Differential activation of the BST2 promoter by long- and short-form GATA1. Activation of the BST2 promoter by the long- and short-form GATA1 in Drosophila Mel-2 cells. Drosophila Mel-2 cells were cotransfected with 1 μg of the BST2 reporter gene construct (pGL3B-BST2pro) and 125 to 500 ng pPacGATA1-L or pPacGATA1-S. For all transfections, constant plasmid was maintained (at 500 ng of the pPac series). The results represent data from 3 experiments as the mean (± SD) fold increases in luciferase activity relative to a control for which pGL3B-BST2pro was cotransfected with 500 ng pPacO vector.