Fujii Shinya, Kazama Tomohiko, Ito Yukihiro, Kojima Soichi, Toriyama Kinya
Graduate School of Agricultural Science, Tohoku University, Sendai, 981-8555, Japan,
Rice (N Y). 2014 Dec;7(1):21. doi: 10.1186/s12284-014-0021-6. Epub 2014 Oct 7.
The pollen function of cytoplasmic male sterile (CMS) plants is often recovered by the Restorer of fertility (Rf) gene encoded by the nuclear genome. An Rf gene of Lead rice type CMS, Rf2, encodes a small mitochondrial glycine-rich protein. RF2 is expected to function by interacting with other proteins, because RF2 has no motifs except for glycine-rich domain.
To elucidate the protein that interacts with RF2, we performed yeast two-hybrid screening. We identified four genes and named RF2-interacting candidate factors (RIF1 to RIF4). A study of subcellular localization demonstrated that only RIF2 was targeted to mitochondria. A pull-down assay using E. coli-produced recombinant GST-tagged RF2 and His-tagged RIF2 confirmed that RF2 interacted with RIF2. RIF2 encodes ubiquitin domain-containing protein.
These results suggest that RIF2 is a candidate factor of a fertility restoration complex of RF2.
细胞质雄性不育（CMS）植株的花粉育性常由核基因组编码的育性恢复基因（Rf）恢复。籼稻型CMS的一个Rf基因Rf2编码一种富含甘氨酸的小线粒体蛋白。由于RF2除了富含甘氨酸结构域外没有其他基序，因此预计它通过与其他蛋白质相互作用发挥功能。
为了阐明与RF2相互作用的蛋白质，我们进行了酵母双杂交筛选。我们鉴定出四个基因，并将其命名为RF2相互作用候选因子（RIF1至RIF4）。亚细胞定位研究表明，只有RIF2定位于线粒体。使用大肠杆菌产生的重组GST标记的RF2和His标记的RIF2进行的下拉试验证实，RF2与RIF2相互作用。RIF2编码含泛素结构域的蛋白质。
这些结果表明，RIF2是RF2育性恢复复合体的候选因子。
