Nucleic Acids Research, 2006, Vol. 34, No. 8 2161 9.0 +14.7 +14.7 Figure 4. Two sets of HS are formed within intron 1 and 30 of hDBP gene. (A) Mapping strategy. The BglI (B) and FspI (F) restriction map of the 105kb-hDBP transgene (positions 37 through +68 kb) indicates the locations of the probes (P3 and P6) used to map HS throughout the gene and into the 30-flanking region. (B) Mapping the HS in intron 1. A 6 kb BglI fragment of intron 1 was mapped using probe P3 that is itself located in intron 1. Two HS were identified in liver chromatin, the more intense and broad HSIV at position +10.3 to +10.9 kb and HSV at position +12.2 kb (positions are relative to the transcription initiation site). These sites are placed on the map below the autoradiograph. Exon 2 (E2) is shown in this map as a filled rectangle. (C) Mapping the hDBP gene 30-flanking region. Probe P6 was used to map a 9.0 kb BglI–FspI fragment spanning terminal exon 13 and the 30-flanking region of hDBP gene. The map below the autoradiograph shows the location of probe P6 used to map HS within the 30 flanking region. HSVI, common to both liver and brain, and liver-specific HSVII were detected. Their positions are placed on the map below the autoradiograph. (D) Summary of DNase I mapping the 105kb-hDBP transgene. The results of the DNase I mapping of the entire 105kb-hDBP transgene (Figures 3 and 4 and data not shown) are summarized. The positions of probes used in the mapping and the specific restriction fragments mapped are indicated on the top diagram (P1–P6; probes, B; BglI, F; FspI, H; HindIII). The positions of each HS are shown in the lower map that also shows positions of the 13 exons (numbered black rectangles) and 12 introns of hDBP gene. Vertical arrows indicate the DNase I HS identified (#; liver, "; brain).