Epigenetic, transcriptional and translational characterization of Sox2 expression during OC development.

<p>(<b>A</b>–<b>C</b>) OC during development. (<b>A</b>) Upper panel: Schematic of the sensory domain, which contains the proximal cochlea duct, showing interkinetic nuclear migration at E13.5. Sox2 expression is indicated by red nuclei. Remaining panels: marker expression at E13.5. All proliferating Ki-67-positive cells are co-labeled for Sox2. (<b>B</b>) Upper panel: schematic of the different cell types found in the maturating OC at P4. Inner hair cell (ihc, arrowhead), three outer hair cells (ohc, arrowheads) and different supporting cells: inner sulcus cells (is); interphalangeal cells (i); pillar cells (p); Deiters' cells (d); Hensen's cells (h); and Claudius cells (c). Remaining panels: marker expression at P4. The quiescence of Sox2-positive supporting cells is indicated by co-labeling with p27Kip1. (<b>C</b>) Upper panel: schematic of the different cell types found in the functional OC at P21. Remaining panels: marker expression at P21. Senescence of Sox2-positive cells is indicated by p16Ink4a expression. (<b>D</b>) RT-PCR of pluripotency marker, hair cell marker and supporting cell marker expression in the OC (E13.5, P4, P21). HPRT1 was used as the loading control. (<b>E</b>) qPCR analysis of six developmentally regulated genes (cMyc, Sox2, Atoh1, Myosin VIIa, p27Kip1 and Prox1) during OC development (E13.5, P4 and P21). The relative expression levels of P4 and P21 were compared with those at E13.5. The transcript levels were normalized to HPRT1/Ubiquitin C levels. Averages of the three independent experiments with SDs are shown (*p<0.05) (i.e., see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036066#pone.0036066.s008" target="_blank">Table S2B</a>). Depending on the temporal expression pattern, genes were assigned to early, transition or differentiation groups (i.e., see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036066#pone.0036066.s003" target="_blank">Figure S3</a>). (<b>F</b>,<b>G</b>) Bisulfite methylation of the Sox2 enhancers (f) (NOP1/2) and (g) (SRR1/2) during OC development (E13.5, P4, P21) (i.e., see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036066#pone.0036066.s004" target="_blank">Figure S4</a>). (Scale Bars: A,B,C, 10 µm).