Fig. 4.
Supershift analysis of proteins binding to involucrin promoter proximal AP1 response element. Nuclear extract was prepared from untreated cultures the day before confluence (preconfluent) or 7 days after confluence either with no treatment (NT), or treated with 2 μM arsenite, 10 μM vanadate, 10 μM cadmium or 3 μM chromate as indicated. The band patterns were examined after incubation in the absence (None) or presence of antibodies to the indicated transcription factors. Solid arrows point to protein complexes with labeled AP1 oligonucleotide, and open arrows show the supershifted bands. Antibody addition resulted in supershifted bands for the underlined AP1 proteins.