Proteomic Analysis of Rodent Ribosomes Revealed Heterogeneity Including Ribosomal Proteins L10-like, L22-like 1, and L39-like
Proteomic Analysis of Rodent Ribosomes Revealed Heterogeneity Including Ribosomal Proteins L10-like, L22-like 1, and L39-like
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DOI：
10.1021/pr9008964
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发表时间：
2010-03-01
影响因子：
4.4
通讯作者：
Nadano, Daita
中科院分区：
文献类型：
--
作者：
Sugihara, Yoshihiko;Honda, Hiroki;Nadano, Daita
由于核糖体蛋白质组成的差异，核糖体结构的异质性在植物和酵母中具有重要的生理意义。哺乳动物基因组学已经证明了许多基因与编码核糖体蛋白的基因是旁系同源的。虽然绝大多数被认为是假基因，但已报道了一些旁系同源物的mRNA表达，如人核糖体蛋白L39-like/L39-2。在本研究中，核糖体从肝脏，乳腺和睾丸的啮齿动物进行了分析，使用组合的二维凝胶电泳自由基和高度还原条件下，和质谱。该系统允许从单个凝胶中鉴定78种核糖体蛋白和Rack 1。异质性的程度远低于植物和酵母核糖体的报道，并与哺乳动物核糖体的已发表的生物化学和遗传学数据雅阁。然而，核糖体蛋白L22的一个未表征的部分，核糖体蛋白L22样1，被确定为一个次要的核糖体成分。核糖体蛋白L10样和L39样，核糖体蛋白L10和L39的旁系同源物，分别被发现在核糖体只从睾丸。逆转录-聚合酶链反应得到支持的证据，L10样和L39样的睾丸中的特异性表达。新合成的L39-like可能被运输到核仁，在那里发生核糖体生物合成，然后并入细胞质中的翻译核糖体。哺乳动物睾丸核糖体的异源性在结构上是不可忽略的，并且可以提供对定制核糖体的功能的有价值的见解。
Heterogeneity of ribosome structure, due to variations in ribosomal protein composition, has been shown to be of physiological significance in plants and yeast. Mammalian genomics have demonstrated numerous genes that are paralogous to genes encoding ribosomal proteins. Although the vast majority are considered to be pseudogenes, mRNA expression of a few paralogues, such as human ribosomal protein L39-like/L39-2, has been reported. In the present study, ribosomes from the liver, mammary gland, and testis of rodents were analyzed using a combination of two-dimensional gel electrophoresis under radical-free and highly reducing conditions, and mass spectrometry. This system allowed identification of 78 ribosomal proteins and Rack1 from a single gel. The degree of heterogeneity was far less than that reported for plant and yeast ribosomes, and was in accord with published biochemical and genetic data for mammalian ribosomes. Nevertheless, an uncharacterized paralogue of ribosomal protein L22, ribosomal protein L22-like 1, was identified as a minor ribosomal component. Ribosomal proteins L10-like and L39-like, paralogues of ribosomal proteins L10 and L39, respectively, were found in ribosomes only from the testis. Reverse transcription-polymerase chain reaction yielded supportive evidence for specific expression of L10-like and L39-like in the testis. Newly synthesized L39-like is likely to be transported to the nucleolus, where ribosome biosynthesis occurs, and then incorporated into translating ribosomes in the cytoplasm. Heterogeneity of mammalian testicular ribosomes is structurally non-negligible, and may offer valuable insights into the function of the customized ribosome.