER, Achim

    2011-01-01

    Whereas in former times horses were reserved primarily for people involved in agriculture, elite equestrians or the military, nowadays equestrian sport has become an activity for people with a wide variety of backgrounds. However, as more and more people become involved with equestrian sport today, the knowledge concerning animal husbandry in general is diminishing due to an alienation from agricultural themes in modern societies. As a consequence, this development affects both riding ability and the appraisal of horses, especially with respect to the purchase of horses. In order to analyse which factors influence purchase decisions in the horse market in conjunction with equestrian experience, 739 horse riders were surveyed on their purchase behaviour in this study. Using cluster analysis, a typology was generated that provides a differentiated picture of the preferences of the various rider groups. Three clusters were distinguished: the “amateurs”, the “experienced” and the “experts”. Taking personal horse riding proficiency into account, it could be concluded that especially the “amateur” group required objective criteria for the evaluation of a horse they are considering purchasing. Alongside “measureable” qualities, such as previous showing success or the level of training of the horse, also other attributes such as the simple handling of the horse should be taken into consideration. As particularly the “amateur” group in equestrian sport is increasing in numbers, it is therefore advisable when preparing a horse for sale to align oneself to the needs of this customer segment in order to ensure an effective and targeted marketing of horses. PMID:24833979

  12. Cigarette advertising in Mumbai, India: targeting different socioeconomic groups, women, and youth

    PubMed Central

    Bansal, R; John, S; Ling, P

    2005-01-01

    Background: Despite a recent surge in tobacco advertising and the recent advertising ban (pending enforcement at the time of this study), there are few studies describing current cigarette marketing in India. This study sought to assess cigarette companies' marketing strategies in Mumbai, India. Methods: A two week field study was conducted in Mumbai in September 2003, observing, documenting, and collecting cigarette advertising on billboards, storefronts and at point of sale along two major thoroughfares, and performing a content analysis of news, film industry, and women's magazines and three newspapers. Results: Cigarette advertising was ubiquitous in the environment, present in news and in film magazines, but not in women's magazines or the newspapers. The four major advertising campaigns all associated smoking with aspiration; the premium brands targeting the higher socioeconomic status market utilised tangible images of westernisation and affluence whereas the "bingo" (low priced) segment advertisements invited smokers to belong to a league of their own and "rise to the taste" using intangible images. Women were not depicted smoking, but were present in cigarette advertisements—for example, a woman almost always accompanied a man in "the man with the smooth edge" Four Square campaign. Advertisements and product placements at low heights and next to candies at point of sale were easily accessible by children. In view of the iminent enforcement of the ban on tobacco advertisements, cigarette companies are increasing advertising for the existing brand images, launching brand extensions, and brand stretching. Conclusion: Cigarette companies have developed sophisticated campaigns targeting men, women, and children in different socioeconomic groups. Many of these strategies circumvent the Indian tobacco advertising ban. Understanding these marketing strategies is critical to mimimise the exploitation of loopholes in tobacco control legislation. PMID:15923471

  13. Transcriptional elongation factor ENL phosphorylated by ATM recruits polycomb and switches off transcription for DSB repair.

    PubMed

    Ui, Ayako; Nagaura, Yuko; Yasui, Akira

    2015-05-07

    Transcription is repressed if a DNA double-strand break (DSB) is introduced in close proximity to a transcriptional activation site at least in part by H2A-ubiquitination. While ATM signaling is involved, how it controls H2A-ubiquitination remains unclear. Here, we identify that, in response to DSBs, a transcriptional elongation factor, ENL (MLLT1), is phosphorylated by ATM at conserved SQ sites. This phosphorylation increases the interaction between ENL and the E3-ubiquitin-ligase complex of Polycomb Repressive Complex 1 (PRC1) via BMI1. This interaction promotes enrichment of PRC1 at transcription elongation sites near DSBs to ubiquitinate H2A leading to transcriptional repression. ENL SQ sites and BMI1 are necessary for KU70 accumulation at DSBs near active transcription sites and cellular resistance to DSBs. Our data suggest that ATM-dependent phosphorylation of ENL functions as switch from elongation to Polycomb-mediated repression to preserve genome integrity.

  14. Ease of opening of blistered solid dosage forms in a senior citizens target group.

    PubMed

    Braun-Münker, Myriam; Ecker, Felix

    2016-10-30

    Blisters differing in design and handling are established as packaging material for solid dosage forms. The ease of opening of blisters influences application and patient's compliance. In this study the influence of visibility and movability of solid dosage forms in blister packaging on both, easy opening and patient's satisfaction, were investigated by target group testing according to ONR CEN/TS 15945. For each testing 20 participants in the age of 65-80 years were recruited randomly. They opened the blisters on realistic terms without any auxiliary devices. Video documentation of the hands' movements was recorded to analyze the opening procedure. To show the influence of visibility of the dosage form in the blister, capsules size 1 were packed in transparent and opaque blisters. A moderate influence of the visibility on both, the ease of opening and patient satisfaction, was observed. A second study dealt with the movability of solid dosage forms in blisters. Therefore, three different sizes of tablets with similar shapes were packed in identical cavities. Limited movability was found as major criterion on effectiveness and effectivity of opening as well as on satisfaction with the opening procedure.

  15. The putative tumor suppressor gene EphA7 is a novel BMI-1 target

    PubMed Central

    Jagemann, Lucas; Nolbrant, Sara; Leefa, Isabelle V.; Offen, Nils; Miharada, Kenichi; Lang, Stefan; Artner, Isabella; Nuber, Ulrike A.

    2016-01-01

    Bmi1 was originally identified as a gene that contributes to the development of mouse lymphoma by inhibiting MYC-induced apoptosis through repression of Ink4a and Arf. It codes for the Polycomb group protein BMI-1 and acts primarily as a transcriptional repressor via chromatin modifications. Although it binds to a large number of genomic regions, the direct BMI-1 target genes described so far do not explain the full spectrum of BMI-1-mediated effects. Here we identify the putative tumor suppressor gene EphA7 as a novel direct BMI-1 target in neural cells and lymphocytes. EphA7 silencing has been reported in several different human tumor types including lymphomas, and our data suggest BMI1 overexpression as a novel mechanism leading to EphA7 inactivation via H3K27 trimethylation and DNA methylation. PMID:27533460

  16. The morphogen Decapentaplegic employs a two-tier mechanism to activate target retinal determining genes during ectopic eye formation in Drosophila

    PubMed Central

    Aggarwal, Poonam; Gera, Jayati; Mandal, Lolitika; Mandal, Sudip

    2016-01-01

    Understanding the role of morphogen in activating its target genes, otherwise epigenetically repressed, during change in cell fate specification is a very fascinating yet relatively unexplored domain. Our in vivo loss-of-function genetic analyses reveal that specifically during ectopic eye formation, the morphogen Decapentaplegic (Dpp), in conjunction with the canonical signaling responsible for transcriptional activation of retinal determining (RD) genes, triggers another signaling cascade. Involving dTak1 and JNK, this pathway down-regulates the expression of polycomb group of genes to do away with their repressive role on RD genes. Upon genetic inactivation of members of this newly identified pathway, the canonical Dpp signaling fails to trigger RD gene expression beyond a threshold, critical for ectopic photoreceptor differentiation. Moreover, the drop in ectopic RD gene expression and subsequent reduction in ectopic photoreceptor differentiation resulting from inactivation of dTak1 can be rescued by down-regulating the expression of polycomb group of genes. Our results unravel an otherwise unknown role of morphogen in coordinating simultaneous transcriptional activation and de-repression of target genes implicating its importance in cellular plasticity. PMID:27270790

  17. Polycomb repressive complex PRC1 spatially constrains the mouse embryonic stem cell genome

    PubMed Central

    Mifsud, Borbala; Dimitrova, Emilia; Matheson, Louise; Tavares-Cadete, Filipe; Furlan-Magaril, Mayra; Segonds-Pichon, Anne; Jurkowski, Wiktor; Wingett, Steven W.; Tabbada, Kristina; Andrews, Simon; Herman, Bram; LeProust, Emily; Osborne, Cameron S.; Koseki, Haruhiko; Fraser, Peter; Luscombe, Nicholas M.; Elderkin, Sarah

    2016-01-01

    The Polycomb Repressive Complexes PRC1 and PRC2 maintain embryonic stem cell (ESC) pluripotency by silencing lineage-specifying developmental regulator genes1. Emerging evidence suggests that Polycomb complexes act through controlling spatial genome organisation2–9. We show that PRC1 functions as a master regulator of ESC genome architecture by organizing genes in three-dimensional interaction networks. The strongest spatial network is composed of the four Hox clusters and early developmental transcription factor genes, the majority of which contact poised enhancers. Removal of Polycomb repression leads to disruption of promoter-promoter contacts in the Hox network. In contrast, promoter-enhancer contacts are maintained, accompanied by widespread acquisition of active chromatin signatures at network enhancers and pronounced transcriptional up-regulation of network genes. Thus, PRC1 physically constrains developmental transcription factor genes and their enhancers in a silenced but poised spatial network. We propose that selective release of genes from this spatial network underlies cell fate specification during early embryonic development. PMID:26323060

  18. Inactivation of Intergenic Enhancers by EBNA3A Initiates and Maintains Polycomb Signatures across a Chromatin Domain Encoding CXCL10 and CXCL9

    PubMed Central

    Harth-Hertle, Marie L.; Scholz, Barbara A.; Erhard, Florian; Glaser, Laura V.; Dölken, Lars; Zimmer, Ralf; Kempkes, Bettina

    2013-01-01

    Epstein-Barr virus (EBV) causes a persistent infection in human B cells by establishing specific transcription programs to control B cell activation and differentiation. Transcriptional reprogramming of EBV infected B cells is predominantly driven by the action of EBV nuclear antigens, among them the transcriptional repressor EBNA3A. By comparing gene expression profiles of wt and EBNA3A negative EBV infected B cells, we have previously identified a broad array of cellular genes controlled by EBNA3A. We now find that genes repressed by EBNA3A in these cells are significantly enriched for the repressive histone mark H3K27me3, which is installed by Polycomb group (PcG) proteins. This PcG-controlled subset of genes also carries H3K27me3 marks in a variety of other tissues, suggesting that the commitment to PcG silencing is an intrinsic feature of these gene loci that can be used by EBNA3A. In addition, EBNA3A targets frequently reside in co-regulated gene clusters. To study the mechanism of gene repression by EBNA3A and to evaluate the relative contribution of PcG proteins during this process, we have selected the genomic neighbors CXCL10 and CXCL9 as a model for co-repressed and PcG-controlled genes. We show that EBNA3A binds to CBF1 occupied intergenic enhancers located between CXCL10 and CXCL9 and displaces the transactivator EBNA2. This impairs enhancer activity, resulting in a rapid transcriptional shut-down of both genes in a CBF1-dependent manner and initiation of a delayed gain of H3K27me3 marks covering an extended chromatin domain. H3K27me3 marks increase gradually and are maintained by EBNA3A. Our study provides direct evidence that repression by EBNA3A requires CBF1 and that EBNA3A and EBNA2 compete for access to CBF1 at identical genomic sites. Most importantly, our results demonstrate that transcriptional silencing by EBNA3A precedes the appearance of repressive PcG marks and indicate that both events are triggered by loss of enhancer activity. PMID

  19. A Multi-Factorial Signature of DNA Sequence and Polycomb Binding Predicts Aberrant CpG Island Methylation

    PubMed Central

    McCabe, Michael T.; Lee, Eva K.; Vertino, Paula M.

    2008-01-01

    Aberrant CpG island methylation is associated with transcriptional silencing of regulatory genes in human cancer. While most CpG islands remain unmethylated, a subset accrues aberrant methylation in cancer via unknown mechanisms. Previously, we showed that CpG islands differ in their intrinsic propensity towards hypermethylation. We developed a classifier (PatMAn) based on the frequencies of seven DNA sequence patterns that discriminated methylation-prone (MP) and methylation-resistant (MR) CpG islands. Here we report on the genome-wide application and direct testing of PatMAn in cancer. Although trained on data from a cell culture model of de novo methylation involving overexpression of DNMT1, PatMAn accurately predicted CpG islands at increased risk of hypermethylation in cancer cell lines and primary tumors. Analysis of CpG islands predicted to be MP revealed a strong association with embryonic targets of Polycomb Repressive Complex 2 (PRC2), indicating that PatMAn predicts not only aberrant methylation, but also PRC2 binding. A second classifier (SUPER-PatMAn) that integrates the seven PatMAn DNA patterns with SUZ12 protein enriched regions as a marker of PRC2 occupancy showed improved performance (prediction accuracy=81-88%). In addition to many non-PRC2 targets, SUPER-PatMAn identified a subset of PRC2 targets that were more likely to be hypermethylated in cancer. Genome-wide, CpG islands predicted to be MP were enriched in genes known to undergo hypermethylation in cancer, genes functioning in transcriptional regulation, and components of developmental pathways. These findings demonstrate that hypermethylation of certain gene loci is controlled in part by an underlying susceptibility influenced by both local sequence context and trans-acting factors. PMID:19118013

  20. Polycomb subunits Ezh1 and Ezh2 regulate the Merkel cell differentiation program in skin stem cells

    PubMed Central

    Bardot, Evan S; Valdes, Victor J; Zhang, Jisheng; Perdigoto, Carolina N; Nicolis, Silvia; Hearn, Stephen A; Silva, Jose M; Ezhkova, Elena

    2013-01-01

    While the Polycomb complex is known to regulate cell identity in ES cells, its role in controlling tissue-specific stem cells is not well understood. Here we show that removal of Ezh1 and Ezh2, key Polycomb subunits, from mouse skin results in a marked change in fate determination in epidermal progenitor cells, leading to an increase in the number of lineage-committed Merkel cells, a specialized subtype of skin cells involved in mechanotransduction. By dissecting the genetic mechanism, we showed that the Polycomb complex restricts differentiation of epidermal progenitor cells by repressing the transcription factor Sox2. Ablation of Sox2 results in a dramatic loss of Merkel cells, indicating that Sox2 is a critical regulator of Merkel cell specification. We show that Sox2 directly activates Atoh1, the obligate regulator of Merkel cell differentiation. Concordantly, ablation of Sox2 attenuated the Ezh1/2-null phenotype, confirming the importance of Polycomb-mediated repression of Sox2 in maintaining the epidermal progenitor cell state. Together, these findings define a novel regulatory network by which the Polycomb complex maintains the progenitor cell state and governs differentiation in vivo. PMID:23673358

  1. The Oncogenic Polycomb Histone Methyltransferase EZH2 Methylates Lysine 120 on Histone H2B and Competes Ubiquitination12

    PubMed Central

    Kogure, Masaharu; Takawa, Masashi; Saloura, Vassiliki; Sone, Kenbun; Piao, Lianhua; Ueda, Koji; Ibrahim, Reem; Tsunoda, Tatsuhiko; Sugiyama, Masanori; Atomi, Yutaka; Nakamura, Yusuke; Hamamoto, Ryuji

    2013-01-01

    The histone methyltransferase enhancer of zeste 2 (EZH2) is known to be a polycomb protein homologous to Drosophila enhancer of zeste and catalyzes the addition of methyl groups to histone H3 at lysine 27 (H3K27). We previously reported that EZH2 was overexpressed in various types of cancer and plays a crucial role in the cell cycle regulation of cancer cells. In the present study, we demonstrated that EZH2 has the function to monomethylate lysine 120 on histone H2B (H2BK120). EZH2-dependent H2BK120 methylation in cancer cells was confirmed with an H2BK120 methylation-specific antibody. Overexpression of EZH2 significantly attenuated the ubiquitination of H2BK120, a key posttranslational modification of histones for transcriptional regulation. Concordantly, knockdown of EZH2 increased the ubiquitination level of H2BK120, suggesting that the methylation of H2BK120 by EZH2 may competitively inhibit the ubiquitination of H2BK120. Subsequent chromatin immunoprecipitation-Seq and microarray analyses identified downstream candidate genes regulated by EZH2 through the methylation of H2BK120. This is the first report to describe a novel substrate of EZH2, H2BK120, unveiling a new aspect of EZH2 functions in human carcinogenesis. PMID:24339737

  2. CpG island erosion, polycomb occupancy and sequence motif enrichment at bivalent promoters in mammalian embryonic stem cells.

    PubMed

    Mantsoki, Anna; Devailly, Guillaume; Joshi, Anagha

    2015-11-19

    In embryonic stem (ES) cells, developmental regulators have a characteristic bivalent chromatin signature marked by simultaneous presence of both activation (H3K4me3) and repression (H3K27me3) signals and are thought to be in a 'poised' state for subsequent activation or silencing during differentiation. We collected eleven pairs (H3K4me3 and H3K27me3) of ChIP sequencing datasets in human ES cells and eight pairs in murine ES cells, and predicted high-confidence (HC) bivalent promoters. Over 85% of H3K27me3 marked promoters were bivalent in human and mouse ES cells. We found that (i) HC bivalent promoters were enriched for developmental factors and were highly likely to be differentially expressed upon transcription factor perturbation; (ii) murine HC bivalent promoters were occupied by both polycomb repressive component classes (PRC1 and PRC2) and grouped into four distinct clusters with different biological functions; (iii) HC bivalent and active promoters were CpG rich while H3K27me3-only promoters lacked CpG islands. Binding enrichment of distinct sets of regulators distinguished bivalent from active promoters. Moreover, a 'TCCCC' sequence motif was specifically enriched in bivalent promoters. Finally, this analysis will serve as a resource for future studies to further understand transcriptional regulation during embryonic development.

  3. CpG island erosion, polycomb occupancy and sequence motif enrichment at bivalent promoters in mammalian embryonic stem cells

    PubMed Central

    Mantsoki, Anna; Devailly, Guillaume; Joshi, Anagha

    2015-01-01

    In embryonic stem (ES) cells, developmental regulators have a characteristic bivalent chromatin signature marked by simultaneous presence of both activation (H3K4me3) and repression (H3K27me3) signals and are thought to be in a ‘poised’ state for subsequent activation or silencing during differentiation. We collected eleven pairs (H3K4me3 and H3K27me3) of ChIP sequencing datasets in human ES cells and eight pairs in murine ES cells, and predicted high-confidence (HC) bivalent promoters. Over 85% of H3K27me3 marked promoters were bivalent in human and mouse ES cells. We found that (i) HC bivalent promoters were enriched for developmental factors and were highly likely to be differentially expressed upon transcription factor perturbation; (ii) murine HC bivalent promoters were occupied by both polycomb repressive component classes (PRC1 and PRC2) and grouped into four distinct clusters with different biological functions; (iii) HC bivalent and active promoters were CpG rich while H3K27me3-only promoters lacked CpG islands. Binding enrichment of distinct sets of regulators distinguished bivalent from active promoters. Moreover, a ‘TCCCC’ sequence motif was specifically enriched in bivalent promoters. Finally, this analysis will serve as a resource for future studies to further understand transcriptional regulation during embryonic development. PMID:26582124

  4. Mobile group II intron based gene targeting in Lactobacillus plantarum WCFS1.

    PubMed

    Sasikumar, Ponnusamy; Paul, Eldho; Gomathi, Sivasamy; Abhishek, Albert; Sasikumar, Sundaresan; Selvam, Govindan Sadasivam

    2016-10-01

    The usage of recombinant lactic acid bacteria for delivery of therapeutic proteins to the mucosa has been emerging. In the present study, an attempt was made to engineer a thyA mutant of Lactobacillus plantarum (L. plantarum) using lactococcal group II intron Ll.LtrB for the development of biologically contained recombinant L. plantarum for prevention of calcium oxalate stone disease. The 3 kb Ll.LtrB intron donor cassettes from the source vector pACD4C was PCR amplified, ligated into pSIP series of lactobacillus vector pLp_3050sAmyA, yielding a novel vector pLpACD4C (8.6 kb). The quantitative real-time PCR experiment shows 94-fold increased expression of Ll.LtrB intron and 14-fold increased expression of ltrA gene in recombinant L. plantarum containing pLpACD4C. In order to target the thyA gene, the potential intron RNA binding sites in the thyA gene of L. plantarum was predicted with help of computer algorithm. The insertion location 188|189s of thyA gene (lowest E-0.134) was chosen and the wild type intron Ll.LtrB was PCR modified, yielding a retargeted intron of pLpACDthyA. The retargeted intron was expressed by using induction peptide (sppIP), subsequently the integration of intron in thyA gene was identified by PCR screening and finally ThyA(-) mutant of L. plantarum (ThyA18) was detected. In vitro growth curve result showed that in the absence of thymidine, colony forming units of mutant ThyA18 was decreased, whereas high thymidine concentration (10 μM) supported the growth of the culture until saturation. In conclusion, ThyA(-) mutant of L. plantarum (ThyA18) constructed in this study will be used as a biologically contained recombinant probiotic to deliver oxalate decarboxylase into the lumen for treatment of hyperoxaluria and calcium oxalate stone deposition.

  5. IMPACT OF ENERGY GROUP STRUCTURE ON NUCLEAR DATA TARGET ACCURACY REQUIREMENTS FOR ADVANCED REACTOR SYSTEMS

    SciTech Connect

    G. Palmiotti; M. Salvatores; H. Hiruta

    2011-06-01

    A target accuracy assessment study using both a fine and a broad energy structure has shown that less stringent nuclear data accuracy requirements are needed for the latter energy structure. However, even though a reduction is observed, still the requirements will be very difficult to be met unless integral experiments are also used to reduce nuclear data uncertainties. Target accuracy assessment is the inverse problem of the uncertainty evaluation. To establish priorities and target accuracies on data uncertainty reduction, a formal approach can be adopted by defining target accuracy on design parameters and finding out required accuracy on data in order to meet them. In fact, the unknown uncertainty data requirements can be obtained by solving a minimization problem where the sensitivity coefficients in conjunction with the constraints on the integral parameters provide the needed quantities for finding the solutions.

  6. The future of fixed target physics: Snowmass E5 working group summary

    SciTech Connect

    Krishna Kumar et al.

    2002-12-10

    Fixed target experimentation remains a vigorous and important tool. In many cases it provides the best technique to study elementary physics. Here the authors explore several areas, where, in the near future, fixed target experiments have the potential to alter the understanding of physics. These include, but are clearly not limited to, high precision tests of CP violation in the Kaon sector, ultra-precise determination of the weak mixing angle and its evolution, and lepton flavor violation.

  7. Internet-Delivered Targeted Group Intervention for Body Dissatisfaction and Disordered Eating in Adolescent Girls: A Randomized Controlled Trial

    ERIC Educational Resources Information Center

    Heinicke, Brooke E.; Paxton, Susan J.; McLean, Sian A.; Wertheim, Eleanor H.

    2007-01-01

    This study evaluated a targeted intervention designed to alleviate body image and eating problems in adolescent girls that was delivered over the internet so as to increase access to the program. The program consisted of six, 90-minute weekly small group, synchronous on-line sessions and was facilitated by a therapist and manual. Participants were…

  8. The Role of Polycomb Group Gene BMI-1 in the Development of Prostate Cancer

    DTIC Science & Technology

    2010-09-01

    1 mole/L EGTA, 1 mol/L EDTA, 20 mmol/L NaF, 100 mmol/L Na3VO4, 0.5% NP-40, 1% Triton X-100, 1 mol/L phenyl methylsulfonyl flouride (pH 7.4)] with...of myelodysplastic syndrome and patient prognosis. Blood. 2006 Jan 1;107(1):305-8. 12. Kim JH, Yoon SY, Kim CN, Joo JH, Moon SK, Choe IS, Choe YK

  9. The Role of Polycomb Group Gene Bmi-1 in the Development of Prostate Cancer

    DTIC Science & Technology

    2011-09-01

    transformed prostate epithelia cells (RWPE-1), PC-3, 22Rν1, DU -145 and LNCaP cancer cells were obtained from ATCC (Manassas, VA). Cells were...expression levels by immunoblot analysis in several human prostate carcinoma cell lines, LNCaP, DU -145 and PC-3, and compared them to NHPE and RWPE-1 cells...Among three cell lines used, LNCaP is androgen-sensitive whereas DU -145 and PC-3 are androgen- independent. The choice of these cells was based on

  10. The Role of Polycomb Group Gene BMI1 in the Development of Prostate Cancer

    DTIC Science & Technology

    2012-07-01

    of patients and majority of these patients progress to castration- resistant prostate cancer (CRPC). A treatment option for CRPC is cytotoxic...cancers (6). Glinsky et al identified BMI1 as one the signature molecules in a broad spectrum of therapy- resistant cancers included CaP (12). Except a...detection kit from MBL International Corporation (Watertown, MA). Briefly, docetaxel resistant and BMI1-silenced docetaxel resistant cells were harvested

  11. The Role of Polycomb Group Gene BMI1 in the Development of Prostate Cancer

    DTIC Science & Technology

    2014-03-01

    herin, N-cadherin, Vimentin, Tenascin C, NF-jB, SLUG, TWIST, SNAIL , b-Catenin, and CXCR4 [32, 33]. Collec- tively, these molecules are thought to...mammary epithelial cells adopt a mesenchymal phenotype and exhibit stem cell-like properties upon expres- sion of SNAIL and TWIST [32]. TWIST is...results in the activation of Phosphatidylinositol 3-kinases/protein kinase B (PI3K/AKT) pathway, stabilization of SNAIL , and downregulation of E-cadherin

  12. Family planning education: working with target groups in the South Pacific.

    PubMed

    Winn, M

    1992-07-01

    Family planning education programs are commonly designed by expert educators who are far removed, in location and experience, from their target audiences. Educators operate on the premise that their job is simply to develop strategies to successfully transfer their knowledge to the target audience. Judgements are often colored by a determination not to offend local sensibilities, which can lead educators to uncritically adopt the local wisdom about what is and is not culturally acceptable. A proper exploration of sexuality is absent from most family planning programs. Usual features of expert-designed family planning programs are an admonishment about people having too many children (the stick), a clear rationale for having fewer children (the carrot), the provision of detailed contraceptive information (the means), and the encouragement of individuals to exercise some personal control over their fertility (the ends). This standard model, although widely used throughout the Pacific, was not adopted by the Family Planning Federation of Australia in its regional family planning education work. The Federation, in conjunction with the independent Family Planning Association in the South Pacific, has taken a more participatory, learner-focused approach that values the contribution of the audience in all phases of the program. There is a huge need to target men, particularly young, unmarried men. The Federation found that not only did Pacific men want to view and discuss the women's documentary video Taboo Talk about family planning issues, they wanted their own men's version. The Federation soon discovered that attempts to meet the requests can easily flounder on the issue of language. The Federation has worked with the target audience to develop a lexicon of acceptable words for reproductive health education.

  13. A Functional Group Approach for Prediction of APPI Response of Organic Synthetic Targets

    NASA Astrophysics Data System (ADS)

    Zhurov, Konstantin O.; Menin, Laure; Di Franco, Thomas; Tsybin, Yury O.

    2015-07-01

    Atmospheric pressure photoionization (APPI) is a technique of choice for ionization of non-polar molecules in mass spectrometry (MS). Reported APPI-based studies tend to focus on a selected compound class, which may contain a variety of functional groups. These studies demonstrate that APPI response frequently differs substantially, indicating a certain dependence on the functional group present. Although this dependence could be employed for APPI response prediction, its systematic use is currently absent. Here, we apply APPI MS to a judiciously-compiled set of 63 compounds containing a number of diverse functional groups commonly utilized in synthesis, reactive functional groups, as well as those containing boron and silicon. Based on the outcome of APPI MS of these compounds, we propose and evaluate a simple guideline to estimate the APPI response for a novel compound, the key properties of which have not been characterized in the gas phase. Briefly, we first identify key functional groups in the compound and gather knowledge on the known ionization energies from the smallest analogues containing said functional groups. We then consider local inductive and resonance effects on said ionization energies for the compounds of interest to estimate the APPI response. Finally, application of APPI MS to compounds of interest considered herein demonstrated extended upper mass ionization limit of 3.5 kDa for non-polymeric compounds.

  14. Chromatin regulated interchange between polycomb repressive complex 2 (PRC2)-Ezh2 and PRC2-Ezh1 complexes controls myogenin activation in skeletal muscle cells

    PubMed Central

    2011-01-01

    Background Polycomb group (PcG) genes code for chromatin multiprotein complexes that are responsible for maintaining gene silencing of transcriptional programs during differentiation and in adult tissues. Despite the large amount of information on PcG function during development and cell identity homeostasis, little is known regarding the dynamics of PcG complexes and their role during terminal differentiation. Results We show that two distinct polycomb repressive complex (PRC)2 complexes contribute to skeletal muscle cell differentiation: the PRC2-Ezh2 complex, which is bound to the myogenin (MyoG) promoter and muscle creatine kinase (mCK) enhancer in proliferating myoblasts, and the PRC2-Ezh1 complex, which replaces PRC2-Ezh2 on MyoG promoter in post-mitotic myotubes. Interestingly, the opposing dynamics of PRC2-Ezh2 and PRC2-Ezh1 at these muscle regulatory regions is differentially regulated at the chromatin level by Msk1 dependent methyl/phospho switch mechanism involving phosphorylation of serine 28 of the H3 histone (H3S28ph). While Msk1/H3S28ph is critical for the displacement of the PRC2-Ezh2 complex, this pathway does not influence the binding of PRC2-Ezh1 on the chromatin. Importantly, depletion of Ezh1 impairs muscle differentiation and the chromatin recruitment of MyoD to the MyoG promoter in differentiating myotubes. We propose that PRC2-Ezh1 is necessary for controlling the proper timing of MyoG transcriptional activation and thus, in contrast to PRC2-Ezh2, is required for myogenic differentiation. Conclusions Our data reveal another important layer of epigenetic control orchestrating skeletal muscle cell terminal differentiation, and introduce a novel function of the PRC2-Ezh1 complex in promoter setting. PMID:21892963

  15. Target marketing of tobacco and alcohol-related products to ethnic minority groups in the United States.

    PubMed

    Moore, D J; Williams, J D; Qualls, W J

    1996-01-01

    This paper examines whether increased consumption of tobacco and alcohol products by minority groups is a function of the target marketing campaigns directed at these groups by marketers, and whether such contributes to the perpetuation of racism. First, a description of the tobacco and alcohol consumption rates of blacks and Hispanics compared to whites is presented, including a comparative analysis of the health effects and mortality rates resulting from the consumption of tobacco and alcohol. Second, the paper examines specific marketing strategies of targeting tobacco and alcohol products to ethnic minority consumers. This is followed by a discussion of whether these practices are a deliberate strategy driven by racism or just the pursuit of profit. A framework for answering the question is provided. Finally, the paper assesses the prospects for change in the future, and analyzes specific needs for future research.

  16. Model fidelity of assertive community treatment for clients with first-episode psychosis: a target group-specific application.

    PubMed

    Verhaegh, M J M; Bongers, I M B; Kroon, H; Garretsen, H F L

    2009-02-01

    Assertive community treatment (ACT) is described as a team treatment model designed to provide assertive, outreaching, comprehensive, community-based, rehabilitation-oriented and supportive psychiatric services for people with severe mental illness as reported by Drake et al. (Psychiatr Serv 52: 179-182, 2001) and Teague et al. (Psychiatr Serv 68: 216-232, 1998). This study explores variations in the way the original components of ACT are implemented for the target group of clients with a first-episode psychosis, and establishes whether these variations lead the treatment model to a higher, more valuable, outcome level. The study also describes how to achieve this optimally effective application of target group-specific treatment services.

  17. [Needs in rehabilitation and rehabilitative care of new target groups. Immigrants in psychosomatic rehabilitation].

    PubMed

    Kobelt, A; Göbber, J; Petermann, F

    2011-04-01

    Treatment of patients with migration background in psychosomatic rehabilitation is gaining in importance. Cultural differences and increased barriers are considered the most important causes for the inferior effective treatment results in psychosomatic rehabilitation and a higher percentage of pensions due to impairment. We discuss perspectives in psychosomatic rehabilitation which not only focus on the migration background as the main cause for inferior effective treatment results, but place greater focus on typical barriers of this patient group. For this reason, the need for more integrative and adapted forms of psychosomatic rehabilitation becomes more evident. Psychosomatic rehabilitation can be adapted by introducing case management, psychosomatic aftercare, and outpatient information groups.

  18. Discovery and Molecular Basis of a Diverse Set of Polycomb Repressive Complex 2 Inhibitors Recognition by EED

    PubMed Central

    Zhang, Man; Zhao, Mengxi; Feng, Lijian; Luo, Xiao; Gao, Zhenting; Huang, Ying; Ardayfio, Ophelia; Zhang, Ji-Hu; Lin, Ying; Fan, Hong; Mi, Yuan; Li, Guobin; Liu, Lei; Feng, Leying; Luo, Fangjun; Teng, Lin; Qi, Wei; Ottl, Johannes; Lingel, Andreas; Bussiere, Dirksen E.; Yu, Zhengtian; Atadja, Peter; Lu, Chris; Li, En; Gu, Justin; Zhao, Kehao

    2017-01-01

    Polycomb repressive complex 2 (PRC2), a histone H3 lysine 27 methyltransferase, plays a key role in gene regulation and is a known epigenetics drug target for cancer therapy. The WD40 domain-containing protein EED is the regulatory subunit of PRC2. It binds to the tri-methylated lysine 27 of the histone H3 (H3K27me3), and through which stimulates the activity of PRC2 allosterically. Recently, we disclosed a novel PRC2 inhibitor EED226 which binds to the K27me3-pocket on EED and showed strong antitumor activity in xenograft mice model. Here, we further report the identification and validation of four other EED binders along with EED162, the parental compound of EED226. The crystal structures for all these five compounds in complex with EED revealed a common deep pocket induced by the binding of this diverse set of compounds. This pocket was created after significant conformational rearrangement of the aromatic cage residues (Y365, Y148 and F97) in the H3K27me3 binding pocket of EED, the width of which was delineated by the side chains of these rearranged residues. In addition, all five compounds interact with the Arg367 at the bottom of the pocket. Each compound also displays unique features in its interaction with EED, suggesting the dynamics of the H3K27me3 pocket in accommodating the binding of different compounds. Our results provide structural insights for rational design of novel EED binder for the inhibition of PRC2 complex activity. PMID:28072869

  19. Polycomb-Mediated Repression and Sonic Hedgehog Signaling Interact to Regulate Merkel Cell Specification during Skin Development

    PubMed Central

    Bar, Carmit; Tsai, Pai-Chi; Valdes, Victor J.; Cohen, Idan; Santoriello, Francis J.; Zhao, Dejian; Hsu, Ya-Chieh; Ezhkova, Elena

    2016-01-01

    An increasing amount of evidence indicates that developmental programs are tightly regulated by the complex interplay between signaling pathways, as well as transcriptional and epigenetic processes. Here, we have uncovered coordination between transcriptional and morphogen cues to specify Merkel cells, poorly understood skin cells that mediate light touch sensations. In murine dorsal skin, Merkel cells are part of touch domes, which are skin structures consisting of specialized keratinocytes, Merkel cells, and afferent neurons, and are located exclusively around primary hair follicles. We show that the developing primary hair follicle functions as a niche required for Merkel cell specification. We find that intraepidermal Sonic hedgehog (Shh) signaling, initiated by the production of Shh ligand in the developing hair follicles, is required for Merkel cell specification. The importance of Shh for Merkel cell formation is further reinforced by the fact that Shh overexpression in embryonic epidermal progenitors leads to ectopic Merkel cells. Interestingly, Shh signaling is common to primary, secondary, and tertiary hair follicles, raising the possibility that there are restrictive mechanisms that regulate Merkel cell specification exclusively around primary hair follicles. Indeed, we find that loss of Polycomb repressive complex 2 (PRC2) in the epidermis results in the formation of ectopic Merkel cells that are associated with all hair types. We show that PRC2 loss expands the field of epidermal cells competent to differentiate into Merkel cells through the upregulation of key Merkel-differentiation genes, which are known PRC2 targets. Importantly, PRC2-mediated repression of the Merkel cell differentiation program requires inductive Shh signaling to form mature Merkel cells. Our study exemplifies how the interplay between epigenetic and morphogen cues regulates the complex patterning and formation of the mammalian skin structures. PMID:27414999

  20. Whole-Faculty Study Groups: Creating Professional Learning Communities That Target Student Learning. Third Edition

    ERIC Educational Resources Information Center

    Murphy, Carlene U.; Lick, Dale W.

    2004-01-01

    Used by hundreds of schools and school districts across the country, the Whole-Faculty Study Group (WFSG) System is a student-driven, holistic process for facilitating major staff development and schoolwide change. While providing a step-by-step methodology for the development and implementation of successful WFSGs, this newest edition of Murphy…

  1. E. coli Group 1 Capsular Polysaccharide Exportation Nanomachinary as a Plausible Antivirulence Target in the Perspective of Emerging Antimicrobial Resistance

    PubMed Central

    Sachdeva, Shivangi; Palur, Raghuvamsi V.; Sudhakar, Karpagam U.; Rathinavelan, Thenmalarchelvi

    2017-01-01

    Bacteria evolving resistance against the action of multiple drugs and its ability to disseminate the multidrug resistance trait(s) across various strains of the same bacteria or different bacterial species impose serious threat to public health. Evolution of such multidrug resistance is due to the fact that, most of the antibiotics target bacterial survival mechanisms which exert selective pressure on the bacteria and aids them to escape from the action of antibiotics. Nonetheless, targeting bacterial virulence strategies such as bacterial surface associated polysaccharides biosynthesis and their surface accumulation mechanisms may be an attractive strategy, as they impose less selective pressure on the bacteria. Capsular polysaccharide (CPS) or K-antigen that is located on the bacterial surface armors bacteria from host immune response. Thus, unencapsulating bacteria would be a good strategy for drug design, besides CPS itself being a good vaccine target, by interfering with CPS biosynthesis and surface assembly pathway. Gram-negative Escherichia coli uses Wzy-polymerase dependent (Groups 1 and 4) and ATP dependent (Groups 1 and 3) pathways for CPS production. Considering E. coli as a case in point, this review explains the structure and functional roles of proteins involved in Group 1 Wzy dependent CPS biosynthesis, surface expression and anchorage in relevance to drug and vaccine developments. PMID:28217109

  2. Physical Interaction between MYCN Oncogene and Polycomb Repressive Complex 2 (PRC2) in Neuroblastoma

    PubMed Central

    Corvetta, Daisy; Chayka, Olesya; Gherardi, Samuele; D'Acunto, Cosimo W.; Cantilena, Sandra; Valli, Emanuele; Piotrowska, Izabela; Perini, Giovanni; Sala, Arturo

    2013-01-01

    CLU (clusterin) is a tumor suppressor gene that we have previously shown to be negatively modulated by the MYCN proto-oncogene, but the mechanism of repression was unclear. Here, we show that MYCN inhibits the expression of CLU by direct interaction with the non-canonical E box sequence CACGCG in the 5′-flanking region. Binding of MYCN to the CLU gene induces bivalent epigenetic marks and recruitment of repressive proteins such as histone deacetylases and Polycomb members. MYCN physically binds in vitro and in vivo to EZH2, a component of the Polycomb repressive complex 2, required to repress CLU. Notably, EZH2 interacts with the Myc box domain 3, a segment of MYC known to be essential for its transforming effects. The expression of CLU can be restored in MYCN-amplified cells by epigenetic drugs with therapeutic results. Importantly, the anticancer effects of the drugs are ablated if CLU expression is blunted by RNA interference. Our study implies that MYC tumorigenesis can be effectively antagonized by epigenetic drugs that interfere with the recruitment of chromatin modifiers at repressive E boxes of tumor suppressor genes such as CLU. PMID:23362253

  3. Most at-risk populations: contextualising HIV prevention programmes targeting marginalised groups in Zanzibar, Tanzania.

    PubMed

    Ahmed, Naheed

    2014-09-01

    According to a 2009 UNAIDS report the HIV/AIDS prevalence rate in Zanzibar, Tanzania, is low in the general population (0.6%), but high among vulnerable groups, specifically sex workers (10.8%), injecting drug users (15.1%), and men who have sex with men (12.3%). In response to this concentrated epidemic, the Government of Zanzibar, international and local non-profit organisations have focused their prevention activities on these marginal populations. Although these efforts are beneficial in terms of disseminating information about HIV/AIDS and referring clients to health clinics, they fail to address how the socio-economic status of these groups places them at a greater risk for contracting and dying from the virus. Furthermore, there is an absence of qualitative research on these populations which is needed to understand the challenges these groups face and to improve the effectiveness of interventions. Through interviews with employees of government agencies and non-profit organisations, medical professionals, vulnerable populations and HIV/AIDS patients, this paper used a political economy of health and syndemic framework to examine how local realities inform and challenge HIV/AIDS programmes in Zanzibar.

  4. The spxB gene as a target to identify Lactobacillus casei group species in cheese.

    PubMed

    Savo Sardaro, Maria Luisa; Levante, Alessia; Bernini, Valentina; Gatti, Monica; Neviani, Erasmo; Lazzi, Camilla

    2016-10-01

    This study focused on the spxB gene, which encodes for pyruvate oxidase. The presence of spxB in the genome and its transcription could be a way to produce energy and allow bacterial growth during carbohydrate starvation. In addition, the activity of pyruvate oxidase, which produces hydrogen peroxide, could be a mechanism for interspecies competition. Because this gene seems to provide advantages for the encoding species for adaptation in complex ecosystems, we studied spxB in a large set of cheese isolates belonging to the Lactobacillus casei group. Through this study, we demonstrated that this gene is widely found in the genomes of members of the L. casei group and shows variability useful for taxonomic studies. In particular, the HRM analysis method allowed for a specific discrimination between Lactobacillus rhamnosus, Lactobacillus paracasei and L. casei. Regarding the coding region, the spxB functionality in cheese was shown for the first time by real-time PCR, and by exploiting the heterogeneity between the L. casei group species, we identified the bacterial communities encoding the spxB gene in this ecosystem. This study allowed for monitoring of the active bacterial community involved in different stages of ripening by following the POX pathway.

  5. Group I Paks as therapeutic targets in NF2-deficient meningioma

    PubMed Central

    Duron, Sergio G.; Campbell, David A.; Ong, Christy C.; Hoeflich, Klaus P.; Chang, Long-Sheng; Welling, D. Bradley; Yang, Zeng-jie; Chernoff, Jonathan

    2015-01-01

    Neurofibromatosis type 2 (NF2) is an autosomal dominant disorder characterized by the development of multiple tumors in the central nervous system, most notably schwannomas and meningiomas. Mutational inactivation of NF2 is found in 40–60% of sporadic meningiomas, but the molecular mechanisms underlying malignant changes of meningioma cells remain unclear. Because group I p21-activated kinases (Paks) bind to and are inhibited by the NF2-encoded protein Merlin, we assessed the signaling and anti-tumor effects of three group-I specific Pak inhibitors - Frax597, 716 and 1036 - in NF2−/− meningiomas in vitro and in an orthotopic mouse model. We found that these Pak inhibitors suppressed the proliferation and motility of both benign (Ben-Men1) and malignant (KT21-MG1) meningiomas cells. In addition, we found a strong reduction in phosphorylation of Mek and S6, and decreased cyclin D1 expression in both cell lines after treatment with Pak inhibitors. Using intracranial xenografts of luciferase-expressing KT21-MG1 cells, we found that treated mice showed significant tumor suppression for all three Pak inhibitors. Similar effects were observed in Ben-Men1 cells. Tumors dissected from treated animals exhibited an increase in apoptosis without notable change in proliferation. Collectively, these results suggest that Pak inhibitors might be useful agents in treating NF2-deficient meningiomas. PMID:25596744

  6. The Bmi-1 polycomb protein antagonizes the (-)-epigallocatechin-3-gallate-dependent suppression of skin cancer cell survival.

    PubMed

    Balasubramanian, Sivaprakasam; Adhikary, Gautam; Eckert, Richard L

    2010-03-01

    The polycomb group (PcG) proteins are epigenetic regulators of gene expression that enhance cell survival. This regulation is achieved via action of two multiprotein PcG complexes--PRC2 (EED) and PRC1 [B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1)]. These complexes modulate gene expression by increasing histone methylation and reducing acetylation--leading to a closed chromatin conformation. Activity of these proteins is associated with increased cell proliferation and survival. We show increased expression of key PcG proteins in immortalized keratinocytes and skin cancer cell lines. We examine the role of two key PcG proteins, Bmi-1 and enhancer of zeste homolog 2 (Ezh2), and the impact of the active agent in green tea, (-)-epigallocatechin-3-gallate (EGCG), on the function of these regulators. EGCG treatment of SCC-13 cells reduces Bmi-1 and Ezh2 level and this is associated with reduced cell survival. The reduction in survival is associated with a global reduction in histone H3 lysine 27 trimethylation, a hallmark of PRC2 complex action. This change in PcG protein expression is associated with reduced expression of key proteins that enhance progression through the cell cycle [cyclin-dependent kinase (cdk)1, cdk2, cdk4, cyclin D1, cyclin E, cyclin A and cyclin B1] and increased expression of proteins that inhibit cell cycle progression (p21 and p27). Apoptosis is also enhanced, as evidenced by increased caspase 9, 8 and 3 cleavage and increased poly(adenosine diphosphate ribose) polymerase cleavage. EGCG treatment also increases Bax and suppresses Bcl-xL expression. Vector-mediated enhanced Bmi-1 expression reverses these EGCG-dependent changes. These findings suggest that green tea polyphenols reduce skin tumor cell survival by influencing PcG-mediated epigenetic regulatory mechanisms.

  7. The Drosophila eve insulator Homie promotes eve expression and protects the adjacent gene from repression by polycomb spreading.

    PubMed

    Fujioka, Miki; Sun, Guizhi; Jaynes, James B

    2013-10-01

    Insulators can block the action of enhancers on promoters and the spreading of repressive chromatin, as well as facilitating specific enhancer-promoter interactions. However, recent studies have called into question whether the activities ascribed to insulators in model transgene assays actually reflect their functions in the genome. The Drosophila even skipped (eve) gene is a Polycomb (Pc) domain with a Pc-group response element (PRE) at one end, flanked by an insulator, an arrangement also seen in other genes. Here, we show that this insulator has three major functions. It blocks the spreading of the eve Pc domain, preventing repression of the adjacent gene, TER94. It prevents activation of TER94 by eve regulatory DNA. It also facilitates normal eve expression. When Homie is deleted in the context of a large transgene that mimics both eve and TER94 regulation, TER94 is repressed. This repression depends on the eve PRE. Ubiquitous TER94 expression is "replaced" by expression in an eve pattern when Homie is deleted, and this effect is reversed when the PRE is also removed. Repression of TER94 is attributable to spreading of the eve Pc domain into the TER94 locus, accompanied by an increase in histone H3 trimethylation at lysine 27. Other PREs can functionally replace the eve PRE, and other insulators can block PRE-dependent repression in this context. The full activity of the eve promoter is also dependent on Homie, and other insulators can promote normal eve enhancer-promoter communication. Our data suggest that this is not due to preventing promoter competition, but is likely the result of the insulator organizing a chromosomal conformation favorable to normal enhancer-promoter interactions. Thus, insulator activities in a native context include enhancer blocking and enhancer-promoter facilitation, as well as preventing the spread of repressive chromatin.

  8. MicroRNA‑128a, BMI1 polycomb ring finger oncogene, and reactive oxygen species inhibit the growth of U‑87 MG glioblastoma cells following exposure to X‑ray radiation.

    PubMed

    Ye, Lan; Yu, Guanying; Wang, Cuihong; Du, Bin; Sun, Dianshui; Liu, Junli; Qi, Tonggang; Yu, Xiaoming; Wei, Wei; Cheng, Jian; Jiang, Yuhua

    2015-10-01

    Radiotherapy is an important therapeutic strategy for the treatment of numerous types of malignant tumors, including glioma. However, radioresistance and anti‑apoptotic mechanisms decrease the efficacy of radiotherapy in many patients with glioma. BMI1 polycomb ring finger oncogene (Bmi‑1) is an oncogene associated with radioresistance in tumor cells. MicroRNA (miRNA)‑128a is a brain-specific miRNA, which suppresses Bmi‑1 expression. The present study investigated the effects of various radiation intensities on U‑87 MG glioma cells, as well as the role of reactive oxygen species (ROS), Bmi‑1, and miRNA‑128a in the cellular response to radiotherapy. The response of U‑87 MG cells following exposure to X‑ray radiation was assessed using a cell growth curve and inhibition ratio. Cell cycle distribution and the levels of intracellular ROS were evaluated by flow cytometry. The mRNA expression levels of Bmi‑1 and those of miRNA‑128a in U‑87 MG cells exposed to X‑ray radiation were evaluated by reverse transcription‑quantitative polymerase chain reaction. X‑ray radiation did not decrease the number of U‑87 MG cells; however, it did inhibit cellular growth in a dose‑dependent manner. Following exposure to X‑ray radiation for 24 h, cell cycle distribution was altered, with an increase in the number of cells in G0/G1 phase. The mRNA expression levels of Bmi‑1 were downregulated in the 1 and 2 Gy groups, and upregulated in the 6 and 8 Gy groups. The expression levels of miRNA‑128a were upregulated in the 1 and 2 Gy groups, and downregulated in the 8 Gy group. The levels of ROS were increased following exposure to ≥2 Gy, and treatment with N-acetyl cysteine was able to induce radioresistance. These results suggested that U‑87 MG cells exhibited radioresistance. High doses of X‑ray radiation increased the expression levels of Bmi‑1, which may be associated with the evasion of cellular senescence. miRNA‑128a and its downstream

  9. Refocusing resolution based on negative refractive-photonic crystal group with Ag defects for target detection and imaging

    NASA Astrophysics Data System (ADS)

    Lian, Yingfei; Zhu, Na; Fang, Yuntuan; Sun, Jiwen; Chen, Junlv; Qian, Huili

    2015-03-01

    Negative refractive-photonic crystal (NR-PC) lenses that can exceed the diffraction limit of focus resolution for imaging and target detection in the near field have gotten more and more special attention in recent years. Three flat lens groups with Ag defects based on NR-PC are designed, and the focusing imaging in the NR-PC three flat lens groups is concluded with the extension of Snell's law, and the influence on the resolution for a target detection dynamic scanning scheme is simulated by using the finite difference time domain method. An optimal-doped structure with Ag defects is achieved by different simulation combinations. The refocusing resolution 0.18834λ is achieved in the optimal structure and there is approximately a 0.06806λ improvement in the refocusing resolution compared to those undoped with Ag (0.2564λ) it also possesses distinct smaller side-lobes than a single flat lens doped with Ag. This means the optimal detecting ability for the three NR-PC flat lens groups with Ag defects is more improved than that for a single undoped and doped with Ag. This is significant for the perfect imaging being achieved for a particle structure.

  10. Life after death: targeting high mobility group box 1 in emergent cancer therapies

    PubMed Central

    Guo, Z Sheng; Liu, Zuqiang; Bartlett, David L; Tang, Daolin; Lotze, Michael T

    2013-01-01

    High mobility group box 1 (HMGB1), an evolutionarily highly conserved and abundant nuclear protein also has roles within the cytoplasm and as an extracellular damage-associated molecular pattern (DAMP) molecule. Extracellular HMGB1 is the prototypic endogenous ‘danger signal’ that triggers inflammation and immunity. Recent findings suggest that posttranslational modifications dictate the cellular localization and secretion of HMGB1. HMGB1 is actively secreted from immune cells and stressed cancer cells, or passively released from necrotic cells. During cancer development or administration of therapeutic agents including chemotherapy, radiation, epigenetic drugs, oncolytic viruses, or immunotherapy, the released HMGB1 may either promote or limit cancer growth, depending on the state of progression and vascularization of the tumor. Extracellular HMGB1 enhances autophagy and promotes persistence of surviving cancer cells following initial activation. When oxidized, it chronically suppresses the immune system to promote cancer growth and progression, thereby enhancing resistance to cancer therapeutics. In its reduced form, it can facilitate and elicit innate and adaptive anti-tumor immunity, recruiting and activating immune cells, in conjunction with cytotoxic agents, particularly in early transplantable tumor models. We hypothesize that HMGB1 also functions as an epigenetic modifier, mainly through regulation of NF-kB-dependent signaling pathways, to modulate the behavior of surviving cancer cells as well as the immune cells found within the tumor microenvironment. This has significant implications for developing novel cancer therapeutics. PMID:23359863

  11. Adherence to highly active antiretroviral therapy in Hyderabad, India: barriers, facilitators and identification of target groups.

    PubMed

    Dworkin, Mark S; Douglas, G W; Sabitha Rani, G P; Chakraborty, Apurba

    2016-03-01

    We assessed the barriers and facilitators to highly active antiretroviral therapy adherence and determined their prevalence among HIV/AIDS patients in Hyderabad, India. We conducted a cross-sectional study among HIV-infected adults prescribed highly active antiretroviral therapy and receiving care from nine clinics. Depression was screened using Patient Health Questionnaire 9 and facilitators of HIV medication adherence were assessed using an 11-item scale which yielded a total positive attitude to disease score. Prevalence ratios of non-adherence between different categories of potential risk factors were calculated. We compared mean 'facilitators to adherence' scores between the adherent and non-adherent population. Multivariable Poisson regression with robust variance was used to identify independent risk factors. Among the 211 respondents, nearly 20% were non-adherent, approximately 8% had either moderately severe or severe depression and mean score for combined facilitators to medication adherence was 33.35 (±7.88) out of a possible 44 points. Factors significantly associated with non-adherence included older age, female sex worker, moderate-to-severe depression and the combined facilitators to medication adherence score. These data from a broad range of clinical settings in Hyderabad reveal that key groups to focus on for adherence intervention are female sex workers, older persons and those with depression.

  12. Developing clinical practice guidelines: target audiences, identifying topics for guidelines, guideline group composition and functioning and conflicts of interest

    PubMed Central

    2012-01-01

    Clinical practice guidelines are one of the foundations of efforts to improve health care. In 1999, we authored a paper about methods to develop guidelines. Since it was published, the methods of guideline development have progressed both in terms of methods and necessary procedures and the context for guideline development has changed with the emergence of guideline clearing houses and large scale guideline production organisations (such as the UK National Institute for Health and Clinical Excellence). It therefore seems timely to, in a series of three articles, update and extend our earlier paper. In this first paper we discuss: the target audience(s) for guidelines and their use of guidelines; identifying topics for guidelines; guideline group composition (including consumer involvement) and the processes by which guideline groups function and the important procedural issue of managing conflicts of interest in guideline development. PMID:22762776

  13. Polycomb repressive complex 2 regulates skeletal growth by suppressing Wnt and TGF-β signalling

    PubMed Central

    Mirzamohammadi, Fatemeh; Papaioannou, Garyfallia; Inloes, Jennifer B.; Rankin, Erinn B.; Xie, Huafeng; Schipani, Ernestina; Orkin, Stuart H.; Kobayashi, Tatsuya

    2016-01-01

    Polycomb repressive complex 2 (PRC2) controls maintenance and lineage determination of stem cells by suppressing genes that regulate cellular differentiation and tissue development. However, the role of PRC2 in lineage-committed somatic cells is mostly unknown. Here we show that Eed deficiency in chondrocytes causes severe kyphosis and a growth defect with decreased chondrocyte proliferation, accelerated hypertrophic differentiation and cell death with reduced Hif1a expression. Eed deficiency also causes induction of multiple signalling pathways in chondrocytes. Wnt signalling overactivation is responsible for the accelerated hypertrophic differentiation and kyphosis, whereas the overactivation of TGF-β signalling is responsible for the reduced proliferation and growth defect. Thus, our study demonstrates that PRC2 has an important regulatory role in lineage-committed tissue cells by suppressing overactivation of multiple signalling pathways. PMID:27329220

  14. Polycomb Repressive Complex 2-Dependent and -Independent Functions of Jarid2 in Transcriptional Regulation in Drosophila

    PubMed Central

    Herz, Hans-Martin; Mohan, Man; Garrett, Alexander S.; Miller, Caitlynn; Casto, David; Zhang, Ying; Seidel, Christopher; Haug, Jeffrey S.; Florens, Laurence; Washburn, Michael P.; Yamaguchi, Masamitsu; Shiekhattar, Ramin

    2012-01-01

    Jarid2 was recently identified as an important component of the mammalian Polycomb repressive complex 2 (PRC2), where it has a major effect on PRC2 recruitment in mouse embryonic stem cells. Although Jarid2 is conserved in Drosophila, it has not previously been implicated in Polycomb (Pc) regulation. Therefore, we purified Drosophila Jarid2 and its associated proteins and found that Jarid2 associates with all of the known canonical PRC2 components, demonstrating a conserved physical interaction with PRC2 in flies and mammals. Furthermore, in vivo studies with Jarid2 mutants in flies demonstrate that among several histone modifications tested, only methylation of histone 3 at K27 (H3K27), the mark implemented by PRC2, was affected. Genome-wide profiling of Jarid2, Su(z)12 (Suppressor of zeste 12), and H3K27me3 occupancy by chromatin immunoprecipitation with sequencing (ChIP-seq) indicates that Jarid2 and Su(z)12 have very similar distribution patterns on chromatin. However, Jarid2 and Su(z)12 occupancy levels at some genes are significantly different, with Jarid2 being present at relatively low levels at many Pc response elements (PREs) of certain Homeobox (Hox) genes, providing a rationale for why Jarid2 was never identified in Pc screens. Gene expression analyses show that Jarid2 and E(z) (Enhancer of zeste, a canonical PRC2 component) are not only required for transcriptional repression but might also function in active transcription. Identification of Jarid2 as a conserved PRC2 interactor in flies provides an opportunity to begin to probe some of its novel functions in Drosophila development. PMID:22354997

  15. Maintenance of leukemic cell identity by the activity of the Polycomb complex PRC1 in mice

    PubMed Central

    Rossi, Alessandra; Ferrari, Karin J.; Piunti, Andrea; Jammula, SriGanesh; Chiacchiera, Fulvio; Mazzarella, Luca; Scelfo, Andrea; Pelicci, Pier Giuseppe; Pasini, Diego

    2016-01-01

    Leukemia is a complex heterogeneous disease often driven by the expression of oncogenic fusion proteins with different molecular and biochemical properties. Whereas several fusion proteins induce leukemogenesis by activating Hox gene expression (Hox-activating fusions), others impinge on different pathways that do not involve the activation of Hox genes (non–Hox-activating fusions). It has been postulated that one of the main oncogenic properties of the HOXA9 transcription factor is its ability to control the expression of the p16/p19 tumor suppressor locus (Cdkn2a), thereby compensating Polycomb-mediated repression, which is dispensable for leukemias induced by Hox-activating fusions. We show, by genetically depleting the H2A ubiquitin ligase subunits of the Polycomb repressive complex 1 (PRC1), Ring1a and Ring1b, that Hoxa9 activation cannot repress Cdkn2a expression in the absence of PRC1 and its dependent deposition of H2AK119 monoubiquitination (H2AK119Ub). This demonstrates the essential role of PRC1 activity in supporting the oncogenic potential of Hox-activating fusion proteins. By combining genetic tools with genome-wide location and transcription analyses, we further show that PRC1 activity is required for the leukemogenic potential of both Hox-activating and non–Hox-activating fusions, thus preventing the differentiation of leukemic cells independently of the expression of the Cdkn2a locus. Overall, our results genetically demonstrate that PRC1 activity and the deposition of H2AK119Ub are critical factors that maintain the undifferentiated identity of cancer cells, positively sustaining the progression of different types of leukemia. PMID:27730210

  16. Mariner Transposons Contain a Silencer: Possible Role of the Polycomb Repressive Complex 2

    PubMed Central

    Beauclair, Linda; Moiré, Nathalie; Arensbuger, Peter; Bigot, Yves

    2016-01-01

    Transposable elements are driving forces for establishing genetic innovations such as transcriptional regulatory networks in eukaryotic genomes. Here, we describe a silencer situated in the last 300 bp of the Mos1 transposase open reading frame (ORF) which functions in vertebrate and arthropod cells. Functional silencers are also found at similar locations within three other animal mariner elements, i.e. IS630-Tc1-mariner (ITm) DD34D elements, Himar1, Hsmar1 and Mcmar1. These silencers are able to impact eukaryotic promoters monitoring strong, moderate or low expression as well as those of mariner elements located upstream of the transposase ORF. We report that the silencing involves at least two transcription factors (TFs) that are conserved within animal species, NFAT-5 and Alx1. These cooperatively act with YY1 to trigger the silencing activity. Four other housekeeping transcription factors (TFs), neuron restrictive silencer factor (NRSF), GAGA factor (GAF) and GTGT factor (GTF), were also found to have binding sites within mariner silencers but their impact in modulating the silencer activity remains to be further specified. Interestingly, an NRSF binding site was found to overlap a 30 bp motif coding a highly conserved PHxxYSPDLAPxD peptide in mariner transposases. We also present experimental evidence that silencing is mainly achieved by co-opting the host Polycomb Repressive Complex 2 pathway. However, we observe that when PRC2 is impaired another host silencing pathway potentially takes over to maintain weak silencer activity. Mariner silencers harbour features of Polycomb Response Elements, which are probably a way for mariner elements to self-repress their transcription and mobility in somatic and germinal cells when the required TFs are expressed. At the evolutionary scale, mariner elements, through their exaptation, might have been a source of silencers playing a role in the chromatin configuration in eukaryotic genomes. PMID:26939020

  17. Gegenees: fragmented alignment of multiple genomes for determining phylogenomic distances and genetic signatures unique for specified target groups.

    PubMed

    Agren, Joakim; Sundström, Anders; Håfström, Therese; Segerman, Bo

    2012-01-01

    The rapid development of Next Generation Sequencing technologies leads to the accumulation of huge amounts of sequencing data. The scientific community faces an enormous challenge in how to deal with this explosion. Here we present a software tool, 'Gegenees', that uses a fragmented alignment approach to facilitate the comparative analysis of hundreds of microbial genomes. The genomes are fragmented and compared, all against all, by a multithreaded BLAST control engine. Ready-made alignments can be complemented with new genomes without recalculating the existing data points. Gegenees gives a phylogenomic overview of the genomes and the alignment can then be mined for genomic regions with conservation patterns matching a defined target group and absent from a background group. The genomic regions are given biomarker scores forming a uniqueness signature that can be viewed and explored, graphically and in tabular form. A primer/probe alignment tool is also included for specificity verification of currently used or new primers. We exemplify the use of Gegenees on the Bacillus cereus group, on Foot and Mouth Disease Viruses, and on strains from the 2011 Escherichia coli O104:H4 outbreak. Gegenees contributes towards an increased capacity of fast and efficient data mining as more and more genomes become sequenced.

  18. Gegenees: Fragmented Alignment of Multiple Genomes for Determining Phylogenomic Distances and Genetic Signatures Unique for Specified Target Groups

    PubMed Central

    Håfström, Therese; Segerman, Bo

    2012-01-01

    The rapid development of Next Generation Sequencing technologies leads to the accumulation of huge amounts of sequencing data. The scientific community faces an enormous challenge in how to deal with this explosion. Here we present a software tool, ‘Gegenees’, that uses a fragmented alignment approach to facilitate the comparative analysis of hundreds of microbial genomes. The genomes are fragmented and compared, all against all, by a multithreaded BLAST control engine. Ready-made alignments can be complemented with new genomes without recalculating the existing data points. Gegenees gives a phylogenomic overview of the genomes and the alignment can then be mined for genomic regions with conservation patterns matching a defined target group and absent from a background group. The genomic regions are given biomarker scores forming a uniqueness signature that can be viewed and explored, graphically and in tabular form. A primer/probe alignment tool is also included for specificity verification of currently used or new primers. We exemplify the use of Gegenees on the Bacillus cereus group, on Foot and Mouth Disease Viruses, and on strains from the 2011 Escherichia coli O104:H4 outbreak. Gegenees contributes towards an increased capacity of fast and efficient data mining as more and more genomes become sequenced. PMID:22723939

  19. A Group Contingency Plus Self-Management Intervention Targeting At-Risk Secondary Students' Class-Work and Active Engagement.

    PubMed

    Trevino-Maack, Sylvia I; Kamps, Debra; Wills, Howard

    2015-01-01

    The purpose of the present study is to show that an independent group contingency (GC) combined with self-management strategies and randomized-reinforcer components can increase the amount of written work and active classroom responding in high school students. Three remedial reading classes and a total of 15 students participated in this study. Students used self-management strategies during independent reading time to increase the amount of writing in their reading logs. They used self-monitoring strategies to record whether or not they performed expected behaviors in class. A token economy using points and tickets was included in the GC to provide positive reinforcement for target responses. The results were analyzed through visual inspection of graphs and effect size computations and showed that the intervention increased the total amount of written words in the students' reading logs and overall classroom and individual student academic engagement.

  20. Injury prevention target groups in soccer: injury characteristics and incidence rates in male junior and senior players.

    PubMed

    Schmikli, Sandor L; de Vries, Wouter R; Inklaar, Han; Backx, Frank J G

    2011-05-01

    To identify target groups for injury prevention in male amateur soccer players under 35 years of age. A computer-assisted telephone survey with a 12-month recall period for injuries in a representative sample of Dutch citizens from the Injuries and Physical Activity Netherlands (IPAN)-database. A comparison of the volume of soccer injuries, the incidence and the need for medical attention per level of exposure and age category. The incidence in seniors was twice that of juniors (17.5% versus 8.1%; odds ratio (OR=2.4). In juniors the overall incidence was lowest in the category with the least amount of soccer exposure time (0-3 h: 2.9%; 3-5 h: 13.0%; 5+ h: 12.3%). A comparable result was found in seniors: (0-3 h: 12.0%; 3-5 h: 21.6%; 5+ h: 21.5%). Within each level of soccer exposure, a different incidence was found in juniors and seniors (0-3 h: OR=4.6; 3-5 h: OR=1.8; 5+ h: OR=1.9). Ankle, knee and upper leg injuries were most common (59.9%). Contusions, strains and sprains dominated (78.1%). Body region and type of injuries were similar in both age categories. Medical treatment for injuries was equally necessary in both age groups. Senior male amateur soccer players and particularly the more skilled seniors (involved in soccer at least 3 h per week), should be primarily targeted for studies on injury risk factors and prevention programs.

  1. Unhealthful Food-and-Beverage Advertising in Subway Stations: Targeted Marketing, Vulnerable Groups, Dietary Intake, and Poor Health.

    PubMed

    Lucan, Sean C; Maroko, Andrew R; Sanon, Omar C; Schechter, Clyde B

    2017-03-07

    Unhealthful food-and-beverage advertising often targets vulnerable groups. The extent of such advertising in subway stations has not been reported and it is not clear how ad placement may relate to subway ridership or community demographics, or what the implications might be for diets and diet-related health in surrounding communities. Riding all subway lines (n = 7) in the Bronx, NY, USA, investigators systematically assessed all print ads (n = 1586) in all stations (n = 68) in 2012. Data about subway ridership came from the Metropolitan Transportation Authority. Demographic data on surrounding residential areas came from the U.S. Census Bureau. Data on dietary intake and diet-related conditions came from a city health-department survey. There were no ads promoting "more-healthful" food-or-beverage items (i.e., fruits, vegetables, whole grains, nuts, water or milk). There were many ads for "less-healthful" items (e.g., candies, chips, sugary cereals, frozen pizzas, "energy" drinks, coffee confections, hard alcohol, and beer). Ad placement did not relate to the number of riders entering at stations. Instead, exposure to food-or-beverage ads generally, and to "less-healthful" ads particularly (specifically ads in Spanish, directed at youth, and/or featuring minorities), was directly correlated with poverty, lower high-school graduation rates, higher percentages of Hispanics, and/or higher percentages of children in surrounding residential areas. Correlations were robust to sensitivity analyses. Additional analyses suggested correlations between ad exposures and sugary-drink consumption, fruit-and-vegetable intake, and diabetes, hypertension, and high-cholesterol rates. Subway-station ads for "less-healthful" items were located disproportionately in areas home to vulnerable populations facing diet and diet-related-health challenges. The fact that uneven ad placement did not relate to total rider counts suggests ads were not directed at the largest

  2. The SAND domain protein ULTRAPETALA1 acts as a trithorax group factor to regulate cell fate in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During development, trithorax group (trxG) chromatin remodeling complexes counteract repression by Polycomb group (PcG) complexes to sustain active expression of key regulatory genes. Although PcG complexes are well characterized in plants, little is known about trxG activities. Here we demonstrate ...

  3. Distinct Cellular Assembly Stoichiometry of Polycomb Complexes on Chromatin Revealed by Single-molecule Chromatin Immunoprecipitation Imaging.

    PubMed

    Tatavosian, Roubina; Zhen, Chao Yu; Duc, Huy Nguyen; Balas, Maggie M; Johnson, Aaron M; Ren, Xiaojun

    2015-11-20

    Epigenetic complexes play an essential role in regulating chromatin structure, but information about their assembly stoichiometry on chromatin within cells is poorly understood. The cellular assembly stoichiometry is critical for appreciating the initiation, propagation, and maintenance of epigenetic inheritance during normal development and in cancer. By combining genetic engineering, chromatin biochemistry, and single-molecule fluorescence imaging, we developed a novel and sensitive approach termed single-molecule chromatin immunoprecipitation imaging (Sm-ChIPi) to enable investigation of the cellular assembly stoichiometry of epigenetic complexes on chromatin. Sm-ChIPi was validated by using chromatin complexes with known stoichiometry. The stoichiometry of subunits within a polycomb complex and the assembly stoichiometry of polycomb complexes on chromatin have been extensively studied but reached divergent views. Moreover, the cellular assembly stoichiometry of polycomb complexes on chromatin remains unexplored. Using Sm-ChIPi, we demonstrated that within mouse embryonic stem cells, one polycomb repressive complex (PRC) 1 associates with multiple nucleosomes, whereas two PRC2s can bind to a single nucleosome. Furthermore, we obtained direct physical evidence that the nucleoplasmic PRC1 is monomeric, whereas PRC2 can dimerize in the nucleoplasm. We showed that ES cell differentiation induces selective alteration of the assembly stoichiometry of Cbx2 on chromatin but not other PRC1 components. We additionally showed that the PRC2-mediated trimethylation of H3K27 is not required for the assembly stoichiometry of PRC1 on chromatin. Thus, these findings uncover that PRC1 and PRC2 employ distinct mechanisms to assemble on chromatin, and the novel Sm-ChIPi technique could provide single-molecule insight into other epigenetic complexes.

  4. Outcomes of hepatitis C screening programs targeted at risk groups hidden in the general population: a systematic review

    PubMed Central

    2014-01-01

    Background Effective screening programs are urgently needed to provide undiagnosed hepatitis C virus (HCV)-infected individuals with therapy. This systematic review of characteristics and outcomes of screening programs for HCV focuses on strategies to identify HCV risk groups hidden in the general population. Methods We conducted a comprehensive search of MEDLINE and EMBASE databases for articles published between 1991–2010, including studies that screened the general population using either a newly developed (nonintegrated) screening program or one integrated in existing health care facilities. Look-back studies, prevalence studies, and programs targeting high-risk groups in care (e.g., current drug users) were excluded. Results After reviewing 7052 studies, we identified 67 screening programs: 24 nonintegrated; 41 programs integrated in a variety of health care facilities (e.g., general practitioner); and 2 programs with both integrated and nonintegrated strategies. Together, these programs identified approximately 25,700 HCV-infected individuals. In general, higher HCV prevalence was found in programs in countries with intermediate to high HCV prevalence, in psychiatric clinics, and in programs that used a prescreening selection based on HCV risk factors. Only 6 programs used a comparison group for evaluation purposes, and 1 program used theory about effective promotion for screening. Comparison of the programs and their effectiveness was hampered by lack of reported data on program characteristics, clinical follow-up, and type of diagnostic test. Conclusions A prescreening selection based on risk factors can increase the efficiency of screening in low-prevalence populations, and we need programs with comparison groups to evaluate effectiveness. Also, program characteristics such as type of diagnostic test, screening uptake, and clinical outcomes should be reported systematically. PMID:24450797

  5. Propagation of trimethylated H3K27 regulated by polycomb protein EED is required for embryogenesis, hematopoietic maintenance, and tumor suppression

    PubMed Central

    Ueda, Takeshi; Nakata, Yuichiro; Nagamachi, Akiko; Yamasaki, Norimasa; Kanai, Akinori; Sera, Yasuyuki; Sasaki, Masato; Matsui, Hirotaka; Honda, Zen-ichiro; Oda, Hideaki; Wolff, Linda; Inaba, Toshiya; Honda, Hiroaki

    2016-01-01

    Polycomb repressive complex 2 (PRC2) catalyzes the monomethylation, dimethylation, and trimethylation of histone H3 Lys27 (H3K27) and acts as a central epigenetic regulator that marks the repressive chromatin domain. Embryonic ectoderm development (EED), an essential component of PRC2, interacts with trimethylated H3K27 (H3K27me3) through the aromatic cage structure composed of its three aromatic amino acids, Phe97, Trp364, and Tyr365. This interaction allosterically activates the histone methyltransferase activity of PRC2 and thereby propagates repressive histone marks. In this study, we report the analysis of knock-in mice harboring the myeloid disorder-associated EED Ile363Met (I363M) mutation, analogous to the EED aromatic cage mutants. The I363M homozygotes displayed a remarkable and preferential reduction of H3K27me3 and died at midgestation. The heterozygotes increased the clonogenic capacity and bone marrow repopulating activity of hematopoietic stem/progenitor cells (HSPCs) and were susceptible to leukemia. Lgals3, a PRC2 target gene encoding a multifunctional galactose-binding lectin, was derepressed in I363M heterozygotes, which enhanced the stemness of HSPCs. Thus, our work provides in vivo evidence that the structural integrity of EED to H3K27me3 propagation is critical, especially for embryonic development and hematopoietic homeostasis, and that its perturbation increases the predisposition to hematologic malignancies. PMID:27578866

  6. Heart disease education and prevention program targeting immigrant Latinos: using focus group responses to develop effective interventions.

    PubMed

    Moreno, C; Alvarado, M; Balcazar, H; Lane, C; Newman, E; Ortiz, G; Forrest, M

    1997-12-01

    Although research has provided considerable knowledge concerning the positive effects of behavioral change on morbidity and mortality from heart disease and related risk factors, some segments of the population have not benefited equitably from this information. In April 1995, the National Heart, Lung, and Blood Institute (NHLBI) conducted seven focus groups to determine knowledge and attitudes about heart disease and associated risk factors, identify media usage and preferences, and assess publications usage and preferences among Spanish-speaking Latino immigrants residing in the Washington, D.C., metropolitan area. This information was gathered to assist in the development of key messages and strategies for the NHLBI Latino Community Cardiovascular Disease Prevention and Outreach Initiative, Salud para su Corazón--a heart disease prevention and education campaign. Findings from these focus groups indicate that Latinos may not benefit from heart disease prevention messages developed for the general population because of language and cultural differences. The researchers concluded that health education and disease prevention programs targeting the Latino community should develop educational materials and interventions that address language preferences and cultural values. Furthermore, to be effective, these programs should show people how to make positive behavioral changes based on their current circumstances, while remaining sensitive to the fact that Latino immigrants face major life adjustments and many are still greatly influenced by their country of origin.

  7. Antiparkinsonian potential of targeting group III metabotropic glutamate receptor subtypes in the rodent substantia nigra pars reticulata

    PubMed Central

    Broadstock, M; Austin, PJ; Betts, MJ; Duty, S

    2012-01-01

    BACKGROUND AND PURPOSE Increased firing of the glutamatergic pathway between the subthalamic nucleus and substantia nigra pars reticulata (SNpr) contributes to the abnormal firing of motor circuits and subsequent motor deficits seen in Parkinson's disease. Broad spectrum agonist-induced activation of presynaptic group III metabotropic glutamate (mGlu) receptors within the SNpr reduced glutamate release and reversed akinesia in the reserpine-treated rat model of Parkinson's disease. Here, we have sought to identify which subtypes of group III mGlu receptor in the SNpr were responsible for these beneficial effects. EXPERIMENTAL APPROACH The ability of the mGlu4 positive allosteric modulator, N-phenyl-7-(hydroxyminocyclopropa[b]chromen-1a-carboxamide) (PHCCC), the mGlu7 allosteric agonist, N,N′-dibenzhydrylethane-1,2-diamine dihydrochloride (AMN082) and the mGlu8-selective agonist (S)-3,4-dicarboxyphenylglycine [(S)-3,4-DCPG] to inhibit KCl-evoked [3H]-D-aspartate release was examined in vitro in rat nigral prisms. Reversal of akinesia in reserpine-treated rats was also assessed following intranigral injection of these agents. KEY RESULTS PHCCC and AMN082 inhibited [3H]-D-aspartate release by 42% and 53%, respectively when given alongside a sub-threshold concentration of the broad spectrum group III agonist, L-2-amino-4-phosphonobutyrate (L-AP4; 1 µM). In contrast (S)-3,4-DCPG failed to inhibit [3H]-D-aspartate release. All three agents also reversed reserpine-induced akinesia although only the effects of PHCCC and AMN082 were inhibited by pre-treatment with the group III antagonist (RS)-α-cyclopropyl-4-phosphonophenylglycine (CPPG). CONCLUSIONS AND IMPLICATIONS These findings reveal that targeting SNpr mGlu4 or mGlu7 receptors, but not mGlu8 receptors, provided relief from akinesia in the reserpine-treated rat model of Parkinson's disease, most likely reflecting inhibition of excess glutamate release in this region. PMID:21627638

  8. The Arabidopsis Polycomb Repressive Complex 1 (PRC1) Components AtBMI1A, B, and C Impact Gene Networks throughout All Stages of Plant Development1[OPEN

    PubMed Central

    Zhou, Yue

    2017-01-01

    Polycomb Group regulation in Arabidopsis (Arabidopsis thaliana) is required to maintain cell differentiation and allow developmental phase transitions. This is achieved by the activity of three PcG repressive complex 2s (PRC2s) and the participation of a yet poorly defined PRC1. Previous results showed that apparent PRC1 components perform discrete roles during plant development, suggesting the existence of PRC1 variants; however, it is not clear in how many processes these components participate. We show that AtBMI1 proteins are required to promote all developmental phase transitions and to control cell proliferation during organ growth and development, expanding their proposed range of action. While AtBMI1 function during germination is closely linked to B3 domain transcription factors VAL1/2 possibly in combination with GT-box binding factors, other AtBMI1 regulatory networks require participation of different factor combinations. Conversely, EMF1 and LHP1 bind many H3K27me3 positive genes up-regulated in atbmi1a/b/c mutants; however, loss of their function affects expression of a different subset, suggesting that even if EMF1, LHP1, and AtBMI1 exist in a common PRC1 variant, their role in repression depends on the functional context. PMID:27837089

  9. Direct interaction of the Polycomb protein with Antennapedia regulatory sequences in polytene chromosomes of Drosophila melanogaster.

    PubMed Central

    Zink, B; Engström, Y; Gehring, W J; Paro, R

    1991-01-01

    The Polycomb (Pc) gene is responsible for the elaboration and maintenance of the expression pattern of the homeotic genes during development of Drosophila. In mutant Pc- embryos, homeotic transcripts are ectopically expressed, leading to abdominal transformations in all segments. From this it was suggested that PC+ acts as a repressor of homeotic gene transcription. We have mapped the cis-acting control sequences of the homeotic Antennapedia (Antp) gene regulated by Pc. Using Antp P1 and P2 promoter fragments linked to the E. coli lacZ reporter gene we show different expression patterns of beta-galactosidase (beta-gal) in transformed Pc+ and Pc- embryos. In addition we are able to visualize by immunocytochemical techniques on polytene chromosomes the direct binding of the Pc protein to the transposed cis-regulatory promoter fragments. However, short Antp P1 promoter constructs which are--due to position effects--ectopically activated in salivary glands, do not reveal a Pc binding signal. Images PMID:1671215

  10. Polycomb proteins control proliferation and transformation independently of cell cycle checkpoints by regulating DNA replication.

    PubMed

    Piunti, Andrea; Rossi, Alessandra; Cerutti, Aurora; Albert, Mareike; Jammula, Sriganesh; Scelfo, Andrea; Cedrone, Laura; Fragola, Giulia; Olsson, Linda; Koseki, Haruhiko; Testa, Giuseppe; Casola, Stefano; Helin, Kristian; d'Adda di Fagagna, Fabrizio; Pasini, Diego

    2014-04-14

    The ability of PRC1 and PRC2 to promote proliferation is a main feature that links polycomb (PcG) activity to cancer. PcGs silence the expression of the tumour suppressor locus Ink4a/Arf, whose products positively regulate pRb and p53 functions. Enhanced PcG activity is a frequent feature of human tumours, and PcG inhibition has been proposed as a strategy for cancer treatment. However, the recurrent inactivation of pRb/p53 responses in human cancers raises a question regarding the ability of PcG proteins to affect cellular proliferation independently from this checkpoint. Here we demonstrate that PRCs regulate cellular proliferation and transformation independently of the Ink4a/Arf-pRb-p53 pathway. We provide evidence that PRCs localize at replication forks, and that loss of their function directly affects the progression and symmetry of DNA replication forks. Thus, we have identified a novel activity by which PcGs can regulate cell proliferation independently of major cell cycle restriction checkpoints.

  11. Product binding enforces the genomic specificity of a yeast Polycomb repressive complex

    PubMed Central

    Dumesic, Phillip A.; Homer, Christina M.; Moresco, James J.; Pack, Lindsey R.; Shanle, Erin K.; Coyle, Scott M.; Strahl, Brian D.; Fujimori, Danica G.; Yates, John R.; Madhani, Hiten D.

    2015-01-01

    SUMMARY We characterize the Polycomb system that assembles repressive subtelomeric domains of H3K27 methylation (H3K27me) in the yeast Cryptococcus neoformans. Purification of this PRC2-like protein complex reveals orthologs of animal PRC2 components as well as a chromodomain-containing subunit, Ccc1, which recognizes H3K27me. Whereas removal of either the EZH or EED ortholog eliminates H3K27me, disruption of mark recognition by Ccc1 causes H3K27me to redistribute. Strikingly, the resulting pattern of H3K27me coincides with domains of heterochromatin marked by H3K9me. Indeed, additional removal of the C. neoformans H3K9 methyltransferase Clr4 results in loss of both H3K9me and the redistributed H3K27me marks. These findings indicate that the anchoring of a chromatin-modifying complex to its product suppresses its attraction to a different chromatin type, explaining how enzymes that act on histones, which often harbor product recognition modules, may deposit distinct chromatin domains despite sharing a highly abundant and largely identical substrate—the nucleosome. PMID:25533783

  12. Polycomb repressive complex 2 structure with inhibitor reveals a mechanism of activation and drug resistance

    PubMed Central

    Brooun, Alexei; Gajiwala, Ketan S.; Deng, Ya-Li; Liu, Wei; Bolaños, Ben; Bingham, Patrick; He, You-Ai; Diehl, Wade; Grable, Nicole; Kung, Pei-Pei; Sutton, Scott; Maegley, Karen A.; Yu, Xiu; Stewart, Al E.

    2016-01-01

    Polycomb repressive complex 2 (PRC2) mediates gene silencing through chromatin reorganization by methylation of histone H3 lysine 27 (H3K27). Overexpression of the complex and point mutations in the individual subunits of PRC2 have been shown to contribute to tumorigenesis. Several inhibitors of the PRC2 activity have shown efficacy in EZH2-mutated lymphomas and are currently in clinical development, although the molecular basis of inhibitor recognition remains unknown. Here we report the crystal structures of the inhibitor-bound wild-type and Y641N PRC2. The structures illuminate an important role played by a stretch of 17 residues in the N-terminal region of EZH2, we call the activation loop, in the stimulation of the enzyme activity, inhibitor recognition and the potential development of the mutation-mediated drug resistance. The work presented here provides new avenues for the design and development of next-generation PRC2 inhibitors through establishment of a structure-based drug design platform. PMID:27122193

  13. Investigating the Role of a Racially Biased Incident on Changes in Culture and Climate Indicators across Targeted and Non-Targeted Groups

    ERIC Educational Resources Information Center

    Yeung, Fanny P.; Johnston, Marc P.

    2014-01-01

    This study explored the influences of a racially biased incident targeting Asian students at a compositionally diverse public research institution on the U.S. West coast after an unplanned incident that occurred during data collection of the Diverse Learning Environments survey. This occurrence created a unique opportunity to explore how 2 cohorts…

  14. Perceptions Toward a Smoking Cessation App Targeting LGBTQ+ Youth and Young Adults: A Qualitative Framework Analysis of Focus Groups

    PubMed Central

    Dash, Darly; Wong, Katy; Shuh, Alanna; Abramowicz, Aneta

    2016-01-01

    Background The prevalence of smoking among lesbian, gay, bisexual, trans, queer, and other sexual minority (LGBTQ+) youth and young adults (YYA) is significantly higher compared with that among non-LGBTQ+ persons. However, in the past, interventions were primarily group cessation classes that targeted LGBTQ+ persons of all ages. mHealth interventions offer an alternate and modern intervention platform for this subpopulation and may be of particular interest for young LGBTQ+ persons. Objective This study explored LGBTQ+ YYA (the potential users’) perceptions of a culturally tailored mobile app for smoking cessation. Specifically, we sought to understand what LGBTQ+ YYA like and dislike about this potential cessation tool, along with how such interventions could be improved. Methods We conducted 24 focus groups with 204 LGBTQ+ YYA (aged 16-29 years) in Toronto and Ottawa, Canada. Participants reflected on how an app might support LGBTQ+ persons with smoking cessation. Participants indicated their feelings, likes and dislikes, concerns, and additional ideas for culturally tailored smoking cessation apps. Framework analysis was used to code transcripts and identify the overarching themes. Results Study findings suggested that LGBTQ+ YYA were eager about using culturally tailored mobile apps for smoking cessation. Accessibility, monitoring and tracking, connecting with community members, tailoring, connecting with social networks, and personalization were key reasons that were valued for a mobile app cessation program. However, concerns were raised about individual privacy and that not all individuals had access to a mobile phone, users might lose interest quickly, an app would need to be marketed effectively, and app users might cheat and lie about progress to themselves. Participants highlighted that the addition of distractions, rewards, notifications, and Web-based and print versions of the app would be extremely useful to mitigate some of their concerns

  15. A Polycomb-mir200 loop regulates clinical outcome in bladder cancer

    PubMed Central

    Feber, Andrew; Segovia, Cristina; García-Escudero, Ramón; Rubio, Carolina; López-Calderón, Fernando F.; Díaz-García, Claudio; Villacampa, Felipe; Duarte, José; Gómez-Rodriguez, María J.; Castellano, Daniel; Rodriguez-Peralto, José L.; de la Rosa, Federico; Beck, Stephan; Paramio, Jesús M.

    2015-01-01

    Bladder cancer (BC) is a highly prevalent disease, ranking fifth in the most common cancers worldwide. Various miRNAs have recently emerged as potential prognostic biomarkers in cancer. The miR-200 family, which repressed the epithelial-to-mesenchymal transition (EMT), is repressed in multiple advanced cancers. However, its expression and function in BC is still poorly understood. Here we show that miR-200 family displays increased expression, probably due to the activation of specific oncogenic signaling pathways, and reduced promoter methylation, in BC compared to normal bladder samples. Furthermore, we show that the expression of these miRNAs is decreased in high grade and stage tumors, and the down-regulation is associated with patient's poor clinical outcome. Our data indicate that the miR-200 family plays distinct roles in Non-Muscle (NMIBC) and Muscle-Invasive BC (MIBC). In MIBC, miR-200 expression post transcriptionally regulates EMT-promoting transcription factors ZEB1 and ZEB2, whereas suppresses BMI1 expression in NMIBC. Interestingly, we show that increased EZH2 and/or BMI1 expression repress the expression of miR-200 family members. Collectively, these findings support a model of BC progression through a coordinated action between the Polycomb Repression Complex (PRC) members repressing the miR-200 expression, which ultimately favors invasive BC development. Since pharmacological inhibition of EZH2 in BC cell lines lead to increased miR-200 expression, our findings may support new therapeutic strategies for BC clinical management. PMID:26517683

  16. Deregulation of polycomb repressor complex 1 modifier AUTS2 in T-cell leukemia

    PubMed Central

    Nagel, Stefan; Pommerenke, Claudia; Meyer, Corinna; Kaufmann, Maren; Drexler, Hans G.; MacLeod, Roderick A.F.

    2016-01-01

    Recently, we identified deregulated expression of the B-cell specific transcription factor MEF2C in T-cell acute lymphoid leukemia (T-ALL). Here, we performed sequence analysis of a regulatory upstream section of MEF2C in T-ALL cell lines which, however, proved devoid of mutations. Unexpectedly, we found strong conservation between the regulatory upstream region of MEF2C (located at chromosomal band 5q14) and an intergenic stretch at 7q11 located between STAG3L4 and AUTS2, covering nearly 20 kb. While the non-coding gene STAG3L4 was inconspicuously expressed, AUTS2 was aberrantly upregulated in 6% of T-ALL patients (public dataset GSE42038) and in 3/24 T-ALL cell lines, two of which represented very immature differentiation stages. AUTS2 expression was higher in normal B-cells than in T-cells, indicating lineage-specific activity in lymphopoiesis. While excluding chromosomal aberrations, examinations of AUTS2 transcriptional regulation in T-ALL cells revealed activation by IL7-IL7R-STAT5-signalling and MEF2C. AUTS2 protein has been shown to interact with polycomb repressor complex 1 subtype 5 (PRC1.5), transforming this particular complex into an activator. Accordingly, expression profiling and functional analyses demonstrated that AUTS2 activated while PCGF5 repressed transcription of NKL homeobox gene MSX1 in T-ALL cells. Forced expression and pharmacological inhibition of EZH2 in addition to H3K27me3 analysis indicated that PRC2 repressed MSX1 as well. Taken together, we found that AUTS2 and MEF2C, despite lying on different chromosomes, share strikingly similar regulatory upstream regions and aberrant expression in T-ALL subsets. Our data implicate chromatin complexes PRC1/AUTS2 and PRC2 in a gene network in T-ALL regulating early lymphoid differentiation. PMID:27322685

  17. Target-specific NMR detection of protein-ligand interactions with antibody-relayed (15)N-group selective STD.

    PubMed

    Hetényi, Anasztázia; Hegedűs, Zsófia; Fajka-Boja, Roberta; Monostori, Éva; Kövér, Katalin E; Martinek, Tamás A

    2016-12-01

    Fragment-based drug design has been successfully applied to challenging targets where the detection of the weak protein-ligand interactions is a key element. (1)H saturation transfer difference (STD) NMR spectroscopy is a powerful technique for this work but it requires pure homogeneous proteins as targets. Monoclonal antibody (mAb)-relayed (15)N-GS STD spectroscopy has been developed to resolve the problem of protein mixtures and impure proteins. A (15)N-labelled target-specific mAb is selectively irradiated and the saturation is relayed through the target to the ligand. Tests on the anti-Gal-1 mAb/Gal-1/lactose system showed that the approach is experimentally feasible in a reasonable time frame. This method allows detection and identification of binding molecules directly from a protein mixture in a multicomponent system.

  18. New partners in regulation of gene expression: the enhancer of Trithorax and Polycomb Corto interacts with methylated ribosomal protein l12 via its chromodomain.

    PubMed

    Coléno-Costes, Anne; Jang, Suk Min; de Vanssay, Augustin; Rougeot, Julien; Bouceba, Tahar; Randsholt, Neel B; Gibert, Jean-Michel; Le Crom, Stéphane; Mouchel-Vielh, Emmanuèle; Bloyer, Sébastien; Peronnet, Frédérique

    2012-01-01

    Chromodomains are found in many regulators of chromatin structure, and most of them recognize methylated lysines on histones. Here, we investigate the role of the Drosophila melanogaster protein Corto's chromodomain. The Enhancer of Trithorax and Polycomb Corto is involved in both silencing and activation of gene expression. Over-expression of the Corto chromodomain (CortoCD) in transgenic flies shows that it is a chromatin-targeting module, critical for Corto function. Unexpectedly, mass spectrometry analysis reveals that polypeptides pulled down by CortoCD from nuclear extracts correspond to ribosomal proteins. Furthermore, real-time interaction analyses demonstrate that CortoCD binds with high affinity RPL12 tri-methylated on lysine 3. Corto and RPL12 co-localize with active epigenetic marks on polytene chromosomes, suggesting that both are involved in fine-tuning transcription of genes in open chromatin. RNA-seq based transcriptomes of wing imaginal discs over-expressing either CortoCD or RPL12 reveal that both factors deregulate large sets of common genes, which are enriched in heat-response and ribosomal protein genes, suggesting that they could be implicated in dynamic coordination of ribosome biogenesis. Chromatin immunoprecipitation experiments show that Corto and RPL12 bind hsp70 and are similarly recruited on gene body after heat shock. Hence, Corto and RPL12 could be involved together in regulation of gene transcription. We discuss whether pseudo-ribosomal complexes composed of various ribosomal proteins might participate in regulation of gene expression in connection with chromatin regulators.

  19. New Partners in Regulation of Gene Expression: The Enhancer of Trithorax and Polycomb Corto Interacts with Methylated Ribosomal Protein L12 Via Its Chromodomain

    PubMed Central

    Coléno-Costes, Anne; Jang, Suk Min; de Vanssay, Augustin; Rougeot, Julien; Bouceba, Tahar; Randsholt, Neel B.; Gibert, Jean-Michel; Le Crom, Stéphane; Mouchel-Vielh, Emmanuèle

    2012-01-01

    Chromodomains are found in many regulators of chromatin structure, and most of them recognize methylated lysines on histones. Here, we investigate the role of the Drosophila melanogaster protein Corto's chromodomain. The Enhancer of Trithorax and Polycomb Corto is involved in both silencing and activation of gene expression. Over-expression of the Corto chromodomain (CortoCD) in transgenic flies shows that it is a chromatin-targeting module, critical for Corto function. Unexpectedly, mass spectrometry analysis reveals that polypeptides pulled down by CortoCD from nuclear extracts correspond to ribosomal proteins. Furthermore, real-time interaction analyses demonstrate that CortoCD binds with high affinity RPL12 tri-methylated on lysine 3. Corto and RPL12 co-localize with active epigenetic marks on polytene chromosomes, suggesting that both are involved in fine-tuning transcription of genes in open chromatin. RNA–seq based transcriptomes of wing imaginal discs over-expressing either CortoCD or RPL12 reveal that both factors deregulate large sets of common genes, which are enriched in heat-response and ribosomal protein genes, suggesting that they could be implicated in dynamic coordination of ribosome biogenesis. Chromatin immunoprecipitation experiments show that Corto and RPL12 bind hsp70 and are similarly recruited on gene body after heat shock. Hence, Corto and RPL12 could be involved together in regulation of gene transcription. We discuss whether pseudo-ribosomal complexes composed of various ribosomal proteins might participate in regulation of gene expression in connection with chromatin regulators. PMID:23071455

  20. Empowering Civil Society To Monitor the Environment: Education for Students, Awareness for the Public, and Functional Literacy for Targeted Groups. WBI Working Papers.

    ERIC Educational Resources Information Center

    Ariasingam, David Lakshmanan

    This paper uses case studies to show that by (1) empowering civil society to monitor the environment through environmental education for primary and secondary students, (2) providing environmental awareness programs for the public, and (3) supporting efforts to improve the functional literacy of targeted groups, the effectiveness and…

  1. Single Older Women Who Applied for the Giving Life More Lustre Course: Are They the Target Group that Was Aimed for?

    ERIC Educational Resources Information Center

    Kremers, Ismay P.; Steverink, Nardi; Albersnagel, Frans A.; Slaets, Joris P. J.

    2007-01-01

    The present study investigated whether the women who applied for the self-management of well-being course Giving life more LUSTRE can be considered the target group that was intended. By comparing the course applicants with a random sample of community dwelling single women, it was found that, as expected, course applicants scored worse on…

  2. Differentiation in Data Analysis & Probability, PreK-Grade 2: A Content Companion for Ongoing Assessment, Grouping Students, Targeting Instruction, and Adjusting Levels of Cognitive Demand

    ERIC Educational Resources Information Center

    Taylor-Cox, Jennifer

    2008-01-01

    This book applies the author's easy but effective differentiation strategies to the data analysis and probability content standard. Taking the foundational elements of differentiation in this book, it helps you: (1) assess students' math abilities quickly and efficiently; (2) group children by need; (3) target instruction to meet every student's…

  3. Neuronal activity controls Bdnf expression via Polycomb de-repression and CREB/CBP/JMJD3 activation in mature neurons

    PubMed Central

    Palomer, Ernest; Carretero, Javier; Benvegnù, Stefano; Dotti, Carlos G.; Martin, Mauricio G.

    2016-01-01

    It has been recently described that in embryonic stem cells, the expression of some important developmentally regulated genes is repressed, but poised for fast activation under the appropriate stimuli. In this work we show that Bdnf promoters are repressed by Polycomb Complex 2 in mature hippocampal neurons, and basal expression is guaranteed by the coexistence with activating histone marks. Neuronal stimulation triggered by N-methyl-D-aspartate application induces the transcription of these promoters by H3K27Me3 demethylation and H3K27Me3 phosphorylation at Serine 28 leading to displacement of EZH2, the catalytic subunit of Polycomb Repressor Complex 2. Our data show that the fast transient expression of Bdnf promoters II and VI after neuronal stimulation is dependent on acetylation of histone H3K27 by CREB-p/CBP. Thus, regulatory mechanisms established during development seem to remain after differentiation controlling genes induced by different stimuli, as would be the case of early memory genes in mature neurons. PMID:27010597

  4. Transcriptional Regulation by Trithorax-Group Proteins

    PubMed Central

    Kingston, Robert E.; Tamkun, John W.

    2014-01-01

    The trithorax group of genes (trxG) was identified in mutational screens that examined developmental phenotypes and suppression of Polycomb mutant phenotypes. The protein products of these genes are primarily involved in gene activation, although some can also have repressive effects. There is no central function for these proteins. Some move nucleosomes about on the genome in an ATP-dependent manner, some covalently modify histones such as methylating lysine 4 of histone H3, and some directly interact with the transcription machinery or are a part of that machinery. It is interesting to consider why these specific members of large families of functionally related proteins have strong developmental phenotypes. PMID:25274705

  5. The cylindrical air holes of the negative-refraction photonic crystal double flat lens group for lightwave target detection and imaging

    NASA Astrophysics Data System (ADS)

    Lu, Jian; Shen, Yang; Shen, TingGen; Lian, YingFei; Wang, FeiFei; Xu, Yang

    2013-06-01

    The influence of the cylindrical air holes of the negative-refraction photonic crystal (NR-PC) double flat lens group on the performance of lightwave target detection and imaging is studied in this paper using the finite-difference time-domain (FDTD) method. Numerical simulations indicate that significant enhancement of the scattering signal can be obtained by using a NR-PC flat lens; consequently, great improvement of the refocusing gain as well as the imaging resolution will be provided. We further research the effects of different positions for target detection by using a NR-PC double flat lens group with cylindrical air holes. Then we use defective air holes instead of perfect ones. By using a dynamic scanning scheme, we find that the distance between two flats could be changed flexibly. And it could improve the lateral resolution of target scanning and enlarge the distance between the target and flat greatly. In conclusion, our investigation optimized the performance of the detection and imaging system, and provided the basis for converting an idealized left-handed material lens into a physically realizable NR-PC double flat lens group.

  6. Trithorax group proteins: switching genes on and keeping them active.

    PubMed

    Schuettengruber, Bernd; Martinez, Anne-Marie; Iovino, Nicola; Cavalli, Giacomo

    2011-11-23

    Cellular memory is provided by two counteracting groups of chromatin proteins termed Trithorax group (TrxG) and Polycomb group (PcG) proteins. TrxG proteins activate transcription and are perhaps best known because of the involvement of the TrxG protein MLL in leukaemia. However, in terms of molecular analysis, they have lived in the shadow of their more famous counterparts, the PcG proteins. Recent advances have improved our understanding of TrxG protein function and demonstrated that the heterogeneous group of TrxG proteins is of critical importance in the epigenetic regulation of the cell cycle, senescence, DNA damage and stem cell biology.

  7. The Moving Group Targets of the Seeds High-Contrast Imaging Survey of Exoplanets and Disks: Results and Observations from the First Three Years

    NASA Technical Reports Server (NTRS)

    Brandt, Timothy D.; Kuzuhara, Masayuki; McElwain, Michael W.; Schlieder, Joshua E.; Wisniewski, John P.; Turner, Edwin L.; Carson, J.; Matsuo, T.; Biller, B.; Bonnefoy, M.; Dressing, C.; Janson, M.; Knapp, G. R.; Moro-Martin, A.; Thalmann, C.; Kudo, T.; Kusakabe, N.; Hashimoto, J.; Abe, L.; Brandner, W.; Currie, T.; Egner, S.; Feldt, M.; Golota, T.; Goto, M.; Brady, C. A.; Guyon, O.; Hayano, Y.; Hyashi, M.; Hayashi, S.; Henning, T.; Hodapp, W.; Ishi, M.; Iye, M.; Kandori, R.

    2014-01-01

    We present results from the first three years of observations of moving group (MG) targets in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) high-contrast imaging survey of exoplanets and disks using the Subaru telescope. We achieve typical contrasts of (is) approximately10(exp 5) at 1" and (is) approximately 10(exp 6) beyond 2" around 63 proposed members of nearby kinematic MGs. We review each of the kinematic associations to which our targets belong, concluding that five, beta Pictoris ((is) approximately 20 Myr), AB Doradus ((is) approximately 100 Myr), Columba ((is) approximately 30 Myr), Tucana-Horogium ((is) approximately 30 Myr), and TW Hydrae ((is) approximately 10 Myr), are sufficiently well-defined to constrain the ages of individual targets. Somewhat less than half of our targets are high-probability members of one of these MGs. For all of our targets, we combine proposed MG membership with other age indicators where available, including Ca ii HK emission, X-ray activity, and rotation period, to produce a posterior probability distribution of age. SEEDS observations discovered a substellar companion to one of our targets, kappa And, a late B star. We do not detect any other substellar companions, but do find seven new close binary systems, of which one still needs to be confirmed. A detailed analysis of the statistics of this sample, and of the companion mass constraints given our age probability distributions and exoplanet cooling models, will be presented in a forthcoming paper.

  8. The moving group targets of the seeds high-contrast imaging survey of exoplanets and disks: Results and observations from the first three years

    SciTech Connect

    Brandt, Timothy D.; Turner, Edwin L.; Janson, M.; Knapp, G. R.; Kuzuhara, Masayuki; McElwain, Michael W.; Schlieder, Joshua E.; Carson, J.; Biller, B.; Bonnefoy, M.; Brandner, W.; Wisniewski, John P.; Hashimoto, J.; Matsuo, T.; Dressing, C.; Moro-Martín, A.; Kudo, T.; Kusakabe, N.; Abe, L.; and others

    2014-05-01

    We present results from the first three years of observations of moving group (MG) targets in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) high-contrast imaging survey of exoplanets and disks using the Subaru telescope. We achieve typical contrasts of ∼10{sup 5} at 1'' and ∼10{sup 6} beyond 2'' around 63 proposed members of nearby kinematic MGs. We review each of the kinematic associations to which our targets belong, concluding that five, β Pictoris (∼20 Myr), AB Doradus (∼100 Myr), Columba (∼30 Myr), Tucana-Horogium (∼30 Myr), and TW Hydrae (∼10 Myr), are sufficiently well-defined to constrain the ages of individual targets. Somewhat less than half of our targets are high-probability members of one of these MGs. For all of our targets, we combine proposed MG membership with other age indicators where available, including Ca II HK emission, X-ray activity, and rotation period, to produce a posterior probability distribution of age. SEEDS observations discovered a substellar companion to one of our targets, κ And, a late B star. We do not detect any other substellar companions, but do find seven new close binary systems, of which one still needs to be confirmed. A detailed analysis of the statistics of this sample, and of the companion mass constraints given our age probability distributions and exoplanet cooling models, will be presented in a forthcoming paper.

  9. Variability in target delineation of cervical carcinoma: A Korean radiation oncology group study (KROG 15-06)

    PubMed Central

    Joo, Ji Hyeon; Cho, Byung Chul; Jeong, Chi Young; Park, Won; Kim, Hak Jae; Yoon, Won Sup; Yoon, Mee Sun; Kim, Ji-Yoon; Choi, Jin Hwa; Choi, Youngmin; Kim, Joo-Young

    2017-01-01

    Purpose To determine inter-observer variability in target volume definition of cervical cancer in radical and adjuvant radiotherapy (RT) settings. Methods Eight physicians contoured CTVs of 2 patients underwent definitive and postoperative RT. Each volume was analyzed using the individual/median volume ratio and generalized conformity index (CIgen). And center of mass (COM) of each contour was calculated. Expert agreement was quantified using an expectation maximization algorithm for Simultaneous Truth and Performance Level Estimation (STAPLE). Results For definitive RT, the individual/median volume ratio ranged from 0.51 to 1.41, and CIgen was 0.531. Mean 3-dimensional distances of average to each COM were 7.8 mm. For postoperative RT setting, corresponding values were 0.65–1.38, 0.563, and 5.3 mm. Kappa value of expert agreement was 0.65 and 0.67, respectively. STAPLE estimates of the sensitivity, specificity, and kappa measures of inter-physician agreement were 0.73, 0.98, and 0.65 for the definitive and 0.75, 0.98, and 0.67 for the adjuvant radiotherapy setting. The largest difference was observed in the superior-inferior direction, particularly in the upper vagina and the common iliac area. Conclusion As there was still some variability in target delineation, more detailed guidelines for target volume delineation and continuing education would help to reduce this uncertainty. PMID:28301492

  10. Prospective Randomized Double-Blind Pilot Study of Site-Specific Consensus Atlas Implementation for Rectal Cancer Target Volume Delineation in the Cooperative Group Setting

    SciTech Connect

    Fuller, Clifton D.; Nijkamp, Jasper; Duppen, Joop C.; Rasch, Coen R.N.; Thomas, Charles R.; Wang, Samuel J.; Okunieff, Paul; Jones, William E.; Baseman, Daniel; Patel, Shilpen; Demandante, Carlo G.N.; Harris, Anna M.; Smith, Benjamin D.; Katz, Alan W.; McGann, Camille

    2011-02-01

    Purpose: Variations in target volume delineation represent a significant hurdle in clinical trials involving conformal radiotherapy. We sought to determine the effect of a consensus guideline-based visual atlas on contouring the target volumes. Methods and Materials: A representative case was contoured (Scan 1) by 14 physician observers and a reference expert with and without target volume delineation instructions derived from a proposed rectal cancer clinical trial involving conformal radiotherapy. The gross tumor volume (GTV), and two clinical target volumes (CTVA, including the internal iliac, presacral, and perirectal nodes, and CTVB, which included the external iliac nodes) were contoured. The observers were randomly assigned to receipt (Group A) or nonreceipt (Group B) of a consensus guideline and atlas for anorectal cancers and then instructed to recontour the same case/images (Scan 2). Observer variation was analyzed volumetrically using the conformation number (CN, where CN = 1 equals total agreement). Results: Of 14 evaluable contour sets (1 expert and 7 Group A and 6 Group B observers), greater agreement was found for the GTV (mean CN, 0.75) than for the CTVs (mean CN, 0.46-0.65). Atlas exposure for Group A led to significantly increased interobserver agreement for CTVA (mean initial CN, 0.68, after atlas use, 0.76; p = .03) and increased agreement with the expert reference (initial mean CN, 0.58; after atlas use, 0.69; p = .02). For the GTV and CTVB, neither the interobserver nor the expert agreement was altered after atlas exposure. Conclusion: Consensus guideline atlas implementation resulted in a detectable difference in interobserver agreement and a greater approximation of expert volumes for the CTVA but not for the GTV or CTVB in the specified case. Visual atlas inclusion should be considered as a feature in future clinical trials incorporating conformal RT.

  11. A Hybrid Chalcone Combining the Trimethoxyphenyl and Isatinyl Groups Targets Multiple Oncogenic Proteins and Pathways in Hepatocellular Carcinoma Cells

    PubMed Central

    Cao, Lili; Zhang, Lijun; Zhao, Xiang; Zhang, Ye

    2016-01-01

    Small molecule inhibitors that can simultaneously inhibit multiple oncogenic proteins in essential pathways are promising therapeutic chemicals for hepatocellular carcinoma (HCC). To combine the anticancer effects of combretastatins, chalcones and isatins, we synthesized a novel hybrid molecule 3’,4’,5’-trimethoxy-5-chloro-isatinylchalcone (3MCIC). 3MCIC inhibited proliferation of cultured HepG2 cells, causing rounding-up of the cells and massive vacuole accumulation in the cytoplasm. Paxillin and focal adhesion plaques were downregulated by 3MCIC. Surprisingly, unlike the microtubule (MT)-targeting agent CA-4 that inhibits tubulin polymerization, 3MCIC stabilized tubulin polymers both in living cells and in cell lysates. 3MCIC treatment reduced cyclin B1, CDK1, p-CDK1/2, and Rb, but increased p53 and p21. Moreover, 3MCIC caused GSK3β degradation by promoting GSK3β-Ser9 phosphorylation. Nevertheless, 3MCIC inhibited the Wnt/β-catenin pathway by downregulating β-catenin, c-Myc, cyclin D1 and E2F1. 3MCIC treatment not only activated the caspase-3-dependent apoptotic pathway, but also caused massive autophagy evidenced by rapid and drastic changes of LC3 and p62. 3MCIC also promoted cleavage and maturation of the lysosomal protease cathepsin D. Using ligand-affinity chromatography (LAC), target proteins captured onto the Sephacryl S1000-C12-3MCIC resins were isolated and analyzed by mass spectrometry (MS). Some of the LAC-MS identified targets, i.e., septin-2, vimentin, pan-cytokeratin, nucleolin, EF1α1/2, EBP1 (PA2G4), cyclin B1 and GSK3β, were further detected by Western blotting. Moreover, both septin-2 and HIF-1α decreased drastically in 3MCIC-treated HepG2 cells. Our data suggest that 3MCIC is a promising anticancer lead compound with novel targeting mechanisms, and also demonstrate the efficiency of LAC-MS based target identification in anticancer drug development. PMID:27525972

  12. Discrimination of Psychrotrophic and Mesophilic Strains of the Bacillus cereus Group by PCR Targeting of Major Cold Shock Protein Genes

    PubMed Central

    Francis, Kevin P.; Mayr, Ralf; von Stetten, Felix; Stewart, Gordon S. A. B.; Scherer, Siegfried

    1998-01-01

    Detection of psychrotrophic strains (those able to grow at or below 7°C) of the Bacillus cereus group (Bacillus cereus, Bacillus thuringiensis, and Bacillus mycoides) in food products is at present extremely slow with conventional microbiology. This is due to an inability to discriminate these cold-adapted strains from their mesophilic counterparts (those able to grow only above 7°C) by means other than growth at low temperature, which takes 5 to 10 days for detection. Here we report the development of a single PCR assay that, using major cold shock protein-specific primers and appropriate annealing temperatures, is capable of both rapidly identifying bacteria of the B. cereus group and discriminating between psychrotrophic and mesophilic strains. It is intended that this development help to more accurately predict the shelf life of refrigerated pasteurized food and dairy products and to reduce the incidence of food poisoning by psychrotrophic strains of the B. cereus group. PMID:9726910

  13. Some evidence for the base-metal potential of the Pretoria Group: stratigraphic targets, tectonic setting and REE patterns

    NASA Astrophysics Data System (ADS)

    Reczko, B. F. F.; Eriksson, P. G.; Snyman, C. P.

    1995-04-01

    The Timeball Hill and Silverton Formations of the 2.1 2.3 Ga Pretoria Group have regional lithological associations which are thought to have been favourable for the genesis of stratiform sulphide deposits. The observed association of carboniferous and pyritic black shales, tuffaceous material, stromatolitic carbonates and inferred turbidity current deposits is common in stratiform sulphide deposits of the sedimentary exhalative group. Massive sulphides in the Silverton Formation are compatible with a syngenetic brine discharge, probably related to deep fracture systems. The basal shales of the Timeball Hill Formation are significantly enriched in base-metals and Ba. Interlayered tuff beds at this stratigraphic level have PGE-contents of up to 1 g/t. The REE-geochemistry of Pretoria Group sedimentary rocks supports hydrothermal activity as an important factor in both stratigraphic units.

  14. Cultural affiliation and the importance of health care attributes. Marketers can develop segmentation strategies for targeted patient groups.

    PubMed

    Dolinsky, A L; Stinerock, R

    1998-01-01

    Culturally based values are known to influence consumer purchase decisions, but little is known about how those values affect health care choices. To rectify that situation and provide health care marketers with a framework for developing culturally based segmentation strategies, the authors undertook an exploratory research project in which Hispanic-, African-, and Anglo-Americans were asked to rate the importance of 16 different health care attributes. Those attributes can be grouped under five categories: quality of physician, quality of nurses and other medical staff, economic issues, access to health care, and nonmedically related experiential aspects. Survey responses identified distinct differences in the importance attached to the various attributes by the three cultural groups. The study also looks at the impact of six demographic and social characteristics on the evaluations made by each cultural group. Those characteristics are educational level, gender, age, health status, marital status, and number of people living in the household.

  15. A Group Contingency plus Self-Management Intervention Targeting At-Risk Secondary Students' Class-Work and Active Engagement

    ERIC Educational Resources Information Center

    Trevino-Maack, Sylvia I.; Kamps, Debra; Wills, Howard

    2015-01-01

    The purpose of the present study is to show that an independent group contingency (GC) combined with self-management strategies and randomized-reinforcer components can increase the amount of written work and active classroom responding in high school students. Three remedial reading classes and a total of 15 students participated in this study.…

  16. Internet Postings Linked to Student Highlight Interest in "Hate Groups": Experts Say Recruitment Efforts Targeting School-Age Youths

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2005-01-01

    In an Internet forum run by the Libertarian National Socialist Green Party, an organization espousing neo-Nazi views, Jeff Weise made his comments about the group in the year leading up to his deadly armed assault at Red Lake High School in Minnesota. The forum lists 34 postings written by the 16-year-old Native American youth. The commentary Mr.…

  17. Asymmetric partitioning of metals among cluster anions and cations generated via laser ablation of mixed aluminum/Group 6 transition metal targets.

    PubMed

    Waller, Sarah E; Mann, Jennifer E; Jarrold, Caroline Chick

    2013-02-28

    While high-power laser ablation of metal alloys indiscriminately produces gas-phase atomic ions in proportion to the abundance of the various metals in the alloy, gas-phase ions produced by moderate-power laser ablation sources coupled with molecular beams are formed by more complicated mechanisms. A mass spectrometric study that directly compares the mass distributions of cluster anions and cations generated from laser ablation of pure aluminum, an aluminum/molybdenum mixed target, and an aluminum/tungsten mixed target is detailed. Mass spectra of anionic species generated from the mixed targets showed that both tungsten and molybdenum were in higher abundance in the negatively charged species than in the target material. Mass spectra of the cationic species showed primarily Al(+) and aluminum oxide and hydroxide cluster cations. No molybdenum- or tungsten-containing cluster cations were definitively assigned. The asymmetric distribution of aluminum and Group 6 transition metals in cation and anion cluster composition is attributed to the low ionization energy of atomic aluminum and aluminum suboxide clusters. In addition, the propensity of both molybdenum and tungsten to form metal oxide cluster anions under the same conditions that favor metallic aluminum cluster anions is attributed to differences in the optical properties of the surface oxide that is present in the metal powders used to prepare the ablation targets. Mechanisms of mixed metal oxide clusters are considered.

  18. Imprinting of the MEA Polycomb gene is controlled by antagonism between MET1 methyltransferase and DME glycosylase.

    PubMed

    Xiao, Wenyan; Gehring, Mary; Choi, Yeonhee; Margossian, Linda; Pu, Hong; Harada, John J; Goldberg, Robert B; Pennell, Roger I; Fischer, Robert L

    2003-12-01

    The MEA Polycomb gene is imprinted in the Arabidopsis endosperm. DME DNA glycosylase activates maternal MEA allele expression in the central cell of the female gametophyte, the progenitor of the endosperm. Maternal mutant dme or mea alleles result in seed abortion. We identified mutations that suppress dme seed abortion and found that they reside in the MET1 methyltransferase gene, which maintains cytosine methylation. Seeds with maternal dme and met1 alleles survive, indicating that suppression occurs in the female gametophyte. Suppression requires a maternal wild-type MEA allele, suggesting that MET1 functions upstream of, or at, MEA. DME activates whereas MET1 suppresses maternal MEA::GFP allele expression in the central cell. MET1 is required for DNA methylation of three regions in the MEA promoter in seeds. Our data suggest that imprinting is controlled in the female gametophyte by antagonism between the two DNA-modifying enzymes, MET1 methyltransferase and DME DNA glycosylase.

  19. Biotechnological applications of mobile group II introns and their reverse transcriptases: gene targeting, RNA-seq, and non-coding RNA analysis

    PubMed Central

    2014-01-01

    Mobile group II introns are bacterial retrotransposons that combine the activities of an autocatalytic intron RNA (a ribozyme) and an intron-encoded reverse transcriptase to insert site-specifically into DNA. They recognize DNA target sites largely by base pairing of sequences within the intron RNA and achieve high DNA target specificity by using the ribozyme active site to couple correct base pairing to RNA-catalyzed intron integration. Algorithms have been developed to program the DNA target site specificity of several mobile group II introns, allowing them to be made into ‘targetrons.’ Targetrons function for gene targeting in a wide variety of bacteria and typically integrate at efficiencies high enough to be screened easily by colony PCR, without the need for selectable markers. Targetrons have found wide application in microbiological research, enabling gene targeting and genetic engineering of bacteria that had been intractable to other methods. Recently, a thermostable targetron has been developed for use in bacterial thermophiles, and new methods have been developed for using targetrons to position recombinase recognition sites, enabling large-scale genome-editing operations, such as deletions, inversions, insertions, and ‘cut-and-pastes’ (that is, translocation of large DNA segments), in a wide range of bacteria at high efficiency. Using targetrons in eukaryotes presents challenges due to the difficulties of nuclear localization and sub-optimal magnesium concentrations, although supplementation with magnesium can increase integration efficiency, and directed evolution is being employed to overcome these barriers. Finally, spurred by new methods for expressing group II intron reverse transcriptases that yield large amounts of highly active protein, thermostable group II intron reverse transcriptases from bacterial thermophiles are being used as research tools for a variety of applications, including qRT-PCR and next-generation RNA sequencing (RNA

  20. Carotenoid derivatives inhibit nuclear factor kappa B activity in bone and cancer cells by targeting key thiol groups.

    PubMed

    Linnewiel-Hermoni, Karin; Motro, Yair; Miller, Yifat; Levy, Joseph; Sharoni, Yoav

    2014-10-01

    Aberrant activation of the nuclear factor kappa B (NFkB) transcription system contributes to cancer progression, and has a harmful effect on bone health. Several major components of the NFkB pathway such as IkB Kinase (IKK) and the NFkB subunits contain cysteine residues that are critical for their activity. The interaction of electrophiles with these cysteine residues results in NFkB inhibition. Carotenoids, hydrophobic plant pigments, are devoid of electrophilic groups, and we have previously demonstrated that carotenoid derivatives, but not the native compounds activate the Nrf2 transcription system. The aim of the current study was to examine whether carotenoid derivatives inhibit NFkB, and, if so, to determine the molecular mechanism underpinning the inhibitory action. We report in the present study that a mixture of oxidized derivatives, prepared by ethanol extraction from partially oxidized lycopene preparation, inhibited NFkB reporter gene activity. In contrast, the intact carotenoid was inactive. A series of synthetic dialdehyde carotenoid derivatives inhibited reporter activity as well as several stages of the NFkB pathway in both cancer and bone cells. The activity of the carotenoid derivatives depended on the reactivity of the electrophilic groups in reactions such as Michael addition to sulfhydryl groups of proteins. Specifically, carotenoid derivatives directly interacted with two key proteins of the NFkB pathway: the IKKβ and the p65 subunit. Direct interaction with IKKβ was found in an in vitro kinase assay with a recombinant enzyme. The inhibition by carotenoid derivatives of p65 transcriptional activity was observed in a reporter gene assay performed in the presence of excess p65. This inhibition action resulted, at least in part, from direct interaction of the carotenoid derivative with p65 leading to reduced binding of the protein to DNA as evidenced by electrophoretic mobility shift assay (EMSA) experiments. Importantly, we found by using

  1. After Action Report: Cursor On Target International User Group Meeting (2nd). Held on 1-2 April 2014

    DTIC Science & Technology

    2014-04-01

    network ( VPN ). At the MITRE Bedford office, where user group meeting attendees arrived in person, ISEE provided a router that formed a site-to-site... VPN with the ISEE lab network. The hub of CoT traffic on the network was a virtual machine (VM) on the CoT VLAN. This VM hosted the CoT router...Office staff conducted weekly or biweekly tests of our MITRE facility, the audio system through DCO, and the Digital Exercise VPN environment. We

  2. Challenges in Teaching Space Physics to Different Target Groups From Space Weather Forecasters to Heavy-weight Theorists

    NASA Astrophysics Data System (ADS)

    Koskinen, H. E.

    2008-12-01

    Plasma physics as the backbone of space physics is difficult and thus the space physics students need to have strong foundations in general physics, in particular in classical electrodynamics and thermodynamics, and master the basic mathematical tools for physicists. In many universities the number of students specializing in space physics at Master's and Doctoral levels is rather small and the students may have quite different preferences ranging from experimental approach to hard-core space plasma theory. This poses challenges in building up a study program that has both the variety and depth needed to motivate the best students to choose this field. At the University of Helsinki we require all beginning space physics students, regardless whether they enter the field as Master's or Doctoral degree students, to take a one-semester package consisting of plasma physics and its space applications. However, some compromises are necessary. For example, it is not at all clear, how thoroughly Landau damping should be taught at the first run or how deeply should the intricacies of collisionless reconnection be discussed. In both cases we have left the details to an optional course in advanced space physics, even with the risk that the student's appreciation of, e.g., reconnection may remain at the level of a magic wand. For learning experimental work, data analysis or computer simulations we have actively pursued arrangements for the Master's degree students to get a summer employments in active research groups, which usually lead to the Master's theses. All doctoral students are members of research groups and participate in experimental work, data analysis, simulation studies or theory development, or any combination of these. We emphasize strongly "learning by doing" all the way from the weekly home exercises during the lecture courses to the PhD theses which in Finland consist typically of 4-6 peer-reviewed articles with a comprehensive introductory part.

  3. Changes in sexual behavior of HIV-infected older adults enrolled in a clinical trial of standalone group psychotherapies targeting depression

    PubMed Central

    Lovejoy, Travis I.; Heckman, Timothy G.; Sikkema, Kathleen J.; Hansen, Nathan B.; Kochman, Arlene

    2014-01-01

    By 2015, one-half of all HIV-positive persons in the U.S. will be 50-plus years of age, and as many as 30% of older adults living with HIV/AIDS continue to engage in unprotected sexual intercourse. Contemporary positive prevention models often include mental health treatment as a key component of HIV prevention interventions. This secondary data analysis characterized longitudinal patterns of sexual behavior in HIV-positive older adults enrolled in a randomized controlled trial of group mental health interventions and assessed the efficacy of psychosocial treatments that targeted depression to reduce sexual risk behavior. Participants were 295 HIV-positive adults ≥ 50 years of age experiencing mild to severe depressive symptoms, randomized to one of three study conditions: a 12-session coping improvement group intervention, a 12-session interpersonal support group intervention, or individual therapy upon request. Approximately one-fifth of participants reported one or more occasions of unprotected anal or vaginal intercourse with HIV-negative sexual partners or persons of unknown HIV serostatus over the study period. Changes in sexual behavior did not vary by intervention condition, indicating that standalone treatments that target and reduce depression may be insufficient to reduce sexual risk behavior in depressed HIV-positive older adults. PMID:24668254

  4. Changes in sexual behavior of HIV-infected older adults enrolled in a clinical trial of standalone group psychotherapies targeting depression.

    PubMed

    Lovejoy, Travis I; Heckman, Timothy G; Sikkema, Kathleen J; Hansen, Nathan B; Kochman, Arlene

    2015-01-01

    By 2015, one-half of all HIV-positive persons in the U.S. will be 50-plus years of age, and as many as 30 % of older adults living with HIV/AIDS continue to engage in unprotected sexual intercourse. Contemporary positive prevention models often include mental health treatment as a key component of HIV prevention interventions. This secondary data analysis characterized longitudinal patterns of sexual behavior in HIV-positive older adults enrolled in a randomized controlled trial of group mental health interventions and assessed the efficacy of psychosocial treatments that targeted depression to reduce sexual risk behavior. Participants were 295 HIV-positive adults ≥50 years of age experiencing mild to severe depressive symptoms, randomized to one of three study conditions: a 12-session coping improvement group intervention, a 12-session interpersonal support group intervention, or individual therapy upon request. Approximately one-fifth of participants reported one or more occasions of unprotected anal or vaginal intercourse with HIV-negative sexual partners or persons of unknown HIV serostatus over the study period. Changes in sexual behavior did not vary by intervention condition, indicating that standalone treatments that target and reduce depression may be insufficient to reduce sexual risk behavior in depressed HIV-positive older adults.

  5. Targeting children of substance-using parents with the community-based group intervention TRAMPOLINE: A randomised controlled trial - design, evaluation, recruitment issues

    PubMed Central

    2012-01-01

    Background Children of substance-abusing parents are at risk for developing psychosocial development problems. In Germany it is estimated that approx. 2.65 million children are affected by parental substance abuse or dependence. Only ten percent of them receive treatment when parents are treated. To date, no evaluated programme for children from substance-affected families exists in Germany. The study described in this protocol is designed to test the effectiveness of the group programme TRAMPOLINE for children aged 8-12 years with at least one substance-abusing or -dependent caregiver. The intervention is specifically geared to issues and needs of children from substance-affected families. Methods/Design The effectiveness of the manualised nine-session group programme TRAMPOLINE is tested among N = 218 children from substance-affected families in a multicentre randomised controlled trial. Outpatient counselling facilities across the nation from different settings (rural/urban, Northern/Southern/Eastern/Western regions of the country) will deliver the interventions, as they hold the primary access to the target group in Germany. The control condition is a group programme with the same duration that is not addiction-specific. We expect that participants in the intervention condition will show a significant improvement in the use of adaptive coping strategies (in general and within the family) compared to the control condition as a direct result of the intervention. Data is collected shortly before and after as well as six months after the intervention. Discussion In Germany, the study presented here is the first to develop and evaluate a programme for children of substance-abusing parents. Limitations and strengths are discussed with a special focus on recruitment challenges as they appear to be the most potent threat to feasibility in the difficult-to-access target group at hand (Trial registration: ISRCTN81470784). PMID:22439919

  6. Development of a quantitative real-time polymerase chain reaction assay to target a novel group of ammonia-producing bacteria found in poultry litter.

    PubMed

    Rothrock, M J; Cook, K L; Lovanh, N; Warren, J G; Sistani, K

    2008-06-01

    Ammonia production in poultry houses has serious implications for flock health and performance, nutrient value of poultry litter, and energy costs for running poultry operations. In poultry litter, the conversion of organic N (uric acid and urea) to NH(4)-N is a microbially mediated process. The urease enzyme is responsible for the final step in the conversion of urea to NH(4)-N. Cloning and analysis of 168 urease sequences from extracted genomic DNA from poultry litter samples revealed the presence of a novel, dominant group of ureolytic microbes (representing 90% of the urease clone library). Specific primers and a probe were designed to target this novel poultry litter urease producer (PLUP) group, and a new quantitative real-time PCR assay was developed. The assay allowed for the detection of 10(2) copies of target urease sequences per PCR reaction (approximately 1 x 10(4) cells per gram of poultry litter), and the reaction was linear over 8 orders of magnitude. Our PLUP group was present only in poultry litter and was not present in environmental samples from diverse agricultural settings. This novel PLUP group represented between 0.1 to 3.1% of the total microbial populations (6.0 x 10(6) to 2.4 x 10(8) PLUP cells per gram of litter) from diverse poultry litter types. The PLUP cell concentrations were directly correlated to the total cell concentrations in the poultry litter and were found to be influenced by the physical parameters of the litters (bedding material, moisture content, pH), as well as the NH(4)-N content of the litters, based on principal component analysis. Chemical parameters (organic N, total N, total C) were not found to be influential in the concentrations of our PLUP group in the diverse poultry litters Future applications of this assay could include determining the efficacy of current NH(4)-N-reducing litter amendments or in designing more efficient treatment protocols.

  7. Interobserver Variability in Target Definition for Hepatocellular Carcinoma With and Without Portal Vein Thrombus: Radiation Therapy Oncology Group Consensus Guidelines

    SciTech Connect

    Hong, Theodore S.; Bosch, Walter R.; Krishnan, Sunil; Kim, Tae K.; Mamon, Harvey J.; Ben-Josef, Edgar; Seong, Jinsil; Haddock, Michael G.; Cheng, Jason C.; Feng, Mary U.; Stephans, Kevin L.; Roberge, David; and others

    2014-07-15

    Purpose: Defining hepatocellular carcinoma (HCC) gross tumor volume (GTV) requires multimodal imaging, acquired in different perfusion phases. The purposes of this study were to evaluate the variability in contouring and to establish guidelines and educational recommendations for reproducible HCC contouring for treatment planning. Methods and Materials: Anonymous, multiphasic planning computed tomography scans obtained from 3 patients with HCC were identified and distributed to a panel of 11 gastrointestinal radiation oncologists. Panelists were asked the number of HCC cases they treated in the past year. Case 1 had no vascular involvement, case 2 had extensive portal vein involvement, and case 3 had minor branched portal vein involvement. The agreement between the contoured total GTVs (primary + vascular GTV) was assessed using the generalized kappa statistic. Agreement interpretation was evaluated using Landis and Koch's interpretation of strength of agreement. The S95 contour, defined using the simultaneous truth and performance level estimation (STAPLE) algorithm consensus at the 95% confidence level, was created for each case. Results: Of the 11 panelists, 3 had treated >25 cases in the past year, 2 had treated 10 to 25 cases, 2 had treated 5 to 10 cases, 2 had treated 1 to 5 cases, 1 had treated 0 cases, and 1 did not respond. Near perfect agreement was seen for case 1, and substantial agreement was seen for cases 2 and 3. For case 2, there was significant heterogeneity in the volume identified as tumor thrombus (range 0.58-40.45 cc). For case 3, 2 panelists did not include the branched portal vein thrombus, and 7 panelists contoured thrombus separately from the primary tumor, also showing significant heterogeneity in volume of tumor thrombus (range 4.52-34.27 cc). Conclusions: In a group of experts, excellent agreement was seen in contouring total GTV. Heterogeneity exists in the definition of portal vein thrombus that may impact treatment planning

  8. Engaging stakeholders and target groups in prioritising a public health intervention: the Creating Active School Environments (CASE) online Delphi study

    PubMed Central

    Morton, Katie L; Atkin, Andrew J; Corder, Kirsten; Suhrcke, Marc; Turner, David; van Sluijs, Esther M F

    2017-01-01

    Objectives Stakeholder engagement and public involvement are considered as integral to developing effective public health interventions and is encouraged across all phases of the research cycle. However, limited guidelines and appropriate tools exist to facilitate stakeholder engagement—especially during the intervention prioritisation phase. We present the findings of an online ‘Delphi’ study that engaged stakeholders (including young people) in the process of prioritising secondary school environment-focused interventions that aim to increase physical activity. Setting Web-based data collection using an online Delphi tool enabling participation of geographically diverse stakeholders. Participants 37 stakeholders participated, including young people (age 13–16 years), parents, teachers, public health practitioners, academics and commissioners; 33 participants completed both rounds. Primary and secondary outcome measures Participants were asked to prioritise a (short-listed) selection of school environment-focused interventions (eg, standing desks, outdoor design changes) based on the criteria of ‘reach’, ‘equality’, ‘acceptability’, ‘feasibility’, ‘effectiveness’ and ‘cost’. Participants were also asked to rank the criteria and the effectiveness outcomes (eg, physical activity, academic achievement, school enjoyment) from most to least important. Following feedback along with any new information provided, participants completed round 2 4 weeks later. Results The intervention prioritisation process was feasible to conduct and comments from participants indicated satisfaction with the process. Consensus regarding intervention strategies was achieved among the varied groups of stakeholders, with ‘active lessons’ being the favoured approach. Participants ranked ‘mental health and well-being’ as the most important outcome followed by ‘enjoyment of school’. The most important criteria was ‘effectiveness’, followed by

  9. Mutations in the FIE and MEA genes that encode interacting polycomb proteins cause parent-of-origin effects on seed development by distinct mechanisms.

    PubMed

    Yadegari, R; Kinoshita, T; Lotan, O; Cohen, G; Katz, A; Choi, Y; Katz, A; Nakashima, K; Harada, J J; Goldberg, R B; Fischer, R L; Ohad, N

    2000-12-01

    In flowering plants, two cells are fertilized in the haploid female gametophyte. Egg and sperm nuclei fuse to form the embryo. A second sperm nucleus fuses with the central cell nucleus, which replicates to generate the endosperm, a tissue that supports embryo development. The FERTILIZATION-INDEPENDENT ENDOSPERM (FIE) and MEDEA (MEA) genes encode WD and SET domain polycomb proteins, respectively. In the absence of fertilization, a female gametophyte with a loss-of-function fie or mea allele initiates endosperm development without fertilization. fie and mea mutations also cause parent-of-origin effects, in which the wild-type maternal allele is essential and the paternal allele is dispensable for seed viability. Here, we show that FIE and MEA polycomb proteins interact physically, suggesting that the molecular partnership of WD and SET domain polycomb proteins has been conserved during the evolution of flowering plants. The overlapping expression patterns of FIE and MEA are consistent with their suppression of gene transcription and endosperm development in the central cell as well as their control of seed development after fertilization. Although FIE and MEA interact, differences in maternal versus paternal patterns of expression, as well as the effect of a recessive mutation in the DECREASE IN DNA METHYLATION1 (DDM1) gene on mutant allele transmission, indicate that fie and mea mutations cause parent-of-origin effects on seed development by distinct mechanisms.

  10. The variant Polycomb Repressor Complex 1 component PCGF1 interacts with a pluripotency sub-network that includes DPPA4, a regulator of embryogenesis

    PubMed Central

    Oliviero, Giorgio; Munawar, Nayla; Watson, Ariane; Streubel, Gundula; Manning, Gwendolyn; Bardwell, Vivian; Bracken, Adrian P.; Cagney, Gerard

    2015-01-01

    PCGF1 encodes one of six human Polycomb RING finger homologs that are linked to transcriptional repression and developmental gene regulation. Individual PCGF proteins define discrete Polycomb Repressor Complex 1 (PRC1) multi-protein complexes with diverse subunit composition whose functions are incompletely understood. PCGF1 is a component of a variant PRC1 complex that also contains the BCL6 co-repressor BCOR and the histone demethylase KDM2B. To further investigate the role of PCGF1, we mapped the physical interactions of the protein under endogenous conditions in a cell model of neuronal differentiation. Using stringent statistical cut-offs, 83 highly enriched interacting proteins were identified, including all previously reported members of the variant PRC1 complex containing PCGF1, as well as proteins linked to diverse cellular pathways such as chromatin and cell cycle regulation. Notably, a sub-network of proteins associated with the establishment and maintenance of pluripotency (NANOG, OCT4, PATZ1, and the developmental regulator DPPA4) were found to independently interact with PCGF1 in a subsequent round of physical interaction mapping experiments. Furthermore, knockdown of PCGF1 results in reduced expression of DPPA4 and other subunits of the variant PRC1 complex at both mRNA and protein levels. Thus, PCGF1 represents a physical and functional link between Polycomb function and pluripotency. PMID:26687479

  11. Targeted Overexpression of EZH2 in the Mammary Gland Disrupts Ductal Morphogenesis and Causes Epithelial Hyperplasia

    PubMed Central

    Li, Xin; Gonzalez, Maria E.; Toy, Katherine; Filzen, Tracey; Merajver, Sofia D.; Kleer, Celina G.

    2009-01-01

    The Polycomb group protein enhancer of zeste homolog 2 (EZH2), which has roles during development of numerous tissues, is a critical regulator of cell type identity. Overexpression of EZH2 has been detected in invasive breast carcinoma tissue samples and is observed in human breast tissue samples of morphologically normal lobules up to 12 years before the development of breast cancer. The function of EZH2 during preneoplastic progression in the mammary gland is unknown. To investigate the role of EZH2 in the mammary gland, we targeted the expression of EZH2 to mammary epithelial cells using the mouse mammary tumor virus long terminal repeat. EZH2 overexpression resulted in aberrant terminal end bud architecture. By the age of 4 months, 100% of female mouse mammary tumor virus-EZH2 virgin mice developed intraductal epithelial hyperplasia resembling the human counterpart accompanied by premature differentiation of ductal epithelial cells and up-regulation of the luminal marker GATA-3. In addition, remodeling of the mammary gland after parturition was impaired and EZH2 overexpression caused delayed involution. Mechanistically, we found that EZH2 physically interacts with β-catenin, inducing β-catenin nuclear accumulation in mammary epithelial cells and activating Wnt/β-catenin signaling. The biological significance of these data to human hyperplasias is demonstrated by EZH2 up-regulation and colocalization with β-catenin in human intraductal epithelial hyperplasia, the earliest histologically identifiable precursor of breast carcinoma. PMID:19661437

  12. Role of group V phospholipase A2 in zymosan-induced eicosanoid generation and vascular permeability revealed by targeted gene disruption*

    PubMed Central

    Satake, Yoshiyuki; Diaz, Bruno L.; Balestrieri, Barbara; Lam, Bing K.; Kanaoka, Yoshihide; Grusby, Michael J.; Arm, Jonathan P.

    2005-01-01

    SUMMARY Conclusions regarding the contribution of low molecular weight secretory phospholipase A2 (sPLA2) enzymes in eicosanoid generation have relied on data obtained from transfected cells or the use of inhibitors that fail to discriminate between individual members of the large family of mammalian sPLA2 enzymes. To elucidate the role of group V sPLA2, we used targeted gene disruption to generate mice lacking this enzyme. Zymosan-induced generation of leukotriene C4 and prostaglandin E2 was attenuated ~50% in peritoneal macrophages from group V sPLA2-null mice compared to macrophages from wild-type littermates. Furthermore, the early phase of plasma exudation in response to intraperitoneal injection of zymosan and the accompanying in vivo generation of cysteinyl leukotrienes were markedly attenuated in group V sPLA2-null mice compared to wild-type controls. These data provide clear evidence of a role for group V sPLA2 in regulating eicosanoid generation in response to an acute innate stimulus of the immune response both in vitro and in vivo, suggesting a role for this enzyme in innate immunity. PMID:14761945

  13. Use of 16S rRNA Gene-Targeted Group-Specific Primers for Real-Time PCR Analysis of Predominant Bacteria in Mouse Feces.

    PubMed

    Yang, Yun-Wen; Chen, Mang-Kun; Yang, Bing-Ya; Huang, Xian-Jie; Zhang, Xue-Rui; He, Liang-Qiang; Zhang, Jing; Hua, Zi-Chun

    2015-10-01

    Mouse models are widely used for studying gastrointestinal (GI) tract-related diseases. It is necessary and important to develop a new set of primers to monitor the mouse gut microbiota. In this study, 16S rRNA gene-targeted group-specific primers for Firmicutes, Actinobacteria, Bacteroidetes, Deferribacteres, "Candidatus Saccharibacteria," Verrucomicrobia, Tenericutes, and Proteobacteria were designed and validated for quantification of the predominant bacterial species in mouse feces by real-time PCR. After confirmation of their accuracy and specificity by high-throughput sequencing technologies, these primers were applied to quantify the changes in the fecal samples from a trinitrobenzene sulfonic acid-induced colitis mouse model. Our results showed that this approach efficiently predicted the occurrence of colitis, such as spontaneous chronic inflammatory bowel disease in transgenic mice. The set of primers developed in this study provides a simple and affordable method to monitor changes in the intestinal microbiota at the phylum level.

  14. Modern Radiation Therapy for Nodal Non-Hodgkin Lymphoma—Target Definition and Dose Guidelines From the International Lymphoma Radiation Oncology Group

    SciTech Connect

    Illidge, Tim; Specht, Lena; Yahalom, Joachim; Aleman, Berthe; Berthelsen, Anne Kiil; Constine, Louis; Dabaja, Bouthaina; Dharmarajan, Kavita; Ng, Andrea; Ricardi, Umberto; Wirth, Andrew

    2014-05-01

    Radiation therapy (RT) is the most effective single modality for local control of non-Hodgkin lymphoma (NHL) and is an important component of therapy for many patients. Many of the historic concepts of dose and volume have recently been challenged by the advent of modern imaging and RT planning tools. The International Lymphoma Radiation Oncology Group (ILROG) has developed these guidelines after multinational meetings and analysis of available evidence. The guidelines represent an agreed consensus view of the ILROG steering committee on the use of RT in NHL in the modern era. The roles of reduced volume and reduced doses are addressed, integrating modern imaging with 3-dimensional planning and advanced techniques of RT delivery. In the modern era, in which combined-modality treatment with systemic therapy is appropriate, the previously applied extended-field and involved-field RT techniques that targeted nodal regions have now been replaced by limiting the RT to smaller volumes based solely on detectable nodal involvement at presentation. A new concept, involved-site RT, defines the clinical target volume. For indolent NHL, often treated with RT alone, larger fields should be considered. Newer treatment techniques, including intensity modulated RT, breath holding, image guided RT, and 4-dimensional imaging, should be implemented, and their use is expected to decrease significantly the risk for normal tissue damage while still achieving the primary goal of local tumor control.

  15. Modern radiation therapy for nodal non-Hodgkin lymphoma-target definition and dose guidelines from the International Lymphoma Radiation Oncology Group.

    PubMed

    Illidge, Tim; Specht, Lena; Yahalom, Joachim; Aleman, Berthe; Berthelsen, Anne Kiil; Constine, Louis; Dabaja, Bouthaina; Dharmarajan, Kavita; Ng, Andrea; Ricardi, Umberto; Wirth, Andrew

    2014-05-01

    Radiation therapy (RT) is the most effective single modality for local control of non-Hodgkin lymphoma (NHL) and is an important component of therapy for many patients. Many of the historic concepts of dose and volume have recently been challenged by the advent of modern imaging and RT planning tools. The International Lymphoma Radiation Oncology Group (ILROG) has developed these guidelines after multinational meetings and analysis of available evidence. The guidelines represent an agreed consensus view of the ILROG steering committee on the use of RT in NHL in the modern era. The roles of reduced volume and reduced doses are addressed, integrating modern imaging with 3-dimensional planning and advanced techniques of RT delivery. In the modern era, in which combined-modality treatment with systemic therapy is appropriate, the previously applied extended-field and involved-field RT techniques that targeted nodal regions have now been replaced by limiting the RT to smaller volumes based solely on detectable nodal involvement at presentation. A new concept, involved-site RT, defines the clinical target volume. For indolent NHL, often treated with RT alone, larger fields should be considered. Newer treatment techniques, including intensity modulated RT, breath holding, image guided RT, and 4-dimensional imaging, should be implemented, and their use is expected to decrease significantly the risk for normal tissue damage while still achieving the primary goal of local tumor control.

  16. High mobility group A1 protein acts as a new target of Notch1 signaling and regulates cell proliferation in T leukemia cells.

    PubMed

    Xi, Yang; Li, Yu-Sang; Tang, He-Bin

    2013-02-01

    Active mutations of Notch1 play pivotal roles during leukemogenesis, but the downstream targets and molecular mechanisms of activated Notch1 signaling have not yet been fully clarified. In this study, we detected the overexpression of the high mobility group A1 (HMGA1) and activation of Notch1 signaling in mouse thymic lymphomas. A direct regulation of Notch1 on HMGA1 transcription was demonstrated and two Notch1/RBPJ cobinding sites of T/CTCCCACA were found in HMGA1 promoter regions. It was the first time demonstrated that HMGA1 was the downstream target of Notch1 signaling. Moreover, knockdown of HMGA1 resulted in significantly impaired cell growth and decreased expressions of cyclin D and cyclin E in human T leukemia cells. The formation of complexes was also observed between HMGA1 and retinoblastoma (RB) protein indicating a mechanism of cell cycle regulation. These findings suggest that activated HMGA1 regulates cell proliferation through the Notch1 signaling pathway, which represents an important molecular pathway leading to leukemogenesis.

  17. The challenge of reducing scientific complexity for different target groups (without losing the essence) - experiences from interdisciplinary audio-visual media production

    NASA Astrophysics Data System (ADS)

    Hezel, Bernd; Broschkowski, Ephraim; Kropp, Jürgen

    2013-04-01

    The Climate Media Factory originates from an interdisciplinary media lab run by the Film and Television University "Konrad Wolf" Potsdam-Babelsberg (HFF) and the Potsdam Institute for Climate Impact Research (PIK). Climate scientists, authors, producers and media scholars work together to develop media products on climate change and sustainability. We strive towards communicating scientific content via different media platforms reconciling the communication needs of scientists and the audience's need to understand the complexity of topics that are relevant in their everyday life. By presenting four audio-visual examples, that have been designed for very different target groups, we show (i) the interdisciplinary challenges during the production process and the lessons learnt and (ii) possibilities to reach the required degree of simplification without the need for dumbing down the content. "We know enough about climate change" is a short animated film that was produced for the German Agency for International Cooperation (GIZ) for training programs and conferences on adaptation in the target countries including Indonesia, Tunisia and Mexico. "Earthbook" is a short animation produced for "The Year of Science" to raise awareness for the topics of sustainability among digital natives. "What is Climate Engineering?". Produced for the Institute for Advanced Sustainability Studies (IASS) the film is meant for an informed and interested public. "Wimmelwelt Energie!" is a prototype of an iPad application for children from 4-6 years of age to help them learn about different forms of energy and related greenhouse gas emissions.

  18. Transcriptional Regulation of Arabidopsis Polycomb Repressive Complex 2 Coordinates Cell-Type Proliferation and Differentiation[OPEN

    PubMed Central

    Pu, Li; Turco, Gina; Morao, Ana Karina; Kim, Dahae

    2016-01-01

    Spatiotemporal regulation of transcription is fine-tuned at multiple levels, including chromatin compaction. Polycomb Repressive Complex 2 (PRC2) catalyzes the trimethylation of Histone 3 at lysine 27 (H3K27me3), which is the hallmark of a repressive chromatin state. Multiple PRC2 complexes have been reported in Arabidopsis thaliana to control the expression of genes involved in developmental transitions and maintenance of organ identity. Here, we show that PRC2 member genes display complex spatiotemporal gene expression patterns and function in root meristem and vascular cell proliferation and specification. Furthermore, PRC2 gene expression patterns correspond with vascular and nonvascular tissue-specific H3K27me3-marked genes. This tissue-specific repression via H3K27me3 regulates the balance between cell proliferation and differentiation. Using enhanced yeast one-hybrid analysis, upstream regulators of the PRC2 member genes are identified, and genetic analysis demonstrates that transcriptional regulation of some PRC2 genes plays an important role in determining PRC2 spatiotemporal activity within a developing organ. PMID:27650334

  19. Polycomb Repressive Complex 2 Regulates MiR-200b in Retinal Endothelial Cells: Potential Relevance in Diabetic Retinopathy

    PubMed Central

    Ruiz, Michael Anthony; Feng, Biao; Chakrabarti, Subrata

    2015-01-01

    Glucose-induced augmented vascular endothelial growth factor (VEGF) production is a key event in diabetic retinopathy. We have previously demonstrated that downregulation of miR-200b increases VEGF, mediating structural and functional changes in the retina in diabetes. However, mechanisms regulating miR-200b in diabetes are not known. Histone methyltransferase complex, Polycomb Repressive Complex 2 (PRC2), has been shown to repress miRNAs in neoplastic process. We hypothesized that, in diabetes, PRC2 represses miR-200b through its histone H3 lysine-27 trimethylation mark. We show that human retinal microvascular endothelial cells exposed to high levels of glucose regulate miR-200b repression through histone methylation and that inhibition of PRC2 increases miR-200b while reducing VEGF. Furthermore, retinal tissue from animal models of diabetes showed increased expression of major PRC2 components, demonstrating in vivo relevance. This research established a repressive relationship between PRC2 and miR-200b, providing evidence of a novel mechanism of miRNA regulation through histone methylation. PMID:25884496

  20. Repression of the soma-specific transcriptome by Polycomb-repressive complex 2 promotes male germ cell development

    PubMed Central

    Mu, Weipeng; Starmer, Joshua; Fedoriw, Andrew M.; Yee, Della; Magnuson, Terry

    2014-01-01

    Polycomb-repressive complex 2 (PRC2) catalyzes the methylation of histone H3 Lys27 (H3K27) and functions as a critical epigenetic regulator of both stem cell pluripotency and somatic differentiation, but its role in male germ cell development is unknown. Using conditional mutagenesis to remove the core PRC2 subunits EED and SUZ12 during male germ cell development, we identified a requirement for PRC2 in both mitotic and meiotic germ cells. We observed a paucity of mutant spermatogonial stem cells (SSCs), which appears independent of repression of the known cell cycle inhibitors Ink4a/Ink4b/Arf. Moreover, mutant spermatocytes exhibited ectopic expression of somatic lamins and an abnormal distribution of SUN1 proteins on the nuclear envelope. These defects were coincident with abnormal chromosome dynamics, affecting homologous chromosome pairing and synapsis. We observed acquisition of H3K27me3 on stage-specific genes during meiotic progression, indicating a requirement for PRC2 in regulating the meiotic transcriptional program. Together, these data demonstrate that transcriptional repression of soma-specific genes by PRC2 facilitates homeostasis and differentiation during mammalian spermatogenesis. PMID:25228648

  1. The Polycomb Repressive Complex 1 Protein BMI1 Is Required for Constitutive Heterochromatin Formation and Silencing in Mammalian Somatic Cells*

    PubMed Central

    Abdouh, Mohamed; Hanna, Roy; El Hajjar, Jida; Flamier, Anthony; Bernier, Gilbert

    2016-01-01

    The polycomb repressive complex 1 (PRC1), containing the core BMI1 and RING1A/B proteins, mono-ubiquitinylates histone H2A (H2Aub) and is associated with silenced developmental genes at facultative heterochromatin. It is, however, assumed that the PRC1 is excluded from constitutive heterochromatin in somatic cells based on work performed on mouse embryonic stem cells and oocytes. We show here that BMI1 is required for constitutive heterochromatin formation and silencing in human and mouse somatic cells. BMI1 was highly enriched at intergenic and pericentric heterochromatin, co-immunoprecipitated with the architectural heterochromatin proteins HP1, DEK1, and ATRx, and was required for their localization. In contrast, BRCA1 localization was BMI1-independent and partially redundant with that of BMI1 for H2Aub deposition, constitutive heterochromatin formation, and silencing. These observations suggest a dynamic and developmentally regulated model of PRC1 occupancy at constitutive heterochromatin, and where BMI1 function in somatic cells is to stabilize the repetitive genome. PMID:26468281

  2. Increased Maternal Genome Dosage Bypasses the Requirement of the FIS Polycomb Repressive Complex 2 in Arabidopsis Seed Development

    PubMed Central

    Kradolfer, David; Hennig, Lars; Köhler, Claudia

    2013-01-01

    Seed development in flowering plants is initiated after a double fertilization event with two sperm cells fertilizing two female gametes, the egg cell and the central cell, leading to the formation of embryo and endosperm, respectively. In most species the endosperm is a polyploid tissue inheriting two maternal genomes and one paternal genome. As a consequence of this particular genomic configuration the endosperm is a dosage sensitive tissue, and changes in the ratio of maternal to paternal contributions strongly impact on endosperm development. The FERTILIZATION INDEPENDENT SEED (FIS) Polycomb Repressive Complex 2 (PRC2) is essential for endosperm development; however, the underlying forces that led to the evolution of the FIS-PRC2 remained unknown. Here, we show that the functional requirement of the FIS-PRC2 can be bypassed by increasing the ratio of maternal to paternal genomes in the endosperm, suggesting that the main functional requirement of the FIS-PRC2 is to balance parental genome contributions and to reduce genetic conflict. We furthermore reveal that the AGAMOUS LIKE (AGL) gene AGL62 acts as a dosage-sensitive seed size regulator and that reduced expression of AGL62 might be responsible for reduced size of seeds with increased maternal genome dosage. PMID:23326241

  3. Polycomb repressive complex 1 provides a molecular explanation for repeat copy number dependency in FSHD muscular dystrophy.

    PubMed

    Casa, Valentina; Runfola, Valeria; Micheloni, Stefano; Aziz, Arif; Dilworth, F Jeffrey; Gabellini, Davide

    2016-12-30

    Repression of repetitive elements is crucial to preserve genome integrity and has been traditionally ascribed to constitutive heterochromatin pathways. FacioScapuloHumeral Muscular Dystrophy (FSHD), one of the most common myopathies, is characterized by a complex interplay of genetic and epigenetic events. The main FSHD form is linked to a reduced copy number of the D4Z4 macrosatellite repeat on 4q35, causing loss of silencing and aberrant expression of the D4Z4-embedded DUX4 gene leading to disease. By an unknown mechanism, D4Z4 copy-number correlates with FSHD phenotype. Here we show that the DUX4 proximal promoter (DUX4p) is sufficient to nucleate the enrichment of both constitutive and facultative heterochromatin components and to mediate a copy-number dependent gene silencing. We found that both the CpG/GC dense DNA content and the repetitive nature of DUX4p arrays are important for their repressive ability. We showed that DUX4p mediates a copy number-dependent Polycomb Repressive Complex 1 (PRC1) recruitment, which is responsible for the copy-number dependent gene repression. Overall, we directly link genetic and epigenetic defects in FSHD by proposing a novel molecular explanation for the copy number-dependency in FSHD pathogenesis, and offer insight into the molecular functions of repeats in chromatin regulation.

  4. The Polycomb Repressive Complex 1 Protein BMI1 Is Required for Constitutive Heterochromatin Formation and Silencing in Mammalian Somatic Cells.

    PubMed

    Abdouh, Mohamed; Hanna, Roy; El Hajjar, Jida; Flamier, Anthony; Bernier, Gilbert

    2016-01-01

    The polycomb repressive complex 1 (PRC1), containing the core BMI1 and RING1A/B proteins, mono-ubiquitinylates histone H2A (H2A(ub)) and is associated with silenced developmental genes at facultative heterochromatin. It is, however, assumed that the PRC1 is excluded from constitutive heterochromatin in somatic cells based on work performed on mouse embryonic stem cells and oocytes. We show here that BMI1 is required for constitutive heterochromatin formation and silencing in human and mouse somatic cells. BMI1 was highly enriched at intergenic and pericentric heterochromatin, co-immunoprecipitated with the architectural heterochromatin proteins HP1, DEK1, and ATRx, and was required for their localization. In contrast, BRCA1 localization was BMI1-independent and partially redundant with that of BMI1 for H2A(ub) deposition, constitutive heterochromatin formation, and silencing. These observations suggest a dynamic and developmentally regulated model of PRC1 occupancy at constitutive heterochromatin, and where BMI1 function in somatic cells is to stabilize the repetitive genome.

  5. The Lineage-Specific Transcription Factor PU.1 Prevents Polycomb-Mediated Heterochromatin Formation at Macrophage-Specific Genes

    PubMed Central

    Tagore, Mohita; McAndrew, Michael J.; Gjidoda, Alison

    2015-01-01

    Lineage-specific transcription factors (TFs) are important determinants of cellular identity, but their exact mode of action has remained unclear. Here we show using a macrophage differentiation system that the lineage-specific TF PU.1 keeps macrophage-specific genes accessible during differentiation by preventing Polycomb repressive complex 2 (PRC2) binding to transcriptional regulatory elements. We demonstrate that the distal enhancer of a gene becomes bound by PRC2 as cells differentiate in the absence of PU.1 binding and that the gene is wrapped into heterochromatin, which is characterized by increased nucleosome occupancy and H3K27 trimethylation. This renders the gene inaccessible to the transcriptional machinery and prevents induction of the gene in response to an external signal in mature cells. In contrast, if PU.1 is bound at the transcriptional regulatory region of a gene during differentiation, PRC2 is not recruited, nucleosome occupancy is kept low, and the gene can be induced in mature macrophages. Similar results were obtained at the enhancers of other macrophage-specific genes that fail to bind PU.1 as an estrogen receptor fusion (PUER) in this system. These results show that one role of PU.1 is to exclude PRC2 and to prevent heterochromatin formation at macrophage-specific genes. PMID:26012552

  6. A strand-specific switch in noncoding transcription switches the function of a Polycomb/Trithorax response element

    PubMed Central

    Trupke, Johanna; Okulski, Helena; Altmutter, Christina; Ruge, Frank; Boidol, Bernd; Kubicek, Stefan; Schmauss, Gerald; Aumayr, Karin; Ruf, Marius; Pospisilik, Andrew; Dimond, Andrew; Senergin, Hasene Basak; Vargas, Marcus L.; Simon, Jeffrey A.; Ringrose, Leonie

    2014-01-01

    Polycomb/Trithorax response elements (PRE/TREs) can switch their function reversibly between silencing and activation, by mechanisms that are poorly understood. Here we show that a switch in forward and reverse noncoding transcription from the Drosophila vestigial (vg) PRE/TRE switches the status of the element between silencing (induced by the forward strand) and activation (induced by the reverse strand). In vitro, both ncRNAs inhibit PRC2 histone methyltransferase activity, but in vivo only the reverse strand binds PRC2. Over-expression of the reverse strand evicts PRC2 from chromatin and inhibits its enzymatic activity. We propose that interactions of RNAs with PRC2 are differentially regulated in vivo, allowing regulated inhibition of local PRC2 activity. Genome-wide analysis shows that strand switching of ncRNAs occurs at several hundred PcG binding sites in fly and vertebrate genomes. This work identifies a novel and potentially widespread class of PRE/TREs that switch function by switching the direction of ncRNA transcription. PMID:25108384

  7. Group Grammar

    ERIC Educational Resources Information Center

    Adams, Karen

    2015-01-01

    In this article Karen Adams demonstrates how to incorporate group grammar techniques into a classroom activity. In the activity, students practice using the target grammar to do something they naturally enjoy: learning about each other.

  8. Targeting Enhancer of Zeste Homolog 2 as a promising strategy for cancer treatment

    PubMed Central

    Marchesi, Irene; Bagella, Luigi

    2016-01-01

    Polycomb group proteins represent a global silencing system involved in development regulation. In specific, they regulate the transition from proliferation to differentiation, contributing to stem-cell maintenance and inhibiting an inappropriate activation of differentiation programs. Enhancer of Zeste Homolog 2 (EZH2) is the catalytic subunit of Polycomb repressive complex 2, which induces transcriptional inhibition through the tri-methylation of histone H3, an epigenetic change associated with gene silencing. EZH2 expression is high in precursor cells while its level decreases in differentiated cells. EZH2 is upregulated in various cancers with high levels associated with metastatic cancer and poor prognosis. Indeed, aberrant expression of EZH2 causes the inhibition of several tumor suppressors and differentiation genes, resulting in an uncontrolled proliferation and tumor formation. This editorial explores the role of Polycomb repressive complex 2 in cancer, focusing in particular on EZH2. The canonical function of EZH2 in gene silencing, the non-canonical activities as the methylation of other proteins and the role in gene transcriptional activation, were summarized. Moreover, mutations of EZH2, responsible for an increased methyltransferase activity in cancer, were recapitulated. Finally, various drugs able to inhibit EZH2 with different mechanism were described, specifically underscoring the effects in several cancers, in order to clarify the role of EZH2 and understand if EZH2 blockade could be a new strategy for developing specific therapies or a way to increase sensitivity of cancer cells to standard therapies. PMID:27081636

  9. Beyond the usual suspects: target group- and behavior-specific factors add to a theory-based sun protection intervention for teenagers.

    PubMed

    Schüz, Natalie; Eid, Michael

    2013-10-01

    Sun protection standards among teenagers are low while sun exposure peaks in this age group. Study 1 explores predictors of adolescent protection intentions and exposure behavior. Study 2 tests the effectiveness of an intervention based on these predictors. Study 1(cross-sectional, N = 207, ages 15-18) and Study 2 (RCT, N = 253, ages 13-19) were conducted in schools. Path models were used to analyze data. Self-efficacy (β = .26, p < .001) and time perspective (β = .17, p = .014) were the strongest predictors of intentions; appearance motivation (β = .54, p < .001) and intention (β = -.18, p = .015) predicted behavior. The intervention effected changes in all predictors except self-efficacy. Changes in outcome expectancies (β = .19, p < .001) and time perspective (β = .09, p = .039) predicted changes in intention, while changes in intention (β = -.17, p = .002) and appearance motivation (β = .29, p < .001) predicted behavior changes. Target group- and behavior-specific intervention components are as important for changes in intentions and behavior as components derived from common health behavior theories.

  10. Trans-splicing Group I Intron Targeting Hepatitis C Virus IRES Mediates Cell Death upon Viral Infection in Huh7.5 Cells

    PubMed Central

    Nawtaisong, Pruksa; Fraser, Mark E.; Carter, James R.; Fraser, Malcolm J.

    2015-01-01

    The HCV-IRES sequence is vital for both protein translation and genome replication and serves as a potential target for anti-HCV therapy. We constructed a series of anti-HCV Group I introns (αHCV-GrpIs) to attack conserved target sites within the HCV IRES. These αHCV-GrpIs were designed to mediate a trans-splicing reaction that replaces the viral RNA genome downstream of the 5’ splice site with a 3’ exon that encodes an apoptosis-inducing gene. Pro-active forms of the apoptosis inducing genes BID, Caspase 3, Caspase 8, or tBax were modified by incorporation of the HCV NS5A/5B cleavage sequence in place of their respective endogenous cleavage sites to ensure that only HCV infected cells would undergo apoptosis following splicing and expression. Huh7.5 cells transfected with each intron were challenged at MOI 0.1 with HCV-Jc1FLAG2 which expresses a Gaussia Luciferase (GLuc) marker. Virus-containing supernatants were then assayed for GLuc expression as a measure of viral replication inhibition. Cellular extracts were analyzed for the presence of correct splice products by RT-PCR and DNA sequencing. We also measured levels of Caspase 3 activity as a means of quantifying apoptotic cell death. Each of these αHCV-GrpI introns was able to correctly splice their 3’ apoptotic exons onto the virus RNA genome at the targeted Uracil, and resulted in greater than 80% suppression of the GLuc marker. A more pronounced suppression effect was observed with TCID50 virus titrations, which demonstrated that these αHCV-GrpIs were able to suppress viral replication by more than 2 logs, or greater than 99%. Robust activation of the apoptotic factor within the challenged cells was evidenced by a significant increase of Caspase 3 activity upon viral infection compared to non-challenged cells. This novel genetic intervention tool may prove beneficial in certain HCV subjects. PMID:25840398

  11. Role of Hepatic-Specific Transcription Factors and Polycomb Repressive Complex 2 during Induction of Fibroblasts to Hepatic Fate

    PubMed Central

    Wee, Ping; Yaqubi, Moein

    2016-01-01

    Direct reprogramming using defined sets of transcription factors (TFs) is a recent strategy for generating induced hepatocytes (iHeps) from fibroblasts for use in regenerative medicine and drug development. Comprehensive studies detailing the regulatory role of TFs during this reprogramming process could help increase its efficiency. This study aimed to find the TFs with the greatest influences on the generation of iHeps from fibroblasts, and to further understand their roles in the regulation of the gene expression program. Here, we used systems biology approaches to analyze high quality expression data sets in combination with TF-binding sites data and protein-protein interactions data during the direct reprogramming of fibroblasts to iHeps. Our results revealed two main patterns for differentially expressed genes (DEGs): up-regulated genes were categorized as hepatic-specific pattern, and down-regulated genes were categorized as mesoderm- and fibroblast-specific pattern. Interestingly, hepatic-specific genes co-expressed and were regulated by hepatic-specific TFs, specifically Hnf4a and Foxa2. Conversely, the mesoderm- and fibroblast-specific pattern was mainly silenced by polycomb repressive complex 2 (PRC2) members, including Suz12, Mtf2, Ezh2, and Jarid2. Independent analysis of both the gene and core regulatory network of DE-TFs showed significant roles for Hnf4a, Foxa2, and PRC2 members in the regulation of the gene expression program and in biological processes during the direct conversion process. Altogether, using systems biology approaches, we clarified the role of Hnf4a and Foxa2 as hepatic-specific TFs, and for the first time, introduced the PRC2 complex as the main regulator that favors the direct reprogramming process in cooperation with hepatic-specific factors. PMID:27902735

  12. Radiation Therapy Oncology Group Consensus Panel Guidelines for the Delineation of the Clinical Target Volume in the Postoperative Treatment of Pancreatic Head Cancer

    SciTech Connect

    Goodman, Karyn A.; Regine, William F.; Dawson, Laura A.; Ben-Josef, Edgar; Haustermans, Karin; Bosch, Walter R.; Turian, Julius; Abrams, Ross A.

    2012-07-01

    Purpose: To develop contouring guidelines to be used in the Radiation Therapy Oncology Group protocol 0848, a Phase III randomized trial evaluating the benefit of adjuvant chemoradiation in patients with resected head of pancreas cancer. Methods and Materials: A consensus committee of six radiation oncologists with expertise in gastrointestinal radiotherapy developed stepwise contouring guidelines and an atlas for the delineation of the clinical target volume (CTV) in the postoperative treatment of pancreas cancer, based on identifiable regions of interest and margin expansions. Areas at risk for subclinical disease to be included in the CTV were defined, including nodal regions, anastomoses, and the preoperative primary tumor location. Regions of interest that could be reproducibly contoured on postoperative imaging after a pancreaticoduodenectomy were identified. Standardized expansion margins to encompass areas at risk were developed after multiple iterations to determine the optimal margin expansions. Results: New contouring recommendations based on CT anatomy were established. Written guidelines for the delineation of the postoperative CTV and normal tissues, as well as a Web-based atlas, were developed. Conclusions: The postoperative abdomen has been a difficult area for effective radiotherapy. These new guidelines will help physicians create fields that better encompass areas at risk and minimize dose to normal tissues.

  13. Novel targets and future strategies for acute cardioprotection: Position Paper of the European Society of Cardiology Working Group on Cellular Biology of the Heart.

    PubMed

    Hausenloy, Derek J; Garcia-Dorado, David; Erik Bøtker, Hans; Davidson, Sean M; Downey, James; Engel, Felix B; Jennings, Robert; Lecour, Sandrine; Leor, Jonathan; Madonna, Rosalinda; Ovize, Michel; Perrino, Cinzia; Prunier, Fabrice; Schulz, Rainer; Sluijter, Joost P G; Van Laake, Linda W; Vinten-Johansen, Jakob; Yellon, Derek M; Ytrehus, Kirsti; Heusch, Gerd; Ferdinandy, Péter

    2017-03-17

    Ischaemic heart disease and the heart failure that often results, remain the leading causes of death and disability in Europe and worldwide. As such, in order to prevent heart failure and improve clinical outcomes in patients presenting with an acute ST-segment elevation myocardial infarction and patients undergoing coronary artery bypass graft surgery, novel therapies are required to protect the heart against the detrimental effects of acute ischaemia/reperfusion injury. During the last three decades, a wide variety of ischaemic conditioning strategies and pharmacological treatments have been tested in the clinic - however, their translation from experimental to clinical studies for improving patient outcomes has been both challenging and disappointing. Therefore, in this Position Paper of the European Society of Cardiology Working Group on Cellular Biology of the Heart, we critically analyse the current state of ischaemic conditioning in both the experimental and clinical settings, provide recommendations for improving its translation into the clinical setting, and highlight novel therapeutic targets and new treatment strategies for reducing acute myocardial ischaemia/reperfusion injury.

  14. Loss of tumor suppressor KDM6A amplifies PRC2-regulated transcriptional repression in bladder cancer and can be targeted through inhibition of EZH2.

    PubMed

    Ler, Lian Dee; Ghosh, Sujoy; Chai, Xiaoran; Thike, Aye Aye; Heng, Hong Lee; Siew, Ee Yan; Dey, Sucharita; Koh, Liang Kai; Lim, Jing Quan; Lim, Weng Khong; Myint, Swe Swe; Loh, Jia Liang; Ong, Pauline; Sam, Xin Xiu; Huang, Dachuan; Lim, Tony; Tan, Puay Hoon; Nagarajan, Sanjanaa; Cheng, Christopher Wai Sam; Ho, Henry; Ng, Lay Guat; Yuen, John; Lin, Po-Hung; Chuang, Cheng-Keng; Chang, Ying-Hsu; Weng, Wen-Hui; Rozen, Steven G; Tan, Patrick; Creasy, Caretha L; Pang, See-Tong; McCabe, Michael T; Poon, Song Ling; Teh, Bin Tean

    2017-02-22

    Trithorax-like group complex containing KDM6A acts antagonistically to Polycomb-repressive complex 2 (PRC2) containing EZH2 in maintaining the dynamics of the repression and activation of gene expression through H3K27 methylation. In urothelial bladder carcinoma, KDM6A (a H3K27 demethylase) is frequently mutated, but its functional consequences and therapeutic targetability remain unknown. About 70% of KDM6A mutations resulted in a total loss of expression and a consequent loss of demethylase function in this cancer type. Further transcriptome analysis found multiple deregulated pathways, especially PRC2/EZH2, in KDM6A-mutated urothelial bladder carcinoma. Chromatin immunoprecipitation sequencing analysis revealed enrichment of H3K27me3 at specific loci in KDM6A-null cells, including PRC2/EZH2 and their downstream targets. Consequently, we targeted EZH2 (an H3K27 methylase) and demonstrated that KDM6A-null urothelial bladder carcinoma cell lines were sensitive to EZH2 inhibition. Loss- and gain-of-function assays confirmed that cells with loss of KDM6A are vulnerable to EZH2. IGFBP3, a direct KDM6A/EZH2/H3K27me3 target, was up-regulated by EZH2 inhibition and contributed to the observed EZH2-dependent growth suppression in KDM6A-null cell lines. EZH2 inhibition delayed tumor onset in KDM6A-null cells and caused regression of KDM6A-null bladder tumors in both patient-derived and cell line xenograft models. In summary, our study demonstrates that inactivating mutations of KDM6A, which are common in urothelial bladder carcinoma, are potentially targetable by inhibiting EZH2.

  15. Polycomb repressive complex 2 (PRC2) silences genes responsible for neurodegeneration

    PubMed Central

    von Schimmelmann, Melanie; Feinberg, Philip A.; Sullivan, Josefa M.; Ku, Stacy M.; Badimon, Ana; Duff, Mary Kaye; Wang, Zichen; Lachmann, Alexander; Dewell, Scott; Ma'ayan, Avi; Han, Ming-Hu; Tarakhovsky, Alexander; Schaefer, Anne

    2016-01-01

    Normal brain function depends on the interaction between highly specialized neurons that operate within anatomically and functionally distinct brain regions. Neuronal specification is driven by transcriptional programs that are established during early neuronal development and remain in place in the adult brain. The fidelity of neuronal specification depends on the robustness of the transcriptional program that supports the neuron type-specific gene expression patterns. Here we show that PRC2, which supports neuron specification during differentiation, contributes to the suppression of a transcriptional program that is detrimental for adult neuron function and survival. We show that PRC2 deficiency in striatal neurons leads to the de-repression of selected, predominantly bivalent PRC2 target genes that are dominated by self-regulating transcription factors normally suppressed in these neurons. The transcriptional changes in PRC2-deficient neurons lead to progressive and fatal neurodegeneration in mice. Our results point to a key role of PRC2 in protecting neurons against degeneration. PMID:27526204

  16. Cultural targeting and tailoring of shared decision making technology: a theoretical framework for improving the effectiveness of patient decision aids in culturally diverse groups.

    PubMed

    Alden, Dana L; Friend, John; Schapira, Marilyn; Stiggelbout, Anne

    2014-03-01

    Patient decision aids are known to positively impact outcomes critical to shared decision making (SDM), such as gist knowledge and decision preparedness. However, research on the potential improvement of these and other important outcomes through cultural targeting and tailoring of decision aids is very limited. This is the case despite extensive evidence supporting use of cultural targeting and tailoring to improve the effectiveness of health communications. Building on prominent psychological theory, we propose a two-stage framework incorporating cultural concepts into the design process for screening and treatment decision aids. The first phase recommends use of cultural constructs, such as collectivism and individualism, to differentially target patients whose cultures are known to vary on these dimensions. Decision aid targeting is operationalized through use of symbols and values that appeal to members of the given culture. Content dimensions within decision aids that appear particularly appropriate for targeting include surface level visual characteristics, language, beliefs, attitudes and values. The second phase of the framework is based on evidence that individuals vary in terms of how strongly cultural norms influence their approach to problem solving and decision making. In particular, the framework hypothesizes that differences in terms of access to cultural mindsets (e.g., access to interdependent versus independent self) can be measured up front and used to tailor decision aids. Thus, the second phase in the framework emphasizes the importance of not only targeting decision aid content, but also tailoring the information to the individual based on measurement of how strongly he/she is connected to dominant cultural mindsets. Overall, the framework provides a theory-based guide for researchers and practitioners who are interested in using cultural targeting and tailoring to develop and test decision aids that move beyond a "one-size fits all" approach

  17. Targeting Organizations: Centralized or Decentralized

    DTIC Science & Technology

    1993-06-01

    target group to �be responsible for all headquarters target analysis functions, provide headquarters data and information on selected targets...them.�42 Forming a joint target group could result in a significant economy of targeting personnel as well as an established procedure for the...analysis of strategic targets, thus reducing the confusion and lack of unity of purpose. In addition, a consolidated target group could ensure all

  18. Identification of Pou5f1, Sox2, and Nanog downstream target genes with statistical confidence by applying a novel algorithm to time course microarray and genome-wide chromatin immunoprecipitation data

    PubMed Central

    Sharov, Alexei A; Masui, Shinji; Sharova, Lioudmila V; Piao, Yulan; Aiba, Kazuhiro; Matoba, Ryo; Xin, Li; Niwa, Hitoshi; Ko, Minoru SH

    2008-01-01

    Background Target genes of a transcription factor (TF) Pou5f1 (Oct3/4 or Oct4), which is essential for pluripotency maintenance and self-renewal of embryonic stem (ES) cells, have previously been identified based on their response to Pou5f1 manipulation and occurrence of Chromatin-immunoprecipitation (ChIP)-binding sites in promoters. However, many responding genes with binding sites may not be direct targets because response may be mediated by other genes and ChIP-binding site may not be functional in terms of transcription regulation. Results To reduce the number of false positives, we propose to separate responding genes into groups according to direction, magnitude, and time of response, and to apply the false discovery rate (FDR) criterion to each group individually. Using this novel algorithm with stringent statistical criteria (FDR < 0.2) to a compendium of published and new microarray data (3, 6, 12, and 24 hr after Pou5f1 suppression) and published ChIP data, we identified 420 tentative target genes (TTGs) for Pou5f1. The majority of TTGs (372) were down-regulated after Pou5f1 suppression, indicating that the Pou5f1 functions as an activator of gene expression when it binds to promoters. Interestingly, many activated genes are potent suppressors of transcription, which include polycomb genes, zinc finger TFs, chromatin remodeling factors, and suppressors of signaling. Similar analysis showed that Sox2 and Nanog also function mostly as transcription activators in cooperation with Pou5f1. Conclusion We have identified the most reliable sets of direct target genes for key pluripotency genes – Pou5f1, Sox2, and Nanog, and found that they predominantly function as activators of downstream gene expression. Thus, most genes related to cell differentiation are suppressed indirectly. PMID:18522731

  19. A genome-wide identification and characterization of mircoRNAs and their targets in 'Suli' pear (Pyrus pyrifolia white pear group).

    PubMed

    Niu, Qingfeng; Qian, Minjie; Liu, Guoqin; Yang, Fengxia; Teng, Yuanwen

    2013-12-01

    MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that are endogenous regulators of gene expression. miRNAs play a crucial role in cells via degradation of target mRNAs or by inhibition of target protein translation. In the present study, 186 new potentially conserved pear miRNAs belonging to 37 families were identified. The length of mature miRNAs ranged from 19 to 24 nt, and most of the miRNAs (154 out of 186) were 21 nt in length. The length of pre-miRNAs in pear was also found to vary from 62 to 282 nt with an average of 105 ± 43 nt. The potential miRNAs belonged to 29 clusters involving 20 different miRNA families. Using these potential miRNAs, we further scoured of the pear genome and found 326 potential target genes, which included transcription factors, stress responsive genes, and the genes involved in transmembrane transport and signal transduction. Gene ontology analysis of these potential targets suggested that 47 biological processes were potentially regulated by miRNAs, including oxidation-reduction, stress response, transport, etc. KEGG pathway analysis showed that the identified miRNAs were found in 15 metabolism networks which were related to starch and sucrose metabolism, and ascorbate and aldarate metabolism, among others. Our study will help in the further understanding of the essential role of miRNAs in growth and development and stress response of pear.

  20. A recommended practical approach to the management of target therapy and angiogenesis inhibitors cardiotoxicity: an opinion paper of the working group on drug cardiotoxicity and cardioprotection, Italian Society of Cardiology

    PubMed Central

    Maurea, Nicola; Spallarossa, Paolo; Cadeddu, Christian; Madonna, Rosalinda; Mele, Donato; Monte, Ines; Novo, Giuseppina; Pagliaro, Pasquale; Pepe, Alessia; Tocchetti, Carlo G.; Zito, Concetta; Mercuro, Giuseppe

    2016-01-01

    The US National Cancer Institute estimates that cardiotoxicity (CTX) from target therapy refers mostly to four groups of drugs: epidermal growth factor receptor 2 inhibitors, angiogenic inhibitors, directed Abelson murine leukemia viral oncogene homolog inhibitors, and proteasome inhibitors. The main cardiotoxic side-effects related to antiepidermal growth factor receptor 2 therapy are left ventricular systolic dysfunction and heart failure. Angiogenesis inhibitors are associated with hypertension, left ventricular dysfunction/heart failure, myocardial ischemia, QT prolongation, and thrombosis. Moreover, other agents may be related to CTX induced by treatment. In this study, we review the guidelines for a practical approach for the management of CTX in patients under anticancer target therapy. PMID:27183530

  1. Tyrosine kinome sequencing of pediatric acute lymphoblastic leukemia: a report from the Children's Oncology Group TARGET Project | Office of Cancer Genomics

    Cancer.gov

    TARGET researchers sequenced the tyrosine kinome and downstream signaling genes in 45 high-risk pediatric ALL cases with activated kinase signaling, including Ph-like ALL, to establish the incidence of tyrosine kinase mutations in this cohort. The study confirmed previously identified somatic mutations in JAK and FLT3, but did not find novel alterations in any additional tyrosine kinases or downstream genes. The mechanism of kinase signaling activation in this high-risk subgroup of pediatric ALL remains largely unknown.

  2. A novel quantitation approach for maximizing detectable targets for offensive/volatile odorants with diverse functional groups by thermal desorption-gas chromatography-mass spectrometry

    PubMed Central

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2016-01-01

    A multitude of analytical systems are needed to analyze diverse odorants with various functionalities. In this study, an experimental method was developed to assess the maximum covering range of odorants using a single experimental setup consisting of a thermal desorber-gas chromatography-mass spectrometry system. To this end, a total of 20 offensive odorants (aldehyde, ketone, ester, alcohol, aromatic, sulfide, amine, and carboxyl) were selected and tested by a single system. The analytical results of standards and environmental samples were evaluated in a number of respects. In the analysis of the standards, all targets were quantified via Carbopack (C + B + X) tube sampling while operating the thermal desorber at −25 °C. The method detection limits of 18 targets (exception of 2 out of the 20 targets: acetaldehyde and methanethiol) were excellent (mean 0.04 ± 0.03 ppb) in terms of their odor threshold values (74.7 ± 140 ~ 624 ± 1,729 ppb). The analysis of organic fertilizer plant samples at a pig farm (slurry treatment facility, compost facility, and ambient air) confirmed the presence of 18 odorants from 0.03 ppb (dimethyldisulfide, ambient sample) to 522 ppb (methyl ethyl ketone, slurry treatment facility). As such, our method allowed simultaneous quantitation of most key odorants with sufficient reliability and sensitivity. PMID:27404037

  3. A novel quantitation approach for maximizing detectable targets for offensive/volatile odorants with diverse functional groups by thermal desorption-gas chromatography-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2016-07-01

    A multitude of analytical systems are needed to analyze diverse odorants with various functionalities. In this study, an experimental method was developed to assess the maximum covering range of odorants using a single experimental setup consisting of a thermal desorber-gas chromatography-mass spectrometry system. To this end, a total of 20 offensive odorants (aldehyde, ketone, ester, alcohol, aromatic, sulfide, amine, and carboxyl) were selected and tested by a single system. The analytical results of standards and environmental samples were evaluated in a number of respects. In the analysis of the standards, all targets were quantified via Carbopack (C + B + X) tube sampling while operating the thermal desorber at ‑25 °C. The method detection limits of 18 targets (exception of 2 out of the 20 targets: acetaldehyde and methanethiol) were excellent (mean 0.04 ± 0.03 ppb) in terms of their odor threshold values (74.7 ± 140 ~ 624 ± 1,729 ppb). The analysis of organic fertilizer plant samples at a pig farm (slurry treatment facility, compost facility, and ambient air) confirmed the presence of 18 odorants from 0.03 ppb (dimethyldisulfide, ambient sample) to 522 ppb (methyl ethyl ketone, slurry treatment facility). As such, our method allowed simultaneous quantitation of most key odorants with sufficient reliability and sensitivity.

  4. Training in Basic Internet Skills for Special Target Groups in Non-Formal Educational Settings--Conclusions from Three Pilot Projects

    ERIC Educational Resources Information Center

    Berger, Andrea; Croll, Jutta

    2012-01-01

    With the progress of Digital Inclusion, it becomes important to address marginalised groups that face specific barriers in being part of the information society. From 2009 to 2011 within the framework of the nation-wide Initiative "Internet erfahren", funded by the German Federal Ministry of Economics, Stiftung Digitale Chancen has…

  5. Can a Targeted, Group-Based CBT Intervention Reduce Depression and Anxiety and Improve Self-Concept in Primary-Age Children?

    ERIC Educational Resources Information Center

    O'Callaghan, Paul; Cunningham, Enda

    2015-01-01

    This pilot study examined the impact of a 10 session, group-based, early-intervention cognitive behavioural therapy (CBT) programme (Cool Connections) on anxiety, depression and self-concept in nine 8-11 year old pupils in Northern Ireland. The intervention was facilitated by a teacher, education welfare officer and two classroom assistants, with…

  6. Targeting binge eating through components of dialectical behavior therapy: preliminary outcomes for individually supported diary card self-monitoring versus group-based DBT.

    PubMed

    Klein, Angela S; Skinner, Jeremy B; Hawley, Kristin M

    2013-12-01

    The current study examined two condensed adaptations of dialectical behavior therapy (DBT) for binge eating. Women with full- or sub-threshold variants of either binge eating disorder or bulimia nervosa were randomly assigned to individually supported self-monitoring using adapted DBT diary cards (DC) or group-based DBT, each 15 sessions over 16 weeks. DC sessions focused on problem-solving diary card completion issues, praising diary card completion, and supporting nonjudgmental awareness of eating-related habits and urges, but not formally teaching DBT skills. Group-based DBT included eating mindfulness, progressing through graded exposure; mindfulness, emotion regulation, and distress tolerance skills; and coaching calls between sessions. Both treatments evidenced large and significant improvements in binge eating, bulimic symptoms, and interoceptive awareness. For group-based DBT, ineffectiveness, drive for thinness, body dissatisfaction, and perfectionism also decreased significantly, with medium to large effect sizes. For DC, results were not significant but large in effect size for body dissatisfaction and medium in effect size for ineffectiveness and drive for thinness. Retention for both treatments was higher than recent trends for eating disorder treatment in fee-for-service practice and for similar clinic settings, but favored DC, with the greater attrition of group-based DBT primarily attributed to its more intensive and time-consuming nature, and dropout overall associated with less pretreatment impairment and greater interoceptive awareness. This preliminary investigation suggests that with both abbreviated DBT-based treatments, substantial improvement in core binge eating symptoms is possible, enhancing potential avenues for implementation beyond more time-intensive DBT.

  7. Targeted vaccination of teenagers following continued rapid endemic expansion of a single meningococcal group W clone (sequence type 11 clonal complex), United Kingdom 2015.

    PubMed

    Campbell, H; Saliba, V; Borrow, R; Ramsay, M; Ladhani, S N

    2015-07-16

    Since the epidemiological year 2009/10, the United Kingdom has experienced a year-on-year increase in meningococcal group W (MenW) disease due to rapid expansion of a single endemic hyper-virulent strain belonging to sequence type 11 clonal complex (cc). This strain was identified among cases diagnosed across all regions and was not linked to travel abroad. Consequently, an adolescent MenACWY conjugate vaccination programme for 13-18 year-olds will be introduced in August 2015, with priority given to 17-18 year-olds (school leavers).

  8. Grepafloxacin, a dimethyl derivative of ciprofloxacin, acts preferentially through gyrase in Streptococcus pneumoniae: role of the C-5 group in target specificity.

    PubMed

    Morris, Julia E; Pan, Xiao-Su; Fisher, L Mark

    2002-02-01

    Grepafloxacin, a 5-methyl-7-piperazinyl-3"-methyl analogue of ciprofloxacin, was used to obtain stepwise-selected mutants of Streptococcus pneumoniae 7785. Analysis of the quinolone resistance-determining regions of the gyrA, gyrB, parC, and parE genes in these mutants revealed that gyrA mutations preceded those in parC. Given that ciprofloxacin (5-H,7-piperazinyl) and AM-1121 (5-H,7-piperazinyl-3"-methyl) both act through topoisomerase IV, we conclude that the 5-methyl group of grepafloxacin favors gyrase in S. pneumoniae.

  9. Enhancing the effectiveness of HIV/AIDS prevention programs targeted to unique population groups in Thailand: lessons learned from applying concepts of diffusion of innovation and social marketing.

    PubMed

    Svenkerud, P J; Singhal, A

    1998-01-01

    Diffusion of innovations theory and social marketing theory have been criticized for their limited applicability in influencing unique population groups (e.g., female commercial sex workers (CSWs) working in low-class brothels). This study investigated the applicability of these two theoretical frameworks in outreach efforts directed to unique populations at high risk for HIV/AIDS in Bangkok, Thailand. Further, this study examined Thai cultural characteristics that influence communication about HIV/AIDS prevention. The results suggest that certain concepts and strategies drawn from the two frameworks were used more or less by effective outreach programs, providing several policy-relevant lessons. Cultural constraints, such as the lack of visibility of the disease and traditional sexual practices, influenced communication about HIV/AIDS prevention.

  10. A screen for new trithorax group genes identified little imaginal discs, the Drosophila melanogaster homologue of human retinoblastoma binding protein 2.

    PubMed Central

    Gildea, J J; Lopez, R; Shearn, A

    2000-01-01

    The proteins encoded by two groups of conserved genes, the Polycomb and trithorax groups, have been proposed to maintain, at the level of chromatin structure, the expression pattern of homeotic genes during Drosophila development. To identify new members of the trithorax group, we screened a collection of deficiencies for intergenic noncomplementation with a mutation in ash1, a trithorax group gene. Five of the noncomplementing deletions uncover genes previously classified as members of the Polycomb group. This evidence suggests that there are actually three groups of genes that maintain the expression pattern of homeotic genes during Drosophila development. The products of the third group appear to be required to maintain chromatin in both transcriptionally inactive and active states. Six of the noncomplementing deficiencies uncover previously unidentified trithorax group genes. One of these deficiencies removes 25D2-3 to 26B2-5. Within this region, there are two, allelic, lethal P-insertion mutations that identify one of these new trithorax group genes. The gene has been called little imaginal discs based on the phenotype of mutant larvae. The protein encoded by the little imaginal discs gene is the Drosophila homologue of human retinoblastoma binding protein 2. PMID:11014813

  11. Expression of the receptor for advanced glycation end products, a target for high mobility group box 1 protein, and its role in chronic recalcitrant rhinosinusitis with nasal polyps.

    PubMed

    Dzaman, Karolina; Szczepanski, Miroslaw J; Molinska-Glura, Marta; Krzeski, Antoni; Zagor, Mariola

    2015-06-01

    A receptor for advanced glycation end products (RAGE) and its ligand high mobility group box 1 (HMGB1) protein has been linked to several chronic diseases, and acts as a trigger for inflammation signaling. Here, we study RAGE and HMGB1 expression in chronic, recalcitrant rhinosinusitis with nasal polyps (CRSwNP) to determine its potential clinical significance, i.e., disease recurrence and severity. RAGE and HMGB1 expression in CRSwNP was evaluated by immunohistochemistry in epithelial cells of fresh sinonasal mucosa samples obtained from the patients diagnosed with recalcitrant CRSwNP (n = 25) and normal control mucosa (NC) (n = 26). RAGE and HMGB1 expression levels in tissues were correlated with disease severity assessed by nasal endoscopy, CT scan, number of previous sinus surgeries, allergy status and nasosinusal microbiology. RAGE and HMGB1 were moderately or strongly expressed in CRSwNP tissue. No or weak RAGE expression was found in NC. HMGB1 was equally strongly expressed in NC. We observed a strong correlation between RAGE and disease severity, recurrence, undergone operations, asthma and aspirin exacerbated respiratory disease (AERD). Elevated RAGE expression is associated with increased disease severity, as well as allergy and AERD in patients with recalcitrant CRSwNP. It is possible that the explanation for recurrent CRSwNP pathogenesis might be related to RAGE overexpression with subsequent sinus mucosa hyperproliferation, necessitating several operations.

  12. The small regulatory RNA FasX enhances group A Streptococcus virulence and inhibits pilus expression via serotype-specific targets.

    PubMed

    Danger, Jessica L; Cao, Tram N; Cao, Tran H; Sarkar, Poulomee; Treviño, Jeanette; Pflughoeft, Kathryn J; Sumby, Paul

    2015-04-01

    Bacterial pathogens commonly show intra-species variation in virulence factor expression and often this correlates with pathogenic potential. The group A Streptococcus (GAS) produces a small regulatory RNA (sRNA), FasX, which regulates the expression of pili and the thrombolytic agent streptokinase. As GAS serotypes are polymorphic regarding (a) FasX abundance, (b) the fibronectin, collagen, T-antigen (FCT) region of the genome, which contains the pilus genes (nine different FCT-types), and (c) the streptokinase-encoding gene (ska) sequence (two different alleles), we sought to test whether FasX regulates pilus and streptokinase expression in a serotype-specific manner. Parental, fasX mutant and complemented derivatives of serotype M1 (ska-2, FCT-2), M2 (ska-1, FCT-6), M6 (ska-2, FCT-1) and M28 (ska-1, FCT-4) isolates were compared. While FasX reduced pilus expression in each serotype, the molecular basis differed, as FasX bound, and inhibited the translation of, different FCT-region mRNAs. FasX enhanced streptokinase expression in each serotype, although the degree of regulation varied. Finally, we established that the regulation afforded by FasX enhances GAS virulence, assessed by a model of bacteremia using human plasminogen-expressing mice. Our data are the first to identify and characterize serotype-specific regulation by an sRNA in GAS, and to show an sRNA directly contributes to GAS virulence.

  13. High School Students Are a Target Group for Fight against Self-Medication with Antimalarial Drugs: A Pilot Study in University of Kinshasa, Democratic Republic of Congo

    PubMed Central

    Kabongo Kamitalu, Ramsès; Aloni, Michel Ntetani

    2016-01-01

    Aim. To assess the self-medication against malaria infection in population of Congolese students in Kinshasa, Democratic Republic of Congo (DRC). Methods. A cross-sectional study was carried out in University of Kinshasa, Kinshasa, Democratic Republic of Congo. Medical records of all students with malaria admitted to Centre de Santé Universitaire of University of Kinshasa from January 1, 2008, to April 30, 2008, were reviewed retrospectively. Results. The median age of the patients was 25.4 years (range: from 18 to 36 years). The majority of them were male (67.9%). Artemisinin-based combination treatments (ACTs) was the most used self-prescribed antimalarial drugs. However, self-medication was associated with the ingestion of quinine in 19.9% of cases. No case of ingestion of artesunate/artemether in monotherapy was found. All the medicines taken were registered in DRC. In this series, self-prescribed antimalarial was very irrational in terms of dose and duration of treatment. Conclusion. This paper highlights self-medication by a group who should be aware of malaria treatment protocols. The level of self-prescribing quinine is relatively high among students and is disturbing for a molecule reserved for severe disease in Congolese health care policy in management of malaria. PMID:27340411

  14. High School Students Are a Target Group for Fight against Self-Medication with Antimalarial Drugs: A Pilot Study in University of Kinshasa, Democratic Republic of Congo.

    PubMed

    Kabongo Kamitalu, Ramsès; Aloni, Michel Ntetani

    2016-01-01

    Aim. To assess the self-medication against malaria infection in population of Congolese students in Kinshasa, Democratic Republic of Congo (DRC). Methods. A cross-sectional study was carried out in University of Kinshasa, Kinshasa, Democratic Republic of Congo. Medical records of all students with malaria admitted to Centre de Santé Universitaire of University of Kinshasa from January 1, 2008, to April 30, 2008, were reviewed retrospectively. Results. The median age of the patients was 25.4 years (range: from 18 to 36 years). The majority of them were male (67.9%). Artemisinin-based combination treatments (ACTs) was the most used self-prescribed antimalarial drugs. However, self-medication was associated with the ingestion of quinine in 19.9% of cases. No case of ingestion of artesunate/artemether in monotherapy was found. All the medicines taken were registered in DRC. In this series, self-prescribed antimalarial was very irrational in terms of dose and duration of treatment. Conclusion. This paper highlights self-medication by a group who should be aware of malaria treatment protocols. The level of self-prescribing quinine is relatively high among students and is disturbing for a molecule reserved for severe disease in Congolese health care policy in management of malaria.

  15. MicroRNA-495 Inhibits Gastric Cancer Cell Migration and Invasion Possibly via Targeting High Mobility Group AT-Hook 2 (HMGA2)

    PubMed Central

    Wang, Huashe; Jiang, Zhipeng; Chen, Honglei; Wu, Xiaobin; Xiang, Jun; Peng, Junsheng

    2017-01-01

    Background Gastric cancer is one of the most common malignancies, and has a high mortality rate. miR-495 acts as a suppressor in some cancers and HMGA2 (high mobility group AT-hook 2) is a facilitator for cell growth and epithelial-mesenchymal transition (EMT), but little is known about their effect in gastric cancer. This study aimed to investigate the role and mechanism of miR-495 in gastric cancer. Material/Methods miR-495 levels were quantitatively analyzed in gastric cancer tissue and GES-1, SGC-7901, BGC-823, and HGC-27 cell lines by qRT-PCR. Levels of miR-495 and HMGA2 were altered by cell transfection, after which cell migration and invasion were examined by Transwell and E-cadherin (CDH1); vimentin (VIM), and alpha smooth muscle actin (ACTA2) were detected by qRT-PCR and Western blotting. The interaction between miR-495 and HMGA2 was verified by dual-luciferase reporter assay. Results miR-495 was significantly downregulated in cancer tissue and cell lines (p<0.05). Its overexpression inhibited cell migration and invasion, elevated CDH1, and inhibited VIM and ACTA2 levels in BGC-823 and HGC-27 cells. miR-495 directly inhibited HMGA2, which was upregulated in gastric cancer tissue, and promoted cell migration and invasion, inhibited CDH1, and elevated VIM and ACTA2. Conclusions miR-495 acts as a tumor suppressor in gastric cancer by inhibiting cell migration and invasion, which may be associated with its direct inhibition on HMGA2. These results suggest a promising therapeutic strategy for gastric cancer treatment. PMID:28159956

  16. Enhancer of polycomb coordinates multiple signaling pathways to promote both cyst and germline stem cell differentiation in the Drosophila adult testis.

    PubMed

    Feng, Lijuan; Shi, Zhen; Chen, Xin

    2017-02-01

    Stem cells reside in a particular microenvironment known as a niche. The interaction between extrinsic cues originating from the niche and intrinsic factors in stem cells determines their identity and activity. Maintenance of stem cell identity and stem cell self-renewal are known to be controlled by chromatin factors. Herein, we use the Drosophila adult testis which has two adult stem cell lineages, the germline stem cell (GSC) lineage and the cyst stem cell (CySC) lineage, to study how chromatin factors regulate stem cell differentiation. We find that the chromatin factor Enhancer of Polycomb [E(Pc)] acts in the CySC lineage to negatively control transcription of genes associated with multiple signaling pathways, including JAK-STAT and EGF, to promote cellular differentiation in the CySC lineage. E(Pc) also has a non-cell-autonomous role in regulating GSC lineage differentiation. When E(Pc) is specifically inactivated in the CySC lineage, defects occur in both germ cell differentiation and maintenance of germline identity. Furthermore, compromising Tip60 histone acetyltransferase activity in the CySC lineage recapitulates loss-of-function phenotypes of E(Pc), suggesting that Tip60 and E(Pc) act together, consistent with published biochemical data. In summary, our results demonstrate that E(Pc) plays a central role in coordinating differentiation between the two adult stem cell lineages in Drosophila testes.

  17. New Cross-Talk Layer between Ultraconserved Non-Coding RNAs, MicroRNAs and Polycomb Protein YY1 in Bladder Cancer

    PubMed Central

    Terreri, Sara; Durso, Montano; Colonna, Vincenza; Romanelli, Alessandra; Terracciano, Daniela; Ferro, Matteo; Perdonà, Sisto; Castaldo, Luigi; Febbraio, Ferdinando; de Nigris, Filomena; Cimmino, Amelia

    2016-01-01

    MicroRNAs (miRNAs) are highly conserved elements in mammals, and exert key regulatory functions. Growing evidence shows that miRNAs can interact with another class of non-coding RNAs, so-called transcribed ultraconserved regions (T-UCRs), which take part in transcriptional, post-transcriptional and epigenetic regulation processes. We report here the interaction of miRNAs and T-UCRs as a network modulating the availability of these non-coding RNAs in bladder cancer cells. In our cell system, antagomiR-596 increased the expression of T-UCR 201+. Moreover, T-UCR 8+ silencing increased miR-596 expression, which in turn reduced total T-UCR 283+, showing that the perturbation of one element in this network changes the expression of other interactors. In addition, we identify the polycomb protein Yin Yang 1 (YY1) as mediator of binding between miR-596 and T-UCR 8+. These new findings describe for the first time a network between T-UCRs, miRNAs and YY1 protein, highlighting the existence of an additional layer of gene expression regulation. PMID:27983635

  18. miR-155 activates cytokine gene expression in Th17 cells by regulating the DNA-binding protein Jarid2 to relieve polycomb-mediated repression.

    PubMed

    Escobar, Thelma M; Kanellopoulou, Chrysi; Kugler, David G; Kilaru, Gokhul; Nguyen, Cuong K; Nagarajan, Vijayaraj; Bhairavabhotla, Ravikiran K; Northrup, Daniel; Zahr, Rami; Burr, Patrick; Liu, Xiuhuai; Zhao, Keji; Sher, Alan; Jankovic, Dragana; Zhu, Jinfang; Muljo, Stefan A

    2014-06-19

    Specification of the T helper 17 (Th17) cell lineage requires a well-defined set of transcription factors, but how these integrate with posttranscriptional and epigenetic programs to regulate gene expression is poorly understood. Here we found defective Th17 cell cytokine expression in miR-155-deficient CD4+ T cells in vitro and in vivo. Mir155 was bound by Th17 cell transcription factors and was highly expressed during Th17 cell differentiation. miR-155-deficient Th17 and T regulatory (Treg) cells expressed increased amounts of Jarid2, a DNA-binding protein that recruits the Polycomb Repressive Complex 2 (PRC2) to chromatin. PRC2 binding to chromatin and H3K27 histone methylation was increased in miR-155-deficient cells, coinciding with failure to express Il22, Il10, Il9, and Atf3. Defects in Th17 cell cytokine expression and Treg cell homeostasis in the absence of Mir155 could be partially suppressed by Jarid2 deletion. Thus, miR-155 contributes to Th17 cell function by suppressing the inhibitory effects of Jarid2.

  19. miR-155 activates cytokine gene expression in Th17 cells by regulating the DNA-binding protein Jarid2 to relieve Polycomb-mediated repression

    PubMed Central

    Escobar, Thelma M.; Kanellopoulou, Chrysi; Kugler, David G.; Kilaru, Gokhul; Nguyen, Cuong K.; Nagarajan, Vijayaraj; Bhairavabhotla, Ravikiran K.; Northrup, Daniel; Zahr, Rami; Burr, Patrick; Liu, Xiuhuai; Zhao, Keji; Sher, Alan; Jankovic, Dragana; Zhu, Jinfang; Muljo, Stefan A.

    2014-01-01

    Specification of the T helper 17 (Th17) cell lineage requires a well defined set of transcription factors, but how these integrate with post-transcriptional and epigenetic programs to regulate gene expression is poorly understood. Here we found defective Th17 cell cytokine expression in miR-155-deficient CD4+ T cells in vitro and in vivo. Mir155 was bound by Th17 cell transcription factors and was highly expressed during Th17 cell differentiation. miR-155-deficient-Th17 and -T regulatory (Treg) cells expressed increased amounts of Jarid2, a DNA-binding protein that recruits the Polycomb Repressive Complex 2 (PRC2) to chromatin. PRC2 binding to chromatin and H3K27 histone methylation was increased in miR-155-deficient cells, coinciding with failure to express Il22, Il10, Il9 and Atf3. Defects in Th17 cell cytokine expression and Treg cell homeostasis in the absence of Mir155 could be partially suppressed by Jarid2 deletion. Thus, miR-155 contributes to Th17 cell function by suppressing the inhibitory effects of Jarid2. PMID:24856900

  20. Specific combinations of boundary element and Polycomb response element are required for the regulation of the Hox genes in Drosophila melanogaster.

    PubMed

    Singh, Narendra Pratap; Mishra, Rakesh Kumar

    2015-11-01

    In the bithorax complex of Drosophila melanogaster, the chromatin boundary elements (BE) demarcate cis-regulatory domains that regulate Hox genes along the anteroposterior body axis. These elements are closely associated with the Polycomb Response Elements (PREs) and restrict the ectopic activation of cis-regulatory domains during development. The relevance of such specific genomic arrangements of regulatory elements remains unclear. Deletions of individual BE-PRE combination result in distinct homeotic phenotypes. In this study, we show that deletion of two such BE-PRE combinations in cis leads to new genetic interactions, which manifests as dorsal closure defect phenotype in adult abdominal epithelia. We further demonstrate that dorsal closure phenotype results from enhanced and ectopic expression of Hox gene Abd-B in the larval epithelial cells. This suggests a specific role of multiple BE-PRE combinations in the larval epithelial cells for regulation of Abd-B. Using chromosome conformation capture experiments, we show that genetic interactions correlate with direct physical interactions among the BE-PRE combinations. Our results demonstrate the functional relevance of the closely associated BE and PRE combinations in regulation of Hox genes.

  1. TNF/p38α/polycomb signaling to Pax7 locus in satellite cells links inflammation to the epigenetic control of muscle regeneration.

    PubMed

    Palacios, Daniela; Mozzetta, Chiara; Consalvi, Silvia; Caretti, Giuseppina; Saccone, Valentina; Proserpio, Valentina; Marquez, Victor E; Valente, Sergio; Mai, Antonello; Forcales, Sonia V; Sartorelli, Vittorio; Puri, Pier Lorenzo

    2010-10-08

    How regeneration cues are converted into the epigenetic information that controls gene expression in adult stem cells is currently unknown. We identified an inflammation-activated signaling in muscle stem (satellite) cells, by which the polycomb repressive complex 2 (PRC2) represses Pax7 expression during muscle regeneration. TNF-activated p38α kinase promotes the interaction between YY1 and PRC2, via threonine 372 phosphorylation of EZH2, the enzymatic subunit of the complex, leading to the formation of repressive chromatin on Pax7 promoter. TNF-α antibodies stimulate satellite cell proliferation in regenerating muscles of dystrophic or normal mice. Genetic knockdown or pharmacological inhibition of the enzymatic components of the p38/PRC2 signaling--p38α and EZH2--invariably promote Pax7 expression and expansion of satellite cells that retain their differentiation potential upon signaling resumption. Genetic knockdown of Pax7 impaired satellite cell proliferation in response to p38 inhibition, thereby establishing the biological link between p38/PRC2 signaling to Pax7 and satellite cell decision to proliferate or differentiate.

  2. The Human Immunodeficiency Virus 1 ASP RNA promotes viral latency by recruiting the Polycomb Repressor Complex 2 and promoting nucleosome assembly.

    PubMed

    Zapata, Juan C; Campilongo, Federica; Barclay, Robert A; DeMarino, Catherine; Iglesias-Ussel, Maria D; Kashanchi, Fatah; Romerio, Fabio

    2017-03-21

    Various epigenetic marks at the HIV-1 5'LTR suppress proviral expression and promote latency. Cellular antisense transcripts known as long noncoding RNAs (lncRNAs) recruit the polycomb repressor complex 2 (PRC2) to gene promoters, which catalyzes trimethylation of lysine 27 on histone H3 (H3K27me3), thus promoting nucleosome assembly and suppressing gene expression. We found that an HIV-1 antisense transcript expressed from the 3'LTR and encoding the antisense protein ASP promotes proviral latency. Expression of ASP RNA reduced HIV-1 replication in Jurkat cells. Moreover, ASP RNA expression promoted the establishment and maintenance of HIV-1 latency in Jurkat E4 cells. We show that this transcript interacts with and recruits PRC2 to the HIV-1 5'LTR, increasing accumulation of the suppressive epigenetic mark H3K27me3, while reducing RNA Polymerase II and thus proviral transcription. Altogether, our results suggest that the HIV-1 ASP transcript promotes epigenetic silencing of the HIV-1 5'LTR and proviral latency through the PRC2 pathway.

  3. Basic Pentacysteine Proteins Repress Abscisic Acid Insensitive4 Expression via Direct Recruitment of the Polycomb-Repressive Complex 2 in Arabidopsis Root Development.

    PubMed

    Mu, Ying; Zou, Meijuan; Sun, Xuwu; He, Baoye; Xu, Xiumei; Liu, Yini; Zhang, Lixin; Chi, Wei

    2017-01-30

    Plant transcription factors generally act in complex regulatory networks that function at multiple levels to govern plant developmental programs. Dissection of the interconnections among different classes of transcription factors can elucidate these regulatory networks and thus improve our understanding of plant development. Here, we investigated the molecular and functional relationships of the transcription factors ABSCISIC ACID INSENSITIVE 4 (ABI4) and members of the BASIC PENTACYSTEINE (BPC) family in lateral root (LR) development of Arabidopsis thaliana Genetic analysis showed that BPCs promote LR development by repressing ABI4 expression. Molecular analysis showed that BPCs bind to the ABI4 promoter and repress ABI4 transcription in roots. BPCs directly recruit the Polycomb Repressive Complex 2 (PRC2) to the ABI4 locus and epigenetically repress ABI4 expression by catalyzing the trimethylation of histone H3 at lysine 27. In addition, BPCs and ABI4 coordinate their activities to fine-tune the levels of PIN-FORMED1, a component of the auxin signaling pathway, and thus modulate LR formation. These results establish a functional relationship between two universal and multiple-role transcription factors and provide insight into the mechanisms of the transcriptional regulatory networks that affect Arabidopsis organogenesis.

  4. Enhancer of polycomb coordinates multiple signaling pathways to promote both cyst and germline stem cell differentiation in the Drosophila adult testis

    PubMed Central

    Feng, Lijuan; Shi, Zhen; Chen, Xin

    2017-01-01

    Stem cells reside in a particular microenvironment known as a niche. The interaction between extrinsic cues originating from the niche and intrinsic factors in stem cells determines their identity and activity. Maintenance of stem cell identity and stem cell self-renewal are known to be controlled by chromatin factors. Herein, we use the Drosophila adult testis which has two adult stem cell lineages, the germline stem cell (GSC) lineage and the cyst stem cell (CySC) lineage, to study how chromatin factors regulate stem cell differentiation. We find that the chromatin factor Enhancer of Polycomb [E(Pc)] acts in the CySC lineage to negatively control transcription of genes associated with multiple signaling pathways, including JAK-STAT and EGF, to promote cellular differentiation in the CySC lineage. E(Pc) also has a non-cell-autonomous role in regulating GSC lineage differentiation. When E(Pc) is specifically inactivated in the CySC lineage, defects occur in both germ cell differentiation and maintenance of germline identity. Furthermore, compromising Tip60 histone acetyltransferase activity in the CySC lineage recapitulates loss-of-function phenotypes of E(Pc), suggesting that Tip60 and E(Pc) act together, consistent with published biochemical data. In summary, our results demonstrate that E(Pc) plays a central role in coordinating differentiation between the two adult stem cell lineages in Drosophila testes. PMID:28196077

  5. The Evolution of Air Force Targeting

    DTIC Science & Technology

    2012-12-01

    campaign against Japan. This group eventually evolved into the first Joint Target Group . The deputy assistant chief of the Air Staff for targeting...Far East Command (GHQ FEC) as- sumed responsibility for targeting. The chief of staff established the GHQ Target Group on 14 July 1950 and made it...responsible for target nominations. However, the GHQ Target Group was not capable of performing this task. The work of this group was nei- ther

  6. HYDROGEN ISOTOPE TARGETS

    DOEpatents

    Ashley, R.W.

    1958-08-12

    The design of targets for use in the investigation of nuclear reactions of hydrogen isotopes by bombardment with accelerated particles is described. The target con struction eomprises a backing disc of a metal selected from the group consisting of molybdenunn and tungsten, a eoating of condensed titaniunn on the dise, and a hydrogen isotope selected from the group consisting of deuterium and tritium absorbed in the coatiag. The proeess for preparing these hydrogen isotope targets is described.

  7. Mammalian-target of rapamycin inhibition with temsirolimus in myelodysplastic syndromes (MDS) patients is associated with considerable toxicity: results of the temsirolimus pilot trial by the German MDS Study Group (D-MDS).

    PubMed

    Wermke, Martin; Schuster, Claudia; Nolte, Florian; Al-Ali, Haifa-Kathrin; Kiewe, Philipp; Schönefeldt, Claudia; Jakob, Christiane; von Bonin, Malte; Hentschel, Leopold; Klut, Ina-Maria; Ehninger, Gerhard; Bornhäuser, Martin; Baretton, Gustavo; Germing, Ulrich; Herbst, Regina; Haase, Detelef; Hofmann, Wolf K; Platzbecker, Uwe

    2016-12-01

    The mammalian-target of rapamycin (also termed mechanistic target of rapamycin, mTOR) pathway integrates various pro-proliferative and anti-apoptotic stimuli and is involved in regulatory T-cell (TREG) development. As these processes contribute to the pathogenesis of myelodysplastic syndromes (MDS), we hypothesized that mTOR modulation with temsirolimus (TEM) might show activity in MDS. This prospective multicentre trial enrolled lower and higher risk MDS patients, provided that they were transfusion-dependent/neutropenic or relapsed/refractory to 5-azacitidine, respectively. All patients received TEM at a weekly dose of 25 mg. Of the 9 lower- and 11 higher-risk patients included, only 4 (20%) reached the response assessment after 4 months of treatment and showed stable disease without haematological improvement. The remaining patients discontinued TEM prematurely due to adverse events. Median overall survival (OS) was not reached in the lower-risk group and 296 days in the higher-risk group. We observed a significant decline of bone marrow (BM) vascularisation (P = 0·006) but were unable to demonstrate a significant impact of TEM on the balance between TREG and pro-inflammatory T-helper-cell subsets within the peripheral blood or BM. We conclude that mTOR-modulation with TEM at a dose of 25 mg per week is accompanied by considerable toxicity and has no beneficial effects in elderly MDS patients.

  8. Polarized Solid State Target

    NASA Astrophysics Data System (ADS)

    Dutz, Hartmut; Goertz, Stefan; Meyer, Werner

    2017-01-01

    The polarized solid state target is an indispensable experimental tool to study single and double polarization observables at low intensity particle beams like tagged photons. It was one of the major components of the Crystal-Barrel experiment at ELSA. Besides the operation of the 'CB frozen spin target' within the experimental program of the Crystal-Barrel collaboration both collaborative groups of the D1 project, the polarized target group of the Ruhr Universität Bochum and the Bonn polarized target group, have made significant developments in the field of polarized targets within the CRC16. The Bonn polarized target group has focused its work on the development of technically challenging polarized solid target systems towards the so called '4π continuous mode polarized target' to operate them in combination with 4π-particle detection systems. In parallel, the Bochum group has developed various highly polarized deuterated target materials and high precision NMR-systems, in the meantime used for polarization experiments at CERN, JLAB and MAMI, too.

  9. New STEM Schools Target Underrepresented Groups

    ERIC Educational Resources Information Center

    Robelen, Erik W.

    2011-01-01

    Few Americans may know about the Grand Challenges for Engineering--from making solar energy affordable to ensuring access to clean water--but the students at a new school on the campus of North Carolina State University are getting to know them firsthand. The set of 21st-century challenges, devised by the National Academy of Engineering, serves as…

  10. Drosophila TDP-43 RNA-Binding Protein Facilitates Association of Sister Chromatid Cohesion Proteins with Genes, Enhancers and Polycomb Response Elements

    PubMed Central

    Misulovin, Ziva; Gause, Maria; Rickels, Ryan A; Shilatifard, Ali

    2016-01-01

    The cohesin protein complex mediates sister chromatid cohesion and participates in transcriptional control of genes that regulate growth and development. Substantial reduction of cohesin activity alters transcription of many genes without disrupting chromosome segregation. Drosophila Nipped-B protein loads cohesin onto chromosomes, and together Nipped-B and cohesin occupy essentially all active transcriptional enhancers and a large fraction of active genes. It is unknown why some active genes bind high levels of cohesin and some do not. Here we show that the TBPH and Lark RNA-binding proteins influence association of Nipped-B and cohesin with genes and gene regulatory sequences. In vitro, TBPH and Lark proteins specifically bind RNAs produced by genes occupied by Nipped-B and cohesin. By genomic chromatin immunoprecipitation these RNA-binding proteins also bind to chromosomes at cohesin-binding genes, enhancers, and Polycomb response elements (PREs). RNAi depletion reveals that TBPH facilitates association of Nipped-B and cohesin with genes and regulatory sequences. Lark reduces binding of Nipped-B and cohesin at many promoters and aids their association with several large enhancers. Conversely, Nipped-B facilitates TBPH and Lark association with genes and regulatory sequences, and interacts with TBPH and Lark in affinity chromatography and immunoprecipitation experiments. Blocking transcription does not ablate binding of Nipped-B and the RNA-binding proteins to chromosomes, indicating transcription is not required to maintain binding once established. These findings demonstrate that RNA-binding proteins help govern association of sister chromatid cohesion proteins with genes and enhancers. PMID:27662615

  11. MtVRN2 is a Polycomb VRN2-like gene which represses the transition to flowering in the model legume Medicago truncatula.

    PubMed

    Jaudal, Mauren; Zhang, Lulu; Che, Chong; Hurley, Daniel G; Thomson, Geoffrey; Wen, Jiangqi; Mysore, Kirankumar S; Putterill, Joanna

    2016-04-01

    Optimising the timing of flowering contributes to successful sexual reproduction and yield in agricultural plants. FLOWERING LOCUS T (FT) genes, first identified in Arabidopsis thaliana (Arabidopsis), promote flowering universally, but the upstream flowering regulatory pathways can differ markedly among plants. Flowering in the model legume, Medicago truncatula (Medicago) is accelerated by winter cold (vernalisation) followed by long day (LD) photoperiods leading to elevated expression of the floral activator, FT-like gene FTa1. However, Medicago, like some other plants, lacks the activator CONSTANS (CO) and the repressor FLOWERING LOCUS C (FLC) genes which directly regulate FT and are key to LD and vernalisation responses in Arabidopsis. Conversely, Medicago has a VERNALISATION2-LIKE VEFS-box gene (MtVRN2). In Arabidopsis AtVRN2 is a key member of a Polycomb complex involved in stable repression of Arabidopsis FLC after vernalisation. VRN2-like genes have been identified in other eudicot plants, but their function has never been reported. We show that Mtvrn2 mutants bypass the need for vernalisation for early flowering in LD conditions in Medicago. Investigation of the underlying mechanism by transcriptome analysis reveals that Mtvrn2 mutants precociously express FTa1 and other suites of genes including floral homeotic genes. Double-mutant analysis indicates that early flowering is dependent on functional FTa1. The broad significance of our study is that we have demonstrated a function for a VRN2-like VEFS gene beyond the Brassicaceae. In particular, MtVRN2 represses the transition to flowering in Medicago by regulating the onset of expression of the potent floral activator, FTa1.

  12. Selective control of Pax7 expression by TNF-activated p38α/polycomb repressive complex 2 (PRC2) signaling during muscle satellite cell differentiation.

    PubMed

    Mozzetta, Chiara; Consalvi, Silvia; Saccone, Valentina; Forcales, Sonia V; Puri, Pier Lorenzo; Palacios, Daniela

    2011-01-15

    Muscle regeneration relies on adult muscle stem (satellite) cells. Inflammatory cues released within the regenerative microenvironment, such as TNFα, instruct different components of the satellite cell niche toward specialized tasks by regulating specific subsets of genes in each individual cell type. However, how regeneration cues are deciphered and interpreted by the multitude of cell types within the regenerative environment is unknown. We have recently identified an inflammation-activated signaling, consisting of p38α-mediated recruitment of polycomb repressive complex 2 (PRC2) to the Pax7 promoter, in satellite cells. Here we show that p38α-PRC2 regulation of Pax7 expression is restricted to a discrete stage of satellite cell-mediated regeneration. In activated satellite cells, Pax7 locus shows a "bivalent" chromatin signature, with co-existence of H3-K27(3me) and H3-K4(3me), that appears to confer responsiveness to p38α-PRC2 signaling. p38α activation resolves bivalence to H3-K27(3me) which results in Pax7 repression, while p38α blockade promotes Pax7 expression by preventing PRC2-mediated H3-K27(3me) and leading to relative increase in H3-K4(3me). Interestingly, in satellite cell-derived myotubes Pax7 expression cannot be re-induced by p38α blockade, revealing a post-mitotic resistance of Pax7 gene to inflammatory cues. Likewise, in other cell types, such as muscle-derived fibroblasts, Pax7 locus is constitutively repressed by PRC2 and is unresponsive to p38α signaling. Finally, we show that Pax7 repression in embryonic stem cells is not directed by p38α signaling, although it is mediated by PRC2. This evidence indicates a cell type- and differentiation-stage specific control of Pax7 transcription by the p38α-PRC2.

  13. Development of real-time PCR assays for detection of the Streptococcus milleri group from cystic fibrosis clinical specimens by targeting the cpn60 and 16S rRNA genes.

    PubMed

    Olson, A B; Sibley, C D; Schmidt, L; Wilcox, M A; Surette, M G; Corbett, C R

    2010-04-01

    Cystic fibrosis (CF) is a multiorgan disease, with the majority of mortalities resulting from pulmonary failure due to repeated pulmonary exacerbations. Recently, members of the Streptococcus anginosus group (S. anginosus, S. constellatus, and S. intermedius), herein referred to as the "Streptococcus milleri group" (SMG) have been implicated as important etiological pathogens contributing to pulmonary exacerbations in CF patients. This is partly due to better microbiological detection of the SMG species through the development of a novel specific medium termed "McKay agar." McKay agar demonstrated that SMG has been an underreported respiratory pathogen contributing to lung exacerbations. Our aim was to develop a real-time PCR assay to expedite the detection of SMG within diagnostic samples. The cpn60 gene was chosen as a target, with all three members amplified using a single hybridization probe set. SMG strain analysis showed that speciation based on melting curve analysis allowed for the majority of the S. constellatus (96%), S. intermedius (94%), and S. anginosus (60%) strains to be correctly identified. To increase specificity for S. anginosus, two 16S rRNA real-time PCR assays were developed targeting the 16S rRNA gene. The 16s_SA assay is specific for S. anginosus (100%), while the 16s_SCI assay is specific for S. constellatus and S. intermedius (100%). These assays can detect <10 genome equivalents in pure culture and >10(4) genome equivalents in sputum samples, making this a great tool for assessment of the presence of SMG in complex polymicrobial samples. Novel molecular methods were developed providing detection ability for SMG, an emerging opportunistic pathogen.

  14. Chromodomain Ligand Optimization via Target-Class Directed Combinatorial Repurposing.

    PubMed

    Barnash, Kimberly D; Lamb, Kelsey N; Stuckey, Jacob I; Norris, Jacqueline L; Cholensky, Stephanie H; Kireev, Dmitri B; Frye, Stephen V; James, Lindsey I

    2016-09-16

    Efforts to develop strategies for small-molecule chemical probe discovery against the readers of the methyl-lysine (Kme) post-translational modification have been met with limited success. Targeted disruption of these protein-protein interactions via peptidomimetic inhibitor optimization is a promising alternative to small-molecule hit discovery; however, recognition of identical peptide motifs by multiple Kme reader proteins presents a unique challenge in the development of selective Kme reader chemical probes. These selectivity challenges are exemplified by the Polycomb repressive complex 1 (PRC1) chemical probe, UNC3866, which demonstrates submicromolar off-target affinity toward the non-PRC1 chromodomains CDYL2 and CDYL. Moreover, since peptidomimetics are challenging subjects for structure-activity relationship (SAR) studies, traditional optimization of UNC3866 would prove costly and time-consuming. Herein, we report a broadly applicable strategy for the affinity-based, target-class screening of chromodomains via the repurposing of UNC3866 in an efficient, combinatorial peptide library. A first-generation library yielded UNC4991, a UNC3866 analogue that exhibits a distinct selectivity profile while maintaining submicromolar affinity toward the CDYL chromodomains. Additionally, in vitro pull-down experiments from HeLa nuclear lysates further demonstrate the selectivity and utility of this compound for future elucidation of CDYL protein function.

  15. Grouping Illumination Frameworks

    ERIC Educational Resources Information Center

    Zdravkovic, Suncica; Economou, Elias; Gilchrist, Alan

    2012-01-01

    According to Koffka (1935), the lightness of a target surface is determined by the relationship between the target and the illumination frame of reference to which it belongs. However, each scene contains numerous illumination frames, and judging each one separately would lead to an enormous amount of computing. Grouping those frames that are in…

  16. Perceiving persons and groups.

    PubMed

    Hamilton, D L; Sherman, S J

    1996-04-01

    This article analyzes the similarities and differences in forming impressions of individuals and in developing conceptions of groups. In both cases, the perceiver develops a mental conception of the target (individual or group) on the basis of available information and uses that information to make judgments about that person or group. However, a review of existing evidence reveals differences in the outcomes of impressions formed of individual and group targets, even when those impressions are based on the very same behavioral information. A model is proposed to account for these differences. The model emphasizes the role of differing expectancies of unity and coherence in individual and group targets, which in turn engage different mechanisms for processing information and making judgments. Implications of the model are discussed.

  17. Significant Reduction of Late Toxicities in Patients With Extremity Sarcoma Treated With Image-Guided Radiation Therapy to a Reduced Target Volume: Results of Radiation Therapy Oncology Group RTOG-0630 Trial

    PubMed Central

    Wang, Dian; Zhang, Qiang; Eisenberg, Burton L.; Kane, John M.; Li, X. Allen; Lucas, David; Petersen, Ivy A.; DeLaney, Thomas F.; Freeman, Carolyn R.; Finkelstein, Steven E.; Hitchcock, Ying J.; Bedi, Manpreet; Singh, Anurag K.; Dundas, George; Kirsch, David G.

    2015-01-01

    Purpose We performed a multi-institutional prospective phase II trial to assess late toxicities in patients with extremity soft tissue sarcoma (STS) treated with preoperative image-guided radiation therapy (IGRT) to a reduced target volume. Patients and Methods Patients with extremity STS received IGRT with (cohort A) or without (cohort B) chemotherapy followed by limb-sparing resection. Daily pretreatment images were coregistered with digitally reconstructed radiographs so that the patient position could be adjusted before each treatment. All patients received IGRT to reduced tumor volumes according to strict protocol guidelines. Late toxicities were assessed at 2 years. Results In all, 98 patients were accrued (cohort A, 12; cohort B, 86). Cohort A was closed prematurely because of poor accrual and is not reported. Seventy-nine eligible patients from cohort B form the basis of this report. At a median follow-up of 3.6 years, five patients did not have surgery because of disease progression. There were five local treatment failures, all of which were in field. Of the 57 patients assessed for late toxicities at 2 years, 10.5% experienced at least one grade ≥ 2 toxicity as compared with 37% of patients in the National Cancer Institute of Canada SR2 (CAN-NCIC-SR2: Phase III Randomized Study of Pre- vs Postoperative Radiotherapy in Curable Extremity Soft Tissue Sarcoma) trial receiving preoperative radiation therapy without IGRT (P < .001). Conclusion The significant reduction of late toxicities in patients with extremity STS who were treated with preoperative IGRT and absence of marginal-field recurrences suggest that the target volumes used in the Radiation Therapy Oncology Group RTOG-0630 (A Phase II Trial of Image-Guided Preoperative Radiotherapy for Primary Soft Tissue Sarcomas of the Extremity) study are appropriate for preoperative IGRT for extremity STS. PMID:25667281

  18. RTOG Sarcoma Radiation Oncologists Reach Consensus on Gross Tumor Volume and Clinical Target Volume on Computed Tomographic Images for Preoperative Radiotherapy of Primary Soft Tissue Sarcoma of Extremity in Radiation Therapy Oncology Group Studies

    SciTech Connect

    Wang Dian; Bosch, Walter; Roberge, David; Finkelstein, Steven E.; Petersen, Ivy; Haddock, Michael; Chen, Yen-Lin E.; Saito, Naoyuki G.; Kirsch, David G.; Hitchcock, Ying J.; Wolfson, Aaron H.; DeLaney, Thomas F.

    2011-11-15

    Objective: To develop a Radiation Therapy Oncology Group (RTOG) atlas delineating gross tumor volume (GTV) and clinical target volume (CTV) to be used for preoperative radiotherapy of primary extremity soft tissue sarcoma (STS). Methods and Materials: A consensus meeting was held during the RTOG meeting in January 2010 to reach agreement about GTV and CTV delineation on computed tomography (CT) images for preoperative radiotherapy of high-grade large extremity STS. Data were presented to address the local extension of STS. Extensive discussion ensued to develop optimal criteria for GTV and CTV delineation on CT images. Results: A consensus was reached on appropriate CT-based GTV and CTV. The GTV is gross tumor defined by T1 contrast-enhanced magnetic resonance images. Fusion of magnetic resonance and images is recommended to delineate the GTV. The CTV for high-grade large STS typically includes the GTV plus 3-cm margins in the longitudinal directions. If this causes the field to extend beyond the compartment, the field can be shortened to include the end of a compartment. The radial margin from the lesion should be 1.5 cm, including any portion of the tumor not confined by an intact fascial barrier, bone, or skin surface. Conclusion: The consensus on GTV and CTV for preoperative radiotherapy of high-grade large extremity STS is available as web-based images and in a descriptive format through the RTOG. This is expected to improve target volume consistency and allow for rigorous evaluation of the benefits and risks of such treatment.

  19. Long Non-coding RNA HOTAIR Expression in Diffuse Large B-Cell Lymphoma: In Relation to Polycomb Repressive Complex Pathway Proteins and H3K27 Trimethylation

    PubMed Central

    Oh, Eun Ji; Kim, Soo Hee; Yang, Woo Ick; Ko, Young Hyeh; Yoon, Sun Och

    2016-01-01

    Background A long non-coding RNA hox transcript antisense intergenic RNA (HOTAIR) is involved in epigenetic regulation through chromatin remodeling by recruiting polycomb repressive complex 2 (PRC2) proteins (EZH2, SUZ12, and EED) that induce histone H3 trimethylation at lysine 27 (H3K27me3). Deregulation of c-MYC and interaction between c-MYC and EZH2 are well known in lymphomagenesis; however, little is known about the expression status of HOTAIR in diffuse large B-cell lymphomas (DLBCLs). Methods The expression status of PRC2 (EZH2, SUZ12, and EED), H3K27me3, c-MYC, and BCL2 was analyzed using immunohistochemistry (n = 231), and HOTAIR was investigated by a quantification real-time polymerase chain reaction method (n = 164) in DLBCLs. Results The present study confirmed the positive correlation among PRC2 proteins, H3K27me3, and c-MYC in DLBCLs. Expression level of HOTAIR was also positively correlated to EZH2 (p < .05, respectively). Between c-MYC and HOTAIR, and between c- MYC/BCL2 co-expression and HOTAIR, however, negative correlation was observed in DLBCLs (p < .05, respectively). High level of H3K27me3 was determined as an independent prognostic marker in poor overall survival (hazard ratio, 2.0; p = .023) of DLBCL patients. High expression of HOTAIR, however, was associated with favorable overall survival (p = .004) in the univariate analysis, but the impact was not significant in the multivariate analysis. The favorable outcome of DLBCL with HOTAIR high expression levels may be related to the negative correlation with c- MYC expression or c-MYC/BCL2 co-expression. Conclusions HOTAIR expression could be one of possible mechanisms for inducing H3K27me3 via EZH2-related PRC2 activation, and induced H3K27me3 may be strongly related to aggressive DLBCLs which show poor patient outcome. PMID:27550047

  20. Naturally occurring anti-cancer agents targeting EZH2.

    PubMed

    Shahabipour, Fahimeh; Caraglia, Michele; Majeed, Muhammed; Derosa, Giuseppe; Maffioli, Pamela; Sahebkar, Amirhossein

    2017-03-18

    Natural products are considered as promising tools for the prevention and treatment of cancer. The enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase unit of polycomb repressor complexes such as PRC2 complex that has oncogenic roles through interference with growth and metastatic potential. Several agents targeting EZH2 has been discovered but they often induce side effects in clinical trials. Recently, EZH2 has emerged as a potential target of natural products with documented anti-cancer effects and this discloses a new scenario for the development of EZH2 inhibitory strategies with agents with low cytotoxic detrimental effects. In fact, several natural products such as curcumin, triptolide, ursolic acid, sulforaphane, davidiin, tanshindiols, gambogic acid, berberine and Alcea rosea have been shown to serve as EZH2 modulators. Mechanisms like inhibition of histone H3K4, H3K27 and H3K36 trimethylation, down-regulation of matrix metalloproteinase expression, competitive binding to the S-adenosylmethionine binding site of EZH2 and modulation of tumor-suppressive microRNAs have been demonstrated to mediate the EZH2-inhibitory activity of the mentioned natural products. This review summarizes the pathways that are regulated by various natural products resulting in the suppression of EZH2, and provides a plausible molecular mechanism for the putative anti-cancer effects of these compounds.

  1. Sputter target

    DOEpatents

    Gates, Willard G.; Hale, Gerald J.

    1980-01-01

    The disclosure relates to an improved sputter target for use in the deposition of hard coatings. An exemplary target is given wherein titanium diboride is brazed to a tantalum backing plate using a gold-palladium-nickel braze alloy.

  2. Which health-related quality of life aspects are important to patients with chronic myeloid leukemia receiving targeted therapies and to health care professionals? GIMEMA and EORTC Quality of Life Group.

    PubMed

    Efficace, Fabio; Breccia, Massimo; Saussele, Susanne; Kossak-Roth, Ute; Cardoni, Annarita; Caocci, Giovanni; Chie, Weichu; Naeem, Adel; Nicolatou-Galitis, Ourania; Cocks, Kim; Vignetti, Marco; Baccarani, Michele; Mandelli, Franco; Sprangers, Mirjam

    2012-09-01

    The objective of this study was to investigate the health-related quality of life (HRQOL) aspects valued the most by patients with chronic myeloid leukemia (CML) receiving targeted therapies (TT), and to compare their perception with that of health-care professionals' (HCPs). Semi-structured interviews were conducted with 137 CML patients receiving TT from five different countries. An additional sample of 99 CML patients, completing an online interview, was considered for supportive analyses. A sample of 59 HCPs from 12 countries also participated in the study. Patients and HCPs were asked to rate and rank the importance of a predefined list of 74 HRQOL aspects of potential relevance for CML patients. Patients and HCPs agreed that the following five aspects are most important: fatigue, muscle cramps, swelling, worries, and uncertainty about health condition in the future, and importance of social support in coping with the disease. However, the difference in rankings between the two groups was substantial with respect to other HRQOL aspects investigated. Patients valued some issues related to symptoms much higher than HCPs, thus suggesting that a better symptom management could be the crucial aspects to improve HRQOL of CML patients.

  3. RGS12TS-S Localizes at Nuclear Matrix-Associated Subnuclear Structures and Represses Transcription: Structural Requirements for Subnuclear Targeting and Transcriptional Repression

    PubMed Central

    Chatterjee, Tapan K.; Fisher, Rory A.

    2002-01-01

    RGS12TS-S, an 1,157-amino-acid RGS protein (regulator of G protein signaling), is a nuclear protein that exhibits a unique pattern of subnuclear organization into nuclear foci or dots when expressed endogenously or ectopically. We now report that RGS12TS-S is a nuclear matrix protein and identify structural determinants that target this protein to the nuclear matrix and to discrete subnuclear sites. We also determine the relationship between RGS12TS-S-decorated nuclear dots and known subnuclear domains involved in control of gene expression and provide the first evidence that RGS12TS-S is functionally involved in the regulation of transcription and cell cycle events. A novel nuclear matrix-targeting sequence was identified that is distinct from a second novel motif needed for targeting RGS12TS-S to nuclear dots. RGS12TS-S nuclear dots were distinct from Cajal bodies, SC-35 domains, promyelocytic leukemia protein nuclear bodies, Polycomb group domains, and DNA replication sites. However, RGS12TS-S inhibited S-phase DNA synthesis in various tumor cell lines independently of Rb and p53 proteins, and its prolonged expression promoted formation of multinucleated cells. Expression of RGS12TS-S dramatically reduced bromo-UTP incorporation into sites of transcription. RGS12TS-S, when tethered to a Gal4 DNA binding domain, dramatically inhibited basal transcription from a Gal4-E1b TATA promoter in a histone deacetylase-independent manner. Structural analysis revealed a role for the unique N-terminal domain of RGS12TS-S in its transcriptional repressor and cell cycle-regulating activities and showed that the RGS domain was dispensable for these functions. These results provide novel insights into the structure and function of RGS12TS-S in the nucleus and demonstrate that RGS12TS-S possesses biological activities distinct from those of other members of the RGS protein family. PMID:12024043

  4. Maximizing Strike Planning Efficiency for a Given Class of Targets

    DTIC Science & Technology

    2010-03-01

    at the same time. In general, the aircraft attack target groups and the target groups contain several single targets. In this research, it is assumed...that every strike package attacks a 4 single target in a target group and returns to base. Therefore, aircraft do not carry different types of weapons...However, different strike packages from different bases can be assigned to a target group containing several single targets where each strike package may

  5. LIQUID TARGET

    DOEpatents

    Martin, M.D.; Salsig, W.W. Jr.

    1959-01-13

    A liquid handling apparatus is presented for a liquid material which is to be irradiated. The apparatus consists essentially of a reservoir for the liquid, a target element, a drain tank and a drain lock chamber. The target is in the form of a looped tube, the upper end of which is adapted to be disposed in a beam of atomic particles. The lower end of the target tube is in communication with the liquid in the reservoir and a means is provided to continuously circulate the liquid material to be irradiated through the target tube. Means to heat the reservoir tank is provided in the event that a metal is to be used as the target material. The apparatus is provided with suitable valves and shielding to provide maximum safety in operation.

  6. Group X

    SciTech Connect

    Fields, Susannah

    2007-08-16

    This project is currently under contract for research through the Department of Homeland Security until 2011. The group I was responsible for studying has to remain confidential so as not to affect the current project. All dates, reference links and authors, and other distinguishing characteristics of the original group have been removed from this report. All references to the name of this group or the individual splinter groups has been changed to 'Group X'. I have been collecting texts from a variety of sources intended for the use of recruiting and radicalizing members for Group X splinter groups for the purpose of researching the motivation and intent of leaders of those groups and their influence over the likelihood of group radicalization. This work included visiting many Group X websites to find information on splinter group leaders and finding their statements to new and old members. This proved difficult because the splinter groups of Group X are united in beliefs, but differ in public opinion. They are eager to tear each other down, prove their superiority, and yet remain anonymous. After a few weeks of intense searching, a list of eight recruiting texts and eight radicalizing texts from a variety of Group X leaders were compiled.

  7. Group Flow and Group Genius

    ERIC Educational Resources Information Center

    Sawyer, Keith

    2015-01-01

    Keith Sawyer views the spontaneous collaboration of group creativity and improvisation actions as "group flow," which organizations can use to function at optimum levels. Sawyer establishes ideal conditions for group flow: group goals, close listening, complete concentration, being in control, blending egos, equal participation, knowing…

  8. Isopermutation group

    SciTech Connect

    Muktibodh, A. S.

    2015-03-10

    The concept of ‘Isotopy’ as formulated by Ruggero Maria Santilli [1, 2, 3] plays a vital role in the development of Iso mathematics. Santilli defined iso-fields of characteristic zero. In this paper we extend this definition to define Iso-Galois fields [4] which are essentially of non-zero characteristic. Isotopically isomorphic realizations of a group define isopermutation group which gives a clear cut distinction between automorphic groups and isotopic groups.

  9. Home Groups.

    ERIC Educational Resources Information Center

    Stahler, Theresa M.

    All students enrolled in the entry level foundations course in the College of Education of Kutztown University (Pennsylvania) participate in home groups, a cooperative learning strategy. Each student is assigned to a five- or six-person home group on the first day of class. Although group placements are made on the basis of class lists, every…

  10. Targeting the Notch-regulated non-coding RNA TUG1 for glioma treatment

    PubMed Central

    Katsushima, Keisuke; Natsume, Atsushi; Ohka, Fumiharu; Shinjo, Keiko; Hatanaka, Akira; Ichimura, Norihisa; Sato, Shinya; Takahashi, Satoru; Kimura, Hiroshi; Totoki, Yasushi; Shibata, Tatsuhiro; Naito, Mitsuru; Kim, Hyun Jin; Miyata, Kanjiro; Kataoka, Kazunori; Kondo, Yutaka

    2016-01-01

    Targeting self-renewal is an important goal in cancer therapy and recent studies have focused on Notch signalling in the maintenance of stemness of glioma stem cells (GSCs). Understanding cancer-specific Notch regulation would improve specificity of targeting this pathway. In this study, we find that Notch1 activation in GSCs specifically induces expression of the lncRNA, TUG1. TUG1 coordinately promotes self-renewal by sponging miR-145 in the cytoplasm and recruiting polycomb to repress differentiation genes by locus-specific methylation of histone H3K27 via YY1-binding activity in the nucleus. Furthermore, intravenous treatment with antisense oligonucleotides targeting TUG1 coupled with a drug delivery system induces GSC differentiation and efficiently represses GSC growth in vivo. Our results highlight the importance of the Notch-lncRNA axis in regulating self-renewal of glioma cells and provide a strong rationale for targeting TUG1 as a specific and potent therapeutic approach to eliminate the GSC population. PMID:27922002

  11. Galaxy groups

    SciTech Connect

    Brent Tully, R.

    2015-02-01

    Galaxy groups can be characterized by the radius of decoupling from cosmic expansion, the radius of the caustic of second turnaround, and the velocity dispersion of galaxies within this latter radius. These parameters can be a challenge to measure, especially for small groups with few members. In this study, results are gathered pertaining to particularly well-studied groups over four decades in group mass. Scaling relations anticipated from theory are demonstrated and coefficients of the relationships are specified. There is an update of the relationship between light and mass for groups, confirming that groups with mass of a few times 10{sup 12}M{sub ⊙} are the most lit up while groups with more and less mass are darker. It is demonstrated that there is an interesting one-to-one correlation between the number of dwarf satellites in a group and the group mass. There is the suggestion that small variations in the slope of the luminosity function in groups are caused by the degree of depletion of intermediate luminosity systems rather than variations in the number per unit mass of dwarfs. Finally, returning to the characteristic radii of groups, the ratio of first to second turnaround depends on the dark matter and dark energy content of the universe and a crude estimate can be made from the current observations of Ω{sub matter}∼0.15 in a flat topology, with a 68% probability of being less than 0.44.

  12. GROUP INEQUALITY

    PubMed Central

    Bowles, Samuel; Loury, Glenn C.; Sethi, Rajiv

    2014-01-01

    We explore the combined effect of segregation in social networks, peer effects, and the relative size of a historically disadvantaged group on the incentives to invest in market-rewarded skills and the dynamics of inequality between social groups. We identify conditions under which group inequality will persist in the absence of differences in ability, credit constraints, or labor market discrimination. Under these conditions, group inequality may be amplified even if initial group differences are negligible. Increases in social integration may destabilize an unequal state and make group equality possible, but the distributional and human capital effects of this depend on the demographic composition of the population. When the size of the initially disadvantaged group is sufficiently small, integration can lower the long-run costs of human capital investment in both groups and result in an increase the aggregate skill share. In contrast, when the initially disadvantaged group is large, integration can induce a fall in the aggregate skill share as the costs of human capital investment rise in both groups. We consider applications to concrete cases and policy implications. PMID:25554727

  13. Whitehead Groups of Spinor Groups

    NASA Astrophysics Data System (ADS)

    Monastyrnyĭ, A. P.; Yanchevskiĭ, V. I.

    1991-02-01

    The Whitehead groups of spinor groups are studied. The known Kneser-Tits conjecture for spinor groups is reduced to a spinor analogue of the Tannaka-Artin problem, namely, to the question of whether the group K1Spin(D), where D is a division ring of exponent 2 , is trivial. A counterexample to the Kneser-Tits problem is constructed in the class of spinor groups. The group K1Spin(D) is computed. The stability of the Whitehead groups of spinor groups under purely transcendental extensions of the ground field is established. The R-equivalence on the k-points of spinor groups and the weak approximation problem are considered. The study of spinor group completes the study of the Whitehead groups of algebraic groups of classical type, that was started in studying reduced K-theory (V.P. Platonov) and was continued for reduced unitary K-theory (V.I. Yanchevskiĭ) and Hermitian K-theory (Platonov and Yanchevskiĭ). Bibliography: 50 titles.

  14. Group Theatre.

    ERIC Educational Resources Information Center

    Clark, Brian

    The group interpretation approach to theatre production is defined as a method that will lead to production of plays that will appeal to "all the layers of the conscious and unconscious mind." In practice, it means that the group will develop and use resources of the theatre that orthodox companies too often ignore. The first two chapters of this…

  15. Group behaviour: leadership by those in need.

    PubMed

    Sumpter, David J T

    2009-04-28

    A new model of animal group behaviour shows that, when the need to reach a target outweighs the costs of splitting from the group, a minority of the most 'needy' individuals become the leaders of large groups.

  16. Tackling Targets.

    ERIC Educational Resources Information Center

    Further Education Unit, London (England).

    This document is designed to help British training and enterprise councils (TECs) and further education (FE) colleges develop and implement strategies for achieving the National Targets for Education and Training (NTET), which were developed by the Confederation of British Industry in 1992 and endorsed by the British government. The findings from…

  17. On Target.

    ERIC Educational Resources Information Center

    Barbalich, Andrea

    1991-01-01

    Campus public relations professionals offer advice for improving the effectiveness of public relations efforts by (1) setting behavioral goals; (2) targeting audiences carefully; (3) focusing appeals by making messages explicit; (4) connecting the public relations message with larger societal issues; and (5) reaching internal as well as external…

  18. Runx1 Regulation of Pu.1 Corepressor/Coactivator Exchange Identifies Specific Molecular Targets for Leukemia Differentiation Therapy*

    PubMed Central

    Gu, Xiaorong; Hu, Zhenbo; Ebrahem, Quteba; Crabb, John S.; Mahfouz, Reda Z.; Radivoyevitch, Tomas; Crabb, John W.; Saunthararajah, Yogen

    2014-01-01

    Gene activation requires cooperative assembly of multiprotein transcription factor-coregulator complexes. Disruption to cooperative assemblage could underlie repression of tumor suppressor genes in leukemia cells. Mechanisms of cooperation and its disruption were therefore examined for PU.1 and RUNX1, transcription factors that cooperate to activate hematopoietic differentiation genes. PU.1 is highly expressed in leukemia cells, whereas RUNX1 is frequently inactivated by mutation or translocation. Thus, coregulator interactions of Pu.1 were examined by immunoprecipitation coupled with tandem mass spectrometry/Western blot in wild-type and Runx1-deficient hematopoietic cells. In wild-type cells, the NuAT and Baf families of coactivators coimmunoprecipitated with Pu.1. Runx1 deficiency produced a striking switch to Pu.1 interaction with the Dnmt1, Sin3A, Nurd, CoRest, and B-Wich corepressor families. Corepressors of the Polycomb family, which are frequently inactivated by mutation or deletion in myeloid leukemia, did not interact with Pu.1. The most significant gene ontology association of Runx1-Pu.1 co-bound genes was with macrophages, therefore, functional consequences of altered corepressor/coactivator exchange were examined at Mcsfr, a key macrophage differentiation gene. In chromatin immunoprecipitation analyses, high level Pu.1 binding to the Mcsfr promoter was not decreased by Runx1 deficiency. However, the Pu.1-driven shift from histone repression to activation marks at this locus, and terminal macrophage differentiation, were substantially diminished. DNMT1 inhibition, but not Polycomb inhibition, in RUNX1-translocated leukemia cells induced terminal differentiation. Thus, RUNX1 and PU.1 cooperate to exchange corepressors for coactivators, and the specific corepressors recruited to PU.1 as a consequence of RUNX1 deficiency could be rational targets for leukemia differentiation therapy. PMID:24695740

  19. Target assembly

    DOEpatents

    Lewis, Richard A.

    1980-01-01

    A target for a proton beam which is capable of generating neutrons for absorption in a breeding blanket includes a plurality of solid pins formed of a neutron emissive target material disposed parallel to the path of the beam and which are arranged axially in a plurality of layers so that pins in each layer are offset with respect to pins in all other layers, enough layers being used so that each proton in the beam will strike at least one pin with means being provided to cool the pins. For a 300 mA, 1 GeV beam (300 MW), stainless steel pins, 12 inches long and 0.23 inches in diameter are arranged in triangular array in six layers with one sixth of the pins in each layer, the number of pins being such that the entire cross sectional area of the beam is covered by the pins with minimum overlap of pins.

  20. Group Learning.

    ERIC Educational Resources Information Center

    Black, Susan

    1992-01-01

    Research suggests that cooperative learning works best when students are first taught group-processing skills, such as leadership, decision making, communication, trust building, and conflict management. Inadequate teacher training and boring assignments can torpedo cooperative learning efforts. Administrators should reassure teachers with…

  1. Accelerator target

    DOEpatents

    Schlyer, D.J.; Ferrieri, R.A.; Koehler, C.

    1999-06-29

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression. 5 figs.

  2. Accelerator target

    DOEpatents

    Schlyer, David J.; Ferrieri, Richard A.; Koehler, Conrad

    1999-01-01

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression.

  3. Local Group

    NASA Astrophysics Data System (ADS)

    Mateo, M.; Murdin, P.

    2000-11-01

    Not long after EDWIN HUBBLE established that galaxies are `island universes' similar to our home galaxy, the MILKY WAY, he realized that a few of these external galaxies are considerably closer to us than any others. In 1936 he first coined the term `Local Group' in his famous book The Realm of the Nebulae to identify our nearest galactic neighbors. More than 60 yr later, the galaxies of the Loca...

  4. Underrepresented groups

    NASA Technical Reports Server (NTRS)

    Peters, David A.

    1990-01-01

    The problem with the shortage of under represented groups in science and engineering is absolutely crucial, especially considering that U.S. will experience a shortage of 560,000 science and engineering personnel by the year 2010. Most studies by the National Science Foundation also concluded that projected shortages cannot be alleviated without significant increases in the involvement of Blacks, Hispanics, Native Americans, handicapped persons, and women.

  5. Targeting circuits

    PubMed Central

    Rajasethupathy, Priyamvada; Ferenczi, Emily; Deisseroth, Karl

    2017-01-01

    Current optogenetic methodology enables precise inhibition or excitation of neural circuits, spanning timescales as needed from the acute (milliseconds) to the chronic (many days or more), for experimental modulation of network activity and animal behavior. Such broad temporal versatility, unique to optogenetic control, is particularly powerful when combined with brain activity measurements that span both acute and chronic timescales as well. This enables, for instance, the study of adaptive circuit dynamics across the intact brain, and tuning interventions to match activity patterns naturally observed during behavior in the same individual. Although the impact of this approach has been greater on basic research than on clinical translation, it is natural to ask if specific neural circuit activity patterns discovered to be involved in controlling adaptive or maladaptive behaviors could become targets for treatment of neuropsychiatric diseases. Here we consider the landscape of such ideas related to therapeutic targeting of circuit dynamics, taking note of developments not only in optical but also in ultrasonic, magnetic, and thermal methods. We note the recent emergence of first-in-kind optogenetically-guided clinical outcomes, as well as opportunities related to the integration of interventions and readouts spanning diverse circuit-physiology, molecular, and behavioral modalities. PMID:27104976

  6. Group Connections: Whole Group Teaching.

    ERIC Educational Resources Information Center

    Griffiths, Dorothy

    2002-01-01

    A learner-centered approach to adult group instruction involved learners in investigating 20th-century events. The approach allowed learners to concentrate on different activities according to their abilities and gave them opportunities to develop basic skills and practice teamwork. (SK)

  7. Design of HIV-1 integrase inhibitors targeting the catalytic domain as well as its interaction with LEDGF/p75: a scaffold hopping approach using salicylate and catechol groups.

    PubMed

    Fan, Xing; Zhang, Feng-Hua; Al-Safi, Rasha I; Zeng, Li-Fan; Shabaik, Yumna; Debnath, Bikash; Sanchez, Tino W; Odde, Srinivas; Neamati, Nouri; Long, Ya-Qiu

    2011-08-15

    HIV-1 integrase (IN) is a validated therapeutic target for antiviral drug design. However, the emergence of viral strains resistant to clinically studied IN inhibitors demands the discovery of novel inhibitors that are structurally as well mechanistically different. Herein, we describe the design and discovery of novel IN inhibitors targeting the catalytic domain as well as its interaction with LEDGF/p75, which is essential for the HIV-1 integration as an IN cofactor. By merging the pharmacophores of salicylate and catechol, the 2,3-dihydroxybenzamide (5a) was identified as a new scaffold to inhibit the strand transfer reaction efficiently. Further structural modifications on the 2,3-dihydroxybenzamide scaffold revealed that the heteroaromatic functionality attached on the carboxamide portion and the piperidin-1-ylsulfonyl substituted at the phenyl ring are beneficial for the activity, resulting in a low micromolar IN inhibitor (5p, IC(50)=5 μM) with more than 40-fold selectivity for the strand transfer over the 3'-processing reaction. More significantly, this active scaffold remarkably inhibited the interaction between IN and LEDGF/p75 cofactor. The prototype example, N-(cyclohexylmethyl)-2,3-dihydroxy-5-(piperidin-1-ylsulfonyl) benzamide (5u) inhibited the IN-LEDGF/p75 interaction with an IC(50) value of 8 μM. Using molecular modeling, the mechanism of action was hypothesized to involve the chelation of the divalent metal ions inside the IN active site. Furthermore, the inhibitor of IN-LEDGF/p75 interaction was properly bound to the LEDGF/p75 binding site on IN. This work provides a new and efficient approach to evolve novel HIV-1 IN inhibitors from rational integration and optimization of previously reported inhibitors.

  8. Design of HIV-1 Integrase Inhibitors Targeting the Catalytic Domain as Well as Its Interaction with LEDGF/p75: A Scaffold Hopping Approach Using Salicylate and Catechol Groups

    PubMed Central

    Fan, Xing; Zhang, Feng-Hua; Al-Safi, Rasha I.; Zeng, Li-Fan; Shabaik, Yumna; Debnath, Bikash; Sanchez, Tino W.; Odde, Srinivas; Neamati, Nouri; Long, Ya-Qiu

    2011-01-01

    HIV-1 integrase (IN) is a validated therapeutic target for antiviral agents. However, the emergence of viral strains resistant to clinically studied IN inhibitors demands new structure and new mechanism IN inhibitors. Herein, we describe the design and discovery of novel IN inhibitors targeting the catalytic domain as well as its interaction with LEDGF/p75, which is essential for the HIV-1 integration as an IN cofactor. By merging the pharmacophores of salicylate and catechol, the 2,3-dihydroxybenzamide (5a) was identified as a new scaffold to inhibit the strand transfer reaction efficiently. Further structural modifications on the 2,3-dihydroxybenzamide scaffold revealed that the heteroaromatic functionality attached on the carboxamide portion and the piperidin-1-ylsulfonyl substituted at the phenyl ring are beneficial for the activity, resulting in a low micromolar IN inhibitor (5p, IC50 = 5 μM) with more than 40-fold selectivity for the strand transfer over the 3′-processing reaction. More significantly, this active scaffold remarkably inhibited the interaction between IN and LEDGF/p75 cofactor. The prototype example, N-(cyclohexylmethyl)-2,3-dihydroxy-5-(piperidin-1-ylsulfonyl) benzamide (5u) inhibited the IN-LEDGF/p75 interaction with an IC50 value of 8 μM. Based on the molecular modeling, the mechanism of action was hypothesized to involve the chelation of the divalent metal ions inside the IN active site. And the inhibitor of IN-LEDGF/p75 interaction was properly bound to the LEDGF/p75 binding site in IN protein. This work provided a new and efficient approach to evolve novel HIV-1 IN inhibitors from rational integration and optimization of previously reported inhibitors. PMID:21778063

  9. Global identification of genes targeted by DNMT3b for epigenetic silencing in lung cancer.

    PubMed

    Teneng, I; Tellez, C S; Picchi, M A; Klinge, D M; Yingling, C M; Snider, A M; Liu, Y; Belinsky, S A

    2015-01-29

    The maintenance cytosine DNA methyltransferase DNMT1 and de novo methyltransferase DNMT3b cooperate to establish aberrant DNA methylation and chromatin complexes to repress gene transcription during cancer development. The expression of DNMT3b was constitutively increased 5-20-fold in hTERT/CDK4-immortalized human bronchial epithelial cells (HBECs) before treatment with low doses of tobacco carcinogens. Overexpression of DNMT3b increased and accelerated carcinogen-induced transformation. Genome-wide profiling of transformed HBECs identified 143 DNMT3b-target genes, many of which were transcriptionally regulated by the polycomb repressive complex 2 (PRC2) complex and silenced through aberrant methylation in non-small-cell lung cancer cell lines. Two genes studied in detail, MAL and OLIG2, were silenced during transformation, initially through enrichment for H3K27me3 and H3K9me2, commonly methylated in lung cancer, and exert tumor suppressor effects in vivo through modulating cancer-related pathways. Re-expression of MAL and OLIG2 to physiological levels dramatically reduced the growth of lung tumor xenografts. Our results identify a key role for DNMT3b in the earliest stages of initiation and provide a comprehensive catalog of genes targeted for silencing by this methyltransferase in non-small-cell lung cancer.

  10. Grainy head and its target genes in epithelial morphogenesis and wound healing.

    PubMed

    Wang, Shenqiu; Samakovlis, Christos

    2012-01-01

    The Grainy head (Grh) family of transcription factors is characterized by a unique DNA-binding domain that binds to a conserved consensus sequence. Nematodes and flies have a single grh gene, whereas mice and humans have evolved three genes encoding Grainy head-like (Grhl) factors. We review the biological function of Grh in different animals and the mechanisms modulating its activity. grh and grhl genes play a remarkably conserved role in epithelial organ development and extracellular barrier repair after tissue damage. Recent studies in flies and vertebrates suggest that Grh factors may be primary determinants of cell adhesion and epithelial tissue formation. Grh proteins can dimerize and act as activators or repressors in different developmental contexts. In flies, tissue-specific, alternative splicing generates different Grh isoforms with different DNA-binding specificities and functions. Grh activity is also modulated by receptor tyrosine kinases: it is phosphorylated by extracellular signal regulated kinase, and this phosphorylation is selectively required for epidermal barrier repair. Two mechanisms have been proposed to explain the repressive function of Grh on target gene transcription. First, Grh can target the Polycomb silencing complex to specific response elements. Second, it can directly compete for DNA binding with transcriptional activators. Understanding the molecular mechanisms of gene regulation by Grh factors is likely to elucidate phylogenetically conserved mechanisms of epithelial cell morphogenesis and regeneration upon tissue damage.

  11. New polycomb group protein enhancer of zeste homolog (EZH) 2-derived peptide with the potential to induce cancer-reactive cytotoxic T lymphocytes in prostate cancer patients with HLA-A3 supertype alleles.

    PubMed

    Minami, Takafumi; Minami, Tomoko; Shimizu, Nobutaka; Yamamoto, Yutaka; De Velasco, Marco A; Nozawa, Masahiro; Yoshimura, Kazuhiro; Harashima, Nanae; Harada, Mamoru; Uemura, Hirotsugu

    2015-05-01

    Analyses on reactivity of anti-cancer cytotoxic T lymphocytes (CTLs) and clinical application of peptide-based anti-cancer vaccine have been mainly focused on patients with HLA-A2 or -A24 alleles. In this study, we identified an enhancer of zeste homolog (EZH) 2-derived peptide applicable for anti-cancer vaccine for prostate cancer patients with HLA-A3 supertype alleles. Five EZH2-derived peptides that were prepared based on the binding motif to the HLA-A3 supertype alleles (HLA-A11, -A31, and -A33) were functionally screened for their potential to induce peptide-specific CTLs from peripheral blood mononuclear cells (PBMCs) of HLA-A3 supertype allele(+) prostate cancer patients. As a result, EZH2733-741 peptide was found to efficiently induce peptide-specific CTLs. The EZH2733-741 peptide-stimulated and purified CD8(+) T cells from PBMCs of HLA-A3 supertype allele(+) prostate cancer patients showed higher cytotoxicity against HLA-A3 supertype allele-expressing LNCaP prostate cancer cells than against parental LNCaP cells. This cytotoxicity against HLA-A3 supertype allele-expressing LNCaP cells was partially but significantly inhibited by the addition of EZH2733-741 peptide-pulsed competitive cells. These results indicate that the EZH2733-741 peptide could be a promising candidate for peptide-based immunotherapy for HLA-A3 supertype allele(+) prostate cancer patients.

  12. Moving targets

    SciTech Connect

    Not Available

    1993-09-01

    This article discusses the conversion of the Westinghouse Corporation's defence arm, Electronic Systems Group, to marketing products for U.S. police rather than for U.S. defense. The uses of electronic defense technology in law enforcement are addressed. Examples of applications include hand held biosensors for detection of drugs and chemicals, remote computers in patrol cars, and a scaled down AWACS radar aircraft.

  13. Therapeutic target database update 2014: a resource for targeted therapeutics.

    PubMed

    Qin, Chu; Zhang, Cheng; Zhu, Feng; Xu, Feng; Chen, Shang Ying; Zhang, Peng; Li, Ying Hong; Yang, Sheng Yong; Wei, Yu Quan; Tao, Lin; Chen, Yu Zong

    2014-01-01

    Here we describe an update of the Therapeutic Target Database (http://bidd.nus.edu.sg/group/ttd/ttd.asp) for better serving the bench-to-clinic communities and for enabling more convenient data access, processing and exchange. Extensive efforts from the research, industry, clinical, regulatory and management communities have been collectively directed at the discovery, investigation, application, monitoring and management of targeted therapeutics. Increasing efforts have been directed at the development of stratified and personalized medicines. These efforts may be facilitated by the knowledge of the efficacy targets and biomarkers of targeted therapeutics. Therefore, we added search tools for using the International Classification of Disease ICD-10-CM and ICD-9-CM codes to retrieve the target, biomarker and drug information (currently enabling the search of almost 900 targets, 1800 biomarkers and 6000 drugs related to 900 disease conditions). We added information of almost 1800 biomarkers for 300 disease conditions and 200 drug scaffolds for 700 drugs. We significantly expanded Therapeutic Target Database data contents to cover >2300 targets (388 successful and 461 clinical trial targets), 20 600 drugs (2003 approved and 3147 clinical trial drugs), 20,000 multitarget agents against almost 400 target-pairs and the activity data of 1400 agents against 300 cell lines.

  14. Cardiovascular group

    NASA Technical Reports Server (NTRS)

    Blomqvist, Gunnar

    1989-01-01

    As a starting point, the group defined a primary goal of maintaining in flight a level of systemic oxygen transport capacity comparable to each individual's preflight upright baseline. The goal of maintaining capacity at preflight levels would seem to be a reasonable objective for several different reasons, including the maintenance of good health in general and the preservation of sufficient cardiovascular reserve capacity to meet operational demands. It is also important not to introduce confounding variables in whatever other physiological studies are being performed. A change in the level of fitness is likely to be a significant confounding variable in the study of many organ systems. The principal component of the in-flight cardiovascular exercise program should be large-muscle activity such as treadmill exercise. It is desirable that at least one session per week be monitored to assure maintenance of proper functional levels and to provide guidance for any adjustments of the exercise prescription. Appropriate measurements include evaluation of the heart-rate/workload or the heart-rate/oxygen-uptake relationship. Respiratory gas analysis is helpful by providing better opportunities to document relative workload levels from analysis of the interrelationships among VO2, VCO2, and ventilation. The committee felt that there is no clear evidence that any particular in-flight exercise regimen is protective against orthostatic hypotension during the early readaptation phase. Some group members suggested that maintenance of the lower body muscle mass and muscle tone may be helpful. There is also evidence that late in-flight interventions to reexpand blood volume to preflight levels are helpful in preventing or minimizing postflight orthostatic hypotension.

  15. Diverse patterns of genomic targeting by transcriptional regulators in Drosophila melanogaster

    PubMed Central

    Slattery, Matthew; Ma, Lijia; Spokony, Rebecca F.; Arthur, Robert K.; Kheradpour, Pouya; Kundaje, Anshul; Nègre, Nicolas; Crofts, Alex; Ptashkin, Ryan; Zieba, Jennifer; Ostapenko, Alexander; Suchy, Sarah; Victorsen, Alec; Jameel, Nader; Grundstad, A. Jason; Gao, Wenxuan; Moran, Jennifer R.; Rehm, E. Jay; Grossman, Robert L.; Kellis, Manolis; White, Kevin P.

    2014-01-01

    Annotation of regulatory elements and identification of the transcription-related factors (TRFs) targeting these elements are key steps in understanding how cells interpret their genetic blueprint and their environment during development, and how that process goes awry in the case of disease. One goal of the modENCODE (model organism ENCyclopedia of DNA Elements) Project is to survey a diverse sampling of TRFs, both DNA-binding and non-DNA-binding factors, to provide a framework for the subsequent study of the mechanisms by which transcriptional regulators target the genome. Here we provide an updated map of the Drosophila melanogaster regulatory genome based on the location of 84 TRFs at various stages of development. This regulatory map reveals a variety of genomic targeting patterns, including factors with strong preferences toward proximal promoter binding, factors that target intergenic and intronic DNA, and factors with distinct chromatin state preferences. The data also highlight the stringency of the Polycomb regulatory network, and show association of the Trithorax-like (Trl) protein with hotspots of DNA binding throughout development. Furthermore, the data identify more than 5800 instances in which TRFs target DNA regions with demonstrated enhancer activity. Regions of high TRF co-occupancy are more likely to be associated with open enhancers used across cell types, while lower TRF occupancy regions are associated with complex enhancers that are also regulated at the epigenetic level. Together these data serve as a resource for the research community in the continued effort to dissect transcriptional regulatory mechanisms directing Drosophila development. PMID:24985916

  16. Diverse patterns of genomic targeting by transcriptional regulators in Drosophila melanogaster.

    PubMed

    Slattery, Matthew; Ma, Lijia; Spokony, Rebecca F; Arthur, Robert K; Kheradpour, Pouya; Kundaje, Anshul; Nègre, Nicolas; Crofts, Alex; Ptashkin, Ryan; Zieba, Jennifer; Ostapenko, Alexander; Suchy, Sarah; Victorsen, Alec; Jameel, Nader; Grundstad, A Jason; Gao, Wenxuan; Moran, Jennifer R; Rehm, E Jay; Grossman, Robert L; Kellis, Manolis; White, Kevin P

    2014-07-01

    Annotation of regulatory elements and identification of the transcription-related factors (TRFs) targeting these elements are key steps in understanding how cells interpret their genetic blueprint and their environment during development, and how that process goes awry in the case of disease. One goal of the modENCODE (model organism ENCyclopedia of DNA Elements) Project is to survey a diverse sampling of TRFs, both DNA-binding and non-DNA-binding factors, to provide a framework for the subsequent study of the mechanisms by which transcriptional regulators target the genome. Here we provide an updated map of the Drosophila melanogaster regulatory genome based on the location of 84 TRFs at various stages of development. This regulatory map reveals a variety of genomic targeting patterns, including factors with strong preferences toward proximal promoter binding, factors that target intergenic and intronic DNA, and factors with distinct chromatin state preferences. The data also highlight the stringency of the Polycomb regulatory network, and show association of the Trithorax-like (Trl) protein with hotspots of DNA binding throughout development. Furthermore, the data identify more than 5800 instances in which TRFs target DNA regions with demonstrated enhancer activity. Regions of high TRF co-occupancy are more likely to be associated with open enhancers used across cell types, while lower TRF occupancy regions are associated with complex enhancers that are also regulated at the epigenetic level. Together these data serve as a resource for the research community in the continued effort to dissect transcriptional regulatory mechanisms directing Drosophila development.

  17. Group evaporation

    NASA Technical Reports Server (NTRS)

    Shen, Hayley H.

    1991-01-01

    Liquid fuel combustion process is greatly affected by the rate of droplet evaporation. The heat and mass exchanges between gas and liquid couple the dynamics of both phases in all aspects: mass, momentum, and energy. Correct prediction of the evaporation rate is therefore a key issue in engineering design of liquid combustion devices. Current analytical tools for characterizing the behavior of these devices are based on results from a single isolated droplet. Numerous experimental studies have challenged the applicability of these results in a dense spray. To account for the droplets' interaction in a dense spray, a number of theories have been developed in the past decade. Herein, two tasks are examined. One was to study how to implement the existing theoretical results, and the other was to explore the possibility of experimental verifications. The current theoretical results of group evaporation are given for a monodispersed cluster subject to adiabatic conditions. The time evolution of the fluid mechanic and thermodynamic behavior in this cluster is derived. The results given are not in the form of a subscale model for CFD codes.

  18. Microenvironmental Targets in Sarcoma

    PubMed Central

    Ehnman, Monika; Larsson, Olle

    2015-01-01

    Sarcomas are rare malignant tumors affecting all age groups. They are typically classified according to their resemblance to corresponding normal tissue. Their heterogeneous features, for example, in terms of disease-driving genetic aberrations and body location, complicate both disease classification and development of novel treatment regimens. Many years of failure of improved patient outcome in clinical trials has led to the conclusion that novel targeted therapies are likely needed in combination with current multimodality regimens. Sarcomas have not, in contrast to the common carcinomas, been the subject of larger systematic studies on how tumor behavior relates to characteristics of the tumor microenvironment. There is consequently an urgent need for identifying suitable molecular targets, not only in tumor cells but also in the tumor microenvironment. This review discusses preclinical and clinical data about potential molecular targets in sarcomas. Studies on targeted therapies involving the tumor microenvironment are prioritized. A greater understanding of the biological context is expected to facilitate more successful design of future clinical trials in sarcoma. PMID:26583076

  19. Students' Target

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03648 Ascraeus Mons

    After examining numerous THEMIS images and using the JMars targeting software, eighth grade students from Charleston Middle School in Charleston, IL, selected the location of -8.37N and 276.66E for capture by the THEMIS visible camera during Mars Odyssey's sixth orbit of Mars on Nov. 22, 2005. The students are investigating relationships between channels, craters, and basins on Mars. The Charleston Middle School students participated in the Mars Student Imaging Project (MSIP) and submitted a proposal to use the THEMIS visible camera.

    Image information: VIS instrument. Latitude 8.8S, Longitude 279.6E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  20. Targeting EZH2-mediated methylation of H3K27 inhibits proliferation and migration of Synovial Sarcoma in vitro

    PubMed Central

    Shen, Jacson K.; Cote, Gregory M.; Gao, Yan; Choy, Edwin; Mankin, Henry J.; Hornicek, Francis J.; Duan, Zhenfeng

    2016-01-01

    Synovial sarcoma is an aggressive soft tissue sarcoma genetically defined by the fusion oncogene SS18-SSX. It is hypothesized that either SS18-SSX disrupts SWI/SNF complex inhibition of the polycomb complex 2 (PRC2) methyltransferase Enhancer of Zeste Homologue 2 (EZH2), or that SS18-SSX is able to directly recruit PRC2 to aberrantly silence target genes. This is of potential therapeutic value as several EZH2 small molecule inhibitors are entering early phase clinical trials. In this study, we first confirmed EZH2 expression in the 76% of human synovial sarcoma samples. We subsequently investigated EZH2 as a therapeutic target in synovial sarcoma in vitro. Knockdown of EZH2 by shRNA or siRNA resulted in inhibition of cell growth and migration across a series of synovial sarcoma cell lines. The EZH2 selective small-molecule inhibitor EPZ005687 similarly suppressed cell proliferation and migration. These data support the hypothesis that targeting EZH2 may be a promising therapeutic strategy in the treatment of synovial sarcoma; clinical trials are initiating enrollment currently. PMID:27125524

  1. KDM2B/FBXL10 targets c-Fos for ubiquitylation and degradation in response to mitogenic stimulation.

    PubMed

    Han, X-R; Zha, Z; Yuan, H-X; Feng, X; Xia, Y-K; Lei, Q-Y; Guan, K-L; Xiong, Y

    2016-08-11

    KDM2B (also known as FBXL10) controls stem cell self-renewal, somatic cell reprogramming and senescence, and tumorigenesis. KDM2B contains multiple functional domains, including a JmjC domain that catalyzes H3K36 demethylation and a CxxC zinc-finger that recognizes CpG islands and recruits the polycomb repressive complex 1. Here, we report that KDM2B, via its F-box domain, functions as a subunit of the CUL1-RING ubiquitin ligase (CRL1/SCF(KDM2B)) complex. KDM2B targets c-Fos for polyubiquitylation and regulates c-Fos protein levels. Unlike the phosphorylation of other SCF (SKP1-CUL1-F-box)/CRL1 substrates that promotes substrates binding to F-box, epidermal growth factor (EGF)-induced c-Fos S374 phosphorylation dissociates c-Fos from KDM2B and stabilizes c-Fos protein. Non-phosphorylatable and phosphomimetic mutations at S374 result in c-Fos protein which cannot be induced by EGF or accumulates constitutively and lead to decreased or increased cell proliferation, respectively. Multiple tumor-derived KDM2B mutations impaired the function of KDM2B to target c-Fos degradation and to suppress cell proliferation. These results reveal a novel function of KDM2B in the negative regulation of cell proliferation by assembling an E3 ligase to targeting c-Fos protein degradation that is antagonized by mitogenic stimulations.

  2. Convergent evolution of chromatin modification by structurally distinct enzymes: comparative enzymology of histone H3 Lys²⁷ methylation by human polycomb repressive complex 2 and vSET.

    PubMed

    Swalm, Brooke M; Hallenbeck, Kenneth K; Majer, Christina R; Jin, Lei; Scott, Margaret Porter; Moyer, Mikel P; Copeland, Robert A; Wigle, Tim J

    2013-07-15

    H3K27 (histone H3 Lys27) methylation is an important epigenetic modification that regulates gene transcription. In humans, EZH (enhancer of zeste homologue) 1 and EZH2 are the only enzymes capable of catalysing methylation of H3K27. There is great interest in understanding structure-function relationships for EZH2, as genetic alterations in this enzyme are thought to play a causal role in a number of human cancers. EZH2 is challenging to study because it is only active in the context of the multi-subunit PRC2 (polycomb repressive complex 2). vSET is a viral lysine methyltransferase that represents the smallest protein unit capable of catalysing H3K27 methylation. The crystal structure of this minimal catalytic protein has been solved and researchers have suggested that vSET might prove useful as an EZH2 surrogate for the development of active site-directed inhibitors. To test this proposition, we conducted comparative enzymatic analysis of human EZH2 and vSET and report that, although both enzymes share similar preferences for methylation of H3K27, they diverge in terms of their permissiveness for catalysing methylation of alternative histone lysine sites, their relative preferences for utilization of multimeric macromolecular substrates, their active site primary sequences and, most importantly, their sensitivity to inhibition by drug-like small molecules. The cumulative data led us to suggest that EZH2 and vSET have very distinct active site structures, despite the commonality of the reaction catalysed by the two enzymes. Hence, the EZH2 and vSET pair of enzymes represent an example of convergent evolution in which distinct structural solutions have developed to solve a common catalytic need.

  3. Joint Targeting: Achieving Effects in an Uncertain Environment

    DTIC Science & Technology

    2007-06-01

    evolved into the first Joint Target Group , which possessed the single point responsibility for the collection and analysis of all intelligence data...Office of Air Force History, 1986) 21-22. 7 Targeting Group did not always achieve success. The nomination of major industrial production...East Command assumed responsibility for targeting in Korea and established the General Headquarters Target Group . The General Headquarters Target

  4. Foucault on targets.

    PubMed

    Lynch, John

    2004-01-01

    This paper seeks to gain an insight into the behavior of a large NHS trust, in its attempt to meet a 90 percent patient access target, in a week long national audit in March 2003. Why did individuals act in dramatically different ways to their norm over this period. The work of Michel Foucault is used to explore these issues. The discourses of power, knowledge, discipline and governmentality are identified as key foucaudian themes that offer an alternative interpretation of how individuals behave in their place of work. The importance of the historical context of discourse within the NHS cannot be underestimated in shaping the behavior of individuals and groups today. Power and knowledge permeate NHS organizations through disciplinary practices and dressage. Governmentality seeks to maintain the status quo through disciplinary processes such as national healthcare targets. The natural response of NHS organizations is therefore, to seek order and conformity rather than disorder and conflict.

  5. Understanding the Function of EZH2 as a Determinant of Breast Cancer Invasion and Metastasis

    DTIC Science & Technology

    2013-04-01

    Epigenetic regulation of cellular memory by the Polycomb and Trithorax group proteins . Annu Rev Genet 38... Polycomb group proteins are major regulators of cellular memory that function in multimeric complexes to regulate the expression of specific genes, mainly...Homolog 2), a Polycomb group protein presumed to function in controlling the transcriptional memory of a cell [1, 2],

  6. Role of p53 in Mammary Epithelial Cell Senescence

    DTIC Science & Technology

    2009-05-01

    Epigenetic regulation of cellular memory by the Polycomb and Trithorax group proteins . Annu...Paro R. Epigenetic regulation of cellular memory by the Polycomb and Trithorax group proteins . Annu Rev Genet 2004;38:413–43. 2. Raaphorst FM...27, 2006 Monitoring Editor: John Cleveland Polycomb group (PcG) protein Bmi-1 is an important regulator of cell proliferation. It

  7. Role of P53 in Mammary Epithelial Cell Senescence

    DTIC Science & Technology

    2006-05-01

    Epigenetic regulation of cellular memory by the Polycomb and Trithorax group ...Dimri. (2006) Mel-18, a polycomb group protein regulates senescence and oncogenesis via transcriptional repression of Bmi-1 and c-Myc...Oncogenesis” National Cancer Institute, NIH, Bethesda, MD 11 1 Mel-18, a polycomb group protein regulates cell proliferation, senescence

  8. Targeted therapy for sarcomas

    PubMed Central

    Forscher, Charles; Mita, Monica; Figlin, Robert

    2014-01-01

    Sarcomas are tumors of mesenchymal origin that make up approximately 1% of human cancers. They may arise as primary tumors in either bone or soft tissue, with approximately 11,280 soft tissue tumors and 2,650 bone tumors diagnosed each year in the United States. There are at least 50 different subtypes of soft tissue sarcoma, with new ones described with ever-increasing frequency. One way to look at sarcomas is to divide them into categories on the basis of their genetic make-up. One group of sarcomas has an identifiable, relatively simple genetic signature, such as the X:18 translocation seen in synovial sarcoma or the 11:22 translocation seen in Ewing’s sarcoma. These specific abnormalities often lead to the presence of fusion proteins, such as EWS-FLI1 in Ewing’s sarcoma, which are helpful as diagnostic tools and may become therapeutic targets in the future. Another group of sarcomas is characterized by complex genetic abnormalities as seen in leiomyosarcoma, osteosarcoma, and undifferentiated sarcoma. It is important to keep these distinctions in mind when contemplating the development of targeted agents for sarcomas. Different abnormalities in sarcoma could be divided by tumor subtype or by the molecular or pathway abnormality. However, some existing drugs or drugs in development may interfere with or alter more than one of the presented pathways. PMID:24669185

  9. Acquisition of a single EZH2 D1 domain mutation confers acquired resistance to EZH2-targeted inhibitors

    PubMed Central

    Baker, Theresa; Nerle, Sujata; Pritchard, Justin; Zhao, Boyang; Rivera, Victor M.

    2015-01-01

    Although targeted therapies have revolutionized cancer treatment, overcoming acquired resistance remains a major clinical challenge. EZH2 inhibitors (EZH2i), EPZ-6438 and GSK126, are currently in the early stages of clinical evaluation and the first encouraging signs of efficacy have recently emerged in the clinic. To anticipate mechanisms of resistance to EZH2i, we used a forward genetic platform combining a mutagenesis screen with next generation sequencing technology and identified a hotspot of secondary mutations in the EZH2 D1 domain (Y111 and I109). Y111D mutation within the WT or A677G EZH2 allele conferred robust resistance to both EPZ-6438 and GSK126, but it only drove a partial resistance within the Y641F allele. EZH2 mutants required histone methyltransferase (HMT) catalytic activity and the polycomb repressive complex 2 (PRC2) components, SUZ12 and EED, to drive drug resistance. Furthermore, D1 domain mutations not only blocked the ability of EZH2i to bind to WT and A677G mutant, but also abrogated drug binding to the Y641F mutant. These data provide the first cellular validation of the mechanistic model underpinning the oncogenic function of WT and mutant EZH2. Importantly, our findings suggest that acquired-resistance to EZH2i may arise in WT and mutant EZH2 patients through a single mutation that remains targetable by second generation EZH2i. PMID:26360609

  10. Cbx7 is epigenetically silenced in glioblastoma and inhibits cell migration by targeting YAP/TAZ-dependent transcription

    PubMed Central

    Nawaz, Zahid; Patil, Vikas; Arora, Anjali; Hegde, Alangar S.; Arivazhagan, Arimappamagan; Santosh, Vani; Somasundaram, Kumaravel

    2016-01-01

    Glioblastomas (GBM) are the most malignant form of astrocytomas which are difficult to treat and portend a grave clinical course and poor prognosis. In this study, we identified Chromobox homolog 7 (Cbx7), a member of Polycomb Repressive Complex 1 (PRC1), as a downregulated gene in GBM owing to its promoter hypermethylation. Bisulphite sequencing and methylation inhibitor treatment established the hypermethylation of Cbx7 in GBM. Exogenous overexpression of Cbx7 induced cell death, inhibited cell proliferation, colony formation and migration/invasion of the glioma cells. GSEA of Cbx7 regulated genes identified Cbx7 as a repressor of transcription co-activators YAP/TAZ, the inhibitory targets of the Hippo signalling pathway. In good correlation, the exogenous expression of Cbx7 repressed the YAP/TAZ-dependent transcription and downregulated CTGF, a bonafide YAP/TAZ target. We also observed reduced levels of phospho-JNK in Cbx7 expressing cells. Additionally, CTGF silencing and pharmacological inhibition of JNK also inhibited glioma cell migration. Further, Cbx7 failed to inhibit cell migration significantly in the presence of exogenously overexpressed CTGF or constitutively active JNK. Thus, our study identifies Cbx7 as an inhibitor of glioma cell migration through its inhibitory effect on YAP/TAZ-CTGF-JNK signalling axis and underscores the importance of epigenetic inactivation of Cbx7 in gliomagenesis. PMID:27291091

  11. [Participation in the cooperation between target group, project and sponsor].

    PubMed

    Wright, M T; Block, M; von Unger, H

    2008-12-01

    The intrinsic connection between empowerment and participation is apparent in the Ottawa Charter on Health Promotion. In order for citizens to reach a higher degree of autonomy and control over health-related factors (empowerment) they need to have an active role in the decision-making processes affecting their lives and the environment in which they live (participation). This implies that many decisions are made affecting the health of citizens over which they have no influence. The question is: Who has the power to make such decisions and how can this power be shared more equitably? This question can be raised not only at the highest political level, but also locally in the context of the collaboration between various stake-holders. The local level plays a key role in deciding which health promotion measures are developed and funded, thus contributing in an important way to strengthening communities. In this article the method "Circles of Decision-Making" is presented as a tool for assisting those working at the local level in determining to what degree the active participation of the various stake-holders has been achieved and in what ways the participation of those "on the outside" of decision-making processes can be strengthened. This method is based on the concept of Participatory Quality Development (PQD) created by the authors and their community partners. PQD uses methods from community-based research to address issues of quality in community-level health promotion and prevention.

  12. Inactivation of Ezh2 Upregulates Gfi1 and Drives Aggressive Myc-Driven Group 3 Medulloblastoma.

    PubMed

    Vo, BaoHan T; Li, Chunliang; Morgan, Marc A; Theurillat, Ilan; Finkelstein, David; Wright, Shaela; Hyle, Judith; Smith, Stephanie M C; Fan, Yiping; Wang, Yong-Dong; Wu, Gang; Orr, Brent A; Northcott, Paul A; Shilatifard, Ali; Sherr, Charles J; Roussel, Martine F

    2017-03-21

    The most aggressive of four medulloblastoma (MB) subgroups are cMyc-driven group 3 (G3) tumors, some of which overexpress EZH2, the histone H3K27 mono-, di-, and trimethylase of polycomb-repressive complex 2. Ezh2 has a context-dependent role in different cancers as an oncogene or tumor suppressor and retards tumor progression in a mouse model of G3 MB. Engineered deletions of Ezh2 in G3 MBs by gene editing nucleases accelerated tumorigenesis, whereas Ezh2 re-expression reversed attendant histone modifications and slowed tumor progression. Candidate oncogenic drivers suppressed by Ezh2 included Gfi1, a proto-oncogene frequently activated in human G3 MBs. Gfi1 disruption antagonized the tumor-promoting effects of Ezh2 loss; conversely, Gfi1 overexpression collaborated with Myc to bypass effects of Trp53 inactivation in driving MB progression in primary cerebellar neuronal progenitors. Although negative regulation of Gfi1 by Ezh2 may restrain MB development, Gfi1 activation can bypass these effects.

  13. Group Dynamics in Automatic Imitation

    PubMed Central

    Wilson, Neil; Reddy, Geetha; Catmur, Caroline

    2016-01-01

    Imitation–matching the configural body movements of another individual–plays a crucial part in social interaction. We investigated whether automatic imitation is not only influenced by who we imitate (ingroup vs. outgroup member) but also by the nature of an expected interaction situation (competitive vs. cooperative). In line with assumptions from Social Identity Theory), we predicted that both social group membership and the expected situation impact on the level of automatic imitation. We adopted a 2 (group membership target: ingroup, outgroup) x 2 (situation: cooperative, competitive) design. The dependent variable was the degree to which participants imitated the target in a reaction time automatic imitation task. 99 female students from two British Universities participated. We found a significant two-way interaction on the imitation effect. When interacting in expectation of cooperation, imitation was stronger for an ingroup target compared to an outgroup target. However, this was not the case in the competitive condition where imitation did not differ between ingroup and outgroup target. This demonstrates that the goal structure of an expected interaction will determine the extent to which intergroup relations influence imitation, supporting a social identity approach. PMID:27657926

  14. Lamin A/C sustains PcG protein architecture, maintaining transcriptional repression at target genes

    PubMed Central

    Cesarini, Elisa; Mozzetta, Chiara; Marullo, Fabrizia; Gregoretti, Francesco; Gargiulo, Annagiusi; Columbaro, Marta; Cortesi, Alice; Antonelli, Laura; Di Pelino, Simona; Squarzoni, Stefano; Palacios, Daniela; Zippo, Alessio; Bodega, Beatrice; Oliva, Gennaro

    2015-01-01

    Beyond its role in providing structure to the nuclear envelope, lamin A/C is involved in transcriptional regulation. However, its cross talk with epigenetic factors—and how this cross talk influences physiological processes—is still unexplored. Key epigenetic regulators of development and differentiation are the Polycomb group (PcG) of proteins, organized in the nucleus as microscopically visible foci. Here, we show that lamin A/C is evolutionarily required for correct PcG protein nuclear compartmentalization. Confocal microscopy supported by new algorithms for image analysis reveals that lamin A/C knock-down leads to PcG protein foci disassembly and PcG protein dispersion. This causes detachment from chromatin and defects in PcG protein–mediated higher-order structures, thereby leading to impaired PcG protein repressive functions. Using myogenic differentiation as a model, we found that reduced levels of lamin A/C at the onset of differentiation led to an anticipation of the myogenic program because of an alteration of PcG protein–mediated transcriptional repression. Collectively, our results indicate that lamin A/C can modulate transcription through the regulation of PcG protein epigenetic factors. PMID:26553927

  15. Lamin A/C sustains PcG protein architecture, maintaining transcriptional repression at target genes.

    PubMed

    Cesarini, Elisa; Mozzetta, Chiara; Marullo, Fabrizia; Gregoretti, Francesco; Gargiulo, Annagiusi; Columbaro, Marta; Cortesi, Alice; Antonelli, Laura; Di Pelino, Simona; Squarzoni, Stefano; Palacios, Daniela; Zippo, Alessio; Bodega, Beatrice; Oliva, Gennaro; Lanzuolo, Chiara

    2015-11-09

    Beyond its role in providing structure to the nuclear envelope, lamin A/C is involved in transcriptional regulation. However, its cross talk with epigenetic factors--and how this cross talk influences physiological processes--is still unexplored. Key epigenetic regulators of development and differentiation are the Polycomb group (PcG) of proteins, organized in the nucleus as microscopically visible foci. Here, we show that lamin A/C is evolutionarily required for correct PcG protein nuclear compartmentalization. Confocal microscopy supported by new algorithms for image analysis reveals that lamin A/C knock-down leads to PcG protein foci disassembly and PcG protein dispersion. This causes detachment from chromatin and defects in PcG protein-mediated higher-order structures, thereby leading to impaired PcG protein repressive functions. Using myogenic differentiation as a model, we found that reduced levels of lamin A/C at the onset of differentiation led to an anticipation of the myogenic program because of an alteration of PcG protein-mediated transcriptional repression. Collectively, our results indicate that lamin A/C can modulate transcription through the regulation of PcG protein epigenetic factors.

  16. Targeted Therapy for Cancer

    Cancer.gov

    Targeted therapy is a type of cancer treatment that targets the changes in cancer cells that help them grow, divide, and spread. Learn how targeted therapy works against cancer and about side effects that may occur.

  17. Group typicality, group loyalty and cognitive development.

    PubMed

    Patterson, Meagan M

    2014-09-01

    Over the course of childhood, children's thinking about social groups changes in a variety of ways. Developmental Subjective Group Dynamics (DSGD) theory emphasizes children's understanding of the importance of conforming to group norms. Abrams et al.'s study, which uses DSGD theory as a framework, demonstrates the social cognitive skills underlying young elementary school children's thinking about group norms. Future research on children's thinking about groups and group norms should explore additional elements of this topic, including aspects of typicality beyond loyalty.

  18. The optimal target hemoglobin.

    PubMed

    Ritz, E; Schwenger, V

    2000-07-01

    There is still controversy concerning the optimal target hemoglobin during treatment with recombinant human erythropoietin (rHuEPO). Some evidence suggests that hemoglobin concentrations higher than currently recommended lead to improvements in cognitive function, physical performance, and rehabilitation. At least in patients with advanced cardiac disease, however, one controlled trial failed to show a benefit from normalizing predialysis hemoglobin concentrations. In contrast, preliminary observations in three additional studies (albeit with limited statistical power) failed to show adverse cardiovascular effects from normalization of hemoglobin, but definite benefit with respect to quality of life, physical performance, and cardiac geometry. These observations are consistent with the notion that hemoglobin concentrations higher than those recommended by the National Kidney Foundation Dialysis Outcomes Quality Initiative Anemia Work Group are beneficial, at least in patients without advanced cardiac disease.

  19. Liquid Hydrogen: Target, Detector

    SciTech Connect

    Mulholland, G.T.; Harigel, G.G.

    2004-06-23

    In 1952 D. Glaser demonstrated that a radioactive source's radiation could boil 135 deg. C superheated-diethyl ether in a 3-mm O glass vessel and recorded bubble track growth on high-speed film in a 2-cm3 chamber. This Bubble Chamber (BC) promised improved particle track time and spatial resolution and cycling rate. Hildebrand and Nagle, U of Chicago, reported Liquid Hydrogen minimum ionizing particle boiling in August 1953. John Wood created the 3.7-cm O Liquid Hydrogen BC at LBL in January 1954. By 1959 the Lawrence Berkley Laboratory (LBL) Alvarez group's '72-inch' BC had tracks in liquid hydrogen. Within 10 years bubble chamber volumes increased by a factor of a million and spread to every laboratory with a substantial high-energy physics program. The BC, particle accelerators and special separated particle beams created a new era of High Energy Physics (HEP) experimentation. The BC became the largest most complex cryogenic installation at the world's HEP laboratories for decades. The invention and worldwide development, deployment and characteristics of these cryogenic dynamic target/detectors and related hydrogen targets are described.

  20. Fostering group identification and creativity in diverse groups: the role of individuation and self-verification.

    PubMed

    Swann, William B; Kwan, Virginia S Y; Polzer, Jeffrey T; Milton, Laurie P

    2003-11-01

    A longitudinal study examined the interplay of identity negotiation processes and diversity in small groups of master's of business administration (MBA) students. When perceivers formed relatively positive impressions of other group members, higher diversity predicted more individuation of targets. When perceivers formed relatively neutral impressions of other group members, however, higher diversity predicted less individuation of targets. Individuation at the outset of the semester predicted self-verification effects several weeks later, and self-verification, in turn, predicted group identification and creative task performance. The authors conclude that contrary to self-categorization theory, fostering individuation and self-verification in diverse groups may maximize group identification and productivity.

  1. Group Cohesion in Experiential Growth Groups

    ERIC Educational Resources Information Center

    Steen, Sam; Vasserman-Stokes, Elaina; Vannatta, Rachel

    2014-01-01

    This article explores the effect of web-based journaling on changes in group cohesion within experiential growth groups. Master's students were divided into 2 groups. Both used a web-based platform to journal after each session; however, only 1 of the groups was able to read each other's journals. Quantitative data collected before and…

  2. Opposites detract: middle school peer group antipathies.

    PubMed

    Laursen, Brett; Bukowski, William M; Nurmi, Jari-Eri; Marion, Donna; Salmela-Aro, Katariina; Kiuru, Noona

    2010-08-01

    This study examines variability in patterns of peer group antipathy. Same-grade adolescent peer groups were identified from sociometric nominations of preferred affiliates in a community sample of 600 Finnish ninth-grade middle school students (mean age=15.0 years). Hierarchical linear modeling determined characteristics of youths in actor groups (nominators) that predicted antipathy for youths in target groups (nominatees) on the basis of target group characteristics. Most antipathies were based on dissimilarity between groups representing the mainstream culture and groups opposed to it. The higher a peer group's school burnout, the more its members disliked students in peer groups with higher school grades and students in peer groups with higher sports participation. Conversely, the higher a peer group's school grades, the more its members disliked students in peer groups with higher school burnout. Students in peer groups with less problem behavior disliked students in peer groups with more problem behavior. There was some evidence of rivalry within the mainstream culture: The higher a group's school grades, the more its members disliked groups whose members participated in sports.

  3. Opposites Detract: Middle School Peer Group Antipathies

    PubMed Central

    Laursen, Brett; Bukowski, William M.; Nurmi, Jari-Eri; Marion, Donna; Salmela-Aro, Katariina; Kiuru, Noona

    2010-01-01

    This study examines variability in patterns of peer group antipathy. Same-grade adolescent peer groups were identified from sociometric nominations of preferred affiliates in a community sample of 600 Finnish 9th grade middle school students (M = 15.0 years-old). Hierarchical linear modeling determined characteristics of youth in actor groups (nominators) that predicted antipathy for youth in target groups (nominatees) on the basis of target group characteristics. Most antipathies were based on dissimilarity between groups representing the mainstream culture and groups opposed to it. The higher a peer group's school burnout, the more its members disliked students in peer groups with higher school grades and students in peer groups with higher sports participation. Conversely, the higher a peer group's school grades, the more its members disliked students in peer groups with higher school burnout. Students in peer groups with less problem behavior disliked students in peer groups with more problem behavior. There was some evidence of rivalry within the mainstream culture: The higher a group's school grades, the more its members disliked those in groups whose members participated in sports. PMID:20378125

  4. 28 CFR 55.17 - Targeting.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... REGARDING LANGUAGE MINORITY GROUPS Minority Language Materials and Assistance § 55.17 Targeting. The term...). “Targeting” refers to a system in which the minority language materials or assistance required by the Act are... targeting system will normally fulfill the Act's minority language requirements if it is designed...

  5. 28 CFR 55.17 - Targeting.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... REGARDING LANGUAGE MINORITY GROUPS Minority Language Materials and Assistance § 55.17 Targeting. The term...). “Targeting” refers to a system in which the minority language materials or assistance required by the Act are... targeting system will normally fulfill the Act's minority language requirements if it is designed...

  6. 28 CFR 55.17 - Targeting.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... REGARDING LANGUAGE MINORITY GROUPS Minority Language Materials and Assistance § 55.17 Targeting. The term...). “Targeting” refers to a system in which the minority language materials or assistance required by the Act are... targeting system will normally fulfill the Act's minority language requirements if it is designed...

  7. 28 CFR 55.17 - Targeting.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... REGARDING LANGUAGE MINORITY GROUPS Minority Language Materials and Assistance § 55.17 Targeting. The term...). “Targeting” refers to a system in which the minority language materials or assistance required by the Act are... targeting system will normally fulfill the Act's minority language requirements if it is designed...

  8. 28 CFR 55.17 - Targeting.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... REGARDING LANGUAGE MINORITY GROUPS Minority Language Materials and Assistance § 55.17 Targeting. The term...). “Targeting” refers to a system in which the minority language materials or assistance required by the Act are... targeting system will normally fulfill the Act's minority language requirements if it is designed...

  9. Polarized internal target apparatus

    DOEpatents

    Holt, R.J.

    1984-10-10

    A polarized internal target apparatus with a polarized gas target of improved polarization and density (achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms) is described.

  10. Polarized internal target apparatus

    DOEpatents

    Holt, Roy J.

    1986-01-01

    A polarized internal target apparatus with a polarized gas target of improved polarization and density achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms.

  11. Electrically charged targets

    DOEpatents

    Goodman, Ronald K.; Hunt, Angus L.

    1984-01-01

    Electrically chargeable laser targets and method for forming such charged targets in order to improve their guidance along a predetermined desired trajectory. This is accomplished by the incorporation of a small amount of an additive to the target material which will increase the electrical conductivity thereof, and thereby enhance the charge placed upon the target material for guidance thereof by electrostatic or magnetic steering mechanisms, without adversely affecting the target when illuminated by laser energy.

  12. Identification of tissue-specific targeting peptide

    NASA Astrophysics Data System (ADS)

    Jung, Eunkyoung; Lee, Nam Kyung; Kang, Sang-Kee; Choi, Seung-Hoon; Kim, Daejin; Park, Kisoo; Choi, Kihang; Choi, Yun-Jaie; Jung, Dong Hyun

    2012-11-01

    Using phage display technique, we identified tissue-targeting peptide sets that recognize specific tissues (bone-marrow dendritic cell, kidney, liver, lung, spleen and visceral adipose tissue). In order to rapidly evaluate tissue-specific targeting peptides, we performed machine learning studies for predicting the tissue-specific targeting activity of peptides on the basis of peptide sequence information using four machine learning models and isolated the groups of peptides capable of mediating selective targeting to specific tissues. As a representative liver-specific targeting sequence, the peptide "DKNLQLH" was selected by the sequence similarity analysis. This peptide has a high degree of homology with protein ligands which can interact with corresponding membrane counterparts. We anticipate that our models will be applicable to the prediction of tissue-specific targeting peptides which can recognize the endothelial markers of target tissues.

  13. Long Non-coding RNA HOTAIR Is Targeted and Regulated by miR-141 in Human Cancer Cells*

    PubMed Central

    Chiyomaru, Takeshi; Fukuhara, Shinichiro; Saini, Sharanjot; Majid, Shahana; Deng, Guoren; Shahryari, Varahram; Chang, Inik; Tanaka, Yuichiro; Enokida, Hideki; Nakagawa, Masayuki; Dahiya, Rajvir; Yamamura, Soichiro

    2014-01-01

    HOTAIR is a long non-coding RNA that interacts with the polycomb repressive complex and suppresses its target genes. HOTAIR has also been demonstrated to promote malignancy. MicroRNA-141 (miR-141) has been reported to play a role in the epithelial to mesenchymal transition process, and the expression of miR-141 is inversely correlated with tumorigenicity and invasiveness in several human cancers. We found that HOTAIR expression is inversely correlated to miR-141 expression in renal carcinoma cells. HOTAIR promotes malignancy, including proliferation and invasion, whereas miR-141 suppresses malignancy in human cancer cells. miR-141 binds to HOTAIR in a sequence-specific manner and suppresses HOTAIR expression and functions, including proliferation and invasion. Both HOTAIR and miR-141 were associated with the immunoprecipitated Ago2 (Argonaute2) complex, and the Ago2 complex cleaved HOTAIR in the presence of miR-141. These results demonstrate that HOTAIR is suppressed by miR-141 in an Ago2-dependent manner. PMID:24616104

  14. Long non-coding RNA HOTAIR is targeted and regulated by miR-141 in human cancer cells.

    PubMed

    Chiyomaru, Takeshi; Fukuhara, Shinichiro; Saini, Sharanjot; Majid, Shahana; Deng, Guoren; Shahryari, Varahram; Chang, Inik; Tanaka, Yuichiro; Enokida, Hideki; Nakagawa, Masayuki; Dahiya, Rajvir; Yamamura, Soichiro

    2014-05-02

    HOTAIR is a long non-coding RNA that interacts with the polycomb repressive complex and suppresses its target genes. HOTAIR has also been demonstrated to promote malignancy. MicroRNA-141 (miR-141) has been reported to play a role in the epithelial to mesenchymal transition process, and the expression of miR-141 is inversely correlated with tumorigenicity and invasiveness in several human cancers. We found that HOTAIR expression is inversely correlated to miR-141 expression in renal carcinoma cells. HOTAIR promotes malignancy, including proliferation and invasion, whereas miR-141 suppresses malignancy in human cancer cells. miR-141 binds to HOTAIR in a sequence-specific manner and suppresses HOTAIR expression and functions, including proliferation and invasion. Both HOTAIR and miR-141 were associated with the immunoprecipitated Ago2 (Argonaute2) complex, and the Ago2 complex cleaved HOTAIR in the presence of miR-141. These results demonstrate that HOTAIR is suppressed by miR-141 in an Ago2-dependent manner.

  15. Large intervening non-coding RNA HOTAIR is an indicator of poor prognosis and a therapeutic target in human cancers.

    PubMed

    Yao, Yanlan; Li, Jinming; Wang, Lunan

    2014-10-20

    In the human genome, the fraction of protein-coding genes that are stably transcribed is only up to 2%, with the remaining numerous RNAs having no protein-coding function. These non-coding RNAs (ncRNAs) have received considerable attention in cancer research in recent years. Breakthroughs have been made in understanding microRNAs and small interfering RNAs, but larger RNAs such as long ncRNAs (lncRNAs) remain an enigma. One lncRNA, HOX antisense intergenic RNA (HOTAIR), has been shown to be dysregulated in many types of cancer, including breast cancer, colorectal cancer, and hepatoma. HOTAIR functions as a regulatory molecule in a wide variety of biological processes. However, its mechanism of action has not been clearly elucidated. It is widely believed that HOTAIR mediates chromosomal remodeling and coordinates with polycomb repressive complex 2 (PRC2) to regulate gene expression. Further study of HOTAIR-related pathways and the role of HOTAIR in tumorigenesis and tumor progression may identify new treatment targets. In this review, we will focus on the characteristics of HOTAIR, as well as data pertaining to its mechanism and its association with cancers.

  16. Group theories: relevance to group safety studies.

    PubMed

    Benevento, A L

    1998-01-01

    Promoting safety in the workplace has been attempted in a variety of ways. Increasingly, industries are using groups such as safety teams and quality circles to promote worker safety. Group influences on individual behavior and attitudes have long been studied in the social psychology literature, but the theories have not been commonly found outside the psychology arena. This paper describes the group theories of group polarization, risky shift, social loafing, groupthink and team think and attempts to apply these theories to existing studies that examine work group influences on safety. Interesting parallels were found but only one study examined group influences as their primary focus of research. Since groups are increasingly used for safety promotion, future research on safety that studies group influences with respect to current group theories is recommended.

  17. SEEDS Moving Group Status Update

    NASA Technical Reports Server (NTRS)

    McElwain, Michael

    2011-01-01

    I will summarize the current status of the SEEDS Moving Group category and describe the importance of this sub-sample for the entire SEEDS survey. This presentation will include analysis of the sensitivity for the Moving Groups with general a comparison to other the other sub-categories. I will discuss the future impact of the Subaru SCExAO system for these targets and the advantage of using a specialized integral field spectrograph. Finally, I will present the impact of a pupil grid mask in order to produce fiducial spots in the focal plane that can be used for both photometry and astrometry.

  18. Reducing Prejudice With Labels: Shared Group Memberships Attenuate Implicit Bias and Expand Implicit Group Boundaries.

    PubMed

    Scroggins, W Anthony; Mackie, Diane M; Allen, Thomas J; Sherman, Jeffrey W

    2016-02-01

    In three experiments, we used a novel Implicit Association Test procedure to investigate the impact of group memberships on implicit bias and implicit group boundaries. Results from Experiment 1 indicated that categorizing targets using a shared category reduced implicit bias by increasing the extent to which positivity was associated with Blacks. Results from Experiment 2 revealed that shared group membership, but not mere positivity of a group membership, was necessary to reduce implicit bias. Quadruple process model analyses indicated that changes in implicit bias caused by shared group membership are due to changes in the way that targets are evaluated, not to changes in the regulation of evaluative bias. Results from Experiment 3 showed that categorizing Black targets into shared group memberships expanded implicit group boundaries.

  19. Constructing Group Learning.

    ERIC Educational Resources Information Center

    Heimlich, Joe E.

    1996-01-01

    Presents guidelines for constructing group learning activities, describes group learning methods (discussion, gaming, role play, simulation, projects), and provides tips for facilitating group activities. (SK)

  20. Fixed target facility at the SSC

    SciTech Connect

    Loken, S.C.; Morfin, J.G.

    1985-01-01

    The question of whether a facility for fixed target physics should be provided at the SSC must be answered before the final technical design of the SSC can be completed, particularly if the eventual form of extraction would influence the magnet design. To this end, an enthusiastic group of experimentalists, theoreticians and accelerator specialists have studied this point. The accelerator physics issues were addressed by a group led by E. Colton whose report is contained in these proceedings. The physics addressable by fixed target was considered by many of the Physics area working groups and in particular by the Structure Function Group. This report is the summary of the working group which considered various SSC fixed target experiments and determined which types of beams and detectors would be required. 13 references, 5 figures.

  1. Human target acquisition performance

    NASA Astrophysics Data System (ADS)

    Teaney, Brian P.; Du Bosq, Todd W.; Reynolds, Joseph P.; Thompson, Roger; Aghera, Sameer; Moyer, Steven K.; Flug, Eric; Espinola, Richard; Hixson, Jonathan

    2012-06-01

    The battlefield has shifted from armored vehicles to armed insurgents. Target acquisition (identification, recognition, and detection) range performance involving humans as targets is vital for modern warfare. The acquisition and neutralization of armed insurgents while at the same time minimizing fratricide and civilian casualties is a mounting concern. U.S. Army RDECOM CERDEC NVESD has conducted many experiments involving human targets for infrared and reflective band sensors. The target sets include human activities, hand-held objects, uniforms & armament, and other tactically relevant targets. This paper will define a set of standard task difficulty values for identification and recognition associated with human target acquisition performance.

  2. Magnetically attached sputter targets

    DOEpatents

    Makowiecki, D.M.; McKernan, M.A.

    1994-02-15

    An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material is described. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly. 11 figures.

  3. Magnetically attached sputter targets

    DOEpatents

    Makowiecki, Daniel M.; McKernan, Mark A.

    1994-01-01

    An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly.

  4. Group Dynamic Processes in Email Groups

    ERIC Educational Resources Information Center

    Alpay, Esat

    2005-01-01

    Discussion is given on the relevance of group dynamic processes in promoting decision-making in email discussion groups. General theories on social facilitation and social loafing are considered in the context of email groups, as well as the applicability of psychodynamic and interaction-based models. It is argued that such theories may indeed…

  5. Perceiving individuals and groups: expectancies, dispositional inferences, and causal attributions.

    PubMed

    Susskind, J; Maurer, K; Thakkar, V; Hamilton, D L; Sherman, J W

    1999-02-01

    Two experiments investigated differences in forming impressions of individual and group targets. Experiment 1 showed that when forming an impression of an individual, perceivers made more extreme trait judgments, made those judgments more quickly and with greater confidence, and recalled more information than when the impression target was a group. Experiment 2 showed that when participants were forming an impression of an individual, expectancy-inconsistent behaviors spontaneously triggered causal attributions to resolve the inconsistency; this was not the case when the impression target was a group. Results are interpreted as reflecting perceivers' a priori assumptions of unity and coherence in individual versus group targets.

  6. Representing and Scoring Track Hypotheses for Multitarget groups

    DTIC Science & Technology

    2007-11-02

    and are extended to a new observation (3) with 11 vehicles of the same type. Each N-track ( target group ) can contribute n of its vehicles to account...existing target groups , each group of some type and having vcj vehicles, whose tracks are being extended into the new observation; and possibly one new... target group of each type (two here) in the new observation with vc’i vehicles each; and the third factor is for false targets. The cost function will

  7. Targeted Cancer Therapies

    MedlinePlus

    ... targets is to determine whether cancer cells produce mutant (altered) proteins that drive cancer progression . For example, ... V600E) in many melanomas . Vemurafenib (Zelboraf®) targets this mutant form of the BRAF protein and is approved ...

  8. High Power Cryogenic Targets

    SciTech Connect

    Gregory Smith

    2011-08-01

    The development of high power cryogenic targets for use in parity violating electron scattering has been a crucial ingredient in the success of those experiments. As we chase the precision frontier, the demands and requirements for these targets have grown accordingly. We discuss the state of the art, and describe recent developments and strategies in the design of the next generation of these targets.

  9. An actionable climate target

    NASA Astrophysics Data System (ADS)

    Geden, Oliver

    2016-05-01

    The Paris Agreement introduced three mitigation targets. In the future, the main focus should not be on temperature targets such as 2 or 1.5 °C, but on the target with the greatest potential to effectively guide policy: net zero emissions.

  10. Adaptive infrared target detection

    NASA Astrophysics Data System (ADS)

    McBride, Jonah C.; Stevens, Mark R.; Eaton, Ross S.; Snorrason, Magnus S.

    2004-09-01

    Automatic Target Recognition (ATR) algorithms are extremely sensitive to differences between the operating conditions under which they are trained and the extended operating conditions (EOCs) in which the fielded algorithms are tested. These extended operating conditions can cause a target's signature to be drastically different from training exemplars/models. For example, a target's signature can be influenced by: the time of day, the time of year, the weather, atmospheric conditions, position of the sun or other illumination sources, the target surface and material properties, the target composition, the target geometry, sensor characteristics, sensor viewing angle and range, the target surroundings and environment, and the target and scene temperature. Recognition rates degrade if an ATR is not trained for a particular EOC. Most infrared target detection techniques are based on a very simple probabilistic theory. This theory states that a pixel should be assigned the label of "target" if a set of measurements (features) is more likely to have come from an assumed (or learned) distribution of target features than from the distribution of background features. However, most detection systems treat these learned distributions as static and they are not adapted to changing EOCs. In this paper, we present an algorithm for assigning a pixel the label of target or background based on a statistical comparison of the distributions of measurements surrounding that pixel in the image. This method provides a feature-level adaptation to changing EOCs. Results are demonstrated on infrared imagery containing several military vehicles.

  11. Can Groups Learn?

    ERIC Educational Resources Information Center

    Cohen, Elizabeth G.; Lotan, Rachel A.; Abram, Percy L.; Scarloss, Beth A.; Schultz, Susan E.

    2002-01-01

    Evaluated the work of sixth grade students' creative problem-solving groups, proposing that providing students with specific guidelines about what makes an exemplary group product would improve the character of the discussion and quality of the group product. Student groups did learn as a result of their discussions and creation of group products.…

  12. Small Groups in Action

    ERIC Educational Resources Information Center

    Suessmuth, Patrick

    1974-01-01

    Small groups can sometimes be difficult to set up and work with properly. A number of tips for small group instruction are divided into seven areas: (1) presenting tasks; (2) group seating; (3) task time; (4) answering questions; (5) teacher's role in observing groups; (6) group noise level patterns; and (7) serial take-ups. (BP)

  13. Lay Conceptions of Sexual Minority Groups.

    PubMed

    Burke, Sara E; LaFrance, Marianne

    2016-04-01

    Bisexual people are often implored to "pick a side," implying that bisexuality is both more controllable and less desirable than heterosexuality or homosexuality. Bisexual people's status as a social group perceived to fall between a traditionally advantaged group and a traditionally disadvantaged group may have the potential to clarify lay conceptions of sexual orientation. We examined participants' views of groups varying in sexual orientation by randomly assigning participants (including heterosexual men and women as well as gay men and lesbian women) from four samples to evaluate heterosexual, bisexual, or homosexual targets (N = 1379). Results provided strong evidence for the previously untested theoretical argument that bisexuality is perceived as less stable than heterosexuality or homosexuality. In addition, participants low in Personal Need for Structure rated female (but not male) bisexuality as relatively stable, suggesting that a preference for simple, binary thinking can partially explain a negative conception of an ostensibly "intermediate" identity. Bisexual targets were perceived as falling between heterosexual and homosexual targets in terms of gender nonconformity, and less decisive, less monogamous, and lacking in positive traits that were associated with homosexual targets. In sum, views of bisexual people were both more negative than and qualitatively different from views of gay men and lesbian women. We discuss the results as an illustration of the complex ways that perceivers' attitudes can differ depending on which target groups they are considering, suggesting that intergroup bias cannot be fully understood without attending to social categories viewed as intermediate.

  14. Group Work: How to Use Groups Effectively

    ERIC Educational Resources Information Center

    Burke, Alison

    2011-01-01

    Many students cringe and groan when told that they will need to work in a group. However, group work has been found to be good for students and good for teachers. Employers want college graduates to have developed teamwork skills. Additionally, students who participate in collaborative learning get better grades, are more satisfied with their…

  15. Group Time: Building Language at Group Time

    ERIC Educational Resources Information Center

    Church, Ellen Booth

    2004-01-01

    This article features energizing and surprising activities for children at group time. In the drawing activity, children are asked to give instructions on how to draw a picture using vocabulary and descriptive language. In the mailbox activity, children will be surprised to discover that they have mail at group time. Mailboxes can be used for…

  16. Bar coded retroreflective target

    DOEpatents

    Vann, Charles S.

    2000-01-01

    This small, inexpensive, non-contact laser sensor can detect the location of a retroreflective target in a relatively large volume and up to six degrees of position. The tracker's laser beam is formed into a plane of light which is swept across the space of interest. When the beam illuminates the retroreflector, some of the light returns to the tracker. The intensity, angle, and time of the return beam is measured to calculate the three dimensional location of the target. With three retroreflectors on the target, the locations of three points on the target are measured, enabling the calculation of all six degrees of target position. Until now, devices for three-dimensional tracking of objects in a large volume have been heavy, large, and very expensive. Because of the simplicity and unique characteristics of this tracker, it is capable of three-dimensional tracking of one to several objects in a large volume, yet it is compact, light-weight, and relatively inexpensive. Alternatively, a tracker produces a diverging laser beam which is directed towards a fixed position, and senses when a retroreflective target enters the fixed field of view. An optically bar coded target can be read by the tracker to provide information about the target. The target can be formed of a ball lens with a bar code on one end. As the target moves through the field, the ball lens causes the laser beam to scan across the bar code.

  17. Group B Strep Infection

    MedlinePlus

    ... Questions OverviewWhat is group B strep?Group B streptococcus, or group B strep for short, is a ... can develop an infection of the lungs (called pneumonia), bloodstream (called sepsis), or the fluid around the ...

  18. Chemoselective Hydroxyl Group Transformation: An Elusive Target‡

    PubMed Central

    Trader, Darci J.; Carlson, Erin E.

    2012-01-01

    The selective reaction of one functional group in the presence of others is not a trivial task. A noteworthy amount of research has been dedicated to the chemoselective reaction of the hydroxyl moiety. This group is prevalent in many biologically important molecules including natural products and proteins. However, targeting the hydroxyl group is difficult for many reasons including its relatively low nucleophilicity in comparison to other ubiquitous functional groups such as amines and thiols. Additionally, many of the developed chemoselective reactions cannot be used in the presence of water. Despite these complications, chemoselective transformation of the hydroxyl moiety has been utilized in the synthesis of complex natural product derivatives, the reaction of tyrosine residues in proteins, the isolation of natural products and is the mechanism of action of myriad drugs. Here, methods for selective targeting of this group, as well as applications of several devised methods, are described. PMID:22695722

  19. Grouping Factors and the Reverse Contrast Illusion.

    PubMed

    Economou, Elias; Zdravković, Sunčica; Gilchrist, Alan

    2015-12-01

    In simultaneous lightness contrast, two identical gray target squares lying on backgrounds of different intensities appear different in lightness. Traditionally, this illusion was explained by lateral inhibitory mechanisms operating retinotopically. More recently, spatial filtering models have been preferred. We report tests of an anchoring theory account in which the illusion is attributed to grouping rules used by the visual system to compute lightness. We parametrically varied the belongingness of two gray target bars to their respective backgrounds so that they either appeared to group with a set of bars flanking them, or they appeared to group with their respective backgrounds. In all variations, the retinal adjacency of the gray squares and their backgrounds was essentially unchanged. We report data from seven experiments showing that manipulation of the grouping rules governs the size and direction of the simultaneous lightness contrast illusion. These results support the idea that simultaneous lightness contrast is the product of anchoring within perceptual groups.

  20. Targeting Notch to target cancer stem cells.

    PubMed

    Pannuti, Antonio; Foreman, Kimberly; Rizzo, Paola; Osipo, Clodia; Golde, Todd; Osborne, Barbara; Miele, Lucio

    2010-06-15

    The cellular heterogeneity of neoplasms has been at the center of considerable interest since the "cancer stem cell hypothesis", originally formulated for hematologic malignancies, was extended to solid tumors. The origins of cancer "stem" cells (CSC) or tumor-initiating cells (TIC; henceforth referred to as CSCs) and the methods to identify them are hotly debated topics. Nevertheless, the existence of subpopulations of tumor cells with stem-like characteristics has significant therapeutic implications. The stem-like phenotype inc