Conlon 9603627 The ribs and the vertebral column arise exclusively from an array of transient embryonic structures, the somites. The mechanism of somite segmentation is of considerable interest as a basic patterning process that directly affects the vertebral column as well as indirectly affecting a wide spectrum of trunk structures in normal human development. Perturbations of somitogenesis by gene mutation and environmental insult are likely to underlie a broad range of congenital malformations including some proportion of spine bifida, non-myopathic scoliosis and other dysraphic disorders. This proposal investigates the hypothesis that the embryonic midline signals to coordinate somite segmentation on the two sides of the embryo. The nature and identity of these signals will be identified by experiments performed in vitro on the embryos of the mouse. The proposed experiments are designed to increase our understanding of segmentation, specifically the way in which it is coordinated in the two segmental primordia, so that they can later give rise to the single, segmented vertebral column.
