Cells must express components of the planar cell polarity system and extracellular matrix to support cytonemes

Abstract

Drosophila dorsal air sac development depends on Decapentaplegic (Dpp) and Fibroblast growth factor (FGF) proteins produced by the wing imaginal disc and transported by cytonemes to the air sac primordium (ASP). Dpp and FGF signaling in the ASP was dependent on components of the planar cell polarity (PCP) system in the disc, and neither Dpp- nor FGF-receiving cytonemes extended over mutant disc cells that lacked them. ASP cytonemes normally navigate through extracellular matrix (ECM) composed of collagen, laminin, Dally and Dally-like (Dlp) proteins that are stratified in layers over the disc cells. However, ECM over PCP mutant cells had reduced levels of laminin, Dally and Dlp, and whereas Dpp-receiving ASP cytonemes navigated in the Dally layer and required Dally (but not Dlp), FGF-receiving ASP cytonemes navigated in the Dlp layer, requiring Dlp (but not Dally). These findings suggest that cytonemes interact directly and specifically with proteins in the stratified ECM.DOI: http://dx.doi.org/10.7554/eLife.18979.001

Cytoneme-mediated signaling essential for tumorigenesis

“…The signaling proteins move along cytonemes and exchange at transient synapses that form where cytonemes contact target cells. These synapses are similar to neuronal synapses in both constitution and properties Roy et al, 2014), and are necessary for paracrine FGF, BMP/Dpp, Hedgehog, Wnt/Wingless (Wnt/Wg), and Notch signaling during normal development of Drosophila epithelial tissues (González-Méndez et al, 2017;Huang and Kornberg, 2016;Roy et al, 2014).…”

Imaging Cytonemes in Drosophila Embryos

“…Earlier studies used CherryCAAX, CD8:Cherry, CD4:IFP2, CD2:GFP, and CD8:GFP to image cytonemes from larval tissues [21,23,24, 39,41]. We successfully imaged the embryonic cytonemes using all these constructs.…”

“…1a). Signal-specific cytonemes were found to interact with components of the extracellular matrix (ECM), through which cytonemes navigate [24]. Cytonemes from the ASP that contact the Dpp source in the wing disc localize the Dpp receptor, receive Dpp, and transport receptor-bound ligand from the source to recipient cells.…”

Hedgehog produced by the Drosophila wing imaginal disc induces distinct expression responses in three target tissues

“…Gal80ts/+ (Ptc overexpression), btl-Gal4, UAS-mCD8:GFP/+; Gal80ts/UAS-Hh:CD2 (Hh:CD2 overexpression) larvae were grown at 18°C until early L3 larvae and were incubated at 29°C for 24 hours prior to dissection. ASP cytonemes were imaged using the hanging drop method (Huang and Kornberg, 2016). For the analysis of cytoneme density, the number of cytonemes in the ASP bulb was counted and the number is expressed relative to perimeter length.…”