Identification of the cis-acting DNA region regulating IGnTC gene transcription. (A) Comparison of transcriptional activities of the IGnTC gene 5′ regions. Different 5′ segments of the IGnTC gene were introduced upstream of the luciferase reporter gene of the pGL3-basic vector. The −322/−251&−77/+62-bp reporter vector had the −322 to −251–bp region inserted immediately upstream of the −77 to +62–bp region. K-562 cells were split into 6-well culture plates at a density of 2 × 105 cells/mL, and transfected with 1.0 μg of the constructed and mock pGL3-basic reporter plasmids. The transcriptional activities of the constructed reporter plasmids in the transfected K-562 cells, with or without sodium butyrate treatment, are schematically represented by □ and ▩, respectively. The results are presented as averages of luciferase activities from 3 repetitions; standard deviations are shown. (B) Nucleotide sequence of the −318 through −253 region of the IGnTC gene. The putative binding motifs for the Oct-2, Sp1, and C/EBPα transcription factors are underlined.
