γH2A-binding protein Brc1 affects centromere function in fission yeast.
The coordinated replication and transcription of pericentromeric repeats enable RNA interference (RNAi)-mediated transmission of pericentromeric heterochromatin in fission yeast, which is essential for the proper function of centromeres. Rad3/ATR kinase phosphorylates histone H2A on serine-128/-129 to create γH2A in pericentromeric heterochromatin during S phase, which recruits Brc1 through its breast cancer gene 1 protein (BRCA1) C-terminal (BRCT) domains. Brc1 prevents the collapse of stalled replication forks; however, it is unknown whether this activity influences centromere function. Here, we show that Brc1 localizes in pericentromeric heterochromatin during S phase, where it enhances Clr4/Suv39-mediated H3 lysine-9 dimethylation (H3K9me2) and gene silencing. Loss of Brc1 increases sensitivity to the microtubule-destabilizing drug thiabendazole (TBZ) and increases chromosome missegregation in the presence of TBZ. Brc1 retains significant function even when it cannot bind γH2A. However, elimination of the serine-121 site on histone H2A, a target of Bub1 spindle assembly checkpoint kinase, sensitizes γH2A-deficient and brc1Δ cells to replication stress and microtubule destabilization. Collective results suggest that Brc1-mediated stabilization of stalled replication forks is necessary for fully efficient transmission of pericentromeric heterochromatin, which is required for accurate chromosome segregation during mitosis.
Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA.
Si Young
SY
Lee
Sophie
S
Rozenzhak
Paul
P
Russell
D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002503:Centromere / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D020090:Chromosome Segregation; D015825:Chromosomes, Fungal; D019175:DNA Methylation; D004261:DNA Replication / Q000235:genetics; D020868:Gene Silencing; D006570:Heterochromatin / Q000235:genetics / Q000378:metabolism; D011495:Histone-Lysine N-Methyltransferase; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D008239:Lysine / Q000235:genetics / Q000378:metabolism; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000235:genetics / Q000378:metabolism; D016196:S Phase / Q000235:genetics; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*
C511286:Brc1 protein, S pombe; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D006570:Heterochromatin; D006657:Histones; D029702:Schizosaccharomyces pombe Proteins; D008780:Methyltransferases; D011495:Histone-Lysine N-Methyltransferase; C112744:clr4 protein, S pombe; D008239:Lysine