Crosstalk of EGFR signalling with Notch and Hippo pathways to regulate cell specification, migration and proliferation in cockroach panoistic ovaries

• Published in: Biology of the cell Vol. 107; no. 8; pp. 273 - 285
• Main Authors: Elshaer, Nashwa, Piulachs, Maria-Dolors
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01-08-2015
• Subjects: Animals; Blattella germanica; Blattellidae - cytology; Blattellidae - enzymology; Blattellidae - genetics; Blattellidae - metabolism; Cell Movement; Cell Proliferation; Drosophila melanogaster; Epidermal growth factor; Female; Follicular cells; Insect Proteins - genetics; Insect Proteins - metabolism; Insect reproduction; Ovary - cytology; Ovary - enzymology; Ovary - growth & development; Ovary - metabolism; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Receptor, Epidermal Growth Factor - genetics; Receptor, Epidermal Growth Factor - metabolism; Receptors, Notch - genetics; Receptors, Notch - metabolism; Signal Transduction; Insect reproduction; Epidermal growth factor; Blattella germanica; Drosophila melanogaster; Follicular cells
• ISSN: 0248-4900; 1768-322X
• DOI: 10.1111/boc.201500003

Background information
Epidermal growth factor receptor (EGFR) signalling is crucial for the regulation of multiple developmental processes. Its function in relation to insect oogenesis has been thoroughly studied in the fly Drosophila melanogaster, which possesses ovaries of the highly modified meroistic type. Conversely, studies in other insect species with different ovary types are scarce. We have studied EGFR functions in the oogenesis of the cockroach Blattella germanica, a phylogenetically basal insect with panoistic ovaries.
Results
In this cockroach, depletion of EGFR expression aborts oocyte maturation and prevents oviposition, as affects the distribution of F‐actins in the follicular cells of the basal ovarian follicle, which triggers premature apoptosis. In the younger ovarian follicles within the ovariole, depletion of EGFR expression reduces the number of follicular cells, possibly because the Hippo pathway is altered; moreover, the concomitant reduction of Notch expression results in the absence of stalk. Finally, depletion of EGFR determines an increase in the number of germinal cells.
Conclusions
In the panoistic ovary of B. germanica, EGFR plays a role in the control of cell proliferation through interaction with Hippo and Notch pathways.
Research article
Epidermal growth factor receptor (EGFR) is essential to complete the development of the ovarian follicle in insects. This protein interacts with Notch and Hippo pathways to regulate cell proliferation, and helps to maintain a balance between the number of follicular cells and the number of germinal cells that left the germarium.