ChIP-seq experiment of the beta-catenin co-factor Bcl9 in developing forelimbs.

We isolated ca. 500 forelimbs at 10 days post coitum, and performed ChIP-seq using anti-Bcl9 antibodies. Bcl9 is a beta-catenin transcriptional cofactor, therefore it allows the identification of binding sites of the canonical Wnt signalling-dependent transcriptional complex. This experiment allowed to define that, in this developmental context, Bcl9 acts as a beta-catenin dedicated partner. Moreover, it established a series of genome-wide Bcl9 (therefore Wnt/beta-catenin) tissue-specific target loci, thereby assessing the genetic relationship existing between Wnt signaling and other signalling cascades (e.g. the Bmp pathway).