GSE161376
DBX2 REGULATION IN LIMBS SUGGESTS INTER-TAD SHARING OF ENHANCERS [4C-Seq]
During tetrapod limb development, the HOXA13 and HOXD13 transcription factors are critical for the emergence and organization of the autopods, the most distal aspect where digits will develop. Since previous work had suggested that the Dbx2 gene is a target of these factors, we set up to analyze in detail this potential regulatory interaction. We used a chromatin conformation capture approach (4Cseq) to characterize the regulatory domain and interactions of the transcription factor Dbx2 and of its neighboring genes Nell2 and Ano6 in distal and/ or proximal forelimbs of E12 mouse embryos. In particular, we analyzed their interaction with distal limb specific regulatory elements (DLE1 and DLE2) by the analysis of H2K27ac coverages (Beccari et al 2016) and Hoxa13/Hoxd13 binding (Sheth R et al 2016). We report that Dbx2, Nell2 and Ano6 are expressed in distal limb buds and are controlled by the same enhancers located close to Dbx2. As the Nell2 and Ano6 genes are localized into two different topologically associating domains (TADs) flanking the Dbx2 locus, we conclude that these enhancers can overcome TAD boundaries in either direction, to co-regulate a set of genes located in distinct chromatin domains. Overall design: 4C seq analysis of the interaction profiles of the Dbx2, Nell2 and Ano6 promoters in E12 embryonic limbs and of the distal limb specific regulatory elements DLE1 and DLE2