Figure 1.

Example of competitive PCR analysis for glutamic acid decarboxylase 67 (GAD₆₇) promoter in a frontal cortex (FC) sample immunoprecipitated with an antibody directed against MeCP₂ (IP) and in the corresponding INPUT. For each sample, four solutions were prepared, each containing the same amount of DNA and increasing amounts of GAD₆₇ internal standard (IS). The upper panels show ethidium bromide gel electrophoresis for the IP and INPUT samples. The two bands in the upper panel correspond to the amplification products of GAD₆₇ IS and GAD₆₇ DNA promoter fragments in each solution. The ratio between the optical density of IS and GAD₆₇ promoters is plotted (lower panels) vs the IS concentrations. At the equivalence point (ratio=1), the amount of GAD₆₇ promoter fragment in the sample is equal to the amount of GAD₆₇ IS. The ratio of IP/INPUT represents the percentage of GAD₆₇ promoter immunoprecipitated by the MeCP₂ antibody. For details of the method, see Dong et al (2007).