Single-stranded DNA arising at telomeres in cdc13 mutants may constitute a specific signal for the RAD9 checkpoint.

Publication Type:

Journal Article

Source:

Molecular and cellular biology, Volume 15, Issue 11, p.6128-38 (1995)

Keywords:

Base Sequence, Cell Cycle Proteins, Cloning, Molecular, Cyclin B, Cyclins, DNA Replication, DNA, Fungal, DNA, Single-Stranded, DNA-Directed DNA Polymerase, Epistasis, Genetic, Fungal Proteins, Gene Deletion, Genes, Fungal, Molecular Sequence Data, Recombination, Genetic, Saccharomyces cerevisiae, Telomere

Abstract:

A cdc13 temperature-sensitive mutant of Saccharomyces cerevisiae arrests in the G2 phase of the cell cycle at the restrictive temperature as a result of DNA damage that activates the RAD9 checkpoint. The DNA lesions present after a failure of Cdc13p function appear to be located almost exclusively in telomere-proximal regions, on the basis of the profile of induced mitotic recombination. cdc13 rad9 cells dividing at the restrictive temperature contain single-stranded DNA corresponding to telomeric and telomere-proximal DNA sequences and eventually lose telomere-associated sequences. These results suggest that the CDC13 product functions in telomere metabolism, either in the replication of telomeric DNA or in protecting telomeres from the double-strand break repair system. Moreover, since cdc13 rad9 cells divide at a wild-type rate for several divisions at the restrictive temperature while cdc13 RAD9 cells arrest in G2, these results also suggest that single-stranded DNA may be a specific signal for the RAD9 checkpoint.