Signaling between somatic follicle cells and the germline patterns the egg and embryo of Drosophila. Author Julie Merkle, Julia Wittes, Trudi Schüpbach Publication Year 2020 Type Journal Article Abstract In Drosophila, specification of the embryonic body axes requires signaling between the germline and the somatic follicle cells. These signaling events are necessary to properly localize embryonic patterning determinants in the egg or eggshell during oogenesis. There are three maternal patterning systems that specify the anterior-posterior axis, and one that establishes the dorsal-ventral axis. We will first review oogenesis, focusing on the establishment of the oocyte and nurse cells and patterning of the follicle cells into different subpopulations. We then describe how two coordinated signaling events between the oocyte and follicle cells establish polarity of the oocyte and localize the anterior determinant bicoid, the posterior determinant oskar, and Gurken/epidermal growth factor (EGF), which breaks symmetry to initiate dorsal-ventral axis establishment. Next, we review how dorsal-ventral asymmetry of the follicle cells is transmitted to the embryo. This process also involves Gurken-EGF receptor (EGFR) signaling between the oocyte and follicle cells, leading to ventrally-restricted expression of the sulfotransferase Pipe. These events promote the ventral processing of Spaetzle, a ligand for Toll, which ultimately sets up the embryonic dorsal-ventral axis. We then describe the activation of the terminal patterning system by specialized polar follicle cells. Finally, we present open questions regarding soma-germline signaling during Drosophila oogenesis required for cell identity and embryonic axis formation. Keywords Animals, Drosophila, Drosophila Proteins, Signal Transduction, Female, Gene Expression Regulation, Developmental, Embryo, Nonmammalian, Oocytes, Oogenesis, Body Patterning Journal Curr Top Dev Biol Volume 140 Pages 55-86 Date Published 2020 ISSN Number 1557-8933 DOI 10.1016/bs.ctdb.2019.10.004 Alternate Journal Curr Top Dev Biol PMID 32591083 PubMedGoogle ScholarBibTeXEndNote X3 XML