title: Heterochromatin regulates cell type-specific long-range chromatin interactions essential for directed recombination.
abstract: Mating-type switching in Schizosaccharomyces pombe involves replacing genetic information at the expressed mat1 locus with sequences copied from one of two silent donor loci, mat2-P or mat3-M, located within a 20-kb heterochromatic domain. Donor selection is dictated by cell type: mat2 is the preferred donor in M cells, and mat3 is the preferred donor in P cells. Here we show that a recombination-promoting complex (RPC) containing Swi2 and Swi5 proteins exhibits cell type-specific localization pattern at the silent mating-type region and this differential localization modulates donor preference during mating-type switching. In P cells, RPC localization is restricted to a recombination enhancer located adjacent to mat3, but in M cells, RPC spreads in cis across the entire silent mating-type interval in a heterochromatin-dependent manner. Our analyses implicate heterochromatin in long-range regulatory interactions and suggest that heterochromatin imposes at the mating-type region structural organization that is important for the donor-choice mechanism.
authors.affiliation: Laboratory of Molecular Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Songtao
authors.initials: S
authors.lastname: Jia
authors.forename: Takatomi
authors.initials: T
authors.lastname: Yamada
authors.forename: Shiv I S
authors.initials: SI
authors.lastname: Grewal
mesh_terms: D002450:Cell Communication; D002843:Chromatin / Q000502:physiology*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D002874:Chromosome Mapping; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D005809:Genes, Regulator; D005812:Genes, Switch; D006570:Heterochromatin / Q000502:physiology*; D008957:Models, Genetic; D011995:Recombination, Genetic; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*
chemical_list: D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D006570:Heterochromatin; D029702:Schizosaccharomyces pombe Proteins; C483769:Swi5 protein, S pombe; C465958:Swi6 protein, S pombe; D014157:Transcription Factors