Contribution of CAF-I to anaphase-promoting-complex-mediated mitotic chromatin assembly in Saccharomyces cerevisiae.
The anaphase-promoting complex (APC) is required for mitotic progression and genomic stability. Recently, we demonstrated that the APC is also required for mitotic chromatin assembly and longevity. Here, we investigated the role the APC plays in chromatin assembly. We show that apc5(CA) mutations genetically interact with the CAF-I genes as well as ASF1, HIR1, and HIR2. When present in multiple copies, the individual CAF-I genes, CAC1, CAC2, and MSI1, suppress apc5(CA) phenotypes in a CAF-1- and Asf1p-independent manner. CAF-I and the APC functionally overlap, as cac1delta cac2delta msi1delta (caf1delta) cells expressing apc5(CA) exhibit a phenotype more severe than that of apc5(CA) or caf1delta. The Ts- phenotypes observed in apc5(CA) and apc5(CA) caf mutants may be rooted in compromised histone metabolism, as coexpression of histones H3 and H4 suppressed the Ts- defects. Synthetic genetic interactions were also observed in apc5(CA) asf1delta cells. Furthermore, increased expression of genes encoding Asf1p, Hir1p, and Hir2p suppressed the apc5(CA) Ts- defect in a CAF-I-dependent manner. Together, these results suggest the existence of a complex molecular mechanism controlling APC-dependent chromatin assembly. Our data suggest the APC functions with the individual CAF-I subunits, Asf1p, and the Hir1p and Hir2p proteins. However, Asf1p and an intact CAF-I complex are dispensable for CAF-I subunit suppression, whereas CAF-I is necessary for ASF1, HIR1, and HIR2 suppression of apc5(CA) phenotypes. We discuss the implications of our observations.
Harkness
Troy A A
TA
Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada. troy.harkness@usask.ca
Arnason
Terra G
TG
Legrand
Charmaine
C
Pisclevich
Marnie G
MG
Davies
Gerald F
GF
Turner
Emma L
EL
D064173:Anaphase-Promoting Complex-Cyclosome; D064193:Apc5 Subunit, Anaphase-Promoting Complex-Cyclosome; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D015966:Gene Expression Regulation, Fungal; D042822:Genomic Instability; D006657:Histones / Q000378:metabolism; D008938:Mitosis; D018832:Molecular Chaperones; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000494:pharmacology; D010641:Phenotype; D021122:Protein Subunits; D012097:Repressor Proteins / Q000494:pharmacology; D012260:Ribonucleases / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D043743:Ubiquitin-Protein Ligase Complexes / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
C577378:APC5 protein, S cerevisiae; C109731:ASF1 protein, S cerevisiae; D064193:Apc5 Subunit, Anaphase-Promoting Complex-Cyclosome; D018797:Cell Cycle Proteins; C078808:HIR1 protein, S cerevisiae; C078809:HIR2 protein, S cerevisiae; D006657:Histones; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D021122:Protein Subunits; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D012260:Ribonucleases; C079009:POP2 protein, S cerevisiae