frizzled 9 is expressed in neural precursor cells in the developing neuraltube

The wnt signaling pathway has important functions in nervous system develop ment. To better understand this process we have cloned and analyzed the exp ression of the wnt receptor, frizzled 9, in the developing nervous system i n mouse, chick and zebrafish. The earliest expression of mouse frizzled 9 m RNA expression begins at E8.5 with expression throughout the entire rostral -caudal neuraxis. This early expression pattern within the neural tube appe ars to be conserved between chick and zebrafish. Expression becomes restric ted to a ventral domain in the mouse ventricular zone at E11.5, a region sp ecified to give rise to neurons and glia. Using a polyclonal antibody to MF Z9 further shows expression limited to neural restricted precursors cells.