School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA.
Nucleic Acids Res. 2011 Jun;39(11):4709-18. doi: 10.1093/nar/gkq1300. Epub 2011 Jan 17.
Eukaryotes produce multiple products from a single gene locus by alternative splicing, translation or promoter usage as mechanisms expanding the complexity of their proteome. Trithorax proteins, including the Arabidopsis Trithorax-like protein ATX1, are histone modifiers regulating gene activity. Here, we report that a novel member of the Trithorax family has a role unrelated to chromatin. It is encoded from an internal promoter in the ATX1 locus as an isoform containing only the SET domain (soloSET). It is located exclusively in the cytoplasm and its substrate is the elongation factor 1A (EF1A). Loss of SET, but not of the histone modifying ATX1-SET activity, affects cytoskeletal actin bundling illustrating that the two isoforms have distinct functions in Arabidopsis cells.
真核生物通过可变剪接、翻译或启动子使用等机制，从单个基因座产生多种产物，从而扩展其蛋白质组的复杂性。Trithorax 蛋白，包括拟南芥 Trithorax 样蛋白 ATX1，是调节基因活性的组蛋白修饰物。在这里，我们报告说，Trithorax 家族的一个新成员与染色质无关。它是从 ATX1 基因座的内部启动子编码的，作为仅包含 SET 结构域（soloSET）的同工型。它仅位于细胞质中，其底物是延伸因子 1A（EF1A）。SET 的缺失，但不是组蛋白修饰的 ATX1-SET 活性的缺失，会影响细胞骨架肌动蛋白的成束，表明这两个同工型在拟南芥细胞中有不同的功能。
