REPRESSION BY THE MAD(MXI1)-SIN3 COMPLEX

The functions of Myc in transformation and transactivation are counter ed by the suppressive actions of the Mad(Mxi1) family. Mad(Mxi1) prote ins not only compete with Myc for dimerization to Max and binding to M yc/Max consensus sites but also recruit powerful repressors of gene ex pression. A prediction of the yin-yang relationship between Myc and Ma d(Mxi1) families would be that the latter constitutes a new class of t umor suppressors. Here, we review the current literature on the Mad(Mx i1) family, with particular attention paid to the molecular mechanisms by which these proteins antagonize the actions of Myc in normal and n eoplastic cells. BioEssays 20:808-818, 1998. (C) 1998 John Wiley & Son s, Inc.