Laboratory of Molecular Medicine and Genomics, Department of Medicine, Surgery and Dentistry "Schola Medica Salernitana", University of Salerno, via S. Allende, 1, 84081, Baronissi, SA, Italy.
Genomix4Life srl, Department of Medicine, Surgery and Dentistry "Schola Medica Salernitana", University of Salerno, Baronissi, SA, Italy.
Genome Biol. 2017 Oct 6;18(1):189. doi: 10.1186/s13059-017-1321-0.
The RNA-binding protein Argonaute 2 (AGO2) is a key effector of RNA-silencing pathways It exerts a pivotal role in microRNA maturation and activity and can modulate chromatin remodeling, transcriptional gene regulation and RNA splicing. Estrogen receptor beta (ERβ) is endowed with oncosuppressive activities, antagonizing hormone-induced carcinogenesis and inhibiting growth and oncogenic functions in luminal-like breast cancers (BCs), where its expression correlates with a better prognosis of the disease.
Applying interaction proteomics coupled to mass spectrometry to characterize nuclear factors cooperating with ERβ in gene regulation, we identify AGO2 as a novel partner of ERβ in human BC cells. ERβ-AGO2 association was confirmed in vitro and in vivo in both the nucleus and cytoplasm and is shown to be RNA-mediated. ChIP-Seq demonstrates AGO2 association with a large number of ERβ binding sites, and total and nascent RNA-Seq in ERβ + vs ERβ - cells, and before and after AGO2 knock-down in ERβ + cells, reveals a widespread involvement of this factor in ERβ-mediated regulation of gene transcription rate and RNA splicing. Moreover, isolation and sequencing by RIP-Seq of ERβ-associated long and small RNAs in the cytoplasm suggests involvement of the nuclear receptor in RISC loading, indicating that it may also be able to directly control mRNA translation efficiency and stability.
These results demonstrate that AGO2 can act as a pleiotropic functional partner of ERβ, indicating that both factors are endowed with multiple roles in the control of key cellular functions.
RNA 结合蛋白 Argonaute 2（AGO2）是 RNA 沉默途径的关键效应因子。它在 microRNA 成熟和活性中发挥着关键作用，并可以调节染色质重塑、转录基因调控和 RNA 剪接。雌激素受体β（ERβ）具有抗肿瘤活性，拮抗激素诱导的癌变，并抑制腔型乳腺癌（BC）中的生长和致癌功能，其表达与疾病的预后较好相关。
应用相互作用蛋白质组学结合质谱法来描述与 ERβ 共同调节基因的核因子，我们鉴定出 AGO2 是人类 BC 细胞中 ERβ 的一种新型伴侣。在体外和体内，在细胞核和细胞质中均证实了 ERβ-AGO2 的相互作用，并且该相互作用是 RNA 介导的。ChIP-Seq 表明 AGO2 与大量的 ERβ 结合位点相关，并且在 ERβ+vs ERβ-细胞中，以及在 ERβ+细胞中敲低 AGO2 之前和之后，总 RNA-Seq 和新生 RNA-Seq 均显示该因子广泛参与 ERβ 介导的基因转录率和 RNA 剪接的调节。此外，通过 RIP-Seq 在细胞质中分离和测序 ERβ 相关的长链和小 RNA，表明核受体参与 RISC 加载，这表明它也可能直接控制 mRNA 翻译效率和稳定性。
这些结果表明 AGO2 可以作为 ERβ 的多功能功能伴侣发挥作用，表明这两个因子在控制关键细胞功能方面都具有多种作用。
