Figure 2.

Identification of ARP-1 as a candidate binding protein of the aro-AII site. (A) The aro-AII-binding protein recognized the sequence “TTGGCCCCT,” which is shown inside the square. The wild-type and mutant oligonucleotide probes, AII, AIIM1, and AIIM3, are shown. Mutations introduced into the aro-AII oligonucleotide are shown by outlined characters. The nucleotide sequence of the ARP-1 binding site in the promoter region of the human and mouse ApoAI gene is also shown in the figure. Tandem repeats of human and mouse ApoAI oligonucleotides are shown in the oligonucleotide by arrows. The box indicates the portion of nucleotides essential for ARP-1 binding as described in our previous report. The putative tandem repeats in the AII probe are shown by broken arrows. (B) A gel shift assay was performed using 5 μg of nuclear protein. A 200-fold molar excess of unlabeled probe was used in the competition assay. The specific signals are indicated by the arrow on left side. The bracket shows the non-specific signals (N.S.). (C) For supershift assays, nuclear protein was incubated with 2 μg of the indicated antibody on ice for 30 min before the addition of a radiolabeled probe. The probe/nuclear protein complex and supershift signals are indicated by the arrow and arrowhead, respectively, on the left side.