Reproductive Center, The Second Affiliated Hospital of Zhengzhou University, 450014, No. 2 Jingba Road, Zhengzhou, Henan, China.
Reproductive Center, The Second Affiliated Hospital of Zhengzhou University, 450014, No. 2 Jingba Road, Zhengzhou, Henan, China.
Mol Cell Endocrinol. 2022 Mar 1;543:111528. doi: 10.1016/j.mce.2021.111528. Epub 2021 Dec 6.
Polycystic ovary syndrome (PCOS) is a metabolic disorder of the reproductive system that affects 6-20% women of reproductive age. Multiple coding and non-coding genes were found to be affected in patients with PCOS, including MALAT1, an 8.7 kb long non-coding RNA. MALAT1 has been found to interact with miRNAs in granulosa cells (GCs); however, its binding proteins in GCs are still unknown. In this study, MALAT1 binding proteins in primary GCs were recruited by RNA antisense purification (RAP) assay and identified by mass spectrometry. The interaction between MALAT1 and proteins was examined by the PAR-CLIP assay and immunofluorescence. Functional studies were performed using the human granulosa-like tumor cell line (KGN) and primary granulosa cells. We identified that MALAT1 interacted with MDM2 and PARP1 in the cell nucleus. MDM2 binds to the 3' segment of MALAT1, containing the ENE domain through the ring finger domain. Knockdown of MALAT1 in GCs increased p53 protein levels by repressing p53 ubiquitination and degradation. MALAT1 promoted the binding between P53 and MDM2, which further boosted P53 proteasome dependent degradation. Knockdown of MALAT1 in KGN cells and primary GCs increased apoptosis and reduced proliferation.
多囊卵巢综合征（PCOS）是一种生殖系统的代谢紊乱疾病，影响着 6-20%的育龄妇女。研究发现，患有 PCOS 的患者有多个编码和非编码基因受到影响，包括 MALAT1，这是一种 8.7kb 长的非编码 RNA。MALAT1 已被发现与颗粒细胞（GCs）中的 miRNAs 相互作用；然而，其在 GCs 中的结合蛋白仍不清楚。在这项研究中，通过 RNA 反义纯化（RAP）测定法招募了原代 GCs 中的 MALAT1 结合蛋白，并通过质谱法对其进行了鉴定。通过 PAR-CLIP 测定法和免疫荧光法检查了 MALAT1 与蛋白质之间的相互作用。使用人颗粒细胞样肿瘤细胞系（KGN）和原代颗粒细胞进行了功能研究。我们发现 MALAT1 在细胞核内与 MDM2 和 PARP1 相互作用。MDM2 通过其环指结构域结合到 MALAT1 的 3' 片段，该片段包含 ENE 结构域。在 GCs 中敲低 MALAT1 通过抑制 p53 的泛素化和降解来增加 p53 蛋白水平。MALAT1 促进了 P53 和 MDM2 之间的结合，从而进一步促进了 P53 蛋白酶体依赖性降解。在 KGN 细胞和原代 GCs 中敲低 MALAT1 增加了细胞凋亡并减少了细胞增殖。
