Snail superfamily genes in brain development: are they involved in mechanisms of cell migration and differentiation?

Abstract

The Snail and Scratch gene families form the metazoan Snail superfamily of zinc-finger transcription factors. In vertebrates, these two families are respectively represented by snail and slug, and by scratch1, -2 genes (Manzanares et al., 2001). These genes play multiple crucial roles in development. Snail-family members trigger epithelial-mesenchymal transitions, which are involved in the formation of mesoderm and neural crest as well as in the acquisition of invasive phenotype in epithelial tumours (Cano et al., 2000; Locascio and Nieto, 2001). Scratch genes are the representation of Snail-superfamily expression in early neuroepithelium. In zebrafish and mouse embryos scratch RNA appears in young postmitotic neurons, suggesting a role in the radial migration and/ or differentiation of these cells (Nakamura et al., 2001; Blanco and Nieto, unpublished results). In this work we have studied these genes in mouse and chick embryos, focusing on the following questions: - the temporal-spatial relationship between scratch expression and that of markers of neuronal differentiation, - the eventual role of Snail and Scratch genes in later migration/ differentiation phenomena like those involved in cerebellar histogenesis, - their possible involvement in the migration of glial and endothelial cells within the developing brain.