@article{Schaffitzel2001,
	title = {In vitro generated antibodies specific for telomeric guanine-quadruplex {DNA} react with {Stylonychia} lemnae macronuclei},
	volume = {98},
	url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=37477&tool=pmcentrez&rendertype=abstract},
	doi = {10.1073/pnas.141229498},
	abstract = {Most eukaryotic telomeres contain a repeating motif with stretches of guanine residues that form a 3-terminal overhang extending beyond the telomeric duplex region. The telomeric repeat of hypotrichous ciliates, d(T4G4), forms a 16-nucleotide 3-overhang. Such sequences can adopt parallel-stranded as well as antiparallel-stranded quadruplex conformations in vitro. Although it has been proposed that guanine-quadruplex conformations may have important cellular roles including telomere function, recombination, and transcription, evidence for the existence of this DNA structure in vivo has been elusive to date. We have generated high-affinity single-chain antibody fragment (scFv) probes for the guanine-quadruplex formed by the Stylonychia telomeric repeat, by ribosome display from the Human Combinatorial Antibody Library. Of the scFvs selected, one (Sty3) had an affinity of K d = 125 pM for the parallel-stranded guanine-quadruplex and could discriminate with at least 1,000-fold specificity between parallel or antiparallel quadruplex conformations formed by the same sequence motif. A second scFv (Sty49) bound both the parallel and antiparallel quadruplex with similar (K d = 35 nM) affinity. Indirect immunofluorescence studies show that Sty49 reacts specifically with the macronucleus but not the micronucleus of Stylonychia lemnae. The replication band, the region where replication and telomere elongation take place, was also not stained, suggesting that the guanine-quadruplex is resolved during replication. Our results provide experimental evidence that the telomeres of Stylonychia macronuclei adopt in vivo a guanine-quadruplex structure, indicating that this structure may have an important role for telomere functioning.},
	number = {15},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	author = {Schaffitzel, Christiane and Berger, Imre and Postberg, Jan and Hanes, Jozef and Lipps, Hans J and Plückthun, Andreas},
	year = {2001},
	note = {Publisher: Biochemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
Publisher: The National Academy of Sciences},
	keywords = {\#nosource, animals, antibodies, dna, dna immunology, g quadruplexes, guanine, humans, hypotrichida, hypotrichida genetics, immunoglobulin fragments, immunoglobulin fragments biosynthesis, immunoglobulin fragments immunology, immunoglobulin variable region, immunoglobulin variable region biosynthesis, immunoglobulin variable region immunology, nucleic acid, protozoan, protozoan biosynthesis, protozoan immunology, repetitive sequences, telomere},
	pages = {8572--8577},
}

{"_id":"4cHsRiAwG4FgjJCJb","bibbaseid":"schaffitzel-berger-postberg-hanes-lipps-plckthun-invitrogeneratedantibodiesspecificfortelomericguaninequadruplexdnareactwithstylonychialemnaemacronuclei-2001","author_short":["Schaffitzel, C.","Berger, I.","Postberg, J.","Hanes, J.","Lipps, H. J","Plückthun, A."],"bibdata":{"bibtype":"article","type":"article","title":"In vitro generated antibodies specific for telomeric guanine-quadruplex DNA react with Stylonychia lemnae macronuclei","volume":"98","url":"http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=37477&tool=pmcentrez&rendertype=abstract","doi":"10.1073/pnas.141229498","abstract":"Most eukaryotic telomeres contain a repeating motif with stretches of guanine residues that form a 3-terminal overhang extending beyond the telomeric duplex region. The telomeric repeat of hypotrichous ciliates, d(T4G4), forms a 16-nucleotide 3-overhang. Such sequences can adopt parallel-stranded as well as antiparallel-stranded quadruplex conformations in vitro. Although it has been proposed that guanine-quadruplex conformations may have important cellular roles including telomere function, recombination, and transcription, evidence for the existence of this DNA structure in vivo has been elusive to date. We have generated high-affinity single-chain antibody fragment (scFv) probes for the guanine-quadruplex formed by the Stylonychia telomeric repeat, by ribosome display from the Human Combinatorial Antibody Library. Of the scFvs selected, one (Sty3) had an affinity of K d = 125 pM for the parallel-stranded guanine-quadruplex and could discriminate with at least 1,000-fold specificity between parallel or antiparallel quadruplex conformations formed by the same sequence motif. A second scFv (Sty49) bound both the parallel and antiparallel quadruplex with similar (K d = 35 nM) affinity. Indirect immunofluorescence studies show that Sty49 reacts specifically with the macronucleus but not the micronucleus of Stylonychia lemnae. The replication band, the region where replication and telomere elongation take place, was also not stained, suggesting that the guanine-quadruplex is resolved during replication. Our results provide experimental evidence that the telomeres of Stylonychia macronuclei adopt in vivo a guanine-quadruplex structure, indicating that this structure may have an important role for telomere functioning.","number":"15","journal":"Proceedings of the National Academy of Sciences of the United States of America","author":[{"propositions":[],"lastnames":["Schaffitzel"],"firstnames":["Christiane"],"suffixes":[]},{"propositions":[],"lastnames":["Berger"],"firstnames":["Imre"],"suffixes":[]},{"propositions":[],"lastnames":["Postberg"],"firstnames":["Jan"],"suffixes":[]},{"propositions":[],"lastnames":["Hanes"],"firstnames":["Jozef"],"suffixes":[]},{"propositions":[],"lastnames":["Lipps"],"firstnames":["Hans","J"],"suffixes":[]},{"propositions":[],"lastnames":["Plückthun"],"firstnames":["Andreas"],"suffixes":[]}],"year":"2001","note":"Publisher: Biochemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland. Publisher: The National Academy of Sciences","keywords":"#nosource, animals, antibodies, dna, dna immunology, g quadruplexes, guanine, humans, hypotrichida, hypotrichida genetics, immunoglobulin fragments, immunoglobulin fragments biosynthesis, immunoglobulin fragments immunology, immunoglobulin variable region, immunoglobulin variable region biosynthesis, immunoglobulin variable region immunology, nucleic acid, protozoan, protozoan biosynthesis, protozoan immunology, repetitive sequences, telomere","pages":"8572–8577","bibtex":"@article{Schaffitzel2001,\n\ttitle = {In vitro generated antibodies specific for telomeric guanine-quadruplex {DNA} react with {Stylonychia} lemnae macronuclei},\n\tvolume = {98},\n\turl = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=37477&tool=pmcentrez&rendertype=abstract},\n\tdoi = {10.1073/pnas.141229498},\n\tabstract = {Most eukaryotic telomeres contain a repeating motif with stretches of guanine residues that form a 3-terminal overhang extending beyond the telomeric duplex region. The telomeric repeat of hypotrichous ciliates, d(T4G4), forms a 16-nucleotide 3-overhang. Such sequences can adopt parallel-stranded as well as antiparallel-stranded quadruplex conformations in vitro. Although it has been proposed that guanine-quadruplex conformations may have important cellular roles including telomere function, recombination, and transcription, evidence for the existence of this DNA structure in vivo has been elusive to date. We have generated high-affinity single-chain antibody fragment (scFv) probes for the guanine-quadruplex formed by the Stylonychia telomeric repeat, by ribosome display from the Human Combinatorial Antibody Library. Of the scFvs selected, one (Sty3) had an affinity of K d = 125 pM for the parallel-stranded guanine-quadruplex and could discriminate with at least 1,000-fold specificity between parallel or antiparallel quadruplex conformations formed by the same sequence motif. A second scFv (Sty49) bound both the parallel and antiparallel quadruplex with similar (K d = 35 nM) affinity. Indirect immunofluorescence studies show that Sty49 reacts specifically with the macronucleus but not the micronucleus of Stylonychia lemnae. The replication band, the region where replication and telomere elongation take place, was also not stained, suggesting that the guanine-quadruplex is resolved during replication. Our results provide experimental evidence that the telomeres of Stylonychia macronuclei adopt in vivo a guanine-quadruplex structure, indicating that this structure may have an important role for telomere functioning.},\n\tnumber = {15},\n\tjournal = {Proceedings of the National Academy of Sciences of the United States of America},\n\tauthor = {Schaffitzel, Christiane and Berger, Imre and Postberg, Jan and Hanes, Jozef and Lipps, Hans J and Plückthun, Andreas},\n\tyear = {2001},\n\tnote = {Publisher: Biochemisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.\nPublisher: The National Academy of Sciences},\n\tkeywords = {\\#nosource, animals, antibodies, dna, dna immunology, g quadruplexes, guanine, humans, hypotrichida, hypotrichida genetics, immunoglobulin fragments, immunoglobulin fragments biosynthesis, immunoglobulin fragments immunology, immunoglobulin variable region, immunoglobulin variable region biosynthesis, immunoglobulin variable region immunology, nucleic acid, protozoan, protozoan biosynthesis, protozoan immunology, repetitive sequences, telomere},\n\tpages = {8572--8577},\n}\n\n","author_short":["Schaffitzel, C.","Berger, I.","Postberg, J.","Hanes, J.","Lipps, H. 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