NGFIA (EGR1) Contains Transcription Activating Domains in Both the Amino Terminal and Carboxyl Terminal Regions of the Protein

We constructed and tested a number of lac repressor fusion proteins containing various portions of the zinc-finger conatining 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 though 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 adomain capable of supressing the N-terminal transcriptional activation function.