Deletion of p66Shc in mice increases the frequency of size‐change mutations in the lacZ transgene

Aging Cell

Elena Beltrami²  Antonella Ruggiero²  Rita Busuttil¹  Enrica Migliaccio²  Pier Giuseppe Pelicci²  Jan Vijg³ 

[1] Department of Cancer Genetics and Genomics, Peter MacCallum Cancer Centre, Melbourne, Vic., Australia;Department of Experimental Oncology, European Institute of Oncology, Milan, Italy;Department of Genetics, Albert Einstein College of Medicine, New York, NY, USA

关键词: cell death;    longevity genes;    mice;    mitochondria;    mutagenesis;    reactive oxygen species;   

DOI  :  10.1111/acel.12036

来源: Wiley

【 摘 要 】

Summary

Upon oxidative challenge the genome accumulates adducts and breaks that activate the DNA damage response to repair, arrest, or eliminate the damaged cell. Thus, reactive oxygen species (ROS) generated by endogenous oxygen metabolism are thought to affect mutation frequency. However, few studies determined the mutation frequency when oxidative stress is reduced. To test whether in vivo spontaneous mutation frequency is altered in mice with reduced oxidative stress and cell death rate, we crossed p66Shc knockout (p66KO) mice, characterized by reduced intracellular concentration of ROS and by impaired apoptosis, with a transgenic line harboring multiple copies of the lacZ mutation reporter gene as part of a plasmid that can be recovered from organs into Escherichia coli to measure mutation rate. Liver and small intestine from 2- to 24-month-old, lacZ (p66Shc+/+) and lacZp66KO mice, were investigated revealing no difference in overall mutation frequency but a significant increase in the frequency of size-change mutations in the intestine of lacZp66KO mice. This difference was further increased upon irradiation of mice with X-ray. In addition, we found that knocking down cyclophilin D, a gene that facilitates mitochondrial apoptosis acting downstream of p66Shc, increased the size-change mutation frequency in small intestine. Size-change mutations also accumulated in death-resistant embryonic fibroblasts from lacZp66KO mice treated with H₂O₂. These results indicate that p66Shc plays a role in the accumulation of DNA rearrangements and suggest that p66Shc functions to clear damaged cells rather than affect DNA metabolism.

【 授权许可】

Unknown   
© 2012 The Authors Aging Cell © 2012 Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland