The apical and basolateral membranes of epithelia are insulated from each other, preventing the transfer of extracellular proteins from one side to the other. Thus, a signalling protein produced apically is not expected to reach basolateral receptors. Evidence suggests that Wingless, the main Drosophila Wnt, is secreted apically in the embryonic epidermis. However, in the wing imaginal disc epithelium, Wingless is mostly seen on the basolateral membrane where it spreads from secreting to receiving cells. Here we examine the apico-basal movement of Wingless in Wingless-producing cells of wing imaginal discs. We find that it is presented first on the apical surface before making its way to the basolateral surface, where it is released and allowed to interact with signalling receptors. We show that Wingless transcytosis involves dynamin-dependent endocytosis from the apical surface. Subsequent trafficking from early apical endosomes to the basolateral surface requires Godzilla, a member of the RNF family of membrane-anchored E3 ubiquitin ligases. Without such transport, Wingless signalling is strongly reduced in this tissue.
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http://dx.doi.org/10.1038/ncb3325 | DOI Listing |
STAR Protoc
January 2025
Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, 38123 Trento, TN, Italy; Department of Medicine, NYU Langone Medical Center, New York, NY 10016, USA. Electronic address:
Reduced expression of nucleolar genes induces stress and DNA damage. Here, we present a protocol to analyze DNA fragmentation at the single-cell level in Drosophila imaginal discs using an optimized alkaline comet assay. We describe steps for larvae development, tissue disaggregation, and single-cell dissociation.
View Article and Find Full Text PDFMethods Mol Biol
January 2025
Department of Integrative Biology and Physiology, Medical School, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, USA.
Homeobox genes (HOX), the master regulators, deploy a unique set of target genes to coordinate and orchestrate the spatiotemporal development of an organism. HOX encoded transcriptional factors regulate the expression of target genes by binding to the specific sequences on the genome. Chromatin Immunoprecipitation (ChIP) and Chromatin Immunoprecipitation with Sequencing (ChIP-Seq) are widely used to map and understand specific gene locus and global regulatory regions on the genome.
View Article and Find Full Text PDFFASEB J
December 2024
Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China.
Elife
November 2024
Department of Genetics, Albert Einstein College of Medicine, Bronx, United States.
Many cell fate decisions are determined transcriptionally. Accordingly, some fate specification is prevented by Inhibitor of DNA-binding (Id) proteins that interfere with DNA binding by master regulatory transcription factors. We show that the Id protein Extra macrochaetae (Emc) also affects developmental decisions by regulating caspase activity.
View Article and Find Full Text PDFPLoS Genet
November 2024
Department of Biological Sciences, Konkuk University, Seoul, Republic of Korea.
Fatty acid-binding proteins (FABPs) are small cytoplasmic proteins involved in intracellular lipid transport and bind free fatty acids, cholesterol, and retinoids. FABP3, the major neuronal FABP in the adult brain, is upregulated in the CSF of patients with Alzheimer's disease (AD). However, the precise role of neuronal FABPs in AD pathogenesis remains unclear.
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