Suppression of Meiotic Recombination by CENP-B Homologs in Schizosaccharomyces pombe.
Meiotic homologous recombination (HR) is not uniform across eukaryotic genomes, creating regions of HR hot- and coldspots. Previous study reveals that the Spo11 homolog Rec12 responsible for initiation of meiotic double-strand breaks in the fission yeast Schizosaccharomyces pombe is not targeted to Tf2 retrotransposons. However, whether Tf2s are HR coldspots is not known. Here, we show that the rates of HR across Tf2s are similar to a genome average but substantially increase in mutants deficient for the CENP-B homologs. Abp1, which is the most prominent of the CENP-B family members and acts as the primary determinant of HR suppression at Tf2s, is required to prevent gene conversion and maintain proper recombination exchange of homologous alleles flanking Tf2s. In addition, Abp1-mediated suppression of HR at Tf2s requires all three of its domains with distinct functions in transcriptional repression and higher-order genome organization. We demonstrate that HR suppression of Tf2s can be robustly maintained despite disruption to chromatin factors essential for transcriptional repression and nuclear organization of Tf2s. Intriguingly, we uncover a surprising cooperation between the histone methyltransferase Set1 responsible for histone H3 lysine 4 methylation and the nonhomologous end joining pathway in ensuring the suppression of HR at Tf2s. Our study identifies a molecular pathway involving functional cooperation between a transcription factor with epigenetic regulators and a DNA repair pathway to regulate meiotic recombination at interspersed repeats.
Biology Department, Boston College, Chestnut Hill, Massachusetts 02467.
Peter
P
Johansen
Biology Department, Boston College, Chestnut Hill, Massachusetts 02467 hugh.cam@bc.edu.
Hugh P
http://orcid.org/0000-0002-1357-8392
HP
Cam
D000251:Adenosine Triphosphatases / Q000378:metabolism; D051936:Centromere Protein B; D002843:Chromatin / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005785:Gene Conversion; D005800:Genes, Fungal; D008540:Meiosis; D046912:Multiprotein Complexes / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011995:Recombination, Genetic; D018626:Retroelements; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism
D051936:Centromere Protein B; D002843:Chromatin; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D018626:Retroelements; D029702:Schizosaccharomyces pombe Proteins; C097691:cbp1 protein, S pombe; C108312:condensin complexes; D000251:Adenosine Triphosphatases
CENP-B; Condensin; NHEJ; Set1; gene conversion; homologous recombination; meiosis; retrotransposons