eased the statistical power of the study, and presumably identified even more striking commonalities. Another aspect to consider is that these microarray experiments were done on placental samples which are composed of different cell types. This heterogeneity can cause noise that disturbs the correct prediction of a co-regulated gene set, and hence of 
the TFs involved in their regulation. Finally, we arbitrarily chose to limit the size of the promoters to be analyzed to 1200 bp. We postulated that the TFs regulating the activity of the modified genes would bind TFBS close to the TSS. If we had chosen other promoter lengths we might get different results. In a previous study published in 2006, Vasarhelyi et al analyzed the promoters of genes found to be modified in preeclamptic placentas. They reported an overrepresentation of TFBS corresponding to NFkB, SREBP and E47. Except for NFkB, the TFs identified in their study 21505263 are different to those reported here, these differences being probably due to the data used for the studies. Vasarhelyi et al extracted data from a number of studies performed between years 2002 to 2005. At that time, microarrays offered only a partial covering of the human genome. Thus, we used more recent data corresponding to microarrays with full coverage of the human genome. Despite all this caveats our study allowed to identify a number of TFs involved in PE. Although a few of them are found to be consistently modified in the preeclamptic placenta at the transcriptional level, many of the TFs identified by our study are regulated by post-transcriptional mechanisms. These post-transcriptional modifications, can be triggered by cellular stresses which are known to be associated with PE such as hypoxia, inflammation, oxidative stress, DNA-damage, etc… The validity of the hypothesis raised by our bioinformatic study need to be confirmed by experimental studies analyzing the implication of these TFs in both, in vitro models and in vivo in preeclamptic placentas. Supporting Information preeclamptic placenta. The lists of up-regulated genes for each of the six preeclamptic placenta microarrays analyzed in this study were confronted using the GENOMATIX list comparison tool. This allowed to identify those genes which were consistently up-regulated. Those showing similar modification in at least 4 studies were considered relevant and included in a final list of consistently up-regulated genes. NUP98-HOXA9 is an oncogenic fusion protein associated with acute myeloid leukemia that consists 11325787 of an N-terminal, FG repeat-rich portion of the nucleoporin NUP98 fused to the homeodomain region of HOXA9. It is the prototype of several similar SB-743921 leukemogenic fusions linking NUP98 to one of several homeodomain-containing transcription factors. NUP98-HOX fusions act as aberrant transcription factors. They induce proliferation and block differentiation in mouse hematopoietic precursors, and cause leukemia in mice. Some of these effects require a functional homeodomain. In human primary hematopoietic cells, NUP98-HOXA9 induces long-term proliferation and blocks differentiation. It is not known whether these effects are dependent on homeodomain-DNA binding. Wild-type HOXA9 overexpression is leukemogenic in mice. It induces proliferation with a differentiation block in mouse hematopoietic cells in vitro, and these effects are dependent on the presence of a functional homeodomain. However, the effects of HOXA9 on the proliferation and differenti
