Biology subjects

Moreno-Sanchez, I.

Publications and source records attributed to Moreno-Sanchez, I..

5 recordsLinked to original sources

bioRxiv2026

Glu1, a conserved GH30_3 β-(1,6)-glucanase requires its catalytic residues for full virulence in Ustilago maydis

Plant-pathogenic fungi cause plant diseases and severe agricultural losses. The fungal cell wall is the first point of contact and defense barrier between fungus and host, maintaining cellular integrity and structural stability but also playing a dynamic role during infection. Through pathogenic development, the fungal cell wall must be continuously remodelled to accommodate morphological transitions and environmental challenges through diverse cell wall modifying enzymes necessary for successful infection. Here, we characterise Glu1, a putative endo-{beta}-(1,6)-glucanase (GH30) from the maize pathogen Ustilago maydis, conserved across Ustilaginales. Structural comparison with characterised GH30 crystal structures shows Glu1 most closely resembles GH30_3 {beta}-(1,6)-glucanases. Glu1 expression is induced during infection, localises to the plasma membrane in close association with the fungal cell wall and is detected in the secreted fraction. Deletion of glu1 reduces virulence, impairs plant colonization and tumour formation, and alters septation and cell morphology under saprophytic growth. Notably, genetic rescue with Glu1 catalytic-site variants largely restores saprophytic phenotypes but not virulence, suggesting a catalytic-dependent function of Glu1 specifically required for infection. Umag_04357, the other GH30 enzyme identified in U. maydis, reveals a conserved GH30 domain, including the catalytic residues, but is expressed at lower levels during infection and its deletion does not affect virulence. Together, our findings indicate that Glu1 is a conserved GH30 enzyme with a {beta}-(1,6)-glucanase-like pocket whose catalytic residues are required for full virulence. To our knowledge, it is the first GH30 enzyme linked to virulence in Basidiomycota and could be considered a potential target for smut disease control.

molecular biology↗

bioRxiv2024

Enhanced RNA-targeting CRISPR-Cas technology in zebrafish

CRISPR-Cas13 systems are widely used in basic and applied sciences. However, its application has recently generated controversy due to collateral activity in mammalian cells and mouse models. Moreover, its efficiency could be improved in vivo. Here, we optimized transient formulations as ribonucleoprotein complexes or mRNA-gRNA combinations to enhance the CRISPR-RfxCas13d system in zebrafish. We i) used chemically modified gRNAs to allow more penetrant loss-of-function phenotypes, ii) improved nuclear RNA-targeting, and iii) compared different computational models and determined the most accurate to predict gRNA activity in vivo. Furthermore, we demonstrated that transient CRISPR-RfxCas13d can effectively deplete endogenous mRNAs in zebrafish embryos without inducing collateral effects, except when targeting extremely abundant and ectopic RNAs. Finally, we implemented alternative RNA-targeting CRISPR-Cas systems with reduced or absent collateral activity. Altogether, these findings contribute to CRISPR-Cas technology optimization for RNA targeting in zebrafish through transient approaches and assist in the progression of in vivo applications.

developmental biology↗

bioRxiv2024

CRISPR-RfxCas13d screening uncovers Bckdk as a post-translational regulator of the maternal-to-zygotic transition in teleosts

The Maternal-to-Zygotic transition (MZT) is a reprograming process encompassing zygotic genome activation (ZGA) and the clearance of maternally-provided mRNAs. While some factors regulating MZT have been identified, there are thousands of maternal RNAs whose function has not been ascribed yet. Here, we have performed a proof-of-principle CRISPR-RfxCas13d maternal screening targeting mRNAs encoding protein kinases and phosphatases in zebrafish and identified Bckdk as a novel post-translational regulator of MZT. Bckdk mRNA knockdown caused epiboly defects, ZGA deregulation, H3K27ac reduction and a partial impairment of miR-430 processing. Phospho-proteomic analysis revealed that Phf10/Baf45a, a chromatin remodeling factor, is less phosphorylated upon Bckdk depletion. Further, phf10 mRNA knockdown also altered ZGA and Phf10 constitutively phosphorylated rescued the developmental defects observed after bckdk mRNA depletion. Altogether, our results demonstrate the competence of CRISPR-RfxCas13d screenings to uncover new regulators of early vertebrate development and shed light on the post-translational control of MZT mediated by protein phosphorylation.

developmental biology↗

bioRxiv2021

Genome editing in animals with minimal PAM CRISPR-Cas9 enzymes

The requirement for Cas nucleases to recognize a specific PAM is a major restriction for genome editing. SpCas9 variants SpG and SpRY, recognizing NGN and NRN PAM, respectively, have contributed to increase the number of editable genomic sites in cell cultures and plants. However, their use has not been demonstrated in animals. We have characterized and optimized the activity of SpG and SpRY in zebrafish and C. elegans. Delivered as mRNA-gRNA or ribonucleoprotein (RNP) complexes, SpG and SpRY were able to induce mutations in vivo, albeit at a lower rate than SpCas9 in equivalent formulations. This lower activity was overcome by optimizing mRNA-gRNA or RNP concentration, leading to efficient mutagenesis at regions inaccessible to SpCas9. We also found that the CRISPRscan algorithm can predict SpG and SpRY activity in vivo. Finally, we applied SpG and SpRY to generate knock-ins by homology-directed repair. Altogether, our results expand the CRISPR-Cas targeting genomic landscape in animals.

genetics↗

bioRxiv2019

N-glycosylation of the protein disulfide isomerase Pdi1 ensures Ustilago maydis virulence

Fungal pathogenesis depends on accurate secretion and location of virulence factors which drive host colonization. Protein glycosylation is a common posttranslational modification of cell wall components and other secreted factors, typically required for correct protein localization, secretion and function. Thus, the absence of glycosylation is associated with animal and plant pathogen avirulence. While the relevance of protein glycosylation for pathogenesis has been well established, the main glycoproteins responsible for the loss of virulence observed in glycosylation-defective fungi have not been identified. Here, we devise a proteomics approach to identify such proteins and use it to demonstrate a role for the highly conserved protein disulfide isomerase Pdi1 in virulence. We show that efficient Pdi1 N-glycosylation, which promotes folding into the correct protein conformation, is required for full pathogenic development of the corn smut fungus Ustilago maydis. Remarkably, the observed virulence defects are reminiscent of those seen in glycosylation-defective cells suggesting that the N-glycosylation of Pdi1 is necessary for the full secretion of virulence factors. All these observations, together with the fact that Pdi1 protein and RNA expression levels rise upon virulence program induction, suggest that Pdi1 glycosylation is a crucial event for pathogenic development in U. maydis. Our results provide new insights into the role of glycosylation in fungal pathogenesis.\n\nAuthor summaryFungal pathogens require virulence factors to be properly secreted and localized to guarantee complete infection. In common with many proteins, virulence factors must be post-translationally modified by glycosylation for normal localization, secretion and function. This is especially important for virulence factors, which are mainly comprised of cell wall and secreted proteins. Aberrant glycosylation leads to a loss of virulence in both animal and plant pathogenic fungi. We have previously demonstrated that glycosylation is important for virulence of the corn smut fungus, Ustilago maydis. However, the glycoproteins involved and their specific roles in the infection process have not yet been reported. Here, we describe a proteomic assay designed to identify glycoproteins involved in plant infection. Using this method, we define the role of Pdi1 protein disulfide isomerase in virulence. Interestingly, abolishing Pdi1 N-glycosylation mimics {Delta}pdi1 defects observed during infection, suggesting that Pdi1 N-glycosylation is required for the secretion of virulence factors. We hypothesize that Pdi1 N-glycosylation is crucial for maintaining proper effector protein folding during the infection process, especially in the harsh conditions found inside the maize plant.

microbiology↗