Loss of a 20S proteasome activator in Saccharomyces cerevisiae downregulates genes important for genomic integrity, increases DNA damage, and selectively sensitizes cells to agents with diverse mechanisms of action
| Autor: | Ajay Pramanik, James Lukose, Kevin M. Doherty, Eric G D Muller, David Botstein, Ronald Charles, Brian E. Snydsman, Carol Wood Moore, Leah D. Pride |
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| Rok vydání: | 2012 |
| Předmět: |
Programmed cell death
Proteasome Endopeptidase Complex Saccharomyces cerevisiae Proteins DNA damage Saccharomyces cerevisiae BLM10/PA200 Down-Regulation Antineoplastic Agents Investigations Genomic Instability Deubiquitinating enzyme UBP3/BLM3 03 medical and health sciences chemistry.chemical_compound Endopeptidases Genetics Molecular Biology Genetics (clinical) 030304 developmental biology Cell Nucleus 0303 health sciences biology Activator (genetics) 030302 biochemistry & molecular biology molecular chaperones DNA replication biology.organism_classification Oxidants Molecular biology Diploidy Methyl methanesulfonate Up-Regulation G2 Phase Cell Cycle Checkpoints chemistry Proteasome Mutation biology.protein M Phase Cell Cycle Checkpoints 20S proteasome activator |
| Zdroj: | G3: Genes|Genomes|Genetics |
| ISSN: | 2160-1836 |
| Popis: | Cytoprotective functions of a 20S proteasome activator were investigated. Saccharomyces cerevisiae [Blm10][1] and human 20S proteasome activator 200 (PA200) are homologs. Comparative genome-wide analyses of untreated diploid cells lacking [Blm10][1] and growing at steady state at defined growth rates revealed downregulation of numerous genes required for accurate chromosome structure, assembly and repair, and upregulation of a specific subset of genes encoding protein-folding chaperones. [Blm10][1] loss or truncation of the [Ubp3][2]/[Blm3][2] deubiquitinating enzyme caused massive chromosomal damage and cell death in homozygous diploids after phleomycin treatments, indicating that [Blm10][1] and [Ubp3][2]/[Blm3][2] function to stabilize the genome and protect against cell death. Diploids lacking [Blm10][1] also were sensitized to doxorubicin, hydroxyurea, 5-fluorouracil, rapamycin, hydrogen peroxide, methyl methanesulfonate, and calcofluor. Fluorescently tagged [Blm10][1] localized in nuclei, with enhanced fluorescence after DNA replication. After DNA damage that caused a classic G2/M arrest, fluorescence remained diffuse, with evidence of nuclear fragmentation in some cells. Protective functions of [Blm10][1] did not require the carboxyl-terminal region that makes close contact with 20S proteasomes, indicating that protection does not require this contact or the truncated [Blm10][1] can interact with the proteasome apart from this region. Without its carboxyl-terminus, [Blm10][1](−339aa) localized to nuclei in untreated, nonproliferating (G) cells, but not during G1 S, G2, and M. The results indicate [Blm10][1] functions in protective mechanisms that include the machinery that assures proper assembly of chromosomes. These essential guardian functions have implications for ubiquitin-independent targeting in anticancer therapy. Targeting [Blm10][1]/PA200 together with one or more of the upregulated chaperones or a conventional treatment could be efficacious. [1]: http://www.yeastgenome.org/cgi-bin/locus.fpl?dbid=S000001887 [2]: http://www.yeastgenome.org/cgi-bin/locus.fpl?dbid=S000000953 |
| Databáze: | OpenAIRE |
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