Brix from Xenopus laevis and Brx1p from yeast define a new family of proteins involved in the biogenesis of large ribosomal subunits
Brix from Xenopus laevis and Brx1p from yeast define a new family of proteins involved in the biogenesis of large ribosomal subunits
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DOI：
10.1515/bc.2001.199
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发表时间：
2001-12-01
影响因子：
3.7
通讯作者：
Kreil, G
中科院分区：
文献类型：
--
作者：
Kaser, A;Bogengruber, E;Kreil, G
从非洲爪蟾早期胚胎的 cDNA 文库中分离出一个克隆，该克隆编码含有 339 个氨基酸的高电荷蛋白质。可以在其序列中识别出两个假定的核定位信号，但没有其他已知的基序或结构域。密切相关的 ORF 存在于人类、线虫、酵母和拟南芥的基因组中。发现 HeLa 细胞或非洲爪蟾卵母细胞中表达的 GFP 融合蛋白位于核仁和卷曲 (Cajal) 小体中。此外，免疫沉淀实验表明，新的爪蟾蛋白与大核糖体亚基的 5S、5.8S 和 28S RNA 相互作用。这种蛋白质和相应的基因被命名为 Brix（非洲爪蟾核糖体的生物发生）。在酿酒酵母中，必需基因 YOL077c（现在命名为 BRX1）编码 Brix 同源物，该同源物也位于核仁中。条件酵母突变体中 Brx1p 的缺失会导致 rRNA 加工缺陷，并阻碍大核糖体亚基的组装。
A clone was isolated from a cDNA library from early embryos of Xenopus laevis that codes for a highly charged protein containing 339 amino acids. Two putative nuclear localization signals could be identified in its sequence, but no other known motifs or domains. Closely related ORFs are present in the genomes of man, C. elegans, yeast and Arabidopsis. A fusion protein with GFP expressed in HeLa cells or Xenopus oocytes was found to be localized in the nucleolus and coiled (Cajal) bodies. Moreover, immuno-precipitation experiments demonstrated that the new Xenopus protein interacts with 5S, 5.8S and 28S RNAs of large ribosomal subunits. The name Brix (biogenesis of ribosomes in Xenopus) is proposed for this protein and the corresponding gene.In Saccharomyces cerevisiae, the essential gene YOL077c, now named BRX1, codes for the Brix homolog, which is also localized in the nucleolus. Depletion of Brx1p in a conditional yeast mutant leads to defects in rRNA processing, and a block in the assembly of large ribosomal subunits.