Nucleolar localization of RPS19 protein in normal cells and mislocalization due to mutations in the nucleolar localization signals in 2 Diamond-Blackfan anemia patients: potential insights into pathophysiology
Nucleolar localization of RPS19 protein in normal cells and mislocalization due to mutations in the nucleolar localization signals in 2 Diamond-Blackfan anemia patients: potential insights into pathophysiology
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DOI：
10.1182/blood-2002-12-3878
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发表时间：
2003-06-15
期刊：
影响因子：
20.3
通讯作者：
Mohandas, N
中科院分区：
文献类型：
--
作者：
Da Costa, L;Tchernia, G;Mohandas, N
核糖体蛋白S19（RPS 19）在Diamond-Blackfan贫血（DBA）中经常发生突变，DBA是一种罕见的先天性再生障碍性贫血。最近的研究表明，在终末红系分化过程中，RPS 19表达降低。目前没有关于正常RPS 19的亚细胞定位和各种RPS 19突变对细胞定位的潜在影响的信息。在本研究中，使用野生型和突变型RPS 19 cDNA，我们探讨了正常和突变蛋白在成纤维细胞系（Cos-7细胞）的亚细胞分布。RPS 19主要在细胞核中检测到，并且更具体地在核仁中，其中RPS 19与核仁蛋白核仁素共定位。使用各种N-末端和C-末端缺失构建体，我们确定了2个核仁定位信号（NoSs）在RPS 19：第一个包括氨基酸Met 1至Arg 16在NH 2-末端和第二个包括Gly 120至Asn 142在CCOH-末端。重要的是，在DBA患者中鉴定的2个突变，Val 15 Phe和Gly 127 Gln，其各自定位于2个NoS中的1个，未能将RPS 19定位于核仁。除了它们的错误定位之外，与野生型相比，2种突变蛋白的表达显著降低。这种蛋白质表达的降低是突变型RPS 19所特有的，因为其他蛋白质的表达是正常的。目前的研究结果使我们能够记录RPS 19中的核仁定位信号，并帮助定义DBA中RPS 19中某些突变的表型后果。(C)2003年，美国血液学会。
Ribosomal protein S19 (RPS19) is frequently mutated in Diamond-Blackfan anemia (DBA), a rare congenital hypoplastic anemia. Recent studies have shown that RPS19 expression decreases during terminal erythroid differentiation. Currently no information is available on the subcellular localization of normal RPS19 and the potential effects of various RPS19 mutations on cellular localization. In the present study, using wild-type and mutant RPS19 cDNA, we explored the subcellular distribution of normal and mutant proteins in a fibroblast cell line (Cos-7 cells). RPS19 was detected primarily in the nucleus, and more specifically in the nucleoli, where RPS19 colocalized with the nucleolar protein nucleolin. Using various N-terminal and C-terminal deletion constructs, we identified 2 nucleolar localization signals (NoSs) in RPS19: the first comprising amino acids Met1 to Arg16 in the NH2-terminus and the second comprising Gly120 to Asn142 in the CCOH-terminus. Importantly, 2 mutations identified in DBA patients, Val15Phe and Gly127Gln, each of which localized to 1 of the 2 NoS, failed to localize RPS19 to the nucleolus. In addition to their mislocalization, there was a dramatic decrease in the expression of the 2 mutant proteins compared to the wild type. This decrease in protein expression was specific for the mutant RPS19, since expression of other proteins was normal. The present findings enable us to document the nucleolar localization signals in RPS19 and help define the phenotypic consequences of some mutations in RPS19 in DBA. (C) 2003 by The American Society of Hematology.