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Human Papillomavirus16 E7 OncoproteinAttenuates DNA DamageCheckpoint Control byIncreasing theProteolytic Turnoverof Claspin Nicole A. SpardyKathryn CovellaElliot Cha2009 год

Human Papillomavirus 16 E7 Oncoprotein Attenuates DNA Damage Checkpoint Control by Increasing the Proteolytic Turnover of Claspin
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Аннотация: The human papillomavirus (HPV) 16 E7 oncoprotein has been reported previously to stimulate DNA damage and to activate host cell DNA damage checkpoints. How HPV-16 E7 maintains proliferation despite activated DNA damage checkpoints is incompletely understood. Here, we provide evidence that cells expressing the HPV-16 E7 oncoprotein can enter mitosis in the presence of DNA damage. We show that this activity of HPV-16 E7 involves attenuation of DNA damage checkpoint control by accelerating the proteolytic turnover of claspin. Claspin mediates the activation of CHK1 by ATR in response to replication stress, and its degradation plays a critical role in DNA damage checkpoint recovery. Expression of a nondegradable mutant of claspin was shown to inhibit mitotic entry in HPV-16 E7-expressing cells. Multiple components of the SCF(beta-TrCP)-based claspin degradation machinery were found deregulated in the presence of HPV-16 E7, including cullin 1, beta-TrCP, Aurora A, and Polo-like kinase-1 (PLK1). In contrast, no difference in the expression level of the claspin deubiquitinating enzyme USP7 was detected. Levels of Aurora A and PLK1 as well as phosphorylated PLK1 at threonine 210, a prerequisite for DNA damage checkpoint recovery, remained detectable following replication stress in HPV-16 E7-expressing cells but not in control cells. In summary, our results suggest that the HPV-16 E7 oncoprotein alleviates DNA damage checkpoint responses and promotes mitotic entry by accelerating claspin degradation through a mechanism that involves deregulation of components of the SCF(beta-TrCP)-based claspin degradation machinery.
Год издания: 2009
Авторы: Nicole A. Spardy, Kathryn Covella, Elliot Cha, Elizabeth E. Hoskins, Susanne I. Wells, Anette Duensing, Stefan Duensing
Издательство: American Association for Cancer Research
Источник: Cancer Research
Ключевые слова: DNA Repair Mechanisms, Cancer-related Molecular Pathways, Genetic factors in colorectal cancer
Другие ссылки: Cancer Research (PDF)
Cancer Research (HTML)
Europe PMC (PubMed Central) (PDF)
Europe PMC (PubMed Central) (HTML)
PubMed Central (HTML)
aacr.figshare.com (PDF)
doi.org (HTML)
aacr.figshare.com (PDF)
doi.org (HTML)
aacr.figshare.com (PDF)
doi.org (HTML)
PubMed (HTML)