<i>Hops/Tmub1</i> Heterozygous Mouse Shows Haploinsufficiency Effect in Influencing p53-Mediated Apoptosis

HOPS is a ubiquitin-like protein implicated in many aspects of cellular function including the regulation of mitotic activity, proliferation, and cellular stress responses. In this study, we focused on the complex relationship between HOPS and the tumor suppressor p53, investigating both transcripti...

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Main Authors: Simona Ferracchiato, Nicola Di-Iacovo, Damiano Scopetti, Danilo Piobbico, Marilena Castelli, Stefania Pieroni, Marco Gargaro, Giorgia Manni, Stefano Brancorsini, Maria Agnese Della-Fazia, Giuseppe Servillo
Format: Article
Language:English
Published: MDPI AG 2021-07-01
Series:International Journal of Molecular Sciences
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Online Access:https://www.mdpi.com/1422-0067/22/13/7186
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Summary:HOPS is a ubiquitin-like protein implicated in many aspects of cellular function including the regulation of mitotic activity, proliferation, and cellular stress responses. In this study, we focused on the complex relationship between HOPS and the tumor suppressor p53, investigating both transcriptional and non-transcriptional p53 responses. Here, we demonstrated that <i>Hops</i> heterozygous mice and mouse embryonic fibroblasts exhibit an impaired DNA-damage response to etoposide-induced double-strand breaks when compared to wild-type genes. Specifically, alterations in HOPS levels caused significant defects in the induction of apoptosis, including a reduction in p53 protein level and percentage of apoptotic cells. We also analyzed the effect of reduced HOPS levels on the DNA-damage response by examining the transcript profiles of p53-dependent genes, showing a suggestive deregulation of the mRNA levels for a number of p53-dependent genes. Taken together, these results show an interesting haploinsufficiency effect mediated by <i>Hops</i> monoallelic deletion, which appears to be enough to destabilize the p53 protein and its functions. Finally, these data indicate a novel role for <i>Hops</i> as a tumor-suppressor gene in DNA damage repair in mammalian cells.
ISSN:1661-6596
1422-0067