RNR1, a 3'-5' exoribonuclease belonging to the RNR superfamily, catalyzes 3' maturation of chloroplast ribosomal RNAs in Arabidopsis thaliana.
RNR1, a 3'-5' exoribonuclease belonging to the RNR superfamily, catalyzes 3' maturation of chloroplast ribosomal RNAs in Arabidopsis thaliana.
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RNR1，一种属于RNR超家族的3'-5'驱虫核酸酶，在拟南芥中催化3'叶绿体核糖体RNA成熟。
DOI：
10.1093/nar/gki576
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发表时间：
2005
影响因子：
14.9
通讯作者：
Gagliardi, D
中科院分区：
文献类型：
--
作者：
Bollenbach, TJ;Lange, H;Gutierrez, R;Erhardt, M;Stern, DB;Gagliardi, D
拟南芥叶绿体含有至少两个3′至5′核糖核酸外切酶，多核苷酸磷酸化酶（PNAP1）和核糖核酸酶R同源物（RNR1）。PNTR参与mRNA和23SrRNA的3′端加工。然而，所观察到的成熟缺陷不影响叶绿体翻译，这表明PNTR在叶绿体rRNA成熟中的整体作用不是必需的。在这里，我们表明，这种作用可以在很大程度上归因于RNR 1，纯合突变体发芽，只有含蔗糖的媒体，并有白色子叶和浅绿色莲座叶。在这些突变体中，叶绿体编码的mRNA和tRNA的积累不受影响，这表明RNR1活性对于它们的加工和周转是不必要的或多余的。然而，几种叶绿体rRNA的积累受到严重影响。高分辨率RNA凝胶印迹分析和5′和3′端定位显示，RNR 1参与23S、16S和5S rRNA的成熟。与此观点一致，在体外，纯化的RNR1可以有效地去除积累的5S rRNA前体的3′延伸。我们的数据表明，成熟叶绿体核糖体RNA的积累减少导致翻译核糖体的数量减少，最终损害叶绿体蛋白质丰度，从而影响植物的生长和发育。
Arabidopsis thaliana chloroplasts contain at least two 3′ to 5′ exoribonucleases, polynucleotide phosphorylase (PNPase) and an RNase R homolog (RNR1). PNPase has been implicated in both mRNA and 23S rRNA 3′ processing. However, the observed maturation defects do not affect chloroplast translation, suggesting that the overall role of PNPase in maturation of chloroplast rRNA is not essential. Here, we show that this role can be largely ascribed to RNR1, for which homozygous mutants germinate only on sucrose-containing media, and have white cotyledons and pale green rosette leaves. Accumulation of chloroplast-encoded mRNAs and tRNAs is unaffected in such mutants, suggesting that RNR1 activity is either unnecessary or redundant for their processing and turnover. However, accumulation of several chloroplast rRNA species is severely affected. High-resolution RNA gel blot analysis, and mapping of 5′ and 3′ ends, revealed that RNR1 is involved in the maturation of 23S, 16S and 5S rRNAs. The 3′ extensions of the accumulating 5S rRNA precursors can be efficiently removed in vitro by purified RNR1, consistent with this view. Our data suggest that decreased accumulation of mature chloroplast ribosomal RNAs leads to a reduction in the number of translating ribosomes, ultimately compromising chloroplast protein abundance and thus plant growth and development.
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影响因子：
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