Olsson Ida, Berrez Jean-Marc, Leipus Arunas, Ostlund Cecilia, Mutvei Ann
School of Life Sciences, Södertörns Högskola, SE-141 89 Huddinge, Sweden.
Exp Cell Res. 2007 May 15;313(9):1778-89. doi: 10.1016/j.yexcr.2007.03.007. Epub 2007 Mar 15.
Arginine methylation is a post-translational modification of proteins implicated in RNA processing, protein compartmentalization, signal transduction, transcriptional regulation and DNA repair. In a screen for proteins associated with the nuclear envelope in the yeast Saccharomyces cerevisiae, we have identified the arginine methyltransferase Rmt2, previously shown to methylate the ribosomal protein L12. By indirect immunofluorescence and subcellular fractionations we demonstrate here that Rmt2 has nuclear and cytoplasmic localizations. Biochemical analysis of a fraction enriched in nuclei reveals that nuclear Rmt2 is resistant to extractions with salt and detergent, indicating an association with structural components. This was supported by affinity purification experiments with TAP-tagged Rmt2. Rmt2 was found to co-purify with the nucleoporins Nup49, Nup57 and Nup100, revealing a novel link between arginine methyltransferases and the nuclear pore complex. In addition, a genome-wide transcription study of the rmt2Delta mutant shows significant downregulation of the transcription of MYO1, encoding the Type II myosin heavy chain required for cytokinesis and cell separation.
精氨酸甲基化是一种蛋白质的翻译后修饰，与RNA加工、蛋白质区室化、信号转导、转录调控及DNA修复有关。在对酿酒酵母中与核膜相关蛋白质的筛选过程中，我们鉴定出了精氨酸甲基转移酶Rmt2，此前已证明它可使核糖体蛋白L12发生甲基化。通过间接免疫荧光和亚细胞分级分离，我们在此证明Rmt2定位于细胞核和细胞质。对富含细胞核的组分进行生化分析发现，细胞核中的Rmt2对盐和去污剂提取具有抗性，表明它与结构成分相关。用TAP标签标记的Rmt2进行的亲和纯化实验支持了这一点。发现Rmt2与核孔蛋白Nup49、Nup57和Nup100共同纯化，揭示了精氨酸甲基转移酶与核孔复合体之间的新联系。此外，对rmt2Δ突变体进行的全基因组转录研究表明，编码胞质分裂和细胞分离所需的II型肌球蛋白重链的MYO1转录显著下调。
