Transcription factor Pbx4 regulates limb development and hematopoiesis in mice

To characterize Pbx4-binding sites on the genome, we conducted ChIP-seq analyses by using testicular lysates from Pbx4-FLAG KI mice. We found Pbx4 preferentially binds to promoters of a large number of genes including other HD-containing protein and ribosomal protein genes, of which mutations are related to anemia. PBX4 binding sites are enriched in motifs similar to those of other HD-containing proteins indicating PBX4, like other PBX members, may act as a cofactor of other proteins. Together, these results show that PBX4 participates limb development and hematopoiesis although its expression in spermatogenic cells but not in other cell types in adult mice is detected. Overall design: As a first step to understand the molecular mechanism of PBX4 function , we carried out ChIP-seq analysis of its binding site in the genome. Because it is only detected to be highly and specifically expressed in spermatogenic cells, we used total testicular cells to do the experiments. About 1400 binding sites (peaks) were identified from pooled analysis of 5 ChIP-seq datasets generated from five different PBX4-FLAG mice