Abstract
Unique among translesion synthesis (TLS) DNA polymerases, pol ζ is essential during embryogenesis. To determine whether pol ζ is necessary for proliferation of normal cells, primary mouse fibroblasts were established in which Rev3L could be conditionally inactivated by Cre recombinase. Cells were grown in 2 O2 to prevent oxidative stress-induced senescence. Cells rapidly became senescent or apoptotic and ceased growth within 3-4 population doublings. Within one population doubling following Rev3L deletion, DNA double-strand breaks and chromatid aberrations were found in 30-50 of cells. These breaks were replication dependent, and found in G1 and G2 phase cells. Double-strand breaks were reduced when cells were treated with the reactive oxygen species scavenger N-acetyl-cysteine, but this did not rescue the cell proliferation defect, indicating that several classes of endogenously formed DNA lesions require Rev3L for tolerance or repair. T-antigen immortalization of cells allowed cell growth. In summary, even in the absence of external challenges to DNA, pol ζ is essential for preventing replication-dependent DNA breaks in every division of normal mammalian cells. Loss of pol ζ in slowly proliferating mouse cells in vivo may allow accumulation of chromosomal aberrations that could lead to tumorigenesis. Pol ζ is unique amongst TLS polymerases for its essential role in cell proliferation.
Original language | English (US) |
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Pages (from-to) | 4473-4482 |
Number of pages | 10 |
Journal | Nucleic acids research |
Volume | 40 |
Issue number | 10 |
DOIs | |
State | Published - May 2012 |
ASJC Scopus subject areas
- Genetics