Role of primary response genes in generating cellular responses to growth factors.

Cellular responses to growth and differentiation factors involve a complex cascade of signals that begins at the cell surface, traverses the cytoplasm, and eventually enters the nucleus. Although a great deal is known about the surface and cytoplasmic stages of this cascade, the nuclear events involved in transducing and translating growth and differentiation signals are less well understood. Recent work has implicated a set of genes known as primary response genes as critical for this process. To propagate the activation signal, these genes possess the ability not only to directly respond to upstream biochemical events, but also to transmit the signal downstream by modulating the unique changes in gene expression necessary for a particular cellular response. In this review we discuss how transcription factors encoded by primary response genes may be responsible for regulating tissue- or stimulus-specific responses associated with cellular activation.