Coordinated morphogenesis of epithelia during development of the Caenorhabditis elegans uterine-vulval connection
Development of the nematode egg-laying system requires the formation of a connection between the uterine lumen acid 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.
© 1996 by the National Academy of Sciences. This paper was presented at a colloquium entitled "Biology of Developmental Transcription Control," organized by Eric H. Davidson, Roy J. Britten, and Gary Felsenfeld, held October 26-28, 1995, at the National Academy of Sciences in Irvine, CA. We thank members of our laboratory for discussion, Gwendolyn Acton and Bob Horvitz for discussions about lin-11, and John White for his many contributions to our thinking about uterine and vulval morphogenesis. Marie-Anne Felix and Dago Dimster Denk provided important editorial comments. This work was supported by the Howard Hughes Medical Institute, with which P.W.S. is an investigator and A.P.N. is an associate.
Published - NEWpnas96.pdf