Figure 2.

Band shift of a DNA fragment containing the cspA promoter by FIS and H-NS. (A) The 310 bp DNA fragment, containing the cspA promoter region including the entire 5′-UTR, labeled with ³²P, was used in electrophoretic mobility shift assay (EMSA) with the indicated amounts of H-NS and/or FIS. DNA-protein complexes formed preferentially or exclusively in the presence of both FIS and H-NS are indicated by arrows or asterisks, respectively. (B) EMSA experiments, carried out in duplicate, were subjected to Western Blot. After electrophoresis and elettroblotting, membranes were alternatively developed with antibodies anti-FIS or anti-H-NS as indicated. Lanes C1 and C2 represent the free FIS and H-NS proteins without DNA, respectively. Proteins concentration is given assuming dimeric structure. For further details see Materials and Methods.