The Experts below are selected from a list of 91260 Experts worldwide ranked by ideXlab platform

Wen-hwa Lee - One of the best experts on this subject based on the ideXlab platform.

  • Temporal, spatial, and cell type–specific control of Cre-mediated DNA Recombination in transgenic mice
    Nature Biotechnology, 1999
    Co-Authors: Ahmad R.h. Utomo, Alexander Yu. Nikitin, Wen-hwa Lee
    Abstract:

    We have developed a universal system for temporal, spatial, and cell type–specific control of gene expression in mice that (1) integrates the advantages of tetracycline-controlled gene expression and Cre-recombinase- loxP site-mediated gene inactivation, and (2) simplifies schemes of animal crosses by combination of two control elements in a single transgene. Two transgenic strains were generated in which the cell type–specific control was provided by either the retinoblastoma gene promoter or the whey acidic protein promoter. Both promoters drive the expression of the reverse tetracycline-controlled transactivator (rtTA). Placed in cis configuration to the rtTA transcription unit, the rtTA-inducible promoter directs expression of Cre recombinase. In both strains crossed with cActXstopXLacZ reporter mice, which have a loxP -stop of transcription/translation- loxP - LacZ cassette driven by chicken β-actin promoter, Cre- loxP -mediated DNA Recombination leading to LacZ expression was accurately regulated in a temporal, spatial, and cell type-specific manner. This approach can be applied to establishment of analogous mouse strains with virtually any promoter as systems to control gene regulation in a variety of cell types.

  • Temporal, spatial, and cell type-specific control of Cre-mediated DNA Recombination in transgenic mice.
    Nature biotechnology, 1999
    Co-Authors: Ahmad Utomo, Alexander Yu. Nikitin, Wen-hwa Lee
    Abstract:

    We have developed a universal system for temporal, spatial, and cell type–specific control of gene expression in mice that (1) integrates the advantages of tetracycline-controlled gene expression and Cre-recombinase-loxP site-mediated gene inactivation, and (2) simplifies schemes of animal crosses by combination of two control elements in a single transgene. Two transgenic strains were generated in which the cell type–specific control was provided by either the retinoblastoma gene promoter or the whey acidic protein promoter. Both promoters drive the expression of the reverse tetracycline-controlled transactivator (rtTA). Placed in cis configuration to the rtTA transcription unit, the rtTA-inducible promoter directs expression of Cre recombinase. In both strains crossed with cActXstopXLacZ reporter mice, which have a loxP-stop of transcription/translation-loxP-LacZ cassette driven by chicken β-actin promoter, Cre-loxP-mediated DNA Recombination leading to LacZ expression was accurately regulated in a temporal, spatial, and cell type-specific manner. This approach can be applied to establishment of analogous mouse strains with virtually any promoter as systems to control gene regulation in a variety of cell types.

Kiyoshi Mizuuchi - One of the best experts on this subject based on the ideXlab platform.

  • polynucleotidyl transfer reactions in site specific DNA Recombination
    Genes to Cells, 1997
    Co-Authors: Kiyoshi Mizuuchi
    Abstract:

    : Site-specific DNA rearrangement reactions are widespread among organisms. They are used, for example, by vertebrates to boost immune response diversity, and in turn by parasitic organisms to evade the host immune system by surface antigen switching. Parasitic genetic elements ubiquitous to most organisms invade new host genomic sites by a variety of types of site-specific Recombination. Polynucleotidyl transfer reactions are central to these DNA Recombination reactions. The recombinase of each reaction system that 'catalyses' such chemical reactions at specific DNA sites are apparently designed to accomplish unique DNA geometrical specificity, or delicate control over the extent or direction of the reaction, with the sacrifice of protein turnover. Here we discuss our current understanding of several issues that relate to the polynucleotidyl transfer steps in several of the better studied site-specific Recombination reactions.

  • Polynucleotidyl transfer reactions in site‐specific DNA Recombination
    Genes to cells : devoted to molecular & cellular mechanisms, 1997
    Co-Authors: Kiyoshi Mizuuchi
    Abstract:

    Site-specific DNA rearrangement reactions are widespread among organisms. They are used, for example, by vertebrates to boost immune response diversity, and in turn by parasitic organisms to evade the host immune system by surface antigen switching. Parasitic genetic elements ubiquitous to most organisms invade new host genomic sites by a variety of types of site-specific Recombination. Polynucleotidyl transfer reactions are central to these DNA Recombination reactions. The recombinase of each reaction system that ‘catalyses’ such chemical reactions at specific DNA sites are apparently designed to accomplish unique DNA geometrical specificity, or delicate control over the extent or direction of the reaction, with the sacrifice of protein turnover. Here we discuss our current understanding of several issues that relate to the polynucleotidyl transfer steps in several of the better studied site-specific Recombination reactions.

Ashok R. Venkitaraman - One of the best experts on this subject based on the ideXlab platform.

  • Emerging functions of BRCA2 in DNA Recombination.
    Trends in biochemical sciences, 2004
    Co-Authors: Luca Pellegrini, Ashok R. Venkitaraman
    Abstract:

    Mutations in the breast cancer susceptibility protein BRCA2 cause inherited susceptibility to breast, ovarian and other cancers. There is now compelling experimental evidence that a major biological function of BRCA2 is the maintenance of chromosome structure stability in dividing cells by regulation of steps in Recombination between homologous DNA strands. Recent experimental findings shape the current models for BRCA2 function, and structural and biochemical advances shed new light on the interactions between BRCA2, the RAD51 recombinase and single-stranded DNA during DNA Recombination.

  • DNA Recombination, chromosomal stability and carcinogenesis: insights into the role of BRCA2.
    DNA repair, 2004
    Co-Authors: Mahmud K K Shivji, Ashok R. Venkitaraman
    Abstract:

    Germline mutations affecting a single allele of BRCA2 increase susceptibility to breast and ovarian cancer, whilst germline inheritance of certain bi-allelic mutations causes a Fanconi anaemia-like syndrome. Here, we review current knowledge of the BRCA2 protein, focussing on recent studies that provide mechanistic insight into its biological function in regulating DNA Recombination reactions mediated by the RAD51 recombinase. We argue that the chromosomal instability and cancer predisposition provoked by BRCA2 inactivation are a consequence of the failure to re-start stalled DNA replication, and to repair DNA double-strand breaks, through error-free pathways that depend on homologous pairing between DNA strands.

  • insights into DNA Recombination from the structure of a rad51 brca2 complex
    Nature, 2002
    Co-Authors: Luca Pellegrini, David S Yu, Thomas Lo, Shubha Anand, T L Blundell, Ashok R. Venkitaraman
    Abstract:

    The breast cancer susceptibility protein BRCA2 controls the function of RAD51, a recombinase enzyme, in pathways for DNA repair by homologous Recombination. We report here the structure of a complex between an evolutionarily conserved sequence in BRCA2 (the BRC repeat) and the RecA-homology domain of RAD51. The BRC repeat mimics a motif in RAD51 that serves as an interface for oligomerization between individual RAD51 monomers, thus enabling BRCA2 to control the assembly of the RAD51 nucleoprotein filament, which is essential for strand-pairing reactions during DNA Recombination. The RAD51 oligomerization motif is highly conserved among RecA-like recombinases, highlighting a common evolutionary origin for the mechanism of nucleoprotein filament formation, mirrored in the BRC repeat. Cancer-associated mutations that affect the BRC repeat disrupt its predicted interaction with RAD51, yielding structural insight into mechanisms for cancer susceptibility.

  • Chromosome stability, DNA Recombination and the BRCA2 tumour suppressor.
    Current opinion in cell biology, 2001
    Co-Authors: Ashok R. Venkitaraman
    Abstract:

    The BRCA2 tumour suppressor works in DNA Recombination and repair pathways to preserve genome integrity. Recent progress provides fresh insights into its role as a regulator of the Rad51 Recombination protein, underpinning a model in which BRCA2's involvement in chromosome stability and tumour suppression arises from its participation in Recombinational processes essential for DNA replication.

T. Ellenberger - One of the best experts on this subject based on the ideXlab platform.

  • A structural basis for allosteric control of DNA Recombination by λ integrase
    Nature, 2005
    Co-Authors: T. Biswas, H. Aihara, M. Radman-livaja, D. Filman, A. Landy, T. Ellenberger
    Abstract:

    Site-specific DNA Recombination is important for basic cellular functions including viral integration, control of gene expression, production of genetic diversity and segregation of newly replicated chromosomes, and is used by bacteriophage λ to integrate or excise its genome into and out of the host chromosome. λ Recombination is carried out by the bacteriophage-encoded integrase protein (λ -int) together with accessory DNA sites and associated bending proteins that allow regulation in response to cell physiology. Here we report the crystal structures of λ -int in higher-order complexes with substrates and regulatory DNAs representing different intermediates along the reaction pathway. The structures show how the simultaneous binding of two separate domains of λ -int to DNA facilitates synapsis and can specify the order of DNA strand cleavage and exchange. An intertwined layer of amino-terminal domains bound to accessory (arm) DNAs shapes the Recombination complex in a way that suggests how arm binding shifts the reaction equilibrium in favour of recombinant products.

  • A structural basis for allosteric control of DNA Recombination by lambda integrase
    Nature, 2005
    Co-Authors: T. Biswas, H. Aihara, M. Radman-livaja, D. Filman, A. Landy, T. Ellenberger
    Abstract:

    Site-specific DNA Recombination is important for basic cellular functions including viral integration, control of gene expression, production of genetic diversity and segregation of newly replicated chromosomes, and is used by bacteriophage lambda to integrate or excise its genome into and out of the host chromosome. lambda Recombination is carried out by the bacteriophage-encoded integrase protein (lambda-int) together with accessory DNA sites and associated bending proteins that allow regulation in response to cell physiology. Here we report the crystal structures of lambda-int in higher-order complexes with substrates and regulatory DNAs representing different intermediates along the reaction pathway. The structures show how the simultaneous binding of two separate domains of lambda-int to DNA facilitates synapsis and can specify the order of DNA strand cleavage and exchange. An intertwined layer of amino-terminal domains bound to accessory (arm) DNAs shapes the Recombination complex in a way that suggests how arm binding shifts the reaction equilibrium in favour of recombinant products.

Alexander Yu. Nikitin - One of the best experts on this subject based on the ideXlab platform.

  • Temporal, spatial, and cell type–specific control of Cre-mediated DNA Recombination in transgenic mice
    Nature Biotechnology, 1999
    Co-Authors: Ahmad R.h. Utomo, Alexander Yu. Nikitin, Wen-hwa Lee
    Abstract:

    We have developed a universal system for temporal, spatial, and cell type–specific control of gene expression in mice that (1) integrates the advantages of tetracycline-controlled gene expression and Cre-recombinase- loxP site-mediated gene inactivation, and (2) simplifies schemes of animal crosses by combination of two control elements in a single transgene. Two transgenic strains were generated in which the cell type–specific control was provided by either the retinoblastoma gene promoter or the whey acidic protein promoter. Both promoters drive the expression of the reverse tetracycline-controlled transactivator (rtTA). Placed in cis configuration to the rtTA transcription unit, the rtTA-inducible promoter directs expression of Cre recombinase. In both strains crossed with cActXstopXLacZ reporter mice, which have a loxP -stop of transcription/translation- loxP - LacZ cassette driven by chicken β-actin promoter, Cre- loxP -mediated DNA Recombination leading to LacZ expression was accurately regulated in a temporal, spatial, and cell type-specific manner. This approach can be applied to establishment of analogous mouse strains with virtually any promoter as systems to control gene regulation in a variety of cell types.

  • Temporal, spatial, and cell type-specific control of Cre-mediated DNA Recombination in transgenic mice.
    Nature biotechnology, 1999
    Co-Authors: Ahmad Utomo, Alexander Yu. Nikitin, Wen-hwa Lee
    Abstract:

    We have developed a universal system for temporal, spatial, and cell type–specific control of gene expression in mice that (1) integrates the advantages of tetracycline-controlled gene expression and Cre-recombinase-loxP site-mediated gene inactivation, and (2) simplifies schemes of animal crosses by combination of two control elements in a single transgene. Two transgenic strains were generated in which the cell type–specific control was provided by either the retinoblastoma gene promoter or the whey acidic protein promoter. Both promoters drive the expression of the reverse tetracycline-controlled transactivator (rtTA). Placed in cis configuration to the rtTA transcription unit, the rtTA-inducible promoter directs expression of Cre recombinase. In both strains crossed with cActXstopXLacZ reporter mice, which have a loxP-stop of transcription/translation-loxP-LacZ cassette driven by chicken β-actin promoter, Cre-loxP-mediated DNA Recombination leading to LacZ expression was accurately regulated in a temporal, spatial, and cell type-specific manner. This approach can be applied to establishment of analogous mouse strains with virtually any promoter as systems to control gene regulation in a variety of cell types.