Figure 1
PDE11A4 is selectively expressed in neurons. Sagittal sections (~2.64 mm lateral from Bregma) were taken from PDE11A wild-type (WT) and knockout (KO) mice and stained for PDE11A4 (PD11A-112; green), nuclei (DAPI; blue), and a marker for neurons (neuron specific enolase, NSE; red), astrocytes (glial fibrillary acidic protein, GFAP; red), dendrites (MAP2; red), or axon bundles (myelin basic protein, MBP; red). (a) Staining for PDE11A4 is far stronger in hippocampi of PDE11A WT mice vs KO mice, arguing for specificity of the antibody. Further, PDE11A4 expression was far stronger in the ventral hippocampal formation (VHIPP) of PDE11A WT mice vs the dorsal hippocampal formation (DHIPP) of PDE11A WT mice, consistent with previous reports using in situ hybridization for mRNA and western blotting for protein. PDE11A4 protein can be seen in the cell body layer and throughout stratum radiatum of CA1. At the anterior edge of the CA1 field (facing left), a slightly more intense patch of staining that extends throughout stratum radiatum in the shape of a narrow triangle is reliably observed across animals. The anatomical localization of this staining suggests it may actually reflect CA2, although it is thought that CA2 is minimally present in VHIPP. Labeling in the cell body layer and stratum radiatum of ventral CA1 abruptly stops anteriorly at the border for CA3 and dorsally at the stratum lacunosum of dentate gyrus. Labeling for PDE11A4 can also be seen in the axon bundle projecting out of the hippocampus. (b) A closer view shows that PDE11A4 is expressed in a subset of neuronal cell bodies, particularly those neurons lying adjacent to the stratum radiatum. (c) In contrast, PDE11A4 does not appear to be expressed in astrocytes. (d) Consistent with its expression throughout the stratum radiatum, PDE11A4 protein expression colocalizes in some instances with the dendritic marker MAP2. (e) PDE11A4 protein expression also colocalizes with MBP. PDE11A4 protein expression in axons is consistent with the fact that faint PDE11A4 protein expression can be measured when western blotting brain regions that, themselves, do not express PDE11A mRNA but do receive projections from the hippocampus (eg, prefrontal cortex and striatum). Histogram stretch and gamma adjustments applied uniformly across PDE11A KO and WT sections for graphical clarity of images.
