Aub and Ago3 exhibit distinct expression patterns during spermatogenesis. (A) Schematic representation of a wild-type Drosophila testis. The asterisk denotes the anterior apex. Germline stem cells (GSCs, shown in red) located next to the hub divide asymmetrically to give rise to GSCs and differentiating gonialblasts. Gonialblasts undergo four rounds of mitotic division, producing germline cysts collectively known as spermatogonia (shown in pink) located in the germinal proliferation center (GPC). Spermatogonia further differentiate into primary spermatocytes (shown in blue). (B) y w testes stained for Aub and Ago3 showing apex region (top), magnified GPC (middle), and primary spermatocytes (bottom). Scale bars represent 50 µm in the top panels and 10 µm in the middle and bottom panels. While Aub was expressed from GSCs to primary spermatocytes, Ago3 was detected only in GPC. (C) Schematic representation of the purification method used to enrich testicular extract with spermatogonia or primary spermatocytes. bam and bgcn mutant testes were used to obtain GPCs containing GSCs and spermatogonia. The apex of can and sa mutant were manually removed to get rid of spermatogonia. (D) Western blots showing the expression of Aub, Ago3, and the loading control α-Tubulin in y w, bam, bgcn, can, and sa testes. Ago3 expression was observed in y w, bam, and bgcn, but not in can and sa testes devoid of GPCs.
