GSE29514
The transcriptional program controlled by Runx1 during early hematopoietic development (ChIP-seq data)
Transcription factors have long been recognised as powerful regulators of mammalian development, yet it is largely unknown how individual key regulators operate within wider regulatory networks.  Here we have used a combination of global gene expression and chromatin-immunoprecipitation approaches across four ES-cell-derived populations of increasing haematopoietic potential to define the transcriptional programme controlled by Runx1, an essential regulator of blood cell specification.  Integrated analysis of these complementary genome-wide datasets allowed us to construct a global regulatory network model, which suggested that core regulatory circuits are activated sequentially during blood specification, but will ultimately collaborate to control many haematopoietically expressed genes.  Using the CD41/integrin alpha 2b gene as a model, cellular and in vivo studies showed that CD41 is controlled by both early and late circuits in fully specified blood cells, but initiation of CD41 expression critically depends on a later subcircuit driven by Runx1.  Taken together, this study represents the first global analysis of the transcriptional programme controlled by any key haematopoietic regulator during the process of early blood cell specification. Moreover, the concept of interplay between sequentially deployed core regulatory circuits is likely to represent a design principle widely applicable to the transcriptional control of mammalian development. Overall design: 4 samples: 3 samples of Runx1 transcription factor ChIP from the Runx1+/VE-cadherin+/CD41+ population, Runx1+/VE-cadherin+/CD41- population and Runx1+/VE-cadherin-/CD41+ population, and 1 Control (IgG).