The Experts below are selected from a list of 1632 Experts worldwide ranked by ideXlab platform
Hisao Masai - One of the best experts on this subject based on the ideXlab platform.
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epstein barr nuclear antigen 1 ebna1 dependent recruitment of origin recognition complex orc on orip of epstein barr virus with purified proteins stimulation by cdc6 through its direct interaction with ebna1
Journal of Biological Chemistry, 2012Co-Authors: Kenji Moriyama, Naoko Yoshizawasugata, Chikashi Obuse, Toshiki Tsurimoto, Hisao MasaiAbstract:Abstract Origin recognition complex (Orc) plays an essential role in directing assembly of prereplicative complex at selective sites on chromosomes. However, Orc from vertebrates is reported to bind to DNA in a sequence-nonspecific manner, and it is still unclear how it selects specific genomic loci and how Cdc6, another conserved AAA+ factor known to interact with Orc, participates in this process. Replication from oriP, the latent origin of Epstein-Barr virus, provides an excellent model system for the study of initiation on the host chromosomes because it is known to depend on prereplicative complex factors, including Orc and Mcm. Here, we show that Orc is recruited selectively at the essential Dyad Symmetry element in nuclear extracts in a manner dependent on EBNA1, which specifically binds to Dyad Symmetry. With purified proteins, EBNA1 can recruit both Cdc6 and Orc independently on a DNA containing EBNA1 binding sites, and Cdc6 facilitates the Orc recruitment by EBNA1. Purified Cdc6 directly binds to EBNA1, whereas association of Orc with EBNA1 requires the presence of the oriP DNA. Nuclease protection assays suggest that Orc associates with DNA segments on both sides adjacent to the EBNA1 binding sites and that this process is stimulated by the presence of Cdc6. Thus, EBNA1 can direct localized assembly of Orc in a process that is facilitated by Cdc6. The possibility of similar modes of recruitment of Orc/Cdc6 at the human chromosomal origins will be discussed.
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epstein barr nuclear antigen 1 ebna1 dependent recruitment of origin recognition complex orc on orip of epstein barr virus with purified proteins stimulation by cdc6 through its direct interaction with ebna1
Journal of Biological Chemistry, 2012Co-Authors: Kenji Moriyama, Naoko Yoshizawasugata, Chikashi Obuse, Toshiki Tsurimoto, Hisao MasaiAbstract:Origin recognition complex (Orc) plays an essential role in directing assembly of prereplicative complex at selective sites on chromosomes. However, Orc from vertebrates is reported to bind to DNA in a sequence-nonspecific manner, and it is still unclear how it selects specific genomic loci and how Cdc6, another conserved AAA+ factor known to interact with Orc, participates in this process. Replication from oriP, the latent origin of Epstein-Barr virus, provides an excellent model system for the study of initiation on the host chromosomes because it is known to depend on prereplicative complex factors, including Orc and Mcm. Here, we show that Orc is recruited selectively at the essential Dyad Symmetry element in nuclear extracts in a manner dependent on EBNA1, which specifically binds to Dyad Symmetry. With purified proteins, EBNA1 can recruit both Cdc6 and Orc independently on a DNA containing EBNA1 binding sites, and Cdc6 facilitates the Orc recruitment by EBNA1. Purified Cdc6 directly binds to EBNA1, whereas association of Orc with EBNA1 requires the presence of the oriP DNA. Nuclease protection assays suggest that Orc associates with DNA segments on both sides adjacent to the EBNA1 binding sites and that this process is stimulated by the presence of Cdc6. Thus, EBNA1 can direct localized assembly of Orc in a process that is facilitated by Cdc6. The possibility of similar modes of recruitment of Orc/Cdc6 at the human chromosomal origins will be discussed. Background: Enzymatic studies on the steps of mammalian DNA replication with purified proteins are essential to elucidate its mechanisms. Results: Association of Orc with oriP requires EBNA1 and is stimulated by Cdc6 directly interacting with EBNA1. Conclusion: EBNA1 recruits Cdc6/Orc at oriP, permitting site-specific assembly of pre-RC. Significance: This study provides novel insight into a mechanism for initiation of mammalian DNA replication with purified factors.
Reinhard Kurth - One of the best experts on this subject based on the ideXlab platform.
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ga binding protein factors in concert with the coactivator creb binding protein p300 control the induction of the interleukin 16 promoter in t lymphocytes
Proceedings of the National Academy of Sciences of the United States of America, 1999Co-Authors: Norbert Bannert, Michael Baier, Andris Avots, Edgar Serfling, Reinhard KurthAbstract:Interleukin 16 (IL-16) is a chemotactic cytokine that binds to the CD4 receptor and affects the activation of T cells and replication of HIV. It is expressed as a large 67-kDa precursor protein (pro-IL-16) in lymphocytes, macrophages, and mast cells, as well as in airway epithelial cells from asthmatics after challenge with allergen. This pro-IL-16 is subsequently processed to the mature cytokine of 13 kDa. To study the expression of IL-16 at the transcriptional level, we cloned the human chromosomal IL-16 gene and analyzed its promoter. The human IL-16 gene consists of seven exons and six introns. The 5′ sequences up to nucleotide −120 of the human and murine IL-16 genes share >84% sequence homology and harbor promoter elements for constitutive and inducible transcription in T cells. Although both promoters lack any TATA box, they contain two CAAT box-like motifs and three binding sites of GA-binding protein (GABP) transcription factors. Two of these motifs are part of a highly conserved and inducible Dyad Symmetry element shown previously to control a remote IL-2 enhancer and the CD18 promoter. In concert with the coactivator CREB binding protein/p300, which interacts with GABPα, the binding of GABPα and -β to the Dyad Symmetry element controls the induction of IL-16 promoter in T cells. Supplementing the data on the processing of pro-IL-16, our results indicate the complexity of IL-16 expression, which is tightly controlled at the transcriptional and posttranslational levels in T lymphocytes.
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GA-binding protein factors, in concert with the coactivator CREB binding protein/p300, control the induction of the interleukin 16 promoter in T lymphocytes.
Proceedings of the National Academy of Sciences of the United States of America, 1999Co-Authors: Norbert Bannert, Michael Baier, Andris Avots, Edgar Serfling, Reinhard KurthAbstract:Interleukin 16 (IL-16) is a chemotactic cytokine that binds to the CD4 receptor and affects the activation of T cells and replication of HIV. It is expressed as a large 67-kDa precursor protein (pro-IL-16) in lymphocytes, macrophages, and mast cells, as well as in airway epithelial cells from asthmatics after challenge with allergen. This pro-IL-16 is subsequently processed to the mature cytokine of 13 kDa. To study the expression of IL-16 at the transcriptional level, we cloned the human chromosomal IL-16 gene and analyzed its promoter. The human IL-16 gene consists of seven exons and six introns. The 5′ sequences up to nucleotide −120 of the human and murine IL-16 genes share >84% sequence homology and harbor promoter elements for constitutive and inducible transcription in T cells. Although both promoters lack any TATA box, they contain two CAAT box-like motifs and three binding sites of GA-binding protein (GABP) transcription factors. Two of these motifs are part of a highly conserved and inducible Dyad Symmetry element shown previously to control a remote IL-2 enhancer and the CD18 promoter. In concert with the coactivator CREB binding protein/p300, which interacts with GABPα, the binding of GABPα and -β to the Dyad Symmetry element controls the induction of IL-16 promoter in T cells. Supplementing the data on the processing of pro-IL-16, our results indicate the complexity of IL-16 expression, which is tightly controlled at the transcriptional and posttranslational levels in T lymphocytes.
Kenji Moriyama - One of the best experts on this subject based on the ideXlab platform.
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epstein barr nuclear antigen 1 ebna1 dependent recruitment of origin recognition complex orc on orip of epstein barr virus with purified proteins stimulation by cdc6 through its direct interaction with ebna1
Journal of Biological Chemistry, 2012Co-Authors: Kenji Moriyama, Naoko Yoshizawasugata, Chikashi Obuse, Toshiki Tsurimoto, Hisao MasaiAbstract:Abstract Origin recognition complex (Orc) plays an essential role in directing assembly of prereplicative complex at selective sites on chromosomes. However, Orc from vertebrates is reported to bind to DNA in a sequence-nonspecific manner, and it is still unclear how it selects specific genomic loci and how Cdc6, another conserved AAA+ factor known to interact with Orc, participates in this process. Replication from oriP, the latent origin of Epstein-Barr virus, provides an excellent model system for the study of initiation on the host chromosomes because it is known to depend on prereplicative complex factors, including Orc and Mcm. Here, we show that Orc is recruited selectively at the essential Dyad Symmetry element in nuclear extracts in a manner dependent on EBNA1, which specifically binds to Dyad Symmetry. With purified proteins, EBNA1 can recruit both Cdc6 and Orc independently on a DNA containing EBNA1 binding sites, and Cdc6 facilitates the Orc recruitment by EBNA1. Purified Cdc6 directly binds to EBNA1, whereas association of Orc with EBNA1 requires the presence of the oriP DNA. Nuclease protection assays suggest that Orc associates with DNA segments on both sides adjacent to the EBNA1 binding sites and that this process is stimulated by the presence of Cdc6. Thus, EBNA1 can direct localized assembly of Orc in a process that is facilitated by Cdc6. The possibility of similar modes of recruitment of Orc/Cdc6 at the human chromosomal origins will be discussed.
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epstein barr nuclear antigen 1 ebna1 dependent recruitment of origin recognition complex orc on orip of epstein barr virus with purified proteins stimulation by cdc6 through its direct interaction with ebna1
Journal of Biological Chemistry, 2012Co-Authors: Kenji Moriyama, Naoko Yoshizawasugata, Chikashi Obuse, Toshiki Tsurimoto, Hisao MasaiAbstract:Origin recognition complex (Orc) plays an essential role in directing assembly of prereplicative complex at selective sites on chromosomes. However, Orc from vertebrates is reported to bind to DNA in a sequence-nonspecific manner, and it is still unclear how it selects specific genomic loci and how Cdc6, another conserved AAA+ factor known to interact with Orc, participates in this process. Replication from oriP, the latent origin of Epstein-Barr virus, provides an excellent model system for the study of initiation on the host chromosomes because it is known to depend on prereplicative complex factors, including Orc and Mcm. Here, we show that Orc is recruited selectively at the essential Dyad Symmetry element in nuclear extracts in a manner dependent on EBNA1, which specifically binds to Dyad Symmetry. With purified proteins, EBNA1 can recruit both Cdc6 and Orc independently on a DNA containing EBNA1 binding sites, and Cdc6 facilitates the Orc recruitment by EBNA1. Purified Cdc6 directly binds to EBNA1, whereas association of Orc with EBNA1 requires the presence of the oriP DNA. Nuclease protection assays suggest that Orc associates with DNA segments on both sides adjacent to the EBNA1 binding sites and that this process is stimulated by the presence of Cdc6. Thus, EBNA1 can direct localized assembly of Orc in a process that is facilitated by Cdc6. The possibility of similar modes of recruitment of Orc/Cdc6 at the human chromosomal origins will be discussed. Background: Enzymatic studies on the steps of mammalian DNA replication with purified proteins are essential to elucidate its mechanisms. Results: Association of Orc with oriP requires EBNA1 and is stimulated by Cdc6 directly interacting with EBNA1. Conclusion: EBNA1 recruits Cdc6/Orc at oriP, permitting site-specific assembly of pre-RC. Significance: This study provides novel insight into a mechanism for initiation of mammalian DNA replication with purified factors.
Norbert Bannert - One of the best experts on this subject based on the ideXlab platform.
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ga binding protein factors in concert with the coactivator creb binding protein p300 control the induction of the interleukin 16 promoter in t lymphocytes
Proceedings of the National Academy of Sciences of the United States of America, 1999Co-Authors: Norbert Bannert, Michael Baier, Andris Avots, Edgar Serfling, Reinhard KurthAbstract:Interleukin 16 (IL-16) is a chemotactic cytokine that binds to the CD4 receptor and affects the activation of T cells and replication of HIV. It is expressed as a large 67-kDa precursor protein (pro-IL-16) in lymphocytes, macrophages, and mast cells, as well as in airway epithelial cells from asthmatics after challenge with allergen. This pro-IL-16 is subsequently processed to the mature cytokine of 13 kDa. To study the expression of IL-16 at the transcriptional level, we cloned the human chromosomal IL-16 gene and analyzed its promoter. The human IL-16 gene consists of seven exons and six introns. The 5′ sequences up to nucleotide −120 of the human and murine IL-16 genes share >84% sequence homology and harbor promoter elements for constitutive and inducible transcription in T cells. Although both promoters lack any TATA box, they contain two CAAT box-like motifs and three binding sites of GA-binding protein (GABP) transcription factors. Two of these motifs are part of a highly conserved and inducible Dyad Symmetry element shown previously to control a remote IL-2 enhancer and the CD18 promoter. In concert with the coactivator CREB binding protein/p300, which interacts with GABPα, the binding of GABPα and -β to the Dyad Symmetry element controls the induction of IL-16 promoter in T cells. Supplementing the data on the processing of pro-IL-16, our results indicate the complexity of IL-16 expression, which is tightly controlled at the transcriptional and posttranslational levels in T lymphocytes.
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GA-binding protein factors, in concert with the coactivator CREB binding protein/p300, control the induction of the interleukin 16 promoter in T lymphocytes.
Proceedings of the National Academy of Sciences of the United States of America, 1999Co-Authors: Norbert Bannert, Michael Baier, Andris Avots, Edgar Serfling, Reinhard KurthAbstract:Interleukin 16 (IL-16) is a chemotactic cytokine that binds to the CD4 receptor and affects the activation of T cells and replication of HIV. It is expressed as a large 67-kDa precursor protein (pro-IL-16) in lymphocytes, macrophages, and mast cells, as well as in airway epithelial cells from asthmatics after challenge with allergen. This pro-IL-16 is subsequently processed to the mature cytokine of 13 kDa. To study the expression of IL-16 at the transcriptional level, we cloned the human chromosomal IL-16 gene and analyzed its promoter. The human IL-16 gene consists of seven exons and six introns. The 5′ sequences up to nucleotide −120 of the human and murine IL-16 genes share >84% sequence homology and harbor promoter elements for constitutive and inducible transcription in T cells. Although both promoters lack any TATA box, they contain two CAAT box-like motifs and three binding sites of GA-binding protein (GABP) transcription factors. Two of these motifs are part of a highly conserved and inducible Dyad Symmetry element shown previously to control a remote IL-2 enhancer and the CD18 promoter. In concert with the coactivator CREB binding protein/p300, which interacts with GABPα, the binding of GABPα and -β to the Dyad Symmetry element controls the induction of IL-16 promoter in T cells. Supplementing the data on the processing of pro-IL-16, our results indicate the complexity of IL-16 expression, which is tightly controlled at the transcriptional and posttranslational levels in T lymphocytes.
Aloys Schepers - One of the best experts on this subject based on the ideXlab platform.
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The Dyad Symmetry Element of Epstein-Barr Virus Is a Dominant but Dispensable Replication Origin
2011Co-Authors: Elisabeth Ott, Paolo Norio ¤a, Marion Ritzi ¤b, Carl Schildkraut, Aloys SchepersAbstract:OriP, the latent origin of Epstein-Barr virus (EBV), consists of two essential elements: the Dyad Symmetry (DS) and the family of repeats (FR). The function of these elements has been predominantly analyzed in plasmids transfected into transformed cells. Here, we examined the molecular functions of DS in its native genomic context and at an ectopic position in the mini-EBV episome. Mini-EBV plasmids contain 41 % of the EBV genome including all information required for the proliferation of human B cells. Both FR and DS function independently of their genomic context. We show that DS is the most active origin of replication present in the mini-EBV genome regardless of its location, and it is characterized by the binding of the origin recognition complex (ORC) allowing subsequent replication initiation. Surprisingly, the integrity of oriP is not required for the formation of the pre-replicative complex (pre-RC) at or near DS. In addition we show that initiation events occurring at sites other than the DS are also limited to once per cell cycle and that they are ORC-dependent. The deletion of DS increases initiation from alternative origins, which are normally used very infrequently in the mini-EBV genome. The sequenceindependent distribution of ORC-binding, pre-RC-assembly, and initiation patterns indicates that a large number of silent origins are present in the mini-EBV genome. We conclude that, in mini-EBV genomes lacking the DS element, the absence o
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cell cycle regulation of chromatin at an origin of dna replication
The EMBO Journal, 2005Co-Authors: Jing Zhou, Aloys Schepers, Charles M Chau, Zhong Deng, Ramin Shiekhattar, Mark Peter Spindler, Paul M LiebermanAbstract:Selection and licensing of mammalian DNA replication origins may be regulated by epigenetic changes in chromatin structure. The Epstein–Barr virus (EBV) origin of plasmid replication (OriP) uses the cellular licensing machinery to regulate replication during latent infection of human cells. We found that the minimal replicator sequence of OriP, referred to as the Dyad Symmetry (DS), is flanked by nucleosomes. These nucleosomes were subject to cell cycle-dependent chromatin remodeling and histone modifications. Restriction enzyme accessibility assay indicated that the DS-bounded nucleosomes were remodeled in late G1. Remarkably, histone H3 acetylation of DS-bounded nucleosomes decreased during late G1, coinciding with nucleosome remodeling and MCM3 loading, and preceding the onset of DNA replication. The ATP-dependent chromatin-remodeling factor SNF2h was also recruited to DS in late G1, and formed a stable complex with HDAC2 at DS. siRNA depletion of SNF2h reduced G1-specific nucleosome remodeling, histone deacetylation, and MCM3 loading at DS. We conclude that an SNF2h–HDAC1/2 complex coordinates G1-specific chromatin remodeling and histone deacetylation with the DNA replication initiation process at OriP.
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human origin recognition complex binds to the region of the latent origin of dna replication of epstein barr virus
The EMBO Journal, 2001Co-Authors: Aloys Schepers, Marion Ritzi, Janet Harwood, John F X Diffley, Kristine Bousset, Elisabeth Kremmer, John L Yates, Wolfgang HammerschmidtAbstract:Epstein–Barr virus (EBV) replicates in its latent phase once per cell cycle in proliferating B cells. The latent origin of DNA replication, oriP, supports replication and stable maintenance of the EBV genome. OriP comprises two essential elements: the Dyad Symmetry (DS) and the family of repeats (FR), both containing clusters of binding sites for the transactivator EBNA1. The DS element appears to be the functional replicator. It is not yet understood how oriP-dependent replication is integrated into the cell cycle and how EBNA1 acts at the molecular level. Using chromatin immunoprecipitation experiments, we show that the human origin recognition complex (hsORC) binds at or near the DS element. The association of hsORC with oriP depends on the DS element. Deletion of this element not only abolishes hsORC binding but also reduces replication initiation at oriP to background level. Co-immunoprecipitation experiments indicate that EBNA1 is associated with hsORC in vivo. These results indicate that oriP might use the same cellular initiation factors that regulate chromosomal replication, and that EBNA1 may be involved in recruiting hsORC to oriP.
