Fig 3.

Role of C/EBP transcription factors in steady-state and emergency granulopoiesis. Activation of the C/EBPβ transcription factor is required to generate increased numbers of granulocytes under emergency conditions, such as severe infection or cytokine exposure, whereas C/EBPα plays a critical role under steady-state conditions. C/EBPβ and C/EBPα share many common target molecules, including genes associated with granulocytic differentiation. By contrast, they show a differing ability to regulate the cell cycle. C/EBPα strongly inhibits the cell cycle, whereas C/EBPβ has a less inhibitory effect. Red arrows indicate extracellular stimuli that activate C/EBPβ.