Confocal analysis of eGFP expression in transgenic gonads. (A) The middle panel depicts the organisation of an Anopheles gambiae testis. In the apical tip the stem cell niche is sustained by a set of somatic cells, called hub cells (pink), which regulate the maintenance of the GSC (dark green) and SSC (dark blue) populations. Upon replication of the GSC, one of the two resulting daughter cells will differentiate into a primary spermatogonium (light green) and begin the developmental maturation process to become mature sperm. Testicular expression of eGFP from transgenic males of Vas1GFP (panels a, b), Vas2GFP (panels c, d) and β2-Tubulin-eGFP (panels e, f). Distribution of eGFP in the entire testes (panels a, c, e). Micrographs of the apical hub regions of transgenic testes (panels b, d, f). The eGFP expression in the GSC region is limited to Vas2GFP (panel d) and is absent in both Vas1GFP (panel b) and in β2-Tubulin-eGFP (panel f). (B) Expression of eGFP in ovarian follicles (panel g, h, i, j) and in germaria (panels k brightfield; l fluorescence). eGFP is expressed in nurse cells of all developing follicles and transported to the oocyte cytoplasm (panel g, i). In germaria eGFP clearly labels germline stem cells (green, GSCs) and developing cystocytes (light green) (panel l). Expression is not detectable in cells of the follicular epithelium (blue, FEC).