Paraspeckle protein p54nrb links Sox9-mediated transcription with RNA processing during chondrogenesis in mice
Paraspeckle protein p54nrb links Sox9-mediated transcription with RNA processing during chondrogenesis in mice
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DOI：
10.1172/jci31373
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发表时间：
2008-09-01
影响因子：
15.9
通讯作者：
Yoneda, Toshiyuki
中科院分区：
文献类型：
--
作者：
Hata, Kenji;Nishimura, Riko;Yoneda, Toshiyuki
Sox 9转录因子在促进软骨形成和调节软骨细胞外基质基因的表达中起重要作用。为了鉴定在促进软骨细胞分化中与Sox 9相互作用的基因，我们筛选了从鼠软骨形成ATDC 5细胞系产生的cDNA文库，以鉴定胶原蛋白II型α 1（Col2al）启动子的激活剂。在这里，我们已经表明，paraspeckle调节蛋白54 kDa核RNA结合蛋白（p54（nrb））是一个重要的联系之间的Sox9调节转录和成熟的Sox9靶基因mRNA。我们发现，p54（nrb）物理相互作用与Sox9和增强Sox9依赖的转录激活的Col2al启动子。在ATDC 5细胞中，p54（nrb）与Sox 9蛋白共定位于核旁斑体中，并且p54（nrb）的敲低抑制Sox 9依赖的Col2al表达和启动子活性。我们产生了一个缺乏RNA识别基序的p54（nrb）突变体结构，突变体p54（nrb）在ATDC 5细胞中的过表达显着改变了paraspeckle体的外观，并抑制Col2al mRNA的成熟。突变型p54nrb抑制间充质细胞和小鼠跖骨外植体的软骨细胞分化。此外，在软骨细胞谱系中表达突变型p54（nrb）的转基因小鼠表现出与软骨形成受损相关的侏儒症。这些数据表明p54（nrb）发挥作用。
The Sox9 transcription factor plays an essential role in promoting chondrogenesis and regulating expression of chondrocyte extracellular-matrix genes. To identify genes that interact with Sox9 in promoting chondrocyte differentiation, we screened a cDNA library generated from the murine chondrogenic ATDC5 cell line to identify activators of the collagen, type II, alpha 1 (Col2al) promoter. Here we have shown that paraspeckle regulatory protein 54-kDa nuclear RNA-binding protein (p54(nrb)) is an essential link between Sox9-regulated transcription and maturation of Sox9-target gene mRNA. We found that p54(nrb) physically interacted with Sox9 and enhanced Sox9-dependent transcriptional activation of the Col2al promoter. In ATDC5 cells, p54(nrb) colocalized with Sox9 protein in nuclear paraspeckle bodies, and knockdown of p54(nrb) suppressed Sox9-dependent Col2al expression and promoter activity. We generated a p54(nrb) mutant construct lacking RNA recognition motifs, and overexpression of mutant p54(nrb) in ATDC5 cells markedly altered the appearance of paraspeckle bodies and inhibited the maturation of Col2al mRNA. The mutant p54nrb inhibited chondrocyte differentiation of mesenchymal cells and mouse metatarsal explants. Furthermore, transgenic mice expressing the mutant p54(nrb) in the chondrocyte lineage exhibited dwarfism associated with impairment of chondrogenesis. These data suggest that p54(nrb) plays.