Expression profiling reveals that ERG and FLI-1 have signatures that are distinct from both ETS2 and MIGR1. (A) RNA for genome-wide expression profiling was extracted from fourth-generation Gata1-knockdown colonies transduced with the MIGR1, MIGR1-ERG, MIGR1-ETS2, and MIGR1-FLI-1. (B) Heat map generated by unsupervised hierarchic clustering reveals that 726 genes discriminate ETS2-, ERG-, and FLI1-overexpressing colonies from MIGR1-transduced cells. (C) Principal component analysis reveals that the ERG and FLI-1 signatures are close to each other and are well separated from MIGR1 and ETS2. This implies that ERG and FLI-1 are more similar to each other than to MIGR1. (D) Heat map showing the top 50 hematopoiesis genes that are differentially expressed in the samples. Red indicates increased expression by 2-fold or more, whereas green depicts decreased expression by 2-fold or more. Genes within blue boxes are those whose expression differs among the ETS family–transduced cells. (E) qRT-PCR confirmation of several differentially expressed genes in the colonies derived from Gata1-knockdown fetal liver hematopoietic cells. Graph depicts mean plus or minus SE for a minimum of 3 independent experiments performed in triplicate. All differences are significant at the 5% level.