Knock-out of the plastid ribosomal protein L11 in Arabidopsis:: effects on mRNA translation and photosynthesis
Knock-out of the plastid ribosomal protein L11 in Arabidopsis:: effects on mRNA translation and photosynthesis
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DOI：
10.1046/j.1365-313x.2001.01076.x
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发表时间：
2001-08-01
期刊：
影响因子：
7.2
通讯作者：
Leister, D
中科院分区：
文献类型：
--
作者：
Pesaresi, P;Varotto, C;Leister, D
拟南芥Prpl11-1突变体是在光系统II有效量子产率下降的基础上从一系列T-DNA标记品系中鉴定出来的。该突变定位于Prpl11，这是一个单拷贝核基因，编码叶绿体核糖体大亚基的Prpl11。拟南芥PRPL11的氨基酸序列与菠菜和原核生物中的L11蛋白非常相似。在prpl11-1突变体中，由于类囊体蛋白复合体和基质蛋白水平的变化，光敏性和叶绿素荧光参数发生了显著变化。所检测的大多数质体体转录本的丰度，如编码光系统II核心复合体和rbcL基因的转录本，并没有减少。在突变植株中，叶绿体核糖体RNA以野生型的数量积累，而rbcL、psbA和psbE基因转录本上的叶绿体多聚体的组装基本保持不变，这表明PRPL11的缺失既不影响叶绿体核糖体的丰度，也不影响它们组装成多聚体。然而，体内翻译实验表明，在prpl11-1质体中，Rubisco大亚基(RbcL)的翻译速率显著降低。我们的数据表明，PRPL11在叶绿体50S核糖体亚基的GTP酶结合中心附近的叶绿体核糖体活性本身中起着重要作用。突变的其他影响，包括叶片的淡绿色和温室条件下生长速度的急剧下降，与叶绿体蛋白质合成水平的降低是一致的。
The prpl11-1 mutant of Arabidopsis thaliana was identified among a collection of T-DNA tagged lines on the basis of a decrease in the effective quantum yield of photosystem II. The mutation responsible was localized to Prpl11, a single-copy nuclear gene that encodes PRPL11, a component of the large subunit of the plastid ribosome. The amino acid sequence of Arabidopsis PRPL11 is very similar to those of L11 proteins from spinach and prokaryotes. In the prpl11-1 mutant, photosensitivity and chlorophyll fluorescence parameters are significantly altered owing to changes in the levels of thylakoid protein complexes and stromal proteins. The abundance of most plastome transcripts examined, such as those of genes coding for the photosystem II core complex and RbcL, is not decreased. Plastid ribosomal RNA accumulates in wild-type amounts, and the assembly of plastid polysomes on the transcripts of the rbcL, psbA and psbE genes remains mainly unchanged in mutant plants, indicating that lack of PRPL11 affects neither the abundance of plastid ribosomes nor their assembly into polysomes. However, in vivo translation assays demonstrate that the rate of translation of the large subunit of Rubisco (RbcL) is significantly reduced in prpl11-1 plastids. Our data suggest a major role for PRPL11 in plastid ribosome activity per se, consistent with its location near the GTPase-binding centre of the chloroplast 50S ribosomal subunit. Additional effects of the mutation, including the pale green colour of the leaves and a drastic reduction in growth rate under greenhouse conditions, are compatible with reduced levels of protein synthesis in plastids.