Enhanced at puberty 1 (EAP1) is a new transcriptional regulator of the female neuroendocrine reproductive axis
J. Clin. Invest. Sabine Heger, et al. 117:2145 doi:10.1172/JCI31752 [Go to this article.]

Figure 3
EAP1 is a nuclear protein with dual transcriptional activity expressed in hypothalamic neurons that facilitate or inhibit the initiation of female puberty. (A) Confocal image of a subregion of the rat POA from a 28-day-old female rat showing that EAP1 has a predominant nuclear localization (green). Notice that not all neurons contain EAP1, as evidenced by the lack of green staining in cell nuclei identified by Hoechst staining (blue). Long arrows indicate EAP1-positive cells; short arrows indicate cells lacking EAP1. (B) Detection of EAP1 (green) in the nucleus of GnRH neurons (red, arrows). (C) Wide-field image of a neuron labeled for EAP1 and Hoechst after constrained iterative deconvolution and 3D reconstruction showing that EAP1 (red) is not associated with condensed chromatin (blue). Scale bars: 40 μm (A); 20 μm (B); 5 μm (C). (D–F) Combined immunohistochemistry–in situ hybridization of brain sections from 28- to 30-day-old female rats showing that EAP1 protein is abundant (D) in cells of the latero-ventral portion of the ventromedial nucleus (LVMH) of the hypothalamus, identified as enkephalinergic by their content of preproenkephalin (preproEnk) mRNA (E and F). The higher-magnification image in F shows that all preproenkephalin mRNA–containing neurons (white grains) are EAP1 positive (brown staining; examples denoted by arrows). 3V, third ventricle. (G–I) EAP1 has a dual transcriptional regulatory activity that requires an intact RING finger domain. (G) In GT1-7 GnRH-producing cells, EAP1 transactivates the GnRH promoter. (H) In the same cells, it represses the preproenkephalin promoter. (I) This repressive activity is also seen in hippocampal neuroprogenitor HiB5 cells. Both the transactivating and repressive activities of EAP1 are abolished by either a single amino acid substitution (C→A) in the EAP1 RING finger domain or by deletion of this domain (ΔR). Numbers above bars represent number of wells/group, and error bars are SEM.