The MYC gene product functions as a DNA-specific transcription factor. A related polypeptide called MAX , for MYC-associated factor X, dimerizes with MYC to optimize DNA binding. A paucity of negative regulatory elements have been reported for the MYC gene which regulate transcription from 2 initiation sites specified by the P1 and P2 promoters. ME1a1, a 16-bp nuclear nuclear factor binding site residing between MYC P1 and P2 transcription initiation sites, is required for P2 activity. MAZ, Its mRNA was present in all tissues tested (except kidney) as a doublet of approximately 2.5 to 2.7 kb, along with differentially expressed minor species. The authors speculated that MAZ may encode a transcription factor with dual roles in transcription initiation and termination.