Molecular and cellular dissection of mating-type switching steps in Schizosaccharomyces pombe.
A strand-specific imprint (break) controls mating-type switching in fission yeast. By introducing a thiamine repressible promoter upstream of the mat1 locus, we can force transcription through the imprinted region, erasing the imprint and inhibiting further mating-type switching, in a reversible manner. Starting from a synchronized, virgin M-cell population, we show that the site- and strand-specific break is formed when DNA replication intermediates appear at mat1 during the first S phase. The formation of the break is concomitant with a replication fork pause and binding of the Swi1 protein at mat1 until early G(2) and then rapidly disappears. Upon its formation, the break remains stable throughout the cell cycle and triggers mating-type switching during the second S phase. Finally, we have recreated the mating-type switching pedigree at the molecular and single-cell levels, allowing for the first time separation between the establishment of imprinting and its developmental fate.
Holmes
Allyson M
AM
Unité de Dynamique du Génome, URA 1644 du CNRS, Departement de la Structure et Dynamique des Génomes, Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France.
Kaykov
Atanas
A
Arcangioli
Benoit
B
D000483:Alleles; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D047369:Chromatin Immunoprecipitation; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004271:DNA, Fungal / Q000378:metabolism; D004268:DNA-Binding Proteins; D015180:Electrophoresis, Gel, Two-Dimensional; D016195:G2 Phase; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D018392:Genomic Imprinting; D007700:Kinetics; D008957:Models, Genetic; D010375:Pedigree; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D016196:S Phase; D012568:Schizosaccharomyces / Q000235:genetics* / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; C513096:swi1 protein, S pombe; D004247:DNA