Long-term perturbation of de novo chromatin assembly during DNA replication has profound effects on epigenome maintenance and cell fate. The early mechanistic origin of these defects is unknown. Here, we combine acute degradation of chromatin assembly factor 1 (CAF-1), a key player in de novo chromatin assembly, with single-cell genomics, quantitative proteomics, and live microscopy to uncover these initiating mechanisms in human cells. CAF-1 loss immediately slows down DNA replication speed and renders nascent DNA hyper-accessible. A rapid cellular response, distinct from canonical DNA damage signaling, is triggered and lowers histone mRNAs. In turn, histone variants’ usage and their modifications are altered, limiting transcriptional fidelity and delaying chromatin maturation within a single S-phase. This multi-level response induces a p53-dependent cell-cycle arrest after mitosis. Our work reveals the immediate consequences of defective de novo chromatin assembly during DNA replication, indicating how at later times the epigenome and cell fate can be altered.

中文翻译：

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对 S 期从头染色质组装缺陷的急性多水平反应


DNA 复制过程中染色质组装从头的长期扰动对表观基因组维持和细胞命运有深远的影响。这些缺陷的早期机械起源尚不清楚。在这里，我们将染色质组装因子 1 （CAF-1） 的急性降解（染色质组装因子 1 （CAF-1））与单细胞基因组学、定量蛋白质组学和实时显微镜相结合，以揭示人类细胞中的这些起始机制。CAF-1 丢失会立即减慢 DNA 复制速度，并使新生 DNA 变得非常容易接近。与经典 DNA 损伤信号转导不同，快速细胞反应被触发并降低组蛋白 mRNA。反过来，组蛋白变体的使用及其修饰被改变，限制了转录保真度并延迟了单个 S 期内的染色质成熟。这种多水平反应在有丝分裂后诱导 p53 依赖性细胞周期停滞。我们的工作揭示了 DNA 复制过程中从头染色质组装缺陷的直接后果，表明表观基因组和细胞命运在以后是如何改变的。