Exposure of single-stranded telomeric DNA causes G2/M cell cycle arrest in Saccharomyces cerevisiae.
Pang T, Wang C, Hsu C, Chen M, Lin J
Journal of Biological Chemistry (2003)
Category: telomere ¤ Added: Jan 14, 2003 ¤ Rating: ◊◊
In S. cerevisiae, Cdc13p is a single-stranded TG1-3 DNA binding protein that protects telomeres and maintains telomere length. A mutant allele of CDC13, cdc13-1, causes accumulation of single-stranded TG1-3 DNA near telomeres, along with a G2/M cell cycle arrest at non-permissive temperatures. We reported here that when the singlestranded TG1-3 DNA is masked by its binding proteins such as S. cerevisiae Gbp2p or S. pombe Tcg1, the growth arrest phenotype of cdc13-1 is rescued. Mutations on Gbp2p that disrupt its binding to the single-stranded TG1-3 DNA render the protein unable to complement the defects of cdc13-1. These results indicate that the presence of singlestranded TG1-3 tail in cdc13-1 cells serves as the signal for cell cycle checkpoint. Moreover, the binding activity of Gbp2p to single-stranded TG1-3 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.