Gene targeting reveals multiple essential functions of the neuregulin signaling system during development of the neuroendocrine and nervous systems.

Mice harboring targeted mutations in neuregulin-1 and its receptors (erbB2, erbB3, and erbB4) have been invaluable tools for testing the roles of these genes in vivo as well as for identifying unexpected functions for this signaling system. This review summarizes the advances in understanding the myriad functions of neuregulins in the nervous and neuroendocrine systems that have been revealed by examining gene-targeted mice.