title: The F-box protein Dia2 overcomes replication impedance to promote genome stability in Saccharomyces cerevisiae.
abstract: The maintenance of DNA replication fork stability under conditions of DNA damage and at natural replication pause sites is essential for genome stability. Here, we describe a novel role for the F-box protein Dia2 in promoting genome stability in the budding yeast Saccharomyces cerevisiae. Like most other F-box proteins, Dia2 forms a Skp1-Cdc53/Cullin-F-box (SCF) E3 ubiquitin-ligase complex. Systematic analysis of genetic interactions between dia2Delta and approximately 4400 viable gene deletion mutants revealed synthetic lethal/synthetic sick interactions with a broad spectrum of DNA replication, recombination, checkpoint, and chromatin-remodeling pathways. dia2Delta strains exhibit constitutive activation of the checkpoint kinase Rad53 and elevated counts of endogenous DNA repair foci and are unable to overcome MMS-induced replicative stress. Notably, dia2Delta strains display a high rate of gross chromosomal rearrangements (GCRs) that involve the rDNA locus and an increase in extrachromosomal rDNA circle (ERC) formation, consistent with an observed enrichment of Dia2 in the nucleolus. These results suggest that Dia2 is essential for stable passage of replication forks through regions of damaged DNA and natural fragile regions, particularly the replication fork barrier (RFB) of rDNA repeat loci. We propose that the SCFDia2 ubiquitin ligase serves to modify or degrade protein substrates that would otherwise impede the replication fork in problematic regions of the genome.
authors.affiliation: Department of Medical Genetics and Microbiology, University of Toronto, Ontario, Canada.
authors.forename: Deborah
authors.initials: D
authors.lastname: Blake
authors.forename: Brian
authors.initials: B
authors.lastname: Luke
authors.forename: Pamela
authors.initials: P
authors.lastname: Kanellis
authors.forename: Paul
authors.initials: P
authors.lastname: Jorgensen
authors.forename: Theo
authors.initials: T
authors.lastname: Goh
authors.forename: Sonya
authors.initials: S
authors.lastname: Penfold
authors.forename: Bobby-Joe
authors.initials: BJ
authors.lastname: Breitkreutz
authors.forename: Daniel
authors.initials: D
authors.lastname: Durocher
authors.forename: Matthias
authors.initials: M
authors.lastname: Peter
authors.forename: Mike
authors.initials: M
authors.lastname: Tyers
mesh_terms: D002453:Cell Cycle; D020090:Chromosome Segregation; D015825:Chromosomes, Fungal; D004249:DNA Damage; D004260:DNA Repair; D004261:DNA Replication; D004271:DNA, Fungal; D044783:F-Box Proteins / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D042822:Genomic Instability; D020411:Oligonucleotide Array Sequence Analysis; D025941:Protein Interaction Mapping; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D004271:DNA, Fungal; C495983:Dia2 protein, S cerevisiae; D044783:F-Box Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D044843:SKP Cullin F-Box Protein Ligases