International Mammalian Genome Society

G16 Neuronal Diversity and Differentiation in the Mouse Embryo Requires the Delta like Gene 1

Kurt Wünsch^§, Ulrich Heinzmann^#, Achim Gossler* and Martin Hrabé de Angelis^§. ^§GSF, Institute of Mammalian Genetics, Neuherberg, Germany; ^#GSF, Institute of Pathology, Neuherberg, Germany; *The Jackson Laboratory Bar Harbor; ME; USA

In the mouse, the Delta homologue Dll1 (Delta-like gene 1) and Notch1 show a strikingly similar expression pattern in the paraxial mesoderm and nervous system during early postimplantation development suggesting that cells in these tissues can communicate by interaction of Dll1 and Notch1 proteins.

By analyzing mice carrying a null mutation of the Notch ligand Delta1, we show that Delta1 is an important regulator of early neuronal differentiation in mice

Progenitor cells of neuronal fate differentiated prematurely and excessively in the central and peripheral nervous system. Genes involved in the Delta-Notch-signal-transduction pathway showed altered gene expression in Dll^1-/- embryos. Both findings are consistent with expected changes after loss of lateral inhibition.

We also present data indicating that the loss of Delta1 function specifically interferes with the formation of certain neuronal cell types. Differentiated cell types were reduced or lost in the ventral spinal cord and in the dorsal root ganglia.