The DNA binding domains of the yeast Ga14 and human c-Jun transcription factors interact through the zinc-finger and bZIP motifs

摘要

Different Gal4 fusion proteins, expressing unrelated transcription activator domains, were found to activate transcription from promoters containing dimerized AP1 DNA binding sites. Transactivation was depend ent on the first 74 amino acids of Ga14. A direct interaction between Ga14 and c-Jun was demonstrated using a GSTGaI4 fusion protein and in vitro translated human c-Jun. The interaction required the zinc finger containing DNA binding domain of Ga14 and the basic-leucine zipper region of c-Jun. These results demonstrated that the specificity of Gal4 fusion proteins in transient transfection experiments in mam malian cells Is not restricted to reporters containing Ga14 binding sites, but also includes promoters con taining AP1 binding sites. Furthermore, the Ga14 fusion proteins also activated transcription from a pUC18 vector fragment containing several putative AP1 bind ing sites. Finally, our results indicate that Ga14 activa tor proteins binding to Ga14 binding sftes and to DNA bound AP1 factors can co-operatively activate tran scription.