The Arabidopsis Mitochondrial Pseudouridine Synthase Homolog FCS1 Plays Critical Roles in Plant Development

Abstract

As the most abundant RNA modification, pseudouridylation has been shown to play critical roles in E. coli, yeast, and humans. However, its function in plants is still unclear. Here, we characterized FCS1, which encodes a pseudouridine synthase in Arabidopsis. fcs1 mutants exhibited severe defects in plant growth, such as delayed development and reduced fertility, and were significantly smaller than the wild type at different developmental stages. FCS1 protein is localized in the mitochondrion. The absence of FCS1 significantly reduces pseudouridylation of mitochondrial 26S rRNA at the U1692 site, which sits in the peptidyl transferase center (PTC). This affection of mitochondrial 26S rRNA may lead to the disruption of mitochondrial translation in the fcs1-1 mutant, causing high accumulation of transcripts but low production of proteins. Dysfunctional mitochondria with abnormal structures were also observed in the fcs1-1 mutant. Overall, our results suggest that FCS1-mediated pseudouridylation of mitochondrial 26S rRNA is required for mitochondrial translation, which is critical for maintaining mitochondrial function and plant development.

The Diversity and Functions of Plant RNA Modifications: What We Know and Where We Go from Here

“…With emerging technologies, we have vastly expanded our knowledge of the diversity and abundance of RNA modifications in various organisms, including plants, in the last few decades, which has been termed by some as the golden period for this field of study (39). Thousands of modified nucleotides in various RNA types such as messenger RNAs (mRNAs), tRNAs, ribosomal RNAs (rRNAs), microRNAs (miRNAs), and long noncoding RNAs (lncRNAs) have been found in various cellular compartments including the nucleus, cytoplasm, chloroplast, and mitochondria (79). In addition to revealing the identities of the modifications, we have also begun uncovering the diverse functional roles of RNA modifications in plants.…”