Influence of POM on Mitf expression in the <i>R227W</i> retina.

<p>(A–F) PITX2 (red) and MITF (green) expression at E10.5 (A–C) and E12.5 (D–F). Limited PITX2⁺ cells were detected in the vitreal chamber (between retina and lens) of wild-type eyes. PITX2⁺ cells were not detected in the vitreal chamber of mutant eyes at E10.5, but were abundant by E12.5 and continuous with POM at the retinal periphery (arrowheads). MITF expression levels were modestly upregulated at E10.5 in the mutant retinas and were clearly elevated by E12.5. (G) Relative expression levels of <i>A-Mitf</i>, <i>H-Mitf</i>, and pan-<i>Mitf</i> in E10.5 whole retina and lens explants cultured for 48 hr. <i>R227W</i> expression levels were normalized to <i>orJ</i>. Invasion of POM into the vitreal chamber did not occur in these cultures (data not shown). (H) Relative expression levels of <i>A-Mitf</i>, <i>H-Mitf</i>, and pan-<i>Mitf</i> in physically manipulated E10.5 <i>R227W</i> whole retina and lens explants cultured for 48 hr after the following manipulations: “−POM” (retina and lens only); “mock” (retina partially separated from lens); “+POM” (retina partially separated from lens with surrounding POM intact); “POM imp” (retina partially separated from lens and POM implanted into vitreal cavity). Expression levels were normalized to the “−POM” condition. * P≤0.05; ** P≤0.01 Scale bar: 50 µm.