Yamashita Yukiko M, Fuller Margaret T
Department of Developmental Biology, School of Medicine, Stanford University, Stanford, California 94305, USA.
Int J Hematol. 2005 Dec;82(5):377-80. doi: 10.1532/IJH97.05097.
The balance between stem cell and differentiating cell populations is critical for the long-term maintenance of tissue renewal for cell types derived from adult stem cell lineages such as blood, skin, intestinal epithelium, and sperm. To keep this balance, stem cells have the potential to divide asymmetrically, producing one daughter cell that maintains stem cell identity and one daughter cell that initiates differentiation. In many adult stem cell systems, the maintenance, proliferation, and number of stem cells appear to be controlled by the microenvironment, or niche. The Drosophila male and female germ line provide excellent model systems in which to study asymmetric stem cell divisions within the stem cell niche. In addition to signals from the niche that specify stem cell self-renewal, the stem cells themselves have elaborate cellular mechanisms to ensure the asymmetric outcome of cell division.
对于源自成体干细胞谱系的细胞类型（如血液、皮肤、肠上皮和精子）而言，干细胞与分化细胞群体之间的平衡对于组织更新的长期维持至关重要。为保持这种平衡，干细胞有潜力进行不对称分裂，产生一个维持干细胞特性的子细胞和一个启动分化的子细胞。在许多成体干细胞系统中，干细胞的维持、增殖和数量似乎受微环境或生态位的控制。果蝇的雄性和雌性生殖系提供了出色的模型系统，可用于研究干细胞生态位内的不对称干细胞分裂。除了来自生态位中指定干细胞自我更新的信号外，干细胞自身还具有精细的细胞机制来确保细胞分裂的不对称结果。
