Intermediates of recombination during mating type switching in Saccharomyces cerevisiae.

Abstract : We have identified two novel intermediates of homothallic switching of the yeast mating type gene, from MATa to MAT alpha. Following HO endonuclease cleavage, 5' to 3' exonucleolytic digestion is observed distal to the HO cut, creating a 3'-ended single-stranded tail. This recision is more extensive in a rad52 strain unable to switch. Surprisingly, the proximal side of the HO cut is protected from degradation; this stabilization depends on the presence of the silent copy donor sequences. A second intermediate was identified by a quantitative application of the polymerase chain reaction (PCR). The Y alpha-MAT distal covalent fragment of the switched product appears 30 min prior to the appearance of the MAT proximal Y alpha junction. No covalent joining of MAT distal to HML distal sequences is detected. We suggested that the MAT DNA distal to the HO cut invades the intact donor and is extended by DNA synthesis. This step is prevented in a rad52 strain. These intermediates are consistent with a model for MAT switching in which only the distal side of the HO cut is initially active in strand invasion and transfer of information from the donor.
Document type :
Journal articles
Complete list of metadatas

https://www.hal.inserm.fr/inserm-01907458
Contributor : Charles White <>
Submitted on : Monday, October 29, 2018 - 10:42:43 AM
Last modification on : Thursday, July 4, 2019 - 2:52:12 PM

Links full text

Identifiers

  • HAL Id : inserm-01907458, version 1
  • PUBMED : 2178924
  • PUBMEDCENTRAL : PMC551719

Collections

Citation

Charles White, J Haber. Intermediates of recombination during mating type switching in Saccharomyces cerevisiae.. EMBO Journal, EMBO Press, 1990, 9 (3), pp.663-73. ⟨inserm-01907458⟩

Share

Metrics

Record views

46