cytoneme-mediated delivery of hedgehog regulates the expression of bone morphogenetic proteins to maintain germline stem cells in drosophilacytoneme-mediated交付刺猬调节骨形成蛋白的表达来维持在果蝇生殖系干细胞.pdf

Cytoneme-Mediated Delivery of Hedgehog Regulates the Expression of Bone Morphogenetic Proteins to Maintain Germline Stem Cells in Drosophila ´ 1 2 ´ 1 Patricia Rojas-Rıos , Isabel Guerrero , Acaimo Gonzalez-Reyes * ´ ´ ´ 1 Centro Andaluz de Biologıa del Desarrollo, CSIC/Universidad Pablo de Olavide, Sevilla, Spain, 2 Centro de Biologıa Molecular Severo Ochoa, CSIC/Universidad Autonoma de Madrid, Madrid, Spain Abstract Stem cells reside in specialised microenvironments, or niches, which often contain support cells that control stem cell maintenance and proliferation. Hedgehog (Hh) proteins mediate homeostasis in several adult niches, but a detailed understanding of Hh signalling in stem cell regulation is lacking. Studying the Drosophila female germline stem cell (GSC) niche, we show that Hh acts as a critical juxtacrine signal to maintain the normal GSC population of the ovary. Hh production in cap cells, a type of niche support cells, is regulated by the Engrailed transcription factor. Hh is then secreted to a second, adjacent population of niche cells, the escort cells, where it activates transcription of the GSC essential factors Decapentaplegic (Dpp) and Glass bottom boat (Gbb). In wild-type niches, Hh protein decorates short filopodia that originate in the support cap cells and that are functionally relevant, as they are required to transduce the Hh pathway in the escort cells and to maintain a normal population of GSCs. These filopodia, reminiscent of wing disc cytonemes, grow several f