HBE is an enhancer active in pluripotent cells.

<p>(A) HBE is a hotspot for the binding of pluripotency factors and Smad3. <i>Nodal</i> regulatory elements are represented by green boxes and <i>Nodal</i> exons by blue boxes. Binding peaks of Nanog, Sox2, Klf4, Oct4, and Smad3 at the <i>Nodal</i> locus in ESCs are represented by black bars that represent either the summit of the peak of ChIP-seq data or its center for ChIP-chip data aligned to UCSC Genome Browser on Mouse Feb. 2006 (NCBI36/mm8) Assembly (<a href="http://genome.ucsc.edu/" target="_blank">http://genome.ucsc.edu/</a>). (B and C) Luciferase reporter assays for early <i>Nodal</i> enhancers using either a minimal (E1b) or the endogenous promoter (NIS), in ESCs (B), or in EpiSCs (C). Luciferase activities are shown relative to HBE construct. An asterisk indicates significant differences from the control (ctrl) (<i>p</i><0.01).