HERC2 Facilitates BLM and WRN Helicase Complex Interaction with RPA to Suppress G-Quadruplex DNA.
HERC2 Facilitates BLM and WRN Helicase Complex Interaction with RPA to Suppress G-Quadruplex DNA.
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DOI：
10.1158/0008-5472.can-18-1877
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发表时间：
2018-10
期刊：
影响因子：
11.2
通讯作者：
Wenwen Wu;N. Rokutanda;Jun Takeuchi;Y. Lai;R. Maruyama;Yukiko Togashi;Hiroyuki Nishikawa;N. Arai;Y. Miyoshi;N. Suzuki;Y. Saeki;Keiji Tanaka;T. Ohta
中科院分区：
文献类型：
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作者：
Wenwen Wu;N. Rokutanda;Jun Takeuchi;Y. Lai;R. Maruyama;Yukiko Togashi;Hiroyuki Nishikawa;N. Arai;Y. Miyoshi;N. Suzuki;Y. Saeki;Keiji Tanaka;T. Ohta
BLM和WRN是基因组稳定性所必需的RecQ DNA解旋酶。在这里，我们证明了HERC 2，一种HECT E3连接酶，对于它们抑制G-四链体（G4）DNA的功能至关重要。HERC 2在细胞周期的S期与BLM、WRN和复制蛋白A（RPA）复合物相互作用。HERC 2的耗尽使RPA从BLM和WRN复合物中解离，并显著增加G4形成。三重缺失揭示HERC 2与BLM和WRN在其G4抑制功能中具有上位关系。在体外，HERC 2将RPA释放到单链DNA（ssDNA）上，而不是锚定到RPA包被的ssDNA上。CRISPR/Cas9介导的HERC 2催化泛素结合位点的缺失抑制了RPA 2的泛素化，导致RPA在解旋酶复合物中积累，并增加了G4，表明E3活性在抑制G4中的重要作用。HERC 2的消耗和E3的失活都使细胞对G4相互作用化合物端粒抑素和吡啶抑素敏感。总体而言，这些结果表明HERC 2是G4抑制的主要调节剂，其影响细胞对G4稳定剂的敏感性。鉴于HERC 2表达在许多类型的癌症中经常减少，HERC 2缺陷导致的G4积累可能为G4稳定剂提供治疗靶点。重要性：HERC 2被揭示为G-四链体的主要调节因子，G-四链体是一种触发基因组不稳定性的DNA二级结构，可能作为癌症治疗中的潜在分子靶点。图形摘要：http://cancerres.aacrjournals.org/content/canres/78/22/6371/F1.large.jpg Cancer Res; 78（22）; 6371-85。©2018 AACR.
BLM and WRN are RecQ DNA helicasesessential for genomic stability. Here, we demonstrate that HERC2, a HECT E3 ligase, is critical for their functions to suppress G-quadruplex (G4) DNA. HERC2 interacted with BLM, WRN, and replication protein A (RPA) complexes during the S-phase of the cell cycle. Depletion of HERC2 dissociated RPA from BLM and WRN complexes and significantly increased G4 formation. Triple depletion revealed that HERC2 has an epistatic relationship with BLM and WRN in their G4-suppressing function. In vitro, HERC2 released RPA onto single-stranded DNA (ssDNA) rather than anchoring onto RPA-coated ssDNA. CRISPR/Cas9-mediated deletion of the catalytic ubiquitin-binding site of HERC2 inhibited ubiquitination of RPA2, caused RPA accumulation in the helicase complexes, and increased G4, indicating an essential role for E3 activity in the suppression of G4. Both depletion of HERC2 and inactivation of E3 sensitized cells to the G4-interacting compounds telomestatin and pyridostatin. Overall, these results indicate that HERC2 is a master regulator of G4 suppression that affects the sensitivity of cells to G4 stabilizers. Given that HERC2 expression is frequently reduced in many types of cancers, G4 accumulation as a result of HERC2 deficiency may provide a therapeutic target for G4 stabilizers.Significance: HERC2 is revealed as a master regulator of G-quadruplex, a DNA secondary structure that triggers genomic instability and may serve as a potential molecular target in cancer therapy.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/22/6371/F1.large.jpg Cancer Res; 78(22); 6371-85. ©2018 AACR.