BMP Signaling and Stem Cell Self-Renewal in the Drosophila Ovary

Bone morphogenetic protein (BMP) ligands from stromal niche cells suppress differentiation and promote germline stem cell self-renewal in the Drosophila ovary. Regulatory factors in the niche and the local extracellular matrix enhance BMP signaling specifically in the stem cell. Regulatory factors in the developing germline and surrounding stromal cells antagonize BMP signaling thereby permitting and promoting differentiation. Soma to soma and germline to soma intercellular communication contributes to the regulation of germline homeostasis. This complex regulation generates a steep BMP signaling gradient that ensures the tight control of self-renewal versus differentiation.