Expression and Function of Small Maf Proteins

　The small Maf factors are DNA binding proteins possessing a basic region-leucine zipper (bZip) motif. One of the features of the bZip proteins is dimerization. Small Maf proteins form homodimers by themselves or heterodimers with other bZip transcription factors, such as CNC family members and bind to the Maf recognition element (MARE, TGCTGAG/CTCAGCA). The presence of a functional regulatory network has been suggested which is composed of various bZip transcription factors interacting with the MARE. When the number of small Maf proteins is reduced, the quantitative balance among the various factors becomes disturbed, which ends in defective thrombopoiesis, neurological disorders, and an abnormal red cell membrane. Making use of biochemical, cytological and genetical approaches, we are striving to decipher the complex system and to elucidate the principles of transcriptional regulatory mechanisms by bZip factors.