AML-1A, but not AML-1B, increases hMIP-1α promoter activity.

The MIP-1α promoter constructs were cotransfected with AML-1A and AML-1B cDNAs in pcDNA3 into ARH-77 (A-C) and MM.1S (D-F) cells, to test the modulating effects of the AML-1 class of TFs on MIP-1α promoter activity. Cotransfection of AML-1A or AML-1B with the luciferase reporter construct (Luc) containing one AML-1 binding motif did not significantly enhance promoter activity. In contrast, cotransfection of the reporter construct that contained 2 AML-1 binding elements with the AML-1A construct into ARH-77 and MM.1S cells significantly increased MIP-1α promoter activity compared with the empty vector (EV) control (Figure 6B,E). Furthermore, cotransfection of the full-length luciferase reporter construct with AML-1A further increased MIP-1α promoter activity (Figure 6A,D). AML-1B significantly decreased full-length MIP-1α promoter activity about 50% in ARH-77 and MM.1S cells compared with the EV control. Similar results were seen in 3 independent experiments (*P < .05).