Newman A P, Sternberg P W
Howard Hughes Medical Institute, Division of Biology, Pasadena, CA, USA.
Proc Natl Acad Sci U S A. 1996 Sep 3;93(18):9329-33. doi: 10.1073/pnas.93.18.9329.
Development of the nematode egg-laying system requires the formation of a connection between the uterine lumen and the developing vulval lumen, thus allowing a passage for eggs and sperm. This relatively simple process serves as a model for certain aspects of organogenesis. Such a connection demands that cells in both tissues become specialized to participate in the connection, and that the specialized cells are brought in register. A single cell, the anchor cell, acts to induce and to organize specialization of the epidermal and uterine epithelia, and registrates these tissues. The inductions act via evolutionarily conserved intercellular signaling pathways. The anchor cell induces the vulva from ventral epithelial cells via the LIN-3 growth factor and LET-23 transmembrane tyrosine kinase. It then induces surrounding uterine intermediate precursors via the receptor LIN-12, a founding member of the Notch family of receptors. Both signaling pathways are used multiple times during development of Caenorhabditis elegans. The outcome of the signaling is context-dependent. Both inductions are reciprocated. After the anchor cell has induced the vulva, it stretches toward the induced vulval cells. After the anchor cell has induced specialized uterine intermediate precursor cells, it fuses with a subset of their progeny.
线虫产卵系统的发育需要在子宫腔和正在发育的外阴腔之间形成连接，从而为卵子和精子提供通道。这个相对简单的过程可作为器官发生某些方面的模型。这种连接要求两个组织中的细胞都特化以参与连接，并且使特化细胞对齐。单个细胞，即锚定细胞，起到诱导和组织表皮及子宫上皮特化的作用，并使这些组织对齐。这些诱导作用通过进化上保守的细胞间信号通路发挥作用。锚定细胞通过LIN-3生长因子和LET-23跨膜酪氨酸激酶从腹侧上皮细胞诱导外阴形成。然后它通过受体LIN-12诱导周围的子宫中间前体细胞，LIN-12是Notch受体家族的创始成员。这两种信号通路在秀丽隐杆线虫的发育过程中都被多次使用。信号传导的结果取决于背景。两种诱导都是相互的。锚定细胞诱导外阴形成后，它会向诱导出的外阴细胞延伸。锚定细胞诱导出特化的子宫中间前体细胞后，它会与它们的一部分后代融合。
