Protection of DNA Ends by Telomeric 3′ G-Tail Sequences
نویسندگان
چکیده
منابع مشابه
Chromosome ends in Drosophila without telomeric DNA sequences.
We have recovered terminal chromosome deletions of the X chromosome of Drosophila [Df(1)RT; RT = receding tips] that break in various positions of the yellow gene (y) region and delete all distal DNA sequences. Terminal DNA fragments are heterogeneous in length. Molecular cloning and sequencing of the terminal DNA fragments revealed that the broken ends of the deleted chromosomes do not carry a...
متن کاملTRF2/RAP1 and DNA-PK mediate a double protection against joining at telomeric ends.
DNA-dependent protein kinase (DNA-PK) is a double-strand breaks repair complex, the subunits of which (KU and DNA-PKcs) are paradoxically present at mammalian telomeres. Telomere fusion has been reported in cells lacking these proteins, raising two questions: how is DNA-PK prevented from initiating classical ligase IV (LIG4)-dependent non-homologous end-joining (C-NHEJ) at telomeres and how is ...
متن کاملG-rich telomeric and ribosomal DNA sequences from the fission yeast genome form stable G-quadruplex DNA structures in vitro and are unwound by the Pfh1 DNA helicase
Certain guanine-rich sequences have an inherent propensity to form G-quadruplex (G4) structures. G4 structures are e.g. involved in telomere protection and gene regulation. However, they also constitute obstacles during replication if they remain unresolved. To overcome these threats to genome integrity, organisms harbor specialized G4 unwinding helicases. In Schizosaccharomyces pombe, one such...
متن کاملLigand selectivity in stabilising tandem parallel folded G-quadruplex motifs in human telomeric DNA sequences.
Biophysical studies of ligand interactions with three human telomeric repeat sequences (d(AGGG(TTAGGG)n, n = 3, 7 and 11)) show that an oxazole-based 'click' ligand, which induces parallel folded quadruplexes, preferentially stabilises longer telomeric repeats providing evidence for selectivity in binding at the interface between tandem quadruplex motifs.
متن کاملRepair of O6-methylguanine adducts in human telomeric G-quadruplex DNA by O6-alkylguanine-DNA alkyltransferase
O(6)-alkylguanine-DNA alkyltransferase (AGT) is a single-cycle DNA repair enzyme that removes pro-mutagenic O(6)-alkylguanine adducts from DNA. Its functions with short single-stranded and duplex substrates have been characterized, but its ability to act on other DNA structures remains poorly understood. Here, we examine the functions of this enzyme on O(6)-methylguanine (6mG) adducts in the fo...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 2007
ISSN: 0021-9258
DOI: 10.1074/jbc.m702171200