Expression data from neurotrophin transgenic mice

A limited number of growth factors are capable of regulating numerous developmental processes, but how they accomplish this is unclear. In the gustatory system, brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT4) have different developmental roles but exert their effects through the same receptors (TrkB and p75). Using genome wide expression analysis, we determined that BDNF and NT4 also regulate the expression of different sets of genes downstream of receptor signaling in geniculate ganglion. These differences in gene expression likely determine their different roles. BDNF and NT4 could function differently because of temporal or spatial differences of expression or the activation of different signaling pathways. BDNF and NT4 regulate cell death, axonal growth and axonal guidance by altering gene expression. Because many of these functions of the two neurotrophins differ in taste development, each likely alters gene expression in a unique way. To determine if removal of BDNF and NT4 alters gene expression in different ways, I will compare microarray gene expression profiles in the geniculate ganglion among BDNF knockout, Nt4 knockout, and wild type mice during development.