Analysis of GATA2 mutants by transcription assays in HEK 293T cells. Bars indicate fold activation of the luciferase reporters in at least 3 independent experiments, each performed in triplicates. Errors bars represent standard error of the mean. P values are indicated for pairwise comparisons using Student t test. (A) A GATA2-responsive reporter (GATA-LUC) containing GATA-binding elements derived from the TCRδ enhancer was cotransfected with expression plasmids for either GATA2 wild-type or GATA2 mutants. A reduced activation was observed for mutants A318T and L321F compared with wild-type GATA2. In contrast, an increased activation was observed for the G320D mutant. The L359V mutant of GATA2, located in ZF2, which is found in ∼ 10% of patients at the progression of CML to AML,²¹  did not show a significant difference in transcriptional activation compared with wild-type GATA2. (B) A CEBPA-responsive reporter (4xCAAT-BS-TK-LUC) containing CEBPA-binding elements was cotransfected with expression plasmids for wild-type CEBPA or a p30 CEBPA truncation mutant in combination with either GATA2 wild type or GATA2 mutants. Enhancement of CEBPA-dependent transcriptional activation by wild-type GATA2 was significantly reduced for all the ZF1-mutants but not for L359V ZF2 mutant. Residual activation of the reporter by the p30 CEBPA truncation mutant was enhanced by coexpression of wild-type GATA2 (dashed line), but this enhancement was markedly reduced for all of the GATA2 mutants tested.