Functional Study Of CG9138 During Oogenesis In Drosophila Melanogaster

Drosophila oogenesis is an excellent model for studying some fundamental questions of cellular and developmental biology. CG9138 mutant animals are lethal at the third instar larval stage, suggesting that CG9138 is an essential gene. Complete removal of CG9138 from the follicle cells using the FLP/FRT system leads to multilayered follicle cells when occurred in the anterior and posterior domains. The multilayered follicle cells lack proper apical-basal polarity and show aberrant distribution of the core components of adherens junctions, such as Drosophila E-cadherin (DE-Cad) and Armadillo (Arm). After the transition from mitosis to endocycles at stage 6, the wild type follicle cells cease proliferation, while additional mitoses take place in CG9138 mutant follicle cells up to stage 8. Notch signaling pathway is not activated in the multilayered follicle cells, indicating that the multilayered phenotype is not caused by inactivation of Notch. In addition, we also found that posterior mutant follicle cells cause mislocalization of Gurken (Grk) and the oocyte nucleus. Taken together, these phenotypes in follicle cells suggest that CG9138 may play a role in cell adhesion to maintain the follicular epithelial integrity.