title: RNase-sensitive DNA modification(s) initiates S. pombe mating-type switching.
abstract: Mating-type switching in fission yeast depends on an imprint at the mat1 locus. Previous data showed that the imprint is made in the DNA strand replicated as lagging. We now identify this imprint as an RNase-sensitive modification and suggest that it consists of one or two RNA residues incorporated into the mat1 DNA. Formation of the imprint requires swi1- and swi3-dependent pausing of the replication fork. Interestingly, swi1 and swi3 mutations that abolish pausing do not affect the use of lagging-strand priming site during replication. We show that the pausing of replication and subsequent formation of the imprint occur after the leading-strand replication complex has passed the site of the imprint and after lagging-strand synthesis has initiated at this proximal priming site. We propose a model in which a swi1- and swi3-dependent signal during lagging-strand synthesis leads to pausing of leading-strand replication and the introduction of the imprint.
authors.affiliation: Marie Curie Research Institute, The Chart, Oxted, Surrey RH8 0TL, UK.
authors.forename: Sonya
authors.initials: S
authors.lastname: Vengrova
authors.forename: Jacob Z
authors.initials: JZ
authors.lastname: Dalgaard
mesh_terms: D001483:Base Sequence; D015139:Blotting, Southern; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D015825:Chromosomes, Fungal; D004261:DNA Replication / Q000502:physiology*; D004271:DNA, Fungal / Q000235:genetics*; D004268:DNA-Binding Proteins; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D018392:Genomic Imprinting; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D009363:Neoplasm Proteins; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D012331:RNA, Fungal / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D018741:Replication Origin; D012260:Ribonucleases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins; D012689:Sequence Homology, Nucleic Acid; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D012331:RNA, Fungal; C078562:SWI1 protein, S cerevisiae; C072981:SWI3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C513096:swi1 protein, S pombe; D012260:Ribonucleases