Cytoplasmic Male Sterility-Related Protein Kinase, OsNek3, is Regulated Downstream of Mitochondrial Protein Phosphatase 2C, DCW11
Cytoplasmic Male Sterility-Related Protein Kinase, OsNek3, is Regulated Downstream of Mitochondrial Protein Phosphatase 2C, DCW11
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DOI：
10.1093/pcp/pcp026
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发表时间：
2009-04-01
影响因子：
4.9
通讯作者：
Toriyama, Kinya
中科院分区：
文献类型：
--
作者：
Fujii, Sota;Yamada, Mari;Toriyama, Kinya
我们在之前的芯片研究中发现，在缺乏花粉萌发能力的水稻CW-CMS系中，OsNek3 （Oryza sativa L. NIMA-related kinase）和DCW11编码线粒体蛋白磷酸酶2C是下调基因。进一步分析DCW11发现DCW11与CW-CMS的发生密切相关。这里我们展示OsNek3和DCW11之间的关系。OsNek3在成熟花粉中优先表达。将Tos17插入OsNek3的基因敲除突变体没有显示出任何花粉缺陷表型。另一方面，过表达OsNek3的植物偶尔会产生一种特殊的花粉结构，即使在花粉成熟阶段，四个花粉粒的外细胞壁也融合在一起，这与拟南芥中的四重突变体相似。OsNek3与含有LIM结构域的蛋白OsPLIM2b相互作用，该蛋白在成熟花粉中表达强烈特异性，这表明OsNek3可能在花粉萌发中发挥作用。在DCW11敲低的细胞系中，OsNek3被证明是下调的，而OsNek3突变不会导致DCW11下调。这些结果表明，在从线粒体到细胞核的逆行信号传导中，OsNek3位于dcw11的下游，并参与了CW-CMS。
OsNek3 (Oryza sativa L. NIMA-related kinase) and DCW11 encoding a mitochondrial putative protein phosphatase 2C were found in our previous microarray study as down-regulated genes in the rice CW-CMS line, which lacked pollen germination ability. Further analysis of DCW11 revealed that DCW11 is strongly correlated with CW-CMS occurrence. Here we show the relationship between OsNek3 and DCW11. OsNek3 was preferentially expressed in mature pollen. A knockout mutant with Tos17 inserted into OsNek3 did not show any pollen-defective phenotype. On the other hand, plants overexpressing OsNek3 occasionally produced a peculiar pollen structure in which the outer cell wall of four pollen grains fused together even at the mature pollen stages, which resembled that of quartet mutants in Arabidopsis. OsNek3 was shown to interact with a LIM domain-containing protein, OsPLIM2b, whose expression was strongly specific in mature pollen, suggesting that OsNek3 might play a role in pollen germination. OsNek3 was shown to be down-regulated in DCW11-knockdown lines, whereas osnek3 mutation did not result in DCW11 down-regulation. These results suggest that OsNek3 is downstream of DCW11in retrograde signaling from the mitochondria to the nucleus and is involved in CW-CMS.