SlRBP1 promotes translational efficiency via SleIF4A2 to maintain chloroplast function in tomato
SlRBP1 promotes translational efficiency via SleIF4A2 to maintain chloroplast function in tomato
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DOI：
10.1093/plcell/koac104
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发表时间：
2022-04-06
期刊：
影响因子：
11.6
通讯作者：
Zhu, Hongliang
中科院分区：
文献类型：
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作者：
Ma, Liqun;Yang, Yongfang;Zhu, Hongliang
富含甘氨酸的RNA结合蛋白（glycine-rich RNA-binding protein，GR-RBP）SlRBP 1通过调节与叶绿体功能相关的关键转录物的翻译效率来维持叶绿体功能，许多富含甘氨酸的RNA结合蛋白（glycine-rich RNA-binding protein，GR-RBP）在RNA加工和代谢中具有重要的功能。在这里，我们描述了番茄（番茄）GR-RBP SlRBP 1在调节mRNA翻译的作用。我们发现，slrbp 1敲低突变体（slrbp 1）显示减少总叶绿素的积累和受损的叶绿体超微结构。这些表型伴随着slrbp 1中与叶绿体功能相关的许多关键转录物水平的失调。此外，天然RNA免疫沉淀测序（nRIP-seq）回收了61个SlRBP 1相关RNA，其中大部分参与光合作用。通过nRIP-qPCR验证SlRBPl与所选靶RNA的结合。有趣的是，在slrbp 1突变体中，由slRBP 1结合的转录本编码的蛋白质的积累，而不是mRNA本身，减少了。多核糖体分析，然后进行RT-qPCR测定表明，slrbp 1植物中靶RNA的多核糖体占有率低于野生型。此外，SlRBP 1与真核生物翻译起始因子SleIF 4A 2相互作用。SlRBP 1的沉默显著降低了SleIF 4A 2与SlRBP 1靶RNA的结合。将这些观察结果结合在一起，我们提出SlRBP 1结合并将RNA引导到SleIF 4A 2翻译起始复合物上，并促进其靶RNA的翻译以调节叶绿体功能。
The glycine-rich RNA-binding protein SlRBP1 maintains chloroplast functions via regulating translational efficiency of key transcripts associated with chloroplast function.Many glycine-rich RNA-binding proteins (GR-RBPs) have critical functions in RNA processing and metabolism. Here, we describe a role for the tomato (Solanum lycopersicum) GR-RBP SlRBP1 in regulating mRNA translation. We found that SlRBP1 knockdown mutants (slrbp1) displayed reduced accumulation of total chlorophyll and impaired chloroplast ultrastructure. These phenotypes were accompanied by deregulation of the levels of numerous key transcripts associated with chloroplast functions in slrbp1. Furthermore, native RNA immunoprecipitation-sequencing (nRIP-seq) recovered 61 SlRBP1-associated RNAs, most of which are involved in photosynthesis. SlRBP1 binding to selected target RNAs was validated by nRIP-qPCR. Intriguingly, the accumulation of proteins encoded by SlRBP1-bound transcripts, but not the mRNAs themselves, was reduced in slrbp1 mutants. Polysome profiling followed by RT-qPCR assays indicated that the polysome occupancy of target RNAs was lower in slrbp1 plants than in wild-type. Furthermore, SlRBP1 interacted with the eukaryotic translation initiation factor SleIF4A2. Silencing of SlRBP1 significantly reduced SleIF4A2 binding to SlRBP1-target RNAs. Taking these observations together, we propose that SlRBP1 binds to and channels RNAs onto the SleIF4A2 translation initiation complex and promotes the translation of its target RNAs to regulate chloroplast functions.