title: Exposure of single-stranded telomeric DNA causes G2/M cell cycle arrest in Saccharomyces cerevisiae.
abstract: In Saccharomyces cerevisiae, Cdc13p is a single-stranded TG(1-3) DNA binding protein that protects telomeres and maintains telomere length. A mutant allele of CDC13, cdc13-1, causes accumulation of single-stranded TG(1-3) DNA near telomeres along with a G(2)/M cell cycle arrest at non-permissive temperatures. We report here that when the single-stranded TG(1-3) DNA is masked by its binding proteins, such as S. cerevisiae Gbp2p or Schizosaccharomyces pombe Tcg1, the growth arrest phenotype of cdc13-1 is rescued. Mutations on Gbp2p that disrupt its binding to the single-stranded TG(1-3) DNA render the protein unable to complement the defects of cdc13-1. These results indicate that the presence of a single-stranded TG(1-3) tail in cdc13-1 cells serves as the signal for the cell cycle checkpoint. Moreover, the binding activity of Gbp2p to single-stranded TG(1-3) DNA appears to be associated with its ability to restore the telomere-lengthening phenotype in cdc13-1 cells. These results indicate that Gbp2p is involved in modulating telomere length.
authors.affiliation: Institutes of Biopharmaceutical Science and Biochemistry, National Yang-Ming University, Taipei 112, Taiwan, Republic of China.
authors.forename: Te-Ling
authors.initials: TL
authors.lastname: Pang
authors.forename: Chen-Yi
authors.initials: CY
authors.lastname: Wang
authors.forename: Chia-Ling
authors.initials: CL
authors.lastname: Hsu
authors.forename: Mei-Yu
authors.initials: MY
authors.lastname: Chen
authors.forename: Jing-Jer
authors.initials: JJ
authors.lastname: Lin
mesh_terms: D020816:Amino Acid Motifs; D001120:Arginine / Q000737:chemistry; D002453:Cell Cycle; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000737:chemistry*; D004926:Escherichia coli / Q000378:metabolism; D016195:G2 Phase; D015723:Gene Library; D005982:Glutathione Transferase / Q000378:metabolism; D008938:Mitosis; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism*; D013696:Temperature
chemical_list: D018076:DNA, Complementary; D004277:DNA, Single-Stranded; D011993:Recombinant Fusion Proteins; D004247:DNA; D001120:Arginine; D005982:Glutathione Transferase