Biology subjects

Bono, F.

Publications and source records attributed to Bono, F..

6 recordsLinked to original sources

bioRxiv2026

A tomato fruit blotch viral replicon defines minimal requirements for cell autonomous replication and identifies functional RNA4-encoded movement and silencing suppression activities

Tomato fruit blotch virus (ToFBV) is an emerging multipartite positive-sense RNA virus associated with blotchy symptoms on tomato fruits and classified within the genus Blunervirus (family Kitaviridae). Despite its increasing agricultural relevance, the study of ToFBV has been hindered by the lack of mechanical transmissibility and the difficulty in reproducing infections under controlled conditions. In this work, we report a preliminary step toward the development of the first infectious agroclone system for ToFBV, based on full-length cDNA copies of its four genomic RNAs. We demonstrate that the cloned viral genome is capable of initiating cell autonomous replication in Nicotiana benthamiana, as indicated by the accumulation of negative-sense RNA intermediates in infiltrated tissues. To further validate the system, RNA3 was engineered to express GFP, enabling visualization of infection foci and confirming active viral replication in both N. benthamiana and tomato. Functional assays of RNA4-encoded proteins demonstrated that it encodes a movement protein capable of complementing movement-deficient viral vectors and a putative suppressor of post-transcriptional gene silencing (PTGS). Together, these results establish a versatile reverse genetics platform for ToFBV, providing new insights into the replication and functional organization of blunerviruses and enabling future studies on virus-host interactions, pathogenicity, and control strategies

microbiology↗

bioRxiv2026

A viroid-like RNA can be transmitted among different Trichoderma species affecting their antagonistic capacity

Viroids are small, circular non-coding RNAs that autonomously replicate in plants, exploiting host cellular machinery for replication and spread. Recent studies reveal that viroid-like agents can infect filamentous fungi, suggesting cross-kingdom interactions. In this study, we report the discovery and the characterization of TsvlRNA1 in Trichoderma spirale, a transmissible viroid-like RNA containing a hammerhead ribozyme in one polarity strand. Bioinformatic data, molecular validation, and reverse genetics experiments demonstrate that TsvlRNA1 is circular with an active ribozyme essential for replication. TsvlRNA1 replicates autonomously and transmits horizontally between Trichoderma species, eliciting 21-23 nt viroid-derived small RNAs consistent with RNA silencing targeting. The biocontrol capacity of Trichoderma against Rhizoctonia solani is variably modulated by TsvlRNA1, with effects ranging from positive to negative depending on host strain. In T. spirale, data suggests genotype-by-agent interactions influence antagonistic potential negatively. TsvlRNA1 transmission via horizontal routes is prevalent, and the viroid-like RNA fails to infect plant hosts experimentally. These results highlight so-far the underappreciated ecological and functional diversity of viroid-like agents in fungi, with implications for fungal biology, biocontrol, and genotype-phenotype relationships in eukaryotes. ImportanceSpecies of the fungal genus Trichoderma play a central role in sustainable agriculture by controlling fungal plant pathogens and supporting plant growth. For this reason, Trichoderma-based products represent a substantial share of the global market for microbial biofungicides. Viroids are the smallest known infectious agents, and their presence in filamentous fungi has only recently been discovered. Consequently, little is known about their biology, transmission, or interactions with fungal hosts. In this study, we describe TsvlRNA1, a viroid-like RNA associated with T. spirale, representing only the second viroid-like RNA to be biologically characterized in fungi. We show that TsvlRNA1 can influence the ability of Trichoderma to inhibit Rhizoctonia solani, a major plant pathogen, demonstrating its biological relevance. Unexpectedly, TsvlRNA1 can be transmitted between different Trichoderma species. This finding raises concerns about the possible transfer of genetic traits between fungi, including those related to fungicide resistance, with important implications for agricultural biocontrol. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=150 SRC="FIGDIR/small/702247v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@1b6de6eorg.highwire.dtl.DTLVardef@c52141org.highwire.dtl.DTLVardef@a61fcorg.highwire.dtl.DTLVardef@1a6f0a4_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2025

The structure of Egalitarian in complex with the K10 mRNA localization signal reveals a modular binding surface required for function

Asymmetric localization of mRNAs is a prevalent mechanism for spatial control of protein function and typically involves active transport by cytoskeletal motors. The mechanisms of recognition of localizing mRNAs by motor complexes are poorly understood. Egalitarian is an adaptor protein that binds localization signals in specific RNAs in Drosophila and recruits them to the dynein-dynactin complex for microtubule-based transport. We determined the crystal structure of Egalitarian in complex with the localization signal of the K10 mRNA. Three structural units of Egalitarian, a 3'-5'exonuclease domain, a linker and a C-terminal domain form shape-specific, base-directed and backbone interactions with the RNA. Based on the structure we identified conserved residues recognizing RNA in vitro. Genome-edited flies with mutations in these residues have deficits in Egalitarian function that are congruent with changes in in vitro RNA binding affinities. Our work demonstrates how a minimal RNA localization signal is recognized by an RNA localization factor.

biochemistry↗

bioRxiv2025

Functional Impact of CYFIP2 RNA Editing on Actin Regulation, Axon Growth, and Spinogenesis

Cytoplasmic FMRP Interacting Protein 2 (CYFIP2) a component of the Wave Regulatory Complex (WRC), one of the most important players in regulating cellular actin dynamics. Interestingly, CYFIP2 transcript undergoes RNA editing, an epitranscriptomic modification catalysed by ADAR enzymes, that leads adenosine (A) to inosine (I) deamination. CYFIP2 editing in the coding sequence results in a K/E substitution at amino acid 320. The functional meaning of this regulation is still unknown. In this study, we aim at investigating the potential implication of CYFIP2 RNA editing related to actin dynamics during cell differentiation, axon development and synaptogenesis in neural cells. We have generated SH-SY5Y neuroblastoma cell lines in which CYFIP2 gene has been functionally inactivated by CRISPR-Cas9 technology. CYFIP2 KO cells showed profound actin filaments disorganisation and loss of the capability to differentiate into a neuronal-like phenotype. Overexpression of both CYFIP2 unedited (K) and edited (E) isoforms rescued normal capability. Finally, we took advantage of primary neuronal culture where endogenous CYFIP2 was knocked down by shRNA technology and CYFIP2 editing variants were overexpressed. While CYFIP2 KD cells reported a decrease in axon development and spine frequency, CYFIP2-E variants increase the number of axon branches, total axon length and dendritic spine frequency compared to either CYFIP2 KD cells or CYFIP-K variants. Overall, our work reveals for the first time a functional significance of the CYFIP2 K/E RNA editing process in regulating the spreading of neuronal axons during the initial stages of in-vitro development and the process of spinogenesis.

cell biology↗

bioRxiv2022

Mechanisms by Which Small Molecule Inhibitors Arrest Sec14 Phosphatidylinositol Transfer Protein Activity

Phosphatidylinositol transfer proteins (PITPs) promote phosphoinositide signaling by enhancing phosphatidylinositol (PtdIns) 4-OH kinase activities in producing signaling pools of PtdIns-4-phosphate. As such, PITPs are key regulators of lipid signaling in eukaryotic cells. While the PITP phospholipid exchange cycle is the engine that stimulates PtdIns 4-OH kinase activity, the protein and lipid dynamics associated with this critical process are not understood. Herein, we use an integrative structural approach that takes advantage of small molecule inhibitors (SMIs) directed against the major yeast PITP (Sec14) to gain new insights into the mechanics of the Sec14 phospholipid exchange cycle from the perspective of protein, phospholipid and SMI dynamics. Moreover, as Sec14 has emerged as an attractive target for next-generation antifungal drugs, the structures of Sec14 bound to SMIs of four different chemotypes reported in this study provide critical information required for structure-based design of next-generation lead compounds that target Sec14 PITPs of virulent fungi.

biophysics↗

bioRxiv2020

An interaction network of RNA-binding proteins involved in Drosophila oogenesis

During Drosophila oogenesis, the localization and translational regulation of maternal transcripts relies on RNA-binding proteins (RBPs). Many of these RBPs localize several mRNAs and may have additional direct interaction partners to regulate their functions. Using immunoprecipitation from whole Drosophila ovaries coupled to mass spectrometry, we examined protein-protein associations of 6 GFP-tagged RBPs expressed at physiological levels. Analysis of the interaction network and further validation in human cells allowed us to identify 26 previously unknown associations, besides recovering several well characterized interactions. We identified interactions between RBPs and several splicing factors, providing links between nuclear and cytoplasmic events of mRNA regulation. Additionally, components of the translational and RNA decay machineries were selectively co-purified with some baits, suggesting a mechanism for how RBPs may regulate maternal transcripts. Given the evolutionary conservation of the studied RBPs, the interaction network presented here provides the foundation for future functional and structural studies of mRNA localization across metazoans.

biochemistry↗