Molecular Visualisation of 80S Ribosome in Drosophila melanogaster

Abstract

Background: The occurrence of translation within the eukaryotic nucleus remains debated. Aim: This study investigated the subcellular distribution of assembled 80S ribosomes in Drosophila melanogaster using a Venus-based ribosomal bimolecular fluorescence complementation (Ribo-BiFC) reporter. Methods: Transgenic flies carrying UAS-RpS18-VN and UAS-RpL11-VC reporter inserts were combined to generate homozygous double-insert lines. Insert presence was verified by single-fly PCR. Reporter expression was induced in larval salivary glands through the GAL4/UAS system, and fixed tissues were examined by confocal fluorescence microscopy. Emetine treatment was used to assess changes in BiFC signal distribution. Results: BiFC fluorescence was detected predominantly in the cytoplasm, with additional signals in nuclear and nucleolar regions of third-instar larval salivary-gland cells. The nucleolar signal was consistently visible in most examined cells. Emetine treatment increased visible fluorescence intensity, particularly in the cytoplasm and near the nuclear periphery. These observations indicate close proximity between the tagged small- and large-subunit ribosomal proteins under the conditions examined. Conclusion: The generated Venus-based Ribo-BiFC transgenic lines provide a practical approach for visualising the subcellular distribution of assembled ribosomal complexes in Drosophila tissues. Nevertheless, BiFC fluorescence alone does not establish active translation, and quantitative analysis, clearly reported replication, negative controls, live-cell imaging, and independent validation are required to support interpretation of nuclear and nucleolar signals.