DNase I footprint of the −142 to −89 NRE. A −178 to +48 fragment was labeled at −178 on the antisense strand and incubated for 30 minutes with 90 μg of nuclear extract from CPAE cells, HeLa cells, Dami cells, or HUVECs or 90 μg of BSA and used in footprinting analysis as described in the Materials and Methods. The −126 to −133 protected sequence is shown on the right. G+A lane corresponds to cleavage at bases G and A by Maxam-Gilbert chemical sequencing of the probe.