Fig. 2.

Schematic exemplifying major pathways and signaling components involved in embryonic NSC proliferation and differentiation. Cell-matrix and cell-cell interactions cooperate with tissue gradients of diffusible molecules and secreted factors from the CSF. Cdc42 and MAPK-Erk signals represent key pathways able to integrate growth factor-derived signaling (EGF, bFGF, IGFs) with adhesion and mechanotransductory signaling mediated by cadherins and integrins. Nuclear downstream factors such as myc, Hes5, Pax6, Id4 exemplify transcriptional regulators of NSC self-renewal