Journal Article

A Genome-Wide Screen Reveals a Role for the HIR Histone Chaperone Complex in Preventing Mislocalization of Budding Yeast CENP-A

Baker, Richard E, Myers, Chad L, Eisenstatt, Jessica R, Basrai, Munira A, Landsman, David, Boone, Charles, Au, Wei-Chun, Costanzo, Michael, Baryshnikova, Anastasia, Rahman, Mahfuzur, Chang, Joy, Ciftci-Yilmaz, Sultan, Zhu, Iris, Meltzer, Paul S, Bilke, Sven, Dawson, Anthony R, Mishra, Prashant K

2018

Overview

Centromeric localization of the evolutionarily conserved centromere-specific histone H3 variant CENP-A (Cse4 in yeast) is essential for faithful chromosome segregation. Overexpression and mislocalization of CENP-A lead to chromosome segregation defects in yeast, flies, and human cells. Overexpression of CENP-A has been observed in human cancers; however, the molecular mechanisms preventing CENP-A mislocalization are not fully understood. Here, we used a genome-wide synthetic genetic array (SGA) to identify gene deletions that exhibit synthetic dosage lethality (SDL) when Cse4 is overexpressed. Deletion for genes encoding the replication-independent histone chaperone HIR complex (HIR1, HIR2, HIR3, HPC2) and a Cse4-specific E3 ubiquitin ligase, PSH1, showed highest SDL. We defined a role for Hir2 in proteolysis of Cse4 that prevents mislocalization of Cse4 to noncentromeric regions for genome stability. Hir2 interacts with Cse4  in vivo, and hir2∆ strains exhibit defects in Cse4 proteolysis and stabilization of chromatin-bound Cse4. Mislocalization of Cse4 to noncentromeric regions with a preferential enrichment at promoter regions was observed in hir2∆ strains. We determined that Hir2 facilitates the interaction of Cse4 with Psh1, and that defects in Psh1-mediated proteolysis contribute to increased Cse4 stability and mislocalization of Cse4 in the hir2∆ strain. In summary, our genome-wide screen provides insights into pathways that regulate proteolysis of Cse4 and defines a novel role for the HIR complex in preventing mislocalization of Cse4 by facilitating proteolysis of Cse4, thereby promoting genome stability.

• Publisher: Genetics Society of America
• Subject: Bioinformatics / Cancer / Cell cycle / Centromere - metabolism / Centromere Protein A - genetics / Centromere Protein A - metabolism / Chromatin / Chromatin - metabolism / Chromosomal Proteins, Non-Histone - genetics / Chromosomal Proteins, Non-Histone - metabolism / Chromosome Segregation / Chromosomes / Clonal deletion / Defects / Deoxyribonucleic acid / DNA / DNA-Binding Proteins - genetics / DNA-Binding Proteins - metabolism / Genes / Genetics / Genome-Wide Association Study / Genomes / Genomics / Histone Chaperones - genetics / Histone Chaperones - metabolism / Histone H3 / Histones - metabolism / Investigations / Kinases / Kinetochores - metabolism / Lethality / Localization / Mammals / Molecular modelling / Nuclear Proteins - genetics / Nuclear Proteins - metabolism / Protein Binding / Proteins / Proteolysis / Repressor Proteins - genetics / Repressor Proteins - metabolism / Saccharomyces cerevisiae - genetics / Saccharomyces cerevisiae Proteins - genetics / Saccharomyces cerevisiae Proteins - metabolism / Saccharomycetales - metabolism / Stability / Ubiquitin / Ubiquitin-protein ligase / Ubiquitin-Protein Ligases - genetics / Ubiquitination / Yeast