Figure 2.
Loss of CREB function affects the differentiation and morphological maturation of newborn dentate granule cells.
a
, Analysis of DCX expression and morphology of newborn cells transduced with GFP-retrovirus (GFP; green) or ACREB-retrovirus (ACREB; green) at 7 dpi. GFP-transduced cells express DCX (red) and have extended an apical dendrite toward the molecular layer (red arrowhead). In contrast, a large number of ACREB-transduced cells are negative for DCX (white arrowhead). ACREB-transduced DCX+ neurons frequently failed to extend an apical dendrite toward the molecular layer (yellow arrowhead). DAPI in blue. Scale bar, 25 μm.
b
, NeuroD expression in newborn cells transduced with GFP-retrovirus (GFP; green) or ACREB-retrovirus (ACREB; green) at 14 dpi. The majority of GFP-transduced cells are NeuroD positive (red) (red arrowheads). In contrast, ACREB-transduced cells are frequently negative for NeuroD expression (white arrowheads). Scale bar, 25 μm.
c
, Quantification of the percentage of retrovirally transduced cells in the granule cell layer expressing DCX. Expression of DCX is significantly reduced among ACREB-transduced cells starting at 5 dpi (*p < 0.05,**p < 0.01, ***p < 0.001).
d
, Quantification of the percentage of retrovirally transduced cells in the granule cell layer expressing NeuroD. Expression of NeuroD is significantly reduced among ACREB-transduced cells after 5 dpi (**p < 0.01, ***p < 0.001).
e
, Morphological analysis of retrovirally transduced immature neurons. The percentage of ACREB-transduced DCX+ immature neurons, which extend an apical dendrite through the granule cell layer toward the molecular layer, is significantly reduced (**p < 0.01, ***p < 0.001).
f
, Confocal three-dimensional reconstruction of dendrites of GFP- and ACREB-transduced immature neurons, which had developed an apical dendrite spanning the granule cell layer at 14 dpi. Scale bar, 25 μm.