Thelander Mattias, Nilsson Anders, Olsson Tina, Johansson Monika, Girod Pierre-Alain, Schaefer Didier G, Zrÿd Jean-Pierre, Ronne Hans
Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Plant Mol Biol. 2007 Jul;64(5):559-73. doi: 10.1007/s11103-007-9176-5. Epub 2007 May 29.
The yeast Snf1, animal AMPK, and plant SnRK1 protein kinases constitute a family of related proteins that have been proposed to serve as metabolic sensors of the eukaryotic cell. We have previously reported the characterization of two redundant SnRK1 encoding genes (PpSNF1a and PpSNF1b) in the moss Physcomitrella patens. Phenotypic analysis of the snf1a snf1b double knockout mutant suggested that SnRK1 is important for the plant's ability to recognize and adapt to conditions of limited energy supply, and also suggested a possible role of SnRK1 in the control of plant development. We have now used a yeast two-hybrid system to screen for PpSnf1a interacting proteins. Two new moss genes were found, PpSKI1 and PpSKI2, which encode highly similar proteins with homologues in vascular plants. Fusions of the two encoded proteins to the green fluorescent protein localize to the nucleus. Knockout mutants for either gene have an excess of gametophores under low light conditions, and exhibit reduced gametophore stem lengths. Possible functions of the new proteins and their connection to the SnRK1 kinase are discussed.
酵母Snf1、动物AMPK和植物SnRK1蛋白激酶构成了一类相关蛋白家族，有人提出它们可作为真核细胞的代谢传感器。我们之前报道了在小立碗藓中两个冗余的SnRK1编码基因（PpSNF1a和PpSNF1b）的特征。对snf1a snf1b双敲除突变体的表型分析表明，SnRK1对于植物识别和适应能量供应有限条件的能力很重要，同时也表明SnRK1在植物发育控制中可能发挥作用。我们现在利用酵母双杂交系统筛选与PpSnf1a相互作用的蛋白。发现了两个新的藓类基因，PpSKI1和PpSKI2，它们编码的蛋白与维管植物中的同源蛋白高度相似。这两个编码蛋白与绿色荧光蛋白的融合产物定位于细胞核。任一基因的敲除突变体在弱光条件下都有过多的配子体，并表现出配子体茎长度缩短。文中讨论了这些新蛋白的可能功能及其与SnRK1激酶的联系。
