Promoter analysis. (A) CpG island search. One CpG island is identified in the core promoter region of the cyclin Agene, and 2 in the far 5′-flank region of cyclin D1 gene by computational analysis. (B) Cyclin A promoter activity. Plasmids containing various lengths of the 5′-flanking region of the cyclin A gene were constructed with the luciferase (Luc) gene in PGL2 vector. HUVECs were transiently transfected with 2 μg plasmid DNA by Lipofectin transfection, and harvested 48 hours after transfection. For each construct, 0.5 μg plasmid pCMV-βGAL was cotransfected to correct for differences in the transfection efficiency. The corrected luciferase activity was then divided by that of the cyclin A −266/+205 plasmid and is presented as relative luciferase activity. Values represent mean (± SD) from 3 separate experiments with triplicates (n = 9).