Journal: Journal of Neurochemistry
Article Title: Gα o1 and Gα o1 /Gα o2 deletion differentially affect hippocampal mossy fiber tract anatomy and neuronal morphogenesis
doi: 10.1111/jnc.16248
Figure Lengend Snippet: Altered projections and reduced size of mossy fiber synaptic areas in the hippocampus of Gα o1 −/− mice. (a) Coronal section from an adult wild‐type mouse brain was immunostained for the vesicular Zinc transporter 3 (ZnT3, heavily marking the mossy fiber tract (mft), and the axonal marker neurofilament heavy chain (NFP)), together with Dapi to depict the gross anatomy of the hippocampus and its layered organization. The mossy fiber tract originates from the granule cells of the dentate gyrus, passes through the hilus, and terminates at the Stratum lucidum (SLU) forming synapses with the CA3 pyramidal cells. (b) Schematic representation of the hippocampus formation and the mossy fiber tract bundles. Before reaching the Stratum lucidum , the mossy fiber tract splits up into two bundles running above and below the pyramidal cells. Arrows indicate the two distance lines measured to determine the gross size of the hippocampus formation in the medio‐lateral (width) and dorso‐ventral (height) axis. GCL, granule cell layer; HIL, hilum ; SLM, Stratum lacunosum/moleculare ; SM, Stratum moleculare; SO, Stratum oriens ; SP, Stratum pyramidale ; SR, Stratum radiatum ; (c) Representative section of a wild‐type hippocampus stained for ZnT3 to demonstrate the mossy fiber tract substructures analyzed for quantification. Mossy fibers project from the hilus above and below the pyramidal cell layer, termed suprapyramidal and infrapyramidal bundle (SPB and IPB) before terminating in the Stratum lucidum (SLU). Length of the IPB, SPB, SPB + SLU, SLU alone as well as the overall length of the tract from the tip of the hilus to the tip of the SLU were determined (see yellow lines for portions of the tract). Additionally, the area of the SLU and the rest of the mossy fiber tract were quantified. (d, e) Representative images of adult wild‐type (same as in c) and a Gα o1 −/− hippocampi stained for ZnT3 are shown. Most strikingly, the MFT appears thinner and the IPB appeared to be longer in the knockout animals than in the wild‐type. (f, g) Quantification of measurements. Both the SLU and overall synaptic mossy fiber area were markedly reduced in Gα o1 −/− animals. General hippocampus width was not significantly altered, hippocampus height was slightly reduced in KO animals. Most prominently, the length of the IPB was reduced in wild‐type compared to the knockout animals, accompanied by a slight reduction in the SBP length. The length of the SLU was moderately reduced in G α O1 knockout animals. The other parameters were unaltered. Bars show means ± SD from N = 4 pooled animals each WT and Gα o1 −/− , 51 (knockout) and 54 (wild‐type) mossy fiber tracts per genotype *** p ≤ 0.001 (h) Confocal imaging and 3D reconstruction from z‐stacks showing ZnT3 expression together with surrounding axons stained by NFP at a wild‐type SLU area (left panel). 3D reconstruction of ZnT3 staining at the SLU area showing the differences in SLU size and IPB length between wild‐type (middle panel) and Gα o1 −/− mice (right panel).
Article Snippet: A polyclonal antibody preferentially recognizing Gα o1 was from Santa Cruz (cat. no. 13532, Santa Cruz, CA, USA).
Techniques: Marker, Staining, Knock-Out, Imaging, Expressing