HETERODIMER FORMATION BETWEEN CREB AND JUN PROTEINS

  • 1 March 1990
    • journal article
    • research article
    • Vol. 5  (3) , 295-302
Abstract
DNA binding protein families have been identified that contain a leucine zipper dimerization motif preceded by a conserved, highly basic domain involved in direct specific interaction with DNA. Members of two of these families, the Jun and Fos related proteins, have been shown to directly interact and form heterodimeric complexes. A third such family known as the CREB or ATF proteins, bind to the sequence element present in promoters from a number of viral and cellular genes; this element can confer cAMP-inductability and E1A-inducibility of transcription. In this report we show that one member of the CREB family can efficiently form a heterodimeric complex with the cJun protein. The DNA binding specificity of the heterodimer was indistinguishable from CREB alone. Transfection studies in undifferentiated F9 cells suggest that the CREB/cJUN heterodimer can form in vivo, but that the complex does not activate transcription. The heterodimer formation between CREB and Jun proteins is highly specific; only one of the two CREB proteins would heterodimerize with cJun and it would not form dimers with JunB or cFos. The interaction of members of these two families of proteins increases the repertoire of possible regulatory complexes that could play an important role in the regulation of transcription of specified cellular genes.