Girard J P, Lehtonen H, Caizergues-Ferrer M, Amalric F, Tollervey D, Lapeyre B
CRBGC du CNRS, Toulouse, France.
EMBO J. 1992 Feb;11(2):673-82. doi: 10.1002/j.1460-2075.1992.tb05099.x.
Among the few proteins of the eukaryotic nucleolus that have been characterized, four proteins, nucleolin, fibrillarin, SSB1 and NSR1, possess a common structural motif, the GAR domain, which is rich in glycine and arginine residues. In order to examine whether the presence of this domain is characteristic of a family of nucleolar proteins, we investigated whether other yeast genes encode proteins containing GAR domains. We report here the sequence and the characterization of a new yeast gene, GAR1, which encodes a protein of 205 residues containing two GAR domains. GAR1 is a non-ribosomal protein, localized in the yeast nucleolus, which is essential for cell growth. Immunoprecipitation with anti-GAR1 antibodies shows that GAR1 is associated with a subset of snoRNAs, including snR10 and snR30. Depletion of GAR1 by expression under the control of a regulated GAL promoter, impairs processing of the 35S primary transcript of pre-rRNA and prevents synthesis of 18S rRNA. GAR1 is thus the fifth member of a family of nucleolar proteins containing GAR domains, and is involved in rRNA metabolism.
在已被鉴定的真核生物核仁的少数几种蛋白质中，核仁素、原纤维蛋白、SSB1和NSR1这四种蛋白质具有一个共同的结构基序，即富含甘氨酸和精氨酸残基的GAR结构域。为了研究该结构域的存在是否为核仁蛋白家族的特征，我们研究了其他酵母基因是否编码含有GAR结构域的蛋白质。我们在此报告一个新的酵母基因GAR1的序列和特征，该基因编码一个含有两个GAR结构域的205个残基的蛋白质。GAR1是一种非核糖体蛋白，定位于酵母核仁，对细胞生长至关重要。用抗GAR1抗体进行免疫沉淀表明，GAR1与包括snR10和snR30在内的一部分小核仁RNA（snoRNA）相关联。在受调控的GAL启动子控制下通过表达使GAR1缺失，会损害前体rRNA的35S初级转录本的加工，并阻止18S rRNA的合成。因此，GAR1是含有GAR结构域的核仁蛋白家族的第五个成员，并参与rRNA代谢。
