Exposure of Single-stranded Telomeric DNA Causes G2/M Cell Cycle Arrest in Saccharomyces cerevisiae

• Published in: The Journal of biological chemistry Vol. 278; no. 11; pp. 9318 - 9321
• Main Authors: Pang, Te-Ling, Wang, Chen-Yi, Hsu, Chia-Ling, Chen, Mei-Yu, Lin, Jing-Jer
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 14.03.2003
• Subjects: Amino Acid Motifs; Arginine - chemistry; Cell Cycle; Cloning, Molecular; DNA - metabolism; DNA, Complementary - metabolism; DNA, Single-Stranded - chemistry; Escherichia coli - metabolism; G2 Phase; Gene Library; Glutathione Transferase - metabolism; Mitosis; Mutagenesis, Site-Directed; Mutation; Plasmids - metabolism; Protein Binding; Recombinant Fusion Proteins - metabolism; Saccharomyces cerevisiae - metabolism; Telomere - metabolism; Temperature
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M208347200

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.