Embryo emergent: elucidating the cell biology of development

The meeting was organized by Cori Bargmann and Richard Harland and held at The University of California, Santa Cruz on July 21–25, 2000.![][1] With the rapid rise in genomic information, increasing knowledge about the intricacies of cell signaling pathways, and a greater understanding of conserved gene functions, the field of developmental biology has reached a new level, where researchers face a different set of challenges. Some of these challenges and the exciting approaches being taken to surmount them were described at the Santa Cruz Conference in Developmental Biology. In this review, we highlight methodological trends and new areas of focus that emerged from the meeting.### Converging pathways, molecular complexityAt the time of the previous Santa Cruz conference in 1996, considerable progress had been made in unraveling signaling and transcriptional regulatory pathways that underlie cell fate choices. A recurring theme of the 2000 meeting was that linear pathways are an oversimplification, and that future research must take into account the many feedback loops and cross‐signaling networks that link regulatory pathways throughout the cell. The complexity of cross‐talk between pathways was ably demonstrated in the yeast by Ira Herskowitz (San Francisco, CA), who described the interplay between the cellular response to high osmolarity, the pheromone response and pseudohyphal growth. These seemingly distinct pathways are mediated by partially overlapping MAP kinase cascades that negatively regulate one another. For example, during the high osmolarity response, the HOG1 MAP kinase is both an activator of this pathway and an inhibitor of FUS1, a target in the pheromone pathway (O'Rourke and Herskowitz, 1998). Yeast researchers are now exploiting DNA microarray technology to assay genome‐wide responses to extrinsic signals, to identify pathway components and to define epistatic relationships among key regulators. The hope is that the technology will become adaptable to more complex systems such as developing Xenopus , where … [1]: /embed/graphic-1.gif