Egr2 activates the Nab1 and Nab2 promoters. A) The plot shows percent identity of the human and mouse Nab2 loci upstream of the first exon. DNase I footprinting analysis of a 1000 bp fragment of the mouse Nab2 promoter in the presence of recombinant Egr2 protein revealed two footprinted regions (solid line) with some weaker protections (dotted lines). The footprinted regions correspond to three of the four previously identified conserved sites [filled circles, 22] that conform to the Egr2 consensus binding site. There was no apparent footprint over putative site #4 identified in previous sequence analysis of the Nab2 promoter  M = marker lane. B) A similar analysis of the mouse Nab1 promoter confirmed binding of Egr2 to the six previously identified conserved binding sites in the mouse Nab1 promoter [filled circles, 22]. C) JEG-3 cells were transfected with a luciferase reporter plasmid containing either the Nab1 or Nab2 promoter, and the indicated amounts of an Egr2 expression construct. The mutant Nab2 promoter contains mutations in the two upstream Egr2 binding sites. Egr2 binding sites are indicated by filled circles. The y-axis shows the fold activation normalized to the activity of the reporter alone. Means and standard deviations of three separate transfections are shown. Activation of both Nab1 and Nab2 promoters by 25 ng Egr2 (compared to control) was statistically significant (P =< 0.002).