A Discrete Transition Zone Organizes the Topological and Regulatory Autonomy of the Adjacent Tfap2c and Bmp7 Genes
Figure 7
Structural partitioning controls enhancer-target gene allocation and modulates enhancers' effective activity on target genes.
Genes and enhancers are shown as rectangles and ovals, respectively. Active promoters and enhancers are marked with arrows and plain colors. The TZ organizes the locus into two distinct, partially overlapping spatial conformations (represented by light blue and green circles), where genes and enhancers can interact. In the heart (A) and forebrain (B), this situation prevents action of one enhancer on a gene in the other domain. In the lateral forebrain, enhancers adjacent to FB1 may contribute to Tfap2c expression. In the medial forebrain (C), the active Bmp7 promoter may compete, non productively, for the forebrain enhancer, and interferes (marked by a yellow oval) with its action on Tfap2c. The TZ may control the strength and therefore the consequences of this interference on Tfap2c expression.