Growth factors and gene expression: fresh insights from arrays

Gene array technology allows researchers to evaluate patterns of gene expression at a genome-wide level. Two recent papers have applied this powerful technique to characterize how gene expression is changed in response to growth factors and mitogens. The studies focus on two important questions concerning specificity in signal transduction. First, are the multiple signaling pathways activated by a single growth factor receptor used to activate gene expression, and if so, do these pathways act combinatorially? Second, how does the initial genetic response of a cell to a signal stimulus relate to the patterns of gene expression that determine that cell's ultimate biological response to the stimulus? Hill and Treisman take a critical look at what these array technology studies tell us concerning these questions and discuss technical issues arising from them.