Tissue maintenance requires a balance between cell production and cell death. The former is dependent on the activity of stem cells, which in turn are dependent on both extrinsic signals produced by surrounding somatic tissue and intrinsic signals to control their behaviour. Additionally, stem cell activity may be regulated by systemic factors, demonstrating the complexity of stem cell regulation. The ovary of Drosophila melanogaster is a useful model for understanding tissue function as production of a viable egg requires the coordination of two different stem cell populations, the germline stem cells and follicle stem cells. In a screen designed to identify genes which regulate early oogenesis in the Drosophila ovary, we identified the four candidate genes which are described in the three papers found in this thesis. The first paper demonstrates that two RNA associated proteins, Ataxin 2 binding protein 1 and Gemin3, are essential for germline stem cell and follicle cell production in a Sex lethal dependent manner. The second shows that Glucuronyl transferase I, which is important for regulating the synthesis of key components of the extracellular matrix known as proteoglycans, is able to regulate the activity of several different signalling pathways. Finally, the third paper suggests that Defective proboscis extension response 9, a brain expressed gene involved in the behavioural response to alcohol, is important for regulating both follicle cells and germline stem cells at a systemic level. Taken together, these papers highlight the importance of intrinsic, extrinsic and systemic signalling in regulating stem cell function during Drosophila oogenesis.