Missense mutations associated with Diamond-Blackfan anemia affect the assembly of ribosomal protein S19 into the ribosome
Missense mutations associated with Diamond-Blackfan anemia affect the assembly of ribosomal protein S19 into the ribosome
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DOI：
10.1093/hmg/ddm120
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发表时间：
2007-07-15
影响因子：
3.5
通讯作者：
Loreni, Fabrizio
中科院分区：
文献类型：
--
作者：
Angelini, Mara;Cannata, Stefano;Loreni, Fabrizio
RPS 19已被确定为与Diamond-Blackfan贫血（DBA）相关的第一个基因，DBA是一种罕见的先天性再生障碍性贫血，包括各种身体畸形。尽管DBA临床表型是否取决于RPS 19的核糖体功能或核糖体外作用或两者兼而有之仍存在疑问，但仍有25%的患者发生突变。具有引入提前终止密码子或消除其的突变的RPS 19 mRNA通过可能导致RPS 19蛋白水平降低的监视机制快速翻转。RPS 19水平的降低已显示导致18 S核糖体RNA成熟的缺陷。不太清楚的是RPS 19中错义突变的影响。为了分析突变型RPS 19的功能特征，我们制备了表达RPS 19的cDNA构建体，其中含有在DBA患者中发现的11个错义突变和一个三核苷酸插入。转染后，我们分析了突变蛋白质的以下性质：（I）蛋白质稳定性，（III）亚细胞定位和（iii）组装成核糖体。我们的研究结果表明，一些RPS 19突变改变了蛋白质定位在核仁结构中的能力，这些突变的RPS 19是非常不稳定的。此外，在这项研究中分析的突变的RPS 19，包括那些出现在核仁中的蛋白质，都不能组装成成熟的核糖体。
RPS19 has been identified as the first gene associated with Diamond-Blackfan anemia (DBA), a rare congenital hypoplastic anemia that includes variable physical malformations. It is mutated in similar to 25% of the patients although doubts remain as to whether DBA clinical phenotype depends on the ribosomal function of RPS19 or on an extra-ribosomal role or on both. RPS19 mRNAs with mutations that introduce premature stop codons or eliminate it are rapidly turned over by the surveillance mechanisms possibly causing a decrease in the RPS19 protein level. A decrease in RPS19 level has been shown to cause a defect in the maturation of 18S ribosomal RNA. Less clear is the effect of missense mutations in RPS19. With the aim of analyzing the functional features of mutated RPS19, we prepared cDNA constructs expressing RPS19 containing 11 missense mutations and a trinucleotide insertion found in DBA patients. After transfection, we analyzed the following properties of the mutated proteins: (I) protein stability, (111) subcellular localization and (iii) assembly into ribosomes. Our results indicate that some RPS19 mutations alter the capacity of the protein to localize in nucleolar structure and these mutated RPS19 are very unstable. Moreover, none of the mutated RPS19 analyzed in this study, including those proteins that appear localized into the nucleolus, is able to be assembled into mature ribosome.