Gel mobility shift analysis of protein binding to the −124 to −83 DNA fragment. Gel mobility shift analysis was performed with the double-stranded DNA fragment containing the −124 to −83 region alone and with 10 μg of cellular protein from H526 cells. The SC Sp1 oligonucleotide (Santa Cruz) contains a consensus Sp1 binding site. The oligonucleotides corresponding to c-kit sequences are: Xma-Nae (−124/−83), XN (−125/−97), XN2 (−102/−82), XN3 (−96/−82). The +/− indicates whether H526 extract was added to the gel shift mixture.