Instead, our data suggest that AML1-ETO acts as a constitutive transcriptional repressor..     ///    "In the first model, AML1-ETO is a constitutive transcriptional repressor of AML1 target genes, regardless of whether they are normally activated or repressed by AML1. "    ///    We also present results of genetic interaction experiments with AML1 co-factors that are not consistent with AML1-ETO behaving as a dominant-negative factor.     ///    "AML1-ETO is thought to interfere with normal AML1 function, although the mechanism by which it does so is unclear. "    ///    "Here, we have used Drosophila genetics to investigate two models of AML1-ETO function. "    ///    "To discriminate between these models, the effects of expressing AML1-ETO were characterized and compared with loss-of-function phenotypes of lozenge (lz), an AML1 homolog expressed during Drosophila eye development. "    ///    "In the second model, AML1-ETO dominantly interferes with AML1 activity by, for example, competing for a common co-factor. "    ///    "Two genes, AML1 and ETO, are fused together at the translocation breakpoint, resulting in the expression of a chimeric protein called AML1-ETO. "