Department of Life Science, National Central University, Zhongli, Taoyuan County, Taiwan, ROC.
Plant Mol Biol. 2010 Sep;74(1-2):119-28. doi: 10.1007/s11103-010-9659-7. Epub 2010 Jul 6.
DEAD-box proteins comprise a large family and function in RNA metabolism. Although DEAD-box proteins are highly conserved among eukaryotes, little is known about the role of DEAD-box proteins in rice. In this study, we identified a rice DEAD-box protein, OsRH36, and demonstrated that OsRH36 and AtRH36 are functional orthologs. OsRH36 was expressed ubiquitously throughout the plant and the OsRH36-GFP fusion protein was localized to the nucleus and nucleolus. Furthermore, functional complementation tests among three homologous DEAD-box protein genes indicated that OsRH36 can restore segregation distortion in the Arabidopsis atrh36-1 mutant, but cannot complement the lethal phenotype in the yeast dbp8p mutant. Moreover, mutation of osrh36 also led to defective transmission of the osrh36 allele, as shown for the atrh36 mutants of Arabidopsis. Previously, we have shown that AtRH36 is involved at an early stage of rRNA maturation and is required for synchronous development of female gametophytes in Arabidopsis. Therefore, we suggest that OsRH36 is required for rRNA biogenesis and megagametogenesis in rice, consistent with the function of AtRH36 in Arabidopsis.
DEAD-box 蛋白包含一个大家族，在 RNA 代谢中发挥作用。虽然 DEAD-box 蛋白在真核生物中高度保守，但人们对其在水稻中的作用知之甚少。本研究鉴定了一个水稻 DEAD-box 蛋白 OsRH36，并证实 OsRH36 和 AtRH36 是功能上的同源物。OsRH36 在植物中广泛表达，OsRH36-GFP 融合蛋白定位于核仁和核仁。此外，三个同源 DEAD-box 蛋白基因的功能互补测试表明，OsRH36 可以恢复拟南芥 atrh36-1 突变体的分离扭曲，但不能补充酵母 dbp8p 突变体的致死表型。此外，osrh36 的突变也导致 osrh36 等位基因的传递缺陷，就像拟南芥的 atrh36 突变体一样。先前，我们已经表明 AtRH36 参与 rRNA 成熟的早期阶段，并且是拟南芥雌性配子体同步发育所必需的。因此，我们认为 OsRH36 是水稻 rRNA 生物发生和大配子发生所必需的，这与 AtRH36 在拟南芥中的功能一致。
