Transcriptional activation by Arabidopsis GT-1 may be through interaction with TFIIA-TBP-TATA complex

GT-1 belongs to the class of trihelix DNA-binding proteins and binds to a promoter sequence found in many different genes. Data presented in this report show that GT-1 contains a trans-activation function in yeast and in plant cells. However, in tobacco BY-2 protoplasts, this activity functions only when an internal region containing the DNA-binding domain is deleted. Gel-shift and co-immunoprecipitation assays have revealed that GT-1 can interact with and stabilize the TFIIA-TBP-TATA complex. These results suggest that GT-1 may activate transcription through direct interaction with the transcriptional pre-initiation complex.