NGFIA (EGR1) contains transcription activating domains in both the amino terminal and carboxyl terminal region of the protein
We constructed and tested a number of lac repressor fusion proteins containing various portions of the zinc-finger containing protein NGFIA for their ability to stimulate transcription of a reporter gene containing lac operators. NGFIA contains two transcription activation regions, found in two distinct regions of the protein. The carboxyl (C) terminal portion of the molecule contains a weak activation domain, including five tandem copies of an eight amino acid repeat (T/S,T/S,F/Y,P,S,P,X,X). These five tandem copies of the repeated sequence activated reporter gene transcription 4-7 fold. Amino acids 1 through 293 in the amino (N) terminus of NGFIA function as a strong transcription activation domain stimulating transcription up to 80-fold. Fusions including amino acids 1-393 failed to activate transcription, indicating the presence of a domain capable of suppressing the N-terminal transcriptional activation function.