During development of the brain, nerve cells become organized into functional units for appropriately connected circuits. Patterns of layers or clustering in the adult brain develop by mechanisms still unclear. There is evidence from many studies that cell-cell interactions and extracellular factors such as cell adhesion molecules play a significant role in organizing such regions before the neuronal connections themselves are established. This project exploits the development of forebrain organization, where novel molecular antibodies have been found to demonstrate formation of a boundary of the region where olfactory inputs terminate. Experimental manipulations utilize the well-established developmental model system of the frog Xenopus. Cell grafting, molecular probes for antibodies and gene expression are used to identify the molecules involved and their relative contributions to defining this regional border. Results will provide an important basis to proceed with analyzing the molecular mechanisms of boundary formation, and so will be important beyond understanding the development of olfactory circuits to understanding the biology of pattern formation in general.
