FIG. 8.

Mutational analysis of HsOrc1 promoter. (A) Nucleotide sequence of HsOrc1 promoter region is shown. The major transcription initiation site is numbered as +1, and the upstream promoter region is numbered relative to the initiation site. The putative Sp1-binding sequences, Sp1P and Sp1D, and the E2F-binding sequences are underlined. Nucleotide sequences of the mutated promoters ΔSp1P, ΔSp1D, and ΔE2F are shown under the wild-type sequence. (B) Activity of the mutated HsOrc1 promoter was examined using the luciferase reporter plasmid. The expression plasmid of IE72 and/or IE19 (1.5 μg each) was transfected with pHsOrc1Luc or its mutated reporter plasmid (1 μg) in a reporter assay similar to that described in the legend to Fig. 7.