The c-myc promoter: still MysterY and challenge.

The transcription factor c-Myc is a key regulator of cell proliferation, cell growth, differentiation, and apoptosis. Deregulated c-myc expression possesses a high transformation potential and the proto-oncogene c-myc represents a promising target in anticancer therapy. This review on the c-myc promoter describes its organization, the different levels of its normal regulation (including initiation and elongation of transcription, the dual P1/P2 promoters, chromatin structure, c-Myc autosuppression) as well as its deregulation in Burkitt's lymphoma. Furthermore, it summarizes the many different transcription factors, signal transduction pathways, and feedback loops that activate or repress c-myc transcription. Finally, a concept for regulation of the c-myc promoter in different biological settings, for example, immediate-early induction, constant expression throughout the cell cycle in continuously cycling cells, repression during terminal differentiation and deregulation in cancer, is formulated.