Institute of Molecular Biology (IMB), 55128, Mainz, Germany.
STEMCELL Technologies Germany GmbH, 50933, Cologne, Germany.
Nat Commun. 2022 Oct 17;13(1):6138. doi: 10.1038/s41467-022-33731-w.
Poly-ADP-ribosylation (PARylation) is regarded as a protein-specific modification. However, some PARPs were recently shown to modify DNA termini in vitro. Here, we use ultrasensitive mass spectrometry (LC-MS/MS), anti-PAR antibodies, and anti-PAR reagents to show that mammalian DNA is physiologically PARylated and to different levels in primary tissues. Inhibition of PAR glycohydrolase (PARG) increases DNA PARylation, supporting that the modification is reversible. DNA PARylation requires PARP1 and in vitro PARP1 PARylates single-stranded DNA, while PARG reverts the modification. DNA PARylation occurs at the N1-position of adenosine residues to form N1-Poly(ADP-ribosyl)-deoxyadenosine. Through partial hydrolysis of mammalian gDNA we identify PAR-DNA via the diagnostic deamination product N1-ribosyl-deoxyinosine to occur in vivo. The discovery of N1-adenosine PARylation as a DNA modification establishes the conceptual and methodological framework to elucidate its biological relevance and extends the role of PARP enzymes.
聚 ADP-核糖基化 (PARylation) 被视为一种蛋白质特异性修饰。然而，最近一些 PARPs 被证明可以在体外修饰 DNA 末端。在这里，我们使用超灵敏质谱 (LC-MS/MS)、抗 PAR 抗体和抗 PAR 试剂来表明哺乳动物 DNA 是生理性 PARylated 的，并且在主要组织中达到不同的水平。PAR 糖基水解酶 (PARG) 的抑制增加了 DNA 的 PARylation，支持该修饰是可逆的。DNA PARylation 需要 PARP1，并且体外 PARP1 PARylates 单链 DNA，而 PARG 则使修饰逆转。DNA PARylation 发生在腺苷残基的 N1 位置，形成 N1-聚（ADP-核糖基）-脱氧腺苷。通过对哺乳动物 gDNA 的部分水解，我们通过诊断脱氨产物 N1-核糖基-脱氧肌苷鉴定出体内发生的 PAR-DNA。N1-腺苷 PARylation 作为一种 DNA 修饰的发现为阐明其生物学相关性奠定了概念和方法框架，并扩展了 PARP 酶的作用。
