Preprints

Progenitor cell dedifferentiation is important for stem cell maintenance during tissue repair and age-related stem cell decline. Here, we use Drosophila ovarian germ cells as a model to study the role of cytonemes in BMP signalling-directed dedifferentiation to germline stem cells. We provide evidence that differentiating germ cell cysts extend cytonemes towards the niche during dedifferentiation to reactivate BMP signalling. We show that the Enabled (Ena) actin polymerase is localised to the tips of germ cell cytonemes and is necessary for robust cytoneme formation, as its mislocalisation reduces the frequency, length and directionality of cytonemes. Furthermore, specifically perturbing cytoneme function through Ena mislocalisation reduces germ cell BMP responsiveness and the ability of differentiating cysts to dedifferentiate. We discuss how cytonemes may be widely used by differentiating cells to re-establish niche contact and signal responsiveness following stem cell loss, promoting robust dedifferentiation of stem cells in diverse contexts.