TY - JOUR

T1 - RNAi and heterochromatin repress centromeric meiotic recombination

AU - Ellermeier, Chad

AU - Higuchi, Emily C

AU - Phadnis, Naina

AU - Holm, Laerke

AU - Geelhood, Jennifer L

AU - Thon, Genevieve

AU - Smith, Gerald R

PY - 2010/5/11

Y1 - 2010/5/11

N2 - During meiosis, the formation of viable haploid gametes from diploid precursors requires that each homologous chromosome pair be properly segregated to produce an exact haploid set of chromosomes. Genetic recombination, which provides a physical connection between homologous chromosomes, is essential in most species for proper homologue segregation. Nevertheless, recombination is repressed specifically in and around the centromeres of chromosomes, apparently because rare centromeric (or pericentromeric) recombination events, when they do occur, can disrupt proper segregation and lead to genetic disabilities, including birth defects. The basis by which centromeric meiotic recombination is repressed has been largely unknown. We report here that, in fission yeast, RNAi functions and Clr4-Rik1 (histone H3 lysine 9 methyltransferase) are required for repression of centromeric recombination. Surprisingly, one mutant derepressed for recombination in the heterochromatic mating-type region during meiosis and several mutants derepressed for centromeric gene expression during mitotic growth are not derepressed for centromeric recombination during meiosis. These results reveal a complex relation between types of repression by heterochromatin. Our results also reveal a previously undemonstrated role for RNAi and heterochromatin in the repression of meiotic centromeric recombination and, potentially, in the prevention of birth defects by maintenance of proper chromosome segregation during meiosis.

AB - During meiosis, the formation of viable haploid gametes from diploid precursors requires that each homologous chromosome pair be properly segregated to produce an exact haploid set of chromosomes. Genetic recombination, which provides a physical connection between homologous chromosomes, is essential in most species for proper homologue segregation. Nevertheless, recombination is repressed specifically in and around the centromeres of chromosomes, apparently because rare centromeric (or pericentromeric) recombination events, when they do occur, can disrupt proper segregation and lead to genetic disabilities, including birth defects. The basis by which centromeric meiotic recombination is repressed has been largely unknown. We report here that, in fission yeast, RNAi functions and Clr4-Rik1 (histone H3 lysine 9 methyltransferase) are required for repression of centromeric recombination. Surprisingly, one mutant derepressed for recombination in the heterochromatic mating-type region during meiosis and several mutants derepressed for centromeric gene expression during mitotic growth are not derepressed for centromeric recombination during meiosis. These results reveal a complex relation between types of repression by heterochromatin. Our results also reveal a previously undemonstrated role for RNAi and heterochromatin in the repression of meiotic centromeric recombination and, potentially, in the prevention of birth defects by maintenance of proper chromosome segregation during meiosis.

KW - Centromere

KW - Chromosomal Proteins, Non-Histone

KW - Chromosomes, Fungal

KW - DNA Breaks, Double-Stranded

KW - Heterochromatin

KW - Histones

KW - Lysine

KW - Meiosis

KW - Methyltransferases

KW - Mutation

KW - RNA Interference

KW - Recombination, Genetic

KW - Repressor Proteins

KW - Schizosaccharomyces

KW - Schizosaccharomyces pombe Proteins

KW - Transcription, Genetic

U2 - 10.1073/pnas.0914160107

DO - 10.1073/pnas.0914160107

M3 - Journal article

C2 - 20421495

VL - 107

SP - 8701

EP - 8705

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 19

ER -