FIG. 6.

Identification of the transcription factors interacting with the E-box site in the LRS. Nuclear extract from DG75 cells was incubated under binding conditions with a ³²P-labelled double-stranded oligonucleotide corresponding to the −66 to −41 LRS region. Antibody supershifts were carried out by incubation with antibodies as indicated below the autoradiograms. The reaction mixtures were analyzed by EMSA. One nonspecific band that was not abolished by competition with unlabelled probe is indicated by a dotted arrow. (A) Eight specific complexes are indicated by solid arrows; three are designated USF and one is designated Max/Mad1/mSin3A, since it contains these three factors. The positions of the immunologically shifted complexes are shown by the solid arrowheads for the anti-Max shifts. (B) Eight specific complexes are indicated by solid arrows: three designated USF, one designated E12, one designated Max/Mad1/mSin3A, and one designated E47. Two complexes are not designated due to the fact that the protein components were not identified. It should be noted that the addition of anti-E12 and anti-E47 antibodies to the reaction mixtures shifted the respective protein complexes to the top of the gel.