The P-type pentatricopeptide repeat protein DWEORG1 is a non-previously reported rPPR protein of Arabidopsis mitochondria

Abstract

Gene expression in plant mitochondria is mainly regulated by nuclear-encoded proteins on a post-transcriptional level. Pentatricopeptide repeat (PPR) proteins play a major role by participating in mRNA stability, splicing, RNA editing, and translation initiation. PPR proteins were also shown to be part of the mitochondrial ribosome (rPPR proteins), which may act as regulators of gene expression in plants. In this study, we focus on a mitochondrial-located P-type PPR protein—DWEORG1—from Arabidopsis thaliana. Its abundance in mitochondria is high, and it has a similar expression pattern as rPPR proteins. Mutant dweorg1 plants exhibit a slow-growth phenotype. Using ribosome profiling, a decrease in translation efficiency for cox2, rps4, rpl5, and ccmFN2 was observed in dweorg1 mutants, correlating with a reduced accumulation of the Cox2 protein in these plants. In addition, the mitochondrial rRNA levels are significantly reduced in dweorg1 compared with the wild type. DWEORG1 co-migrates with the ribosomal proteins Rps4 and Rpl16 in sucrose gradients, suggesting an association of DWEORG1 with the mitoribosome. Collectively, this data suggests that DWEORG1 encodes a novel rPPR protein that is needed for the translation of cox2, rps4, rpl5, and ccmFN2 and provides a stabilizing function for mitochondrial ribosomes.

PPR proteins in plants: roles, mechanisms, and prospects for rice research

“…P-type PPR proteins predominantly participate in organelle RNA transcript splicing, stability, and translation. PLS-type PPR proteins mainly function in mitochondrial and chloroplastic RNA editing ( Gruttner et al., 2022 ). These two PPR protein types may exhibit partially overlapping functions in regulating RNA splicing and editing.…”

Development and Investigation of HRM Markers to Discriminate Two Ogura Cytoplasmic Male Sterility Restorer Genes in Radish

“…Evidence suggests that PPR proteins are involved in the post-transcriptional regulation of chloroplast and mitochondrial genes, including RNA maturation, editing, intron splicing, transcript stabilization, and translation initiation. The synergy of RNA metabolism has profound effects on the biogenesis and function of both chloroplasts and mitochondria, influencing processes such as photosynthesis, respiration, development, and environmental responses in plants [20,22,23]. The male sterility recovery gene likely evolved through numerous interactions with the host in the symbiotic relationship with mitochondria.…”