The transcription factor Isl1 is associated with multiple signalling pathways important during genital development

To identify regulatory targets of the transcription factor Isl1 in the developing mouse genitalia, we performed ChIP-Seq using an anti-ISL1 rabbit monoclonal antibody on pooled chromatin isolated from multiple E14.5 mouse embryonic genital tubercles (GT). Our analysis identified more than 7,054 genomic regions enriched in both of two replicates. The majority of these binding sites are located more than 5 kb from the closest annotated transcriptional start site (TSS), with nearly one third of the binding sites more than 50kb away from the nearest TSS. A de novo motif search using HOMER demonstrated that GT Isl1 ChIP-seq peaks are enriched for a motif that matches the consensus sequence bound by Isl1 in other tissues. When compared to active enhancers in the GT identified using H3K27ac ChIP-Seq, we found that Isl1 binding sites are strongly enriched in the GT compared to other embryonic tissues. Further analysis of the location of Isl1 peaks revealed a strong association with genes implicated in limb and urogenital development. We conclude that there is a strong association between Isl1 regulatory activity and genes involved in genital development. Examination of Isl1 transcription factor binding in two replicates of chromatin isolated from the developing genital tubercles of E14.5 mouse embryos using ChIP-Seq.