MYC Associated Factor X (MAX)

MAX is a member of the basic helix-loop-helix leucine zipper (bHLHZ) family of transcription factors. It is able to form homodimers and heterodimers with other family members, which include Mad, Mxi1 and Myc. Myc is an oncoprotein implicated in cell proliferation, differentiation and apoptosis. The homodimers and heterodimers compete for a common DNA target site (the E box) and rearrangement among these dimer forms provides a complex system of transcriptional regulation. Unlike MYC, the steady state level of MAX RNA was not significantly modulated with respect to proliferation or differentiation. Unlike MYC RNA, MAX RNA was relatively stable with a half-life of more than 3 hours, and therefore it did not exhibit the characteristic short half-life of RNAs encoded by most immediate early genes.