Identification and characterization of a special type of subnuclear structure: AGGF1-coated paraspeckles
Identification and characterization of a special type of subnuclear structure: AGGF1-coated paraspeckles
复制标题
特殊类型亚核结构的鉴定和表征：AGGF1-包被的paraspeckles
DOI：
10.1096/fj.202101690rr
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发表时间：
2022-06-01
期刊：
影响因子：
4.8
通讯作者：
Wang，Qing K.
中科院分区：
文献类型：
--
作者：
Zhao，Jinyan;Xie，Wen;Wang，Qing K.
AGGF1是本课题组描述的具有G-Patch和FHA结构域1的血管生成因子。AGGF1的功能获得突变导致Klippel-Trenaunay综合征，而躯体功能丧失突变导致癌症。类核膜是一种小的无膜亚核结构，直径0.5-1μm，由作为支架的lncRNANEAT1和三个核心核糖核酸结合蛋白NONO、PSPC1和Psf组成。在这里，我们证明AGGF1是副斑的一个关键的调节和结构成分，它诱导副斑的形成，形成副斑的外缘，包裹在NONO/PSF/PSPC1/NEAT1核心上，并调节副斑的大小和数量。AGGF1-Paraspeckles比传统的Paraspeckles更大(>；1μm)。RNA-FISH结合免疫组织化学染色显示，AGGF1、NONO和NEAT1_2共定位于20.58%的NEAT1_2阳性旁小叶中。在机制上，AGGF1与NONO、PSF和HNRNPK相互作用，上调NEAT1_2，这是一个23kbNEAT1转录本，在调节副斑点的大小和数量方面发挥关键作用。RNA免疫沉淀显示AGGF1与NEAT1相互作用，这可能是形成AGGF1-准蛋白链的另一种可能机制。NEAT1_2基因敲除减少了AGGF1-蛋白链的数量和大小。在功能上，AGGF1调节选择性RNA剪接，因为它降低了CD44模型中的外显子跳过/包涵体比率。AGGF1也定位于一些没有NEAT1或NONO的核灶中，这表明AGGF1是其他类型AGGF1阳性核凝聚体(称为AGGF1-小体)的重要液-液相分离(LLP)驱动因素。我们的结果确定了一种特殊类型的AGGF1包被的副眼球，并为了解副眼球的形成、结构和功能提供了重要的见解。
AGGF1 is an angiogenic factor with G‐Patch and FHA domains 1 described by our group. Gain‐of‐function mutations in AGGF1 cause Klippel–Trenaunay syndrome, whereas somatic loss‐of‐function mutations cause cancer. Paraspeckles are small membraneless subnuclear structures with a diameter of 0.5–1 μm, and composed of lncRNANEAT1as the scaffold and three core RNA‐binding proteins NONO, PSPC1, and PSF. Here, we show that AGGF1 is a key regulatory and structural component of paraspeckles that induces paraspeckle formation, forms an outside rim of paraspeckles, wraps around the NONO/PSF/PSPC1/NEAT1core, and regulates the size and number of paraspeckles. AGGF1‐paraspeckles are larger (>1 μm) than conventional paraspeckles. RNA‐FISH in combination with immunostaining shows that AGGF1, NONO, andNEAT1_2co‐localize in 20.58% ofNEAT1_2‐positive paraspeckles. Mechanistically, AGGF1 interacts with NONO, PSF, and HNRNPK, and upregulatesNEAT1_2, a longer, 23 kbNEAT1transcript with a key role in regulation of paraspeckle size and number. RNA‐immunoprecipitation shows that AGGF1 interacts withNEAT1, which may be another possible mechanism underlying the formation of AGGF1‐paraspeckles.NEAT1_2knockdown reduces the number and size of AGGF1‐paraspeckles. Functionally, AGGF1 regulates alternative RNA splicing as it decreases the exon skipping/inclusion ratio in aCD44model. AGGF1 is also localized in some nuclear foci withoutNEAT1or NONO, suggesting that AGGF1 is an important liquid–liquid phase separation (LLPS) driver for other types of AGGF1‐positive nuclear condensates (referred to as AGGF1‐bodies). Our results identify a special type of AGGF1‐coated paraspeckles and provide important insights into the formation, structure, and function of paraspeckles.