Cells depleted for RPS19, a protein associated with Diamond Blackfan Anemia, show defects in 18S ribosomal RNA synthesis and small riblosomal subunit production
Cells depleted for RPS19, a protein associated with Diamond Blackfan Anemia, show defects in 18S ribosomal RNA synthesis and small riblosomal subunit production
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DOI：
10.1016/j.bcmd.2007.02.001
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发表时间：
2007-07-01
影响因子：
2.3
通讯作者：
Mason, Philip J.
中科院分区：
文献类型：
--
作者：
Idol, Rachel A.;Robledo, Sara;Mason, Philip J.
大约 25% 的骨髓衰竭综合征钻石黑扇贫血 (DBA) 病例中编码小亚基核糖体蛋白 19 (RPS19) 的基因发生突变，这是一种以红细胞生成失败为特征的儿童疾病。在这些病例中，DBA 作为常染色体显性性状遗传，RPS19 单倍体不足被认为是导致该疾病的原因。为了研究 DBA 的分子发病机制，我们使用 siRNA 来降低两种人类细胞系（HeLa 细胞和 U-2 OS 骨肉瘤细胞）中 RPS19 的水平。 RPS19水平降低的细胞显示小40S核糖体亚基和成熟80S核糖体的数量显着减少，而大60S亚基过量。这些细胞在 18S rRNA 生成方面存在缺陷，并积累了 21 S 和 20S 核前 rRNA 分子，表明 RPS 19 是 rRNA 加工中特定步骤所必需的。 RPS19 耗尽通过转录后机制导致 RPS6 和 RPS16 的稳态水平降低，而 RPL7 和 RPL26 的水平未改变，表明核糖体蛋白的水平是由亚基组装决定的。这对 DBA 的发病机制具有有趣的意义，表明任何 RPS 蛋白的缺乏都可能具有类似的作用，因此可能是导致 DBA 的原因。最后，在具有突变的 DBA 患者的细胞系中，我们发现 21S rRNA 前体水平升高，但蔗糖梯度上的核糖体谱或 RPS19 的稳态水平没有异常，这表明某些细胞可以部分补偿 RPS19 一个等位基因的丢失。我们得出的结论是，核糖体生物发生的缺陷可能是钻石黑扇贫血症病理学的基础。 (c) 2007 Elsevier Inc. 保留所有权利。
The gene encoding the small subunit ribosomal protein 19 (RPS19) is mutated in about 25% of cases of the bone marrow failure syndrome Diamond Blackfan Anemia (DBA), a childhood disease characterized by failure of red cell production. In these cases DBA is inherited as an autosomal dominant trait and RPS19 haploinsufficiency is thought to cause the disease. To study the molecular pathogenesis of DBA we used siRNA to decrease the level of RPS19 in two human cell lines, HeLa cells and U-2 OS osteosarcoma, cells. Cells with reduced RPS19 levels showed a dramatic reduction in the amounts of small 40S ribosome subunits and mature 80S ribosomes and an excess of large 60S subunits. These cells were defective in 18S rRNA production and accumulated 21 S and 20S nuclear pre-rRNA molecules, suggesting that RPS 19 is required for specific steps in rRNA processing. RPS19 depletion produced a reduction in steady-state levels of RPS6 and RPS16 via a post-transcriptional mechanism while the levels of RPL7 and RPL26 were unaltered, indicating that levels of ribosomal proteins are determined by subunit assembly. This has interesting implications for the pathogenesis of DBA suggesting that deficiency of any of the RPS proteins might have a similar effect and thus may be responsible for causing DBA. Finally in cell lines from DBA patients with mutations we find increased levels of 21S rRNA precursors but no abnormality in the ribosome profile on sucrose gradients or in the steady-state levels of RPS19 suggesting that some cells can partially compensate for the loss of one allele of RPS19. We conclude that defects in ribosome biogenesis may underlie the pathology of Diamond Blackfan Anemia. (c) 2007 Elsevier Inc. All rights reserved.