Meiotic recombination initiated by a double-strand break in rad50{Delta} yeast cells otherwise unable to initiate meiotic recombination
- Brandeis Univ., Waltham, MA (United States)
- Tufts Univ., Boston, MA (United States); and others
Meiotic recombination in Saccharomyces cerevisiae is initiated by double-strand breaks (DSBs). We have developed a system to compare the properties of meiotic DSBs with those created by the site-specific HO endonuclease. HO endonuclease was expressed under the control of the meiotic-specific SPO13 promoter, creating a DSB at a single site on one of yeast`s 16 chromosomes. In Rad{sup +} strains the times of appearance of the HO-induced DSBs and of subsequent recombinants are coincident with those induced by normal meiotic DSBs. Physical monitoring of DNA showed that SPO13::HO induced gene conversions both in Rad{sup +} and in rad50{Delta} cells that cannot initiate normal meiotic DSBs. We find that the RAD50 gene is important, but not essential, for recombination even after a DSB has been created in a meiotic cell. In rad50{Delta} cells, some DSBs are not repaired until a broken chromosome has been packaged into a spore and is subsequently germinated. This suggests that a broken chromosome does not signal an arrest of progression through meiosis. The recombination defect in rad50{Delta} diploids is not, however, meiotic specific, as mitotic rad50 diploids, experiencing an HO-induced DSB, exhibit similar departures from wild-type recombination. 57 refs., 5 figs., 3 tabs.
- OSTI ID:
- 543013
- Journal Information:
- Genetics, Vol. 143, Issue 2; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
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