Illustration of a dimer of the Mad-Max transcription factors (blue) bound to a synthetic DNA (deoxyribonucleic acid, yellow) molecule. Transcription factors are proteins that bind to specific sequences of DNA and control the transcription (transfer) of genetic information from DNA to RNA (ribonucleic acid). Mad and Max are components of the Myc/Max/Mad family of transcription factors that regulate cell growth, differentiation and apoptosis (programmed cell death). Binding of Mad-Max to DNA promotes cell differentiation and quiescence (reversible growth arrest).