Graduate School of Human Development and Environment, Kobe University, Kobe, 657-8501, Japan.
J Biol Dyn. 2012;6:267-76. doi: 10.1080/17513758.2011.560290. Epub 2011 Jun 24.
The Drosophila posterior midgut epithelium mainly consists of intestinal stem cells (ISCs); semi-differentiated cells, i.e. enteroblasts (EBs); and two types of fully differentiated cells, i.e. enteroendocrine cells (EEs) and enterocytes (ECs), which are controlled by signalling pathways. In [M. Kuwamura, K. Maeda, and T. Adachi-Yamada, Mathematical modeling and experiments for the proliferation and differentiation of Drosophila intestinal stem cells I, J. Biol. Dyn. 4 (2009), pp. 248-257], on the basis of the functions of the Wnt and Notch signalling pathways, we studied the regulatory mechanism for the proliferation and differentiation of ISCs under the assumption that the Wnt proteins are supplied from outside the cellular system of ISCs. In this paper, we experimentally show that the Wnt proteins are specifically expressed in ISCs, EBs, and EEs, and theoretically show that the cellular system of ISCs can be self-maintained under the assumption that the Wnt proteins are produced in the cellular system of ISCs. These results provide a useful basis for determining whether an environmental niche is required for maintaining the cellular system of tissue stem cells.
果蝇的后肠上皮主要由肠干细胞 (ISCs)组成; 半分化细胞，即肠成细胞 (EBs); 和两种完全分化的细胞，即肠内分泌细胞 (EEs) 和肠细胞 (ECs)，它们受信号通路的控制。在 [M. Kuwamura、K. Maeda 和 T. Adachi-Yamada，《果蝇肠干细胞增殖和分化的数学建模与实验 I》，J. Biol. Dyn. 4 (2009)，第 248-257 页] 中，基于 Wnt 和 Notch 信号通路的功能，我们研究了 ISCs 增殖和分化的调控机制，假设 Wnt 蛋白是从 ISCs 的细胞系统外部供应的。在本文中，我们通过实验证明 Wnt 蛋白在 ISCs、EBs 和 EEs 中特异性表达，并从理论上证明，假设 Wnt 蛋白在 ISCs 的细胞系统中产生，ISCs 的细胞系统可以自我维持。这些结果为确定组织干细胞的细胞系统是否需要一个环境龛来维持提供了有用的依据。
