The ATR-Chk1 pathway plays a role in the generation of centrosome aberrations induced by Rad51C dysfunction

Abstract

Rad51C is a central component of two complexes formed by five Rad51 paralogs in vertebrates. These complexes are involved in repairing DNA double-strand breaks through homologous recombination. Despite accumulating evidence suggesting that the paralogs may prevent aneuploidy by controlling centrosome integrity, Rad51C's role in maintaining chromosome stability remains unclear. Here we demonstrate that Rad51C deficiency leads to both centrosome aberrations in an ATR-Chk1-dependent manner and increased aneuploidy in human cells. While it was reported that Rad51C deficiency did not cause centrosome aberrations in interphase in hamster cells, such aberrations were observed in interphase in HCT116 cells with Rad51C dysfunction. Caffeine treatment and down-regulation of ATR, but not that of ATM, reduced the frequency of centrosome aberrations in the mutant cells. Silencing of Rad51C by RNA interference in HT1080 cells resulted in similar aberrations. Treatment with a Chk1 inhibitor and silencing of Chk1 also reduced the frequency in HCT116 mutants. Accumulation of Chk1 at the centrosome and nuclear foci of γH2AX were increased in the mutants. Moreover, the mutant cells had a higher frequency of aneuploidy. These findings indicate that the ATR-Chk1 pathway plays a role in increased centrosome aberrations induced by Rad51C dysfunction.

Oncogenes induce senescence with incomplete growth arrest and suppress the DNA damage response in immortalized cells

“…There are numerous reports demonstrating that aneuploidy can be triggered by the centrosome dysfunction (Katsura et al , 2009). To address whether SWING state associates with centrosome dysfunction, we compared the number of centrosomes detected by immunofluorescence with anti-γ-tubulin antibody in control MCF10A and MCF10A/NeuT cells.…”

Spontaneous slow replication fork progression elicits mitosis alterations in homologous recombination-deficient mammalian cells

“…In addition, CHK1 activation controls centrosome alterations and amplification (25,(53)(54)(55). However, The mean value ± SD from three independent experiments was calculated.…”

“…Replication forks are routinely inactivated by endogenous stress (17,18); therefore, HR should play an essential role to protect cells against these types of stresses, and HR deficiency should reveal endogenous replication stress. Remarkably, unchallenged HR-deficient (HR − ) cells display both a genome-wide decrease in replication fork speed (19) and a spontaneous increase in the frequency of cells containing extra centrosomes (20)(21)(22)(23)(24)(25)(26)(27)(28). Two hypotheses may account for these two phenotypes.…”

Differential Requirements for the RAD51 Paralogs in Genome Repair and Maintenance in Human Cells

“…Typically, classical RAD51 paralog deficient cells are sensitive to DNA damaging agents including ionizing radiation (IR) and DNA crosslinking agents such as mitomycin C (Liu et al 1998;Takata et al 2001Takata et al , 2000Tebbs et al 1995;Yonetani et al 2005). Mutant cells display increased spontaneous chromosomal abnormalities, decreased frequencies of DNA damage-induced sister chromatid exchanges, reduced DNA damage-induced RAD51 focus formation, and deficiencies in replication fork protection (Badie et al 2009;Bishop et al 1998;Cui et al 1999;Date et al 2006;Deans et al 2003;French et al 2002;Griffin et al 2000;Katsura et al 2009;Liu et al 1998;Pierce et al 1999;Rodrigue et al 2006;Smiraldo et al 2005;Somyajit et al 2015;Sung et al 2003;Takata et al 2001;Yoshihara et al 2004;Saxena et al 2018). Overexpression of the core RAD51 recombinase partially suppresses DNA damage sensitivity of chicken classical RAD51 paralog mutant cells, suggesting a link with RAD51 function (Takata et al 2001).…”