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R L Teplitz - One of the best experts on this subject based on the ideXlab platform.
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Telomere Telomere interactions and candidate Telomere Binding Protein s in mammalian sperm cells
Experimental Cell Research, 1997Co-Authors: Andrei O. Zalensky, Nikolai V. Tomilin, Irina A. Zalenskaya, R L TeplitzAbstract:We have used fluorescent in situ hybridization to localize Telomeres within the nuclei of sperm from six mammals (human, rat, mouse, stallion, boar, and bull). In minimally swollen sperm of mouse and rat, most of the Telomeres are clustered within a limited area in the posterior part of nuclei. In sperm of other species, Telomeres associate into tetrameres and dimers. On swelling of sperm cells with heparin/dithiotriethol, Telomere associations disperse, and hybridization signals become smaller in size and their numbers approach or correspond to the number of chromosome ends in a haploid genome. Quantitation of Telomere loci indicates that dimeric associations are prominent features of mammalian sperm nuclear architecture. Higher order Telomere-Telomere interactions and organization develop during meiotic stages of human spermatogenesis. At this stage, Telomeres also become associated with the nuclear membrane. In an attempt to elucidate the molecular mechanisms underlying Telomere interactions in sperm, we have identified a novel Protein activity that binds to the double-stranded telomeric repeat (TTAGGG)n. Sperm Telomere Binding Protein(s) (STBP) was extracted from human and bull sperm by 0.5 M NaCl. STBP does not bind single-stranded telomeric DNA and is highly specific for single base substitutions in a duplex DNA sequence. Depending on the conditions of Binding, we observed the formation of several nucleoProtein complexes. We have shown that there is a transition between complexes, which indicates that the slower migrating complex is a multimer of the higher mobility one. We propose that STBP participates in association between the Telomere domains which were microscopically observed in mammalian spermatozoa.
H J Lipps - One of the best experts on this subject based on the ideXlab platform.
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Organization of the macronuclear gene-sized pieces of stichotrichous ciliates into a higher order structure via Telomere–matrix interactions
Chromosome Research, 2002Co-Authors: F Jönsson, J Postberg, Christiane Schaffitzel, H J LippsAbstract:Macronuclear DNA of stichotrichous ciliates occurs in small ‘gene-sized’ molecules with sizes of about 0.5 to 40 kb. Each of these molecules is terminated by telomeric sequences of defined length. A single macronucleus contains up to 10^8 DNA molecules; due to the high concentration of telomeric sequences in this nucleus it is an attractive model to study Telomere behaviour. We recently provided evidence that macronuclear Telomeres are attached to the nuclear matrix and that this interaction is mediated by the Telomere Binding Protein (TeBP). Using various experimental approaches, we now demonstrate that Telomeres as well as both subunits of the Telomere Binding Protein are associated with the nuclear matrix. However, there is no direct Binding of telomeric DNA to the matrix but Telomere matrix interaction is exclusively mediated by the TeBP. In addition, we show that telomeric sequences adopt in vivo the antiparallel G-quartet structure when bound to the nuclear matrix. These data not only allow us to propose a model for macronuclear architecture but may also be relevant for further analysis of Telomere–matrix interactions in higher eukaryotes.
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organization of the macronuclear gene sized pieces of stichotrichous ciliates into a higher order structure via Telomere matrix interactions
Chromosome Research, 2002Co-Authors: F Jönsson, J Postberg, Christiane Schaffitzel, H J LippsAbstract:Macronuclear DNA of stichotrichous ciliates occurs in small ‘gene-sized’ molecules with sizes of about 0.5 to 40 kb. Each of these molecules is terminated by telomeric sequences of defined length. A single macronucleus contains up to 108 DNA molecules; due to the high concentration of telomeric sequences in this nucleus it is an attractive model to study Telomere behaviour. We recently provided evidence that macronuclear Telomeres are attached to the nuclear matrix and that this interaction is mediated by the Telomere Binding Protein (TeBP). Using various experimental approaches, we now demonstrate that Telomeres as well as both subunits of the Telomere Binding Protein are associated with the nuclear matrix. However, there is no direct Binding of telomeric DNA to the matrix but Telomere matrix interaction is exclusively mediated by the TeBP. In addition, we show that telomeric sequences adopt in vivo the antiparallel G-quartet structure when bound to the nuclear matrix. These data not only allow us to propose a model for macronuclear architecture but may also be relevant for further analysis of Telomere–matrix interactions in higher eukaryotes.
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Association of the Telomere-Telomere-Binding Protein complex of hypotrichous ciliates with the nuclear matrix and dissociation during replication.
Journal of cell science, 2001Co-Authors: J Postberg, S A Juranek, S Feiler, H Kortwig, F Jönsson, H J LippsAbstract:Telomeric interactions with the nuclear matrix have been described in a variety of eukaryotic cells and seem to be essential for specific nuclear localization. Macronuclear DNA of hypotrichous ciliates occurs in small gene-sized DNA molecules, each being terminated by Telomeres. Each macronucleus contains over 10(8 )individual DNA molecules. Owing to the high number of Telomeres present in this nucleus it provides an excellent model to study Telomere behaviour throughout the cell cycle. In this study we provide experimental evidence that the Telomere-Telomere-Binding Protein (TEBP) complex specifically interacts with components of the nuclear matrix in vivo. In the course of replication the specific interaction of the TEBP with components of the nuclear matrix is resolved and an attachment of the Telomeres to the matrix no longer occurs.
Daniela Rhodes - One of the best experts on this subject based on the ideXlab platform.
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sequence specific dna recognition by the myb like domain of the human Telomere Binding Protein trf1 a model for the Protein dna complex
Nucleic Acids Research, 1998Co-Authors: Peter Konig, Louise Fairall, Daniela RhodesAbstract:Telomeres consist of tandem arrays of short G-rich sequence motifs packaged by specific DNA Binding Proteins. In humans the double-stranded telomeric TTAGGG repeats are specifically bound by TRF1 and TRF2. Although Telomere Binding Proteins from evolutionarily distant species are not sequence homologues, they share a Myb-like DNA Binding motif. Here we have used gel retardation, primer extension and DNase I footprinting analyses to define the Binding site of the isolated Myb-like domain of TRF1 and present a three-dimensional model for its interaction with human telomeric DNA. Our results suggest that the Myb-like domain of TRF1 recognizes a Binding site centred on the sequence GGGTTA and that its DNA Binding mode is similar to that of the homeodomain-like motifs of the yeast Telomere Binding Protein RAP1. The implications of these findings for recognition of telomeric DNA in general are discussed.
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promotion of parallel dna quadruplexes by a yeast Telomere Binding Protein a circular dichroism study
Proceedings of the National Academy of Sciences of the United States of America, 1994Co-Authors: Rafael Giraldo, Masashi Suzuki, Lynda Chapman, Daniela RhodesAbstract:Abstract Repressor-activator Protein 1 (RAP1) has an essential role in the maintenance of yeast Telomeres. Yeast telomeric DNA consists of simple repeated G-rich sequences that are bound by RAP1. We have found that RAP1, in addition to its known Binding activity for double-stranded DNA, interacts with the G-rich strand containing guanine base (G)-tetrads. We show here using circular dichroism spectroscopy that RAP1 promotes the formation of one particular type of DNA quadruplex, parallel G4-DNA. Furthermore, RAP1 is able to bind to both preformed parallel and antiparallel DNA quadruplexes. These results have implications for the possible use of DNA quadruplexes in Telomere-Telomere association in vivo.
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the yeast Telomere Binding Protein rap1 binds to and promotes the formation of dna quadruplexes in telomeric dna
The EMBO Journal, 1994Co-Authors: Rafael Giraldo, Daniela RhodesAbstract:The Protein RAP1 is essential for the maintenance of the Telomeres of Saccharomyces cerevisiae and binds in vitro to multiple sites found within the TG1-3 telomeric repeats. We show here that, in addition to its known Binding activity for double-stranded DNA, RAP1 binds sequence-specifically to the GT-strands. This indicates that RAP1 is the Protein that binds to the telomeric terminal GT-tails. Furthermore, we have found that RAP1 binds to and promotes the formation of G-tetrads, i.e. DNA quadruplexes, in GT-strand oligonucleotides at nanomolar concentrations. The formation of DNA quadruplexes appears to involve the intermolecular association of GT-strands. The minimal DNA-Binding domain of RAP1 (DBD) binds only to double-stranded DNA, so that the novel DNA-Binding activity we have found involves regions of the Protein located outside of the DBD. The finding that a telomeric Protein promotes the formation of G-tetrads argues for the use of DNA quadruplexes in Telomere association.
Jing-jer Lin - One of the best experts on this subject based on the ideXlab platform.
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dynamic dna shortening by Telomere Binding Protein cdc13
Journal of the American Chemical Society, 2021Co-Authors: Yiyun Lin, Yenchan Chang, Ryosuke L Ohniwa, Jing-jer LinAbstract:Telomeres are essential for chromosome maintenance. Cdc13 is a single-stranded telomeric DNA Binding Protein that caps Telomeres and regulates telomerase function in yeast. Although specific Binding of Cdc13 to telomeric DNA is critical for Telomere protection, the detail mechanism how Cdc13-DNA complex protects Telomere is unclear. Using two single-molecule methods, tethered particle motion and atomic force microscopy, we demonstrate that specific Binding of Cdc13 on single-stranded telomeric DNA shortens duplex DNA into distinct states differed by ∼70-80 base pairs. DNA shortening by Cdc13 is dynamic and independent of duplex DNA sequences or length. Significantly, we found that Pif1 helicase is incapable of removing Cdc13 from the shortened DNA-Cdc13 complex, suggesting that Cdc13 forms structurally stable complex by shortening of the bound DNA. Together our data identified shortening of DNA by Cdc13 and provided an indication for efficient protection of Telomere ends by the shortened DNA-Cdc13 complex.
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The U3 small nucleolar ribonucleoProtein component Imp4p is a telomeric DNA-Binding Protein
The Biochemical journal, 2007Co-Authors: Yi-ching Hsieh, Ying-yuan Lee, Chun-chen Kuo, Yi-chien Lin, Jing-jer LinAbstract:Imp4p is a component of U3 snoRNP (small nucleolar ribonucleoProtein) involved in the maturation of 18S rRNA. We have shown that Imp4p interacts with Cdc13p, a single-stranded Telomere-Binding Protein involved in Telomere maintenance. To understand the role of Imp4p in Telomeres, we purified recombinant Imp4p Protein and tested its Binding activity towards telomeric DNA using electrophoretic mobility-shift assays. Our results showed that Imp4p bound specifically to single-stranded telomeric DNA in vitro. The interaction of Imp4p to Telomeres in vivo was also demonstrated by chromatin immunoprecipitation experiments. Significantly, the Binding of Imp4p to Telomeres was not limited to yeast Proteins, since the hImp4 (human Imp4) also bound to vertebrate single-stranded telomeric DNA. Thus we conclude that Imp4p is a novel telomeric DNA-Binding Protein that, in addition to its role in rRNA processing, might participate in Telomere function.
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the telomerase recruitment domain of the Telomere Binding Protein cdc13 is regulated by mec1p tel1p dependent phosphorylation
Nucleic Acids Research, 2006Co-Authors: Shunfu Tseng, Jing-jer Lin, Shuchun TengAbstract:The DNA damage-responsive Protein kinases ATM and ATR phosphorylate SQ/TQ motifs that lie in clusters in most of their in vivo targets. Budding yeast Cdc13p contains two clusters of SQ/TQ motifs, suggesting that it might be a target of Mec1p/Tel1p (yeast ATR/ATM). Here we demonstrated that the telomerase recruitment domain of Cdc13p is phosphorylated by Mec1p and Tel1p. Gel analysis showed that Cdc13p contains a Mec1/Tel1-dependent post-translational modification. Using an immunoprecipitate (IP)-kinase assay, we showed that Mec1p phosphorylates Cdc13p on serine 225, 249, 255 and 306, and Tel1p phosphorylates Cdc13p on serine 225, 249 and 255 in vitro. Phenotypic analysis in vivo revealed that the mutations in the Cdc13p SQ motifs phosphorylated by Mec1p and Tel1p caused multiple Telomere and growth defects. In addition, normal Telomere length and growth could be restored by expressing a Cdc13–Est1p hybrid Protein. These results demonstrate the telomerase recruitment domain of Cdc13p as an important new Telomere-specific target of Mec1p/Tel1p.
Irina A. Zalenskaya - One of the best experts on this subject based on the ideXlab platform.
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Telomere–Telomere Interactions and Candidate Telomere Binding Protein(s) in Mammalian Sperm Cells
Experimental Cell Research, 1997Co-Authors: Andrei O. Zalensky, Teplitz Rl, Nikolai V. Tomilin, Irina A. Zalenskaya, E. M. BradburyAbstract:Abstract We have used fluorescentin situhybridization to localize Telomeres within the nuclei of sperm from six mammals (human, rat, mouse, stallion, boar, and bull). In minimally swollen sperm of mouse and rat, most of the Telomeres are clustered within a limited area in the posterior part of nuclei. In sperm of other species, Telomeres associate into tetrameres and dimers. On swelling of sperm cells with heparin/dithiotriethol, Telomere associations disperse, and hybridization signals become smaller in size and their numbers approach or correspond to the number of chromosome ends in a haploid genome. Quantitation of Telomere loci indicates that dimeric associations are prominent features of mammalian sperm nuclear architecture. Higher order Telomere–Telomere interactions and organization develop during meiotic stages of human spermatogenesis. At this stage, Telomeres also become associated with the nuclear membrane. In an attempt to elucidate the molecular mechanisms underlying Telomere interactions in sperm, we have identified a novel Protein activity that binds to the double-stranded telomeric repeat (TTAGGG)n. Sperm Telomere Binding Protein(s) (STBP) was extracted from human and bull sperm by 0.5MNaCl. STBP does not bind single-stranded telomeric DNA and is highly specific for single base substitutions in a duplex DNA sequence. Depending on the conditions of Binding, we observed the formation of several nucleoProtein complexes. We have shown that there is a transition between complexes, which indicates that the slower migrating complex is a multimer of the higher mobility one. We propose that STBP participates in association between the Telomere domains which were microscopically observed in mammalian spermatozoa.
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Telomere Telomere interactions and candidate Telomere Binding Protein s in mammalian sperm cells
Experimental Cell Research, 1997Co-Authors: Andrei O. Zalensky, Nikolai V. Tomilin, Irina A. Zalenskaya, R L TeplitzAbstract:We have used fluorescent in situ hybridization to localize Telomeres within the nuclei of sperm from six mammals (human, rat, mouse, stallion, boar, and bull). In minimally swollen sperm of mouse and rat, most of the Telomeres are clustered within a limited area in the posterior part of nuclei. In sperm of other species, Telomeres associate into tetrameres and dimers. On swelling of sperm cells with heparin/dithiotriethol, Telomere associations disperse, and hybridization signals become smaller in size and their numbers approach or correspond to the number of chromosome ends in a haploid genome. Quantitation of Telomere loci indicates that dimeric associations are prominent features of mammalian sperm nuclear architecture. Higher order Telomere-Telomere interactions and organization develop during meiotic stages of human spermatogenesis. At this stage, Telomeres also become associated with the nuclear membrane. In an attempt to elucidate the molecular mechanisms underlying Telomere interactions in sperm, we have identified a novel Protein activity that binds to the double-stranded telomeric repeat (TTAGGG)n. Sperm Telomere Binding Protein(s) (STBP) was extracted from human and bull sperm by 0.5 M NaCl. STBP does not bind single-stranded telomeric DNA and is highly specific for single base substitutions in a duplex DNA sequence. Depending on the conditions of Binding, we observed the formation of several nucleoProtein complexes. We have shown that there is a transition between complexes, which indicates that the slower migrating complex is a multimer of the higher mobility one. We propose that STBP participates in association between the Telomere domains which were microscopically observed in mammalian spermatozoa.
