Adachi-Yamada Takashi, O'Connor Michael B
Department of Sciences for Natural Environment, Faculty of Human Development, Kobe University, Japan.
Dev Biol. 2002 Nov 1;251(1):74-90. doi: 10.1006/dbio.2002.0821.
Smooth gradients of the morphogens Hh, Dpp, and Wg are required for proper development of Drosophila imaginal discs. Here, it is reported that, when a discontinuity is generated between two adjacent cells in the reception of either the Dpp or Wg signal, then cells on either side of the discontinuity boundary undergo apoptosis by activating the c-Jun N-terminal Kinase (JNK) pathway. Furthermore, in the medial region of the wing imaginal disc, the JNK pathway is also activated if cells do not receive the proper levels of Dpp and Hh signals. These observations suggest that cells within a developing field have the ability to access their spatial positions by comparing the level of morphogen signal they receive with that of their neighbors. This phenomenon is likely related to the process of cell competition, and we suggest that it is an evolutionarily important mechanism that helps prevent abnormal tissue specification and growth during development.
形态发生素Hh、Dpp和Wg的平滑梯度对于果蝇成虫盘的正常发育是必需的。在此报道，当在Dpp或Wg信号接收的两个相邻细胞之间产生不连续性时，那么不连续边界两侧的细胞通过激活c-Jun氨基末端激酶（JNK）途径而发生凋亡。此外，在翅成虫盘的内侧区域，如果细胞没有接收到适当水平的Dpp和Hh信号，JNK途径也会被激活。这些观察结果表明，发育场中的细胞有能力通过比较它们接收到的形态发生素信号水平与相邻细胞的信号水平来确定自己的空间位置。这种现象可能与细胞竞争过程有关，并且我们认为这是一种在进化上重要的机制，有助于防止发育过程中异常的组织特化和生长。
