Developmental progression of cortical YFP expression.

Abstract

<p>Left column: 200 µm coronal sections from YFP-H MeCP2J littermate pairs (∼ Bregma 0.14 mm in WT). The anterior commissure was used as a reference anatomical marker. Right column: maximum intensity projections of confocal fluorescence imaging z-stacks from cingulate cortex. The red box in P9 mutant (rotated 90° clockwise) corresponds to the region imaged in each brain. Single bright YFP⁺ L5 pyramidal neurons are observed in both genotypes as early as P9. By P12 YFP expression has been strongly upregulated in the WT, after which the number of YFP⁺ cells continues to increase more slowly until stabilizing to mature levels sometime between P21 and P40. The number of YFP⁺ cells in mutant males also continues to increase, but at a slower rate, and final levels remain below those seen in the WT. All confocal fluorescence images shown were obtained from the brain section shown except P9 WT, which was obtained from a tissue section 400 µm anterior due to sparse YFP labeling at this age. Left column scale bar = 0.5 mm. Right column scale bar = 100 µm.</p