National Institute of Vegetable and Tea Science, 360 Kusawa, Ano, Tsu, Mie 514-2392, Japan.
J Exp Bot. 2012 Jan;63(1):251-60. doi: 10.1093/jxb/err257. Epub 2011 Sep 16.
Retrograde signalling from the plastid to the nucleus, also known as plastid signalling, plays a key role in coordinating nuclear gene expression with the functional state of plastids. Inhibitors that cause plastid dysfunction have been suggested to generate specific plastid signals related to their modes of action. However, the molecules involved in plastid signalling remain to be identified. Genetic studies indicate that the plastid-localized pentatricopeptide repeat protein GUN1 mediates signalling under several plastid signalling-related conditions. To elucidate further the nature of plastid signals, investigations were carried out to determine whether different plastid signal-inducing treatments had similar effects on plastids and on nuclear gene expression. It is demonstrated that norflurazon and lincomycin treatments and the plastid protein import2-2 (ppi2-2) mutation, which causes a defect in plastid protein import, all resulted in similar changes at the gene expression level. Furthermore, it was observed that these three treatments resulted in defective RNA editing in plastids. This defect in RNA editing was not a secondary effect of down-regulation of pentatricopeptide repeat protein gene expression in the nucleus. The results indicate that these three treatments, which are known to induce plastid signals, affect RNA editing in plastids, suggesting an unprecedented link between plastid signalling and RNA editing.
从质体到细胞核的逆行信号，也称为质体信号，在协调核基因表达与质体的功能状态方面起着关键作用。已经有人提出，导致质体功能障碍的抑制剂可能会产生与其作用模式相关的特定质体信号。然而，参与质体信号的分子仍有待确定。遗传研究表明，质体定位的五肽重复蛋白 GUN1 在几种与质体信号相关的条件下介导信号。为了进一步阐明质体信号的性质，进行了研究以确定不同的质体信号诱导处理是否对质体和核基因表达有相似的影响。结果表明，norflurazon 和 lincomycin 处理以及质体蛋白导入 2-2（ppi2-2）突变（导致质体蛋白导入缺陷）都导致基因表达水平的相似变化。此外，观察到这三种处理导致质体中 RNA 编辑出现缺陷。这种 RNA 编辑的缺陷不是核 pentatricopeptide repeat protein 基因表达下调的继发效应。结果表明，这三种已知诱导质体信号的处理会影响质体中的 RNA 编辑，这表明质体信号与 RNA 编辑之间存在前所未有的联系。
