CAF Proteins Help SOT1 Regulate the Stability of Chloroplast ndhA Transcripts

• Published in: International journal of molecular sciences Vol. 22; no. 23; p. 12639
• Main Authors: Li, Xiuming, Luo, Wenzhen, Zhou, Wen, Yin, Xiaopeng, Wang, Xuemei, Li, Xiujin, Jiang, Chenchen, Zhang, Qingqing, Kang, Xiaojing, Zhang, Aihong, Zhang, Yi, Lu, Congming
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 23.11.2021; MDPI
• Subjects: Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Binding sites; chloroplast; Chloroplasts; Chloroplasts - genetics; Chloroplasts - metabolism; Cloning; Electron transport; Endonuclease; Gene expression; Gene Expression Profiling; Genomes; Introns; Metabolism; NADH; NADH dehydrogenase; NADH Dehydrogenase - genetics; ndhA; Nicotinamide adenine dinucleotide; pentatricopeptide repeat protein; Photosystem I; Protein turnover; Proteins; RNA Splicing; RNA Splicing Factors - metabolism; RNA Stability; Sequence Analysis, RNA; Splicing; Stability; RNA stability; chloroplast; ndhA; pentatricopeptide repeat protein; RNA splicing
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms222312639

Protein-mediated RNA stabilization plays profound roles in chloroplast gene expression. Genetic studies have indicated that chloroplast transcripts, encoding a key subunit of the NADH dehydrogenase-like complex that mediates photosystem I cyclic electron transport and facilitates chlororespiration, are stabilized by PPR53 and its orthologs, but the underlying mechanisms are unclear. Here, we report that CHLOROPLAST RNA SPLICING 2 (CRS2)-ASSOCIATED FACTOR (CAF) proteins activate SUPPRESSOR OF THYLAKOID FORMATION 1 (SOT1), an ortholog of PPR53 in , enhancing their affinity for the 5' ends of transcripts to stabilize these molecules while inhibiting the RNA endonuclease activity of the SOT1 C-terminal SMR domain. In addition, we established that SOT1 improves the splicing efficiency of by facilitating the association of CAF2 with the intron, which may be due to the SOT1-mediated stability of the transcripts. Our findings shed light on the importance of PPR protein interaction partners in moderating RNA metabolism.