Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.
Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.
Nature. 2021 Dec;600(7890):748-753. doi: 10.1038/s41586-021-04200-z. Epub 2021 Dec 1.
Centromeric integrity is key for proper chromosome segregation during cell division. Centromeres have unique chromatin features that are essential for centromere maintenance. Although they are intrinsically fragile and represent hotspots for chromosomal rearrangements, little is known about how centromere integrity in response to DNA damage is preserved. DNA repair by homologous recombination requires the presence of the sister chromatid and is suppressed in the G1 phase of the cell cycle. Here we demonstrate that DNA breaks that occur at centromeres in G1 recruit the homologous recombination machinery, despite the absence of a sister chromatid. Mechanistically, we show that the centromere-specific histone H3 variant CENP-A and its chaperone HJURP, together with dimethylation of lysine 4 in histone 3 (H3K4me2), enable a succession of events leading to the licensing of homologous recombination in G1. H3K4me2 promotes DNA-end resection by allowing DNA damage-induced centromeric transcription and increased formation of DNA-RNA hybrids. CENP-A and HJURP interact with the deubiquitinase USP11, enabling formation of the RAD51-BRCA1-BRCA2 complex and rendering the centromeres accessible to RAD51 recruitment and homologous recombination in G1. Finally, we show that inhibition of homologous recombination in G1 leads to centromeric instability and chromosomal translocations. Our results support a model in which licensing of homologous recombination at centromeric breaks occurs throughout the cell cycle to prevent the activation of mutagenic DNA repair pathways and preserve centromeric integrity.
着丝粒完整性对于细胞分裂过程中染色体的正确分离至关重要。着丝粒具有独特的染色质特征,对维持着丝粒至关重要。尽管它们本质上很脆弱,是染色体重排的热点,但对于如何在 DNA 损伤时保持着丝粒的完整性知之甚少。同源重组的 DNA 修复需要姐妹染色单体的存在,并且在细胞周期的 G1 期受到抑制。在这里,我们证明尽管不存在姐妹染色单体,但在 G1 期发生在着丝粒上的 DNA 断裂会招募同源重组机制。从机制上讲,我们表明着丝粒特异性组蛋白 H3 变体 CENP-A 及其伴侣 HJURP,与组蛋白 3 赖氨酸 4 的二甲基化(H3K4me2)一起,能够引发一系列事件,导致在 G1 期获得同源重组的许可。H3K4me2 通过允许 DNA 损伤诱导的着丝粒转录和增加 DNA-RNA 杂交体的形成,促进 DNA 末端切除。CENP-A 和 HJURP 与去泛素化酶 USP11 相互作用,使 RAD51-BRCA1-BRCA2 复合物形成,并使 RAD51 在 G1 期招募和同源重组能够到达着丝粒。最后,我们表明在 G1 期抑制同源重组会导致着丝粒不稳定和染色体易位。我们的结果支持这样一种模型,即在整个细胞周期中,着丝粒断裂处的同源重组的许可发生,以防止激活诱变性 DNA 修复途径并保持着丝粒的完整性。
Mol Biol Cell. 2017-1-1
PLoS Genet. 2014-4-24
Mol Cell Proteomics. 2016-3
Results Probl Cell Differ. 2022
Proc Natl Acad Sci U S A. 2025-8-26
Cancers (Basel). 2025-3-11
Nat Rev Mol Cell Biol. 2025-3-25
Cells. 2025-2-13
Proc Natl Acad Sci U S A. 2024-12-3
Nat Rev Genet. 2025-2
Nat Cell Biol. 2021-4
Commun Biol. 2021-3-26
Proc Natl Acad Sci U S A. 2021-3-9
Nature. 2020-7-15