DNase I hypersensitivity of Kit 5′-flanking, exon I, and first intron region in chromatin from Kit-expressing and nonexpressing cells. (A) DNA from nuclei treated with DNase I was digested with EcoRI and hybridized to probe A (see panel B). HS sites are indicated. (B) Restriction map of the region analyzed. (C) Fine mapping of HS3 to HS6. Probes and restriction enzymes used are indicated. Molecular weight markers correspond to bands obtained by double digestion with EcoRI/XbaI, EcoRI/HindIII, and EcoRI/SacI of plasmids containing the cloned EcoRI fragment (A), run and hybridized in parallel to the gDNA. Similarly, double digestions (C) were XbaI/Bgl I, XbaI/Bgl II, and XbaI/HindIII for plasmids containing the cloned XbaI fragment; BamHI/BglII, BamHI/PstI (BamHI fragment); and BamHI/PstI, BamHI/XbaI BamHI/HindIII (BamHI/Bgl I fragment). The nucleotide sequence of the first exon/first intron of the Kit gene is reported in GenBank (NT_039306). Nucleotide 1 of the first intron corresponds to nucleotide 559 of this sequence; the positions of the HindIII (near HS2), Bgl II (near HS3-4) and XbaI (near HS5-6) sites correspond to nucleotides 1071, 4941, and 7047 of the first intron, respectively.