Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, 78957, USA.
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China.
Nat Commun. 2021 Nov 4;12(1):6362. doi: 10.1038/s41467-021-26588-y.
SPINDOC is tightly associated with the histone H3K4me3 effector protein SPIN1. To gain a better understanding of the biological roles of SPINDOC, we identified its interacting proteins. Unexpectedly, SPINDOC forms two mutually exclusive protein complexes, one with SPIN1 and the other with PARP1. Consistent with its ability to directly interact with PARP1, SPINDOC expression is induced by DNA damage, likely by KLF4, and recruited to DNA lesions with dynamics that follows PARP1. In SPINDOC knockout cells, the levels of PARylation are reduced, in both the absence and presence of DNA damage. The SPINDOC/PARP1 interaction promotes the clearance of PARP1 from damaged DNA, and also impacts the expression of known transcriptional targets of PARP1. To address the in vivo roles of SPINDOC in PARP1 regulation, we generate SPINDOC knockout mice, which are viable, but slightly smaller than their wildtype counterparts. The KO mice display reduced levels of PARylation and, like PARP1 KO mice, are hypersensitive to IR-induced DNA damage. The findings identify a SPIN1-independent role for SPINDOC in the regulation of PARP1-mediated PARylation and the DNA damage response.
SPINDOC 与组蛋白 H3K4me3 效应蛋白 SPIN1 紧密相关。为了更好地了解 SPINDOC 的生物学作用，我们鉴定了其相互作用蛋白。出乎意料的是，SPINDOC 形成了两个相互排斥的蛋白质复合物，一个与 SPIN1 结合，另一个与 PARP1 结合。与它能够直接与 PARP1 相互作用一致，SPINDOC 的表达受 DNA 损伤诱导，可能由 KLF4 诱导，并且与 PARP1 的动力学一起被募集到 DNA 损伤部位。在 SPINDOC 敲除细胞中，PAR 化水平降低，无论是在没有 DNA 损伤的情况下还是存在 DNA 损伤的情况下。SPINDOC/PARP1 相互作用促进了 PARP1 从受损 DNA 上的清除，也影响了 PARP1 的已知转录靶标的表达。为了研究 SPINDOC 在 PARP1 调节中的体内作用，我们生成了 SPINDOC 敲除小鼠，这些小鼠是可存活的，但比其野生型对应物略小。KO 小鼠的 PAR 化水平降低，并且与 PARP1 KO 小鼠一样，对 IR 诱导的 DNA 损伤敏感。这些发现确定了 SPINDOC 在调节 PARP1 介导的 PAR 化和 DNA 损伤反应中的 SPIN1 非依赖性作用。
