Marwedel Tanja, Ishibashi Toyotaka, Lorbiecke René, Jacob Silke, Sakaguchi Kengo, Sauter Margret
Institut für Allgemeine Botanik, Universität Hamburg, Ohnhorststrasse 18, 22609 Hamburg, Germany.
Planta. 2003 Jul;217(3):457-65. doi: 10.1007/s00425-003-1001-z. Epub 2003 Mar 14.
DNA replication is a process that is highly conserved among eukaryotes. Nonetheless, little is known about the proteins involved in it in plants. Replication protein A (RPA) is a heterotrimeric, single-stranded DNA-binding protein with several functions in DNA metabolism in humans and yeast and supposedly also in plants. Here we report on the regulation of OsRPA2, the 32-kDa subunit of RPA from rice ( Oryza sativa L.). We found conserved regulation mechanisms at the level of gene expression between animal and plant RPA2 genes and distinct features of OsRPA2 regulation at the level of protein expression. Unlike in animals or in yeast, protein abundance in rice was regulated in a cell cycle phase-specific manner and was altered after UV-C light exposure. On the other hand, posttranslational modification through phosphorylation did not appear to play a pivotal role in rice as it does in animal cells. Our results indicate that plant-specific mechanisms of regulation have evolved for RPA2 within the generally well-conserved process of DNA replication, suggesting specific requirements for regulation of DNA metabolism in plants as compared to other eukaryotes.
DNA复制是真核生物中高度保守的过程。尽管如此，人们对植物中参与该过程的蛋白质知之甚少。复制蛋白A（RPA）是一种异源三聚体单链DNA结合蛋白，在人类和酵母的DNA代谢中具有多种功能，在植物中可能也有类似功能。本文我们报道了水稻（Oryza sativa L.）RPA的32 kDa亚基OsRPA2的调控机制。我们发现动植物RPA2基因在基因表达水平上存在保守的调控机制，而OsRPA2在蛋白质表达水平上具有独特的调控特征。与动物或酵母不同，水稻中的蛋白质丰度以细胞周期阶段特异性方式调控，且在紫外线C照射后发生改变。另一方面，磷酸化的翻译后修饰在水稻中似乎不像在动物细胞中那样起关键作用。我们的结果表明，在普遍保守的DNA复制过程中，植物已经进化出RPA2特异性的调控机制，这表明与其他真核生物相比，植物对DNA代谢调控有特定需求。
