The present invention relates to methods for identifying interacting regions of transcription factors, and methods for identifying agents which modulate the interactions, useful for affecting gene regulation, for example, cellular transformation. A site within residues 130-154 and within residues 343-358 in Stat3 were found to interact with the transcription factor c-Jun. On c-Jun, a site within residues 105 and 334, and more particularly, between 105 and 263, interact with Stat3. These sites of interactions permit methods for identifying agents which modulate the interaction between these transcription factors to modulate gene transcription.