AF10 transforming regions activate transcription when fused to GAL4 or MLL DNA-binding domains.

(A) A luciferase reporter gene containing GAL4 binding sites upstream of a thymidine kinase or E1b promoter was cotransfected into Raji cells with expression constructs encoding GAL4 fusions of ENL or AF10. Luciferase activity was corrected for transfection efficiency based on the activity of a cotransfected β-galactosidase expression construct. The transcriptional activating potential for each fusion construct is expressed as the fold induction relative to GAL4 DNA-binding domain alone. (B) A luciferase reporter gene under control of HoxA7 upstream sequences (pGL3-HoxA7) was cotransfected into 293T cells with expression constructs encodingMLL5′ or various MLL fusion cDNAs. Data were corrected for transfection efficiencies as described above and normalized to protein levels. Bars represent the mean and SD of 3 replicates. (C) The transcriptional activation properties of various mutant MLL-AF10 fusion cDNAs (shown schematically on the left) were determined using transient cotransfection conditions identical to those described in panel B.