DNase I protection of the <i>vapBC-1</i> locus control region by Fis and Vap proteins.

<p>(A) The ³²P-labeled sense strand of 153 bp DNA substrate containing <i>vapB-1</i> TIR and upstream sequence in the <i>vapBC-1</i> locus control region, is shown with numbers indicating the distance from the 5′-labeled end. The putative Fis site (<i>underline</i>), inverted repeat regions (<i>arrows</i>), <i>vapB-1</i> translation start ATG (<i>italics</i>), and G cleavage products (<i>*</i>) seen in (D, <i>lane G</i>) are noted. On each gel shown, a 10 bp DNA ladder (<i>lane M</i>), 153 bp substrate without protein (<i>lane 1</i>), and DNase I digest of the substrate (<i>lane 2</i>) are indicated. Gels show DNase I cleavage products from samples containing: (B) a Fis∶DNA molar ratio of 2∶1, 7.5∶1, 15∶1, or 30∶1 (<i>lanes 3–6</i>), (C) a VapBC-1∶DNA molar ratio of 2∶1, 7.5∶1, 15∶1, or 30∶1 (<i>lanes 3–6</i>) or 40∶1 VapB-1∶DNA (<i>lane 7</i>), and (D) VapC-1∶DNA molar ratio of 40∶1 or 80∶1 (<i>lanes 3</i> and <i>4</i>). Vertical bars indicate the DNase I footprint from protein binding. Arrows (<) in panel <i>D</i> indicate DNase I hypersensitive sites. The gels each represent one of two independent experiments.