NCIt definition : MYC Family Genes encode MYC Family Proteins, class III bHLH leucine zipper transcription
factors having cellular proliferative and apoptotic roles. Dimerization via leucine
zippers of MYC proteins with bHLH/lz proteins, such as MAX, is required for efficient
DNA binding. Leucine zippers are present in many gene regulatory proteins, including
CREB proteins, Jun/AP1 transcription factors, and FOS-type proteins, as well as MYC
proteins. The periodically repeated leucine side chains extending from one alpha helix
interdigitate with leucine residues of another alpha helix, facilitating coiled-coil
dimerization; like charge repulsion in this region perturbs homodimer formation; heterodimers
are promoted by opposing charge attractions. c-MYC transcription factor binds to CAC(GA)TG
DNA sites. MYC sequences have been highly conserved throughout evolution, from Drosophila
to vertebrates. (NCI);