RNA from Kc tissue culture cells was profiled. This is replicate 3. See Kai et al. (2005). Developmental Biology, in press.

This series compares gene expression between germ line stem cells (GSCs) purified either from bam mutant or Dpp-overexpressing ovaries, with gene expression in Kc cells.

RNA from dissected ovary tips of c587-GAL4; hsbam UAS-dpp females 50hr after a single heat shock to induce GSC differentiation ; expt 2; these tips contain reverted GSCs; See Kai et al. (2005). Developmental Biology, in press.

RNA from dissected ovary tips of c587-GAL4; hsbam UAS-dpp females 0hr after a single heat shock to induce GSC differentiation ; expt 2; these tips are enriched in GSCs; See Kai et al. (2005). Developmental Biology, in press.

RNA from dissected ovary tips of c587-GAL4; hsbam UAS-dpp females 0hr after a single heat shock to induce GSC differentiation ; expt 1; these tips are enriched in GSCs; See Kai et al. (2005). Developmental Biology, in press.

RNA from Kc tissue culture cells was profiled. This is replicate 2. See Kai et al. (2005). Developmental Biology, in press.

RNA from Kc tissue culture cells was profiled. This is replicate 1. See Kai et al. (2005). Developmental Biology, in press.

gene expression is tested for an association with GSCs by comparing expression levels in ovary tips of c587-GAL4; hs-bam UAS-dpp females at 0 hr, 20 hr and 50 hr after heat shock ; results of two independent experiments are given as expt 1 and expt 2.

RNA from dissected ovary tips of c587-GAL4; hsbam UAS-dpp females 20hr after a single heat shock to induce GSC differentiation ; expt 1; these tips lack GSCs; See Kai et al. (2005). Developmental Biology, in press.

Drosophila adult females but not males contain high levels of the steroid hormone ecdysone, however, the roles played by steroid signaling during Drosophila gametogenesis remain poorly understood. Drosophila germ cells in both sexes initially follow a similar pathway. After germline stem cells are established, their daughters form interconnected cysts surrounded by somatic escort (female) or cyst (male) cells and enter meiosis. Subsequently, female cysts acquire a new covering of somatic cells to form follicles. Knocking down expression of the heterodimeric ecdysteroid receptor (EcR/Usp) or the E75 early response gene in escort cells disrupts 16-cell cyst production, meiotic entry and follicle formation. Escort cells lose their squamous morphology and unsheath germ cells. By contrast, disrupting ecdysone signaling in males does not perturb cyst development or ensheathment. Thus, sex-specific steroid signaling is essential for female germ cell development at the time male and female pathways diverge. Our results suggest that steroid signaling plays an important sex-specific role in early germ cell development in Drosophila, a strategy that may be conserved in mammals.