Abstract
During telomere replication in yeast, chromosome ends acquire an S-phase-specific overhang of the guanosine-rich strand. Here it is shown that in cells lacking Ku, a heterodimeric protein involved in nonhomologous DNA end joining, these overhangs are present throughout the cell cycle. In vivo cross-linking experiments demonstrated that Ku is bound to telomeric DNA. These results show that Ku plays a direct role in establishing a normal DNA end structure on yeast chromosomes, conceivably by functioning as a terminus-binding factor. Because Ku-mediated DNA end joining involving telomeres would result in chromosome instability, our data also suggest that Ku has a distinct function when bound to telomeres.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antigens, Nuclear*
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Binding Sites
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Chromosomes, Fungal / chemistry
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Chromosomes, Fungal / metabolism*
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DNA Helicases*
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DNA, Fungal / chemistry
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DNA, Fungal / metabolism*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Fungal Proteins / metabolism*
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G2 Phase
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Genes, Fungal
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Ku Autoantigen
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Mitosis
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Mutation
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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S Phase
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Saccharomyces cerevisiae / cytology
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins*
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Telomerase / genetics
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Telomerase / metabolism
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Telomere / metabolism*
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Temperature
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Transformation, Genetic
Substances
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Antigens, Nuclear
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DNA, Fungal
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DNA-Binding Proteins
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Fungal Proteins
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Nuclear Proteins
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Saccharomyces cerevisiae Proteins
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high affinity DNA-binding factor, S cerevisiae
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Telomerase
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DNA Helicases
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XRCC5 protein, human
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Xrcc6 protein, human
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Ku Autoantigen