The Budding Yeast Ubiquitin Protease Ubp7 Is a Novel Component Involved in S Phase Progression

DNA damage must be repaired in an accurate and timely fashion to preserve genome stability. Cellular mechanisms preventing genome instability are crucial to human health because genome instability is considered a hallmark of cancer. Collectively referred to as the DNA damage response, conserved path...

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Bibliographic Details
Published inThe Journal of biological chemistry Vol. 291; no. 9; pp. 4442 - 4452
Main Authors Böhm, Stefanie, Szakal, Barnabas, Herken, Benjamin W., Sullivan, Meghan R., Mihalevic, Michael J., Kabbinavar, Faiz F., Branzei, Dana, Clark, Nathan L., Bernstein, Kara A.
Format Journal Article
LanguageEnglish
Published United States Elsevier Inc 26.02.2016
American Society for Biochemistry and Molecular Biology
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Summary:DNA damage must be repaired in an accurate and timely fashion to preserve genome stability. Cellular mechanisms preventing genome instability are crucial to human health because genome instability is considered a hallmark of cancer. Collectively referred to as the DNA damage response, conserved pathways ensure proper DNA damage recognition and repair. The function of numerous DNA damage response components is fine-tuned by posttranslational modifications, including ubiquitination. This not only involves the enzyme cascade responsible for conjugating ubiquitin to substrates but also requires enzymes that mediate directed removal of ubiquitin. Deubiquitinases remove ubiquitin from substrates to prevent degradation or to mediate signaling functions. The Saccharomyces cerevisiae deubiquitinase Ubp7 has been characterized previously as an endocytic factor. However, here we identify Ubp7 as a novel factor affecting S phase progression after hydroxyurea treatment and demonstrate an evolutionary and genetic interaction of Ubp7 with DNA damage repair pathways of homologous recombination and nucleotide excision repair. We find that deletion of UBP7 sensitizes cells to hydroxyurea and cisplatin and demonstrate that factors that stabilize replication forks are critical under these conditions. Furthermore, ubp7Δ cells exhibit an S phase progression defect upon checkpoint activation by hydroxyurea treatment. ubp7Δ mutants are epistatic to factors involved in histone maintenance and modification, and we find that a subset of Ubp7 is chromatin-associated. In summary, our results suggest that Ubp7 contributes to S phase progression by affecting the chromatin state at replication forks, and we propose histone H2B ubiquitination as a potential substrate of Ubp7.
Bibliography:Present address: Molecular Pathology and Dept. of Translational Genomics, University of Cologne, 50931 Cologne, Germany
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M115.671057