Abstract
EMBO J 30 6, 1093–1103 (2011); published online February 18 2011 The erythroid versus myeloid lineage fate decision controlled by cross-antagonism between GATA1 and PU.1 serves as a mechanistic paradigm for transcription factor interplay during lineage specification. In this issue of The EMBO Journal, Monteiro et al (2011) examined this paradigm in blood populations in zebrafish embryos, and demonstrated that, unexpectedly, the regulatory interactions between GATA1 and PU.1 lead to different outcomes depending on the cellular contexts and the development stages. GATA1/PU.1 cross-antagonism is also modulated by a third factor transcriptional intermediate factor 1γ (TIF1γ), a chromatin-associated haematopoietic regulator.