Attenuated Late-Phase Arc Transcription in the Dentate Gyrus of Mice Lacking Egr3

Figure 3

Accelerated loss of exploration-induced Arc expression in the DG of Egr3^−/− mice. Sample confocal images are provided (a) of the DG suprapyramidal blade (DG_SP) from WT (top row) and Egr3^−/− (bottom row) mice under baseline control (caged) conditions, versus 60 minutes (early) and 480 minutes (late) following a five-minute exposure to a novel environment (red = Arc, blue = DAPI, scale bar = 100 μm). Consistent with these images, graphs of DG_SP (b) show that novel exploration induces Arc expression immediately (0′) in all mice and that in WT mice Arc transcription persists throughout all time points observed. In Egr3^−/− mice, however, exploration-induced Arc expression is selectively reduced in the late, protein synthesis-dependent phase of transcription (i.e., 240′ and 480′) relative to their WT littermates. In contrast, significant induction of Arc expression in the DG infrapyramidal blade (b) is not apparent in WT mice until 240 min postexploration and is completely absent in Egr3^−/− mice ( relative to caged control of the same genotype; ^† relative to Egr3^−/−; graphs display mean ± SEM).

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(b)

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