ARGONAUTE (AGO) proteins are key effectors of small RNA (sRNA)-mediated gene silencing in plants. While the conserved globular domains of AGOs have been extensively studied, the N-terminal extension (NTE) has remained functionally elusive. This thesis demonstrates that the AGO NTE acts as a fine-tuning module that modulates subcellular localization, protein interactions, and post-translational regulation in Arabidopsis thaliana. Comparative analysis of AGO sequences across plant species revealed significant variability in NTE length and composition, correlating with AGO clade-specific functions. Functional assays showed that NTEs harbor nuclear export motifs and serve as interaction platforms for the methyltransferase PRMT5, which catalyzes symmetric arginine dimethylation (sDMA). Loss arginine methylated reshaped the AGO1 interactome and revealed altered stability and turnover, suggesting that arginine methylation is a key regulatory mechanism. This work proposes a revised model in which the NTE integrates spatial, structural, and biochemical information to adjust AGO function with temporal and functional precision.
| Date of Award | 23 Jun 2025 |
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| Original language | English |
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| Supervisor | Nicolás Gerardo Bologna (Director) |
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Characterization of N-terminal extensions and their impact on the functionality of plant ARGONAUTE proteins
Martín Merchán, A. (Author). 23 Jun 2025
Student thesis: Doctoral thesis
Martín Merchán, A. (Author), Bologna, N. G. (Director),
23 Jun 2025Student thesis: Doctoral thesis
Student thesis: Doctoral thesis