TAF7 (TAFII55) plays a role in the transcription activation by c-Jun

c-Jun is a member of the AP- 1 family of transcription factors regulating expression of specific target genes in a variety of cellular processes including proliferation, stress response, and tumorigenicity. In the present study we have analyzed the mechanism of c- Jun function as a transactivator with respect to members of the basal transcription machinery, TATA- binding protein-associated factors ( TAFs). We show that one member of the family, human TAF7 ( formerly TAF(II)55), physically interacts with c- Jun through two independent interaction domains, within the N- and C- terminal part of c-Jun. Interaction in vitro correlates with enhanced transactivation function of c- Jun in HEK293 and COS cells in the presence of increasing amounts of TAF7. TAF7 interacts preferentially with DNA- bound phosphorylated c- Jun, suggesting that TAF7 represents a novel c- Jun co- activator mediating activation of AP- 1 target genes in response to extracellular signals.