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Discrimintion and Mapping of the Primary and Processed Transcripts in Maize Mitochondrion Using a Circular RT-PCR-based Strategy
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The PPR-SMR Protein ATP4 Is Required for Editing the Chloroplast rps8 mRNA in Rice and Maize
Jinghong Zhang1, Yipo Guo1, Qian Fang1
1National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
Plant Physiology
|September 15, 2020
Summary
Rice mutants lacking the ATP4 protein show cold sensitivity due to impaired ribosomal protein S8 (rps8) RNA editing. ATP4 is crucial for rps8 editing, suggesting a novel role for PPR-SMR proteins in chloroplast RNA metabolism.
Area of Science:
- Plant molecular biology
- Chloroplast gene expression
- RNA processing and modification
Background:
- Pentatricopeptide repeat (PPR) proteins regulate chloroplast gene expression.
- P-type PPR proteins are involved in RNA stabilization, translation, and splicing.
- The role of the small MutS-related (SMR) domain in PPR proteins is largely unknown.
Purpose of the Study:
- To investigate the function of the PPR-SMR protein ATP4 in rice (Oryza sativa).
- To elucidate the role of OsATP4 in chloroplast gene expression and RNA editing.
- To understand the contribution of the SMR domain to ATP4 function.
Main Methods:
- Characterization of the rice mutant osatp4.
- Analysis of chloroplast gene expression and RNA editing in wild-type and mutant plants.
- Complementation analysis using transgenic osatp4 mutants.
Main Results:
- OsATP4 is essential for the accumulation of rpl16-rpl14 transcripts and for the editing of rps8 transcripts in rice.
- osatp4 mutants exhibit chlorotic phenotypes and plastid-ribosome deficiency, particularly under cold conditions.
- The rps8 editing defect in osatp4 mutants is independent of rpl16-rpl14 transcript levels and directly causes cold sensitivity.
Conclusions:
- ATP4 plays a dual role in chloroplast gene expression, regulating both transcript accumulation and RNA editing.
- The SMR domain of ATP4 is critical for its function in rps8 RNA editing.
- ATP4 likely facilitates RNA editing by promoting the access of editing factors to their targets.
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