Biology subjects

Cadoudal, A.

Publications and source records attributed to Cadoudal, A..

3 recordsLinked to original sources

bioRxiv2025

Loss of tRNA uridine thiolation affects mRNA translation, protein production, and sulfur-compound metabolism in Arabidopsis

The uridine at position 34 of tRNA anticodon loops is always modified at variable levels depending on environmental conditions, but a function for this highly conserved modification has not been firmly established. Using Arabidopsis thaliana, we show that the thiolation of U34 is a prerequisite for the subsequent modifications at position 32 and 37 of the tRNALys(UUU) anticodon loop, revealing a novel modification network. Surprisingly, the level of tRNALys(UUU) is strongly increased rather than reduced in the ctu1 or ctu2 mutant backgrounds that prevent these modifications. This suggests the existence of a regulatory feedback loop that drives the transcription of this specific tRNA gene family. Furthermore, we observed that the ability of the ribosome to decode AAA, GAA and CAA codons is impaired when the thiol group is lost, leading to a reduction in protein production, especially for genes enriched in these codons. Finally, we show that loss of tRNA thiolation results in variations in levels of many proteins involved in sulfur-compound metabolism and several sulfur-containing metabolites, suggesting that the level of tRNA thiolation may act as a sensor that regulates these processes.

molecular biology↗

bioRxiv2024

Regulation of co-translational mRNA decay by PAP and DXO1 in Arabidopsis

BackgroundmRNA decay is central in the regulation of mRNA homeostasis in the cell. The recent discovery of a co-translational mRNA decay pathway (also called CTRD) has changed our understanding of the mRNA decay process. This pathway has emerged as an evolutionarily conversed mechanism essential for specific physiological processes in eukaryotes, especially in plants. In Arabidopsis, this pathway is targeted mainly by the exoribonuclease XRN4. However, the details of the molecular regulation of this pathway are still unclear. ResultsIn this study, we first tested the role of the 3'-phosphoadenosine 5'-phosphate (PAP), an inhibitor of exoribonucleases in the regulation of CTRD. Using 5Pseq approach, we discovered that FRY1 inactivation impaired XRN4-CTRD activity. Based on this finding, we demonstrated that exogenous PAP treatment stabilizes CTRD mRNA targets. Furthermore, we also tested the implication of the exoribonuclease DXO1 in CTRD regulation. We found that DXO1, another exoribonuclease sensitive to PAP, is also involved in the CTRD pathway, especially by targeting NAD+-capped mRNAs. DXO1 specifically targets mRNAs linked to stress response. ConclusionsOur study provides further insights into the regulation of CTRD in Arabidopsis and demonstrates that other exoribonucleases can be implicated in this pathway.

plant biology↗

bioRxiv2024

Genome-wide analysis of mRNA decay in Arabidopsis shoot and root reveals the importance of co-translational mRNA decay in the general mRNA turnover

Until recently, the general 5-3 mRNA decay was placed in the cytosol after the mRNA was released from ribosomes. However, the discovery of an additional 5 to 3 pathway, the Co-Translational mRNA Decay (CTRD), changed this paradigm. Up to date, defining the real contribution of CTRD in the general mRNA turnover has been hardly possible as the enzyme involved in this pathway is also involved in cytosolic decay. Here we overcame this obstacle and created an Arabidopsis line specifically impaired for CTRD called XRN4{Delta}CTRD. Through a genome-wide analysis of mRNA decay rate in shoot and root, we tested the importance of CTRD in mRNA turnover. First, we observed that mRNAs tend to be more stable in root than in shoot. Next, using XRN4{Delta}CTRD line, we demonstrated that CTRD is a major determinant in mRNA turnover. In shoot, the absence of CTRD leads to the stabilization of thousands of transcripts while in root its absence is highly compensated resulting in faster decay rates. We demonstrated that this faster decay rate is partially due to the XRN4-dependent cytosolic decay. Finally, we correlated this organ-specific effect with XRN4{Delta}CTRD line phenotypes revealing a crucial role of CTRD in mRNA homeostasis and proper organ development.

plant biology↗