9507151 Hardin This work will seek to investigate a specific interaction between mesenchymal and epithelial cells, the attachment of secondary mesenchyme cells (SMCs) to animal pole ectoderm. This interaction occurs during the process of gastrulation in the sea urchin embryo. The sea urchin offers the advantage of ease of manipulation and observation of single cells. This laboratory will use both embryological manipulations and molecular biological techniques, taking advantage of available sea urchin homologues of mesoderm-specific transcription factors to examine the interaction of these cells with their target epithelium. The following questions will be investigated: i). what is the time course of molecular differentiation of a known target for mesenchymal attachment, the animal pole?, ii). is msx-2 gene expression regulated by cell-cell interactions in the animal pole target region?, iii). how does incorrect expression of msx-2 transcripts affect epithelial-mesenchymal interactions?, and iv). how is expression of the snail gene regulated during mesenchymal interaction? This work is likely to provide important information regarding the nature of epithelial-mesenchymal interactions during development. ***
