<p>(A–F) Double-labeled immunofluorescence analyses for Col II THD (IIF antibody) and calnexin in E16.5 femurs in WT (<b>A–C</b>) and S1P<i><sup>cko</sup></i> (<b>D–F</b>). Signals from calnexin (<b>A, D</b>) are shown in green (white arrows) and those from Col II THD (<b>B, E</b>) are shown in red (white arrowheads) with composite signals shown in <b>C</b> and <b>F</b>. (<b>G–L</b>) Double-labeled immunofluorescence analyses for Col II THD and XBP-1 in E16.5 femurs in WT (<b>G–I</b>) and S1P<i><sup>cko</sup></i> (<b>J-L</b>). Individual signals from XBP-1 (<b>G, J</b>) are shown in green (white arrows) and those from Col II THD (<b>H, K</b>) are shown in red (white arrowheads), with composite signals shown in <b>I</b> and <b>L</b>. All images shown are for mature columnar proliferative chondrocytes in the WT and a corresponding region in S1P<i><sup>cko</sup></i> (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105674#pone.0105674.s001" target="_blank">Fig. S1A</a>). Bar (all panels): 10 µm.</p
