Journal: Frontiers in behavioral neuroscience

Article Title: Arc-driven mGRASP highlights CA1 to CA3 synaptic engrams.

doi: 10.3389/fnbeh.2022.1072571

Figure Lengend Snippet: FIGURE 2 cFostTA-dependent expression of mGRASP in dCA1 upon exposure to an Enriched Environment or Trace Fear Conditioning. Schematic description of the viral injection sites in WT animals (A), the viral constructs injected (B) and the experimental design (C) to determine the expression kinetics of post-mGRASP in dCA1 under the control of cFos upon exposure to EE or HC. (D) Confocal pictures, single Z-planes, of dCA1 at different time points after induction of post-mGRASP expression. Red, dTomato; blue, DAPI. White triangles indicate RFP-positive cells. D, Dorsal, V, Ventral. Scale bar = 20 µm. (E) Percentage of dTomato-expressing over DAPI-positive cells in dCA1 after exposure to EE or HC. The levels of dTomato reached a peak at 3 days (p3d-24h = 0.01, p3d-5d = 0.7, p3d-7d = 0.3, p3d-10d = 0.037, p3d−HC = 0.048; all n = 5; Kruskal–Wallis test after Dunn’s correction for multiple comparisons). (F) Schematic description of the experimental design to determine the dCA1 expression levels of post-mGRASP under the control of cFos upon exposure to TFC, EE, or HC. (G) Confocal pictures, single Z-planes, of dCA1 at different time points after induction of post-mGRASP. Red, dTomato; blue, DAPI. White triangles indicate dTomato-positive cells. D, Dorsal, V, Ventral. Scale bar = 20 µm. (H) The percentage of dTomato-expressing over DAPI-positive cells in dCA1 was not significantly different after exposure to TFC, EE or HC (pTFC−HC = 0.41 and pEE−HC = 0.26, all n = 6; Kruskal–Wallis test after Dunn’s correction for multiple comparisons). (I) Percentage of freezing time during the context probe 3 days after TFC training (p = 0.03, n = 6; Wilcoxon Signed-rank test). *p < 0.05.

Article Snippet: On the training day mice were put into a square conditioning chamber (19 cm × 19 cm, black metal walls, stainless steel grid floor, white light illumination, and ethanol odor) (Panlab) which we defined as Context A.

Techniques: Expressing, Injection, Construct, Control

Journal: Frontiers in behavioral neuroscience

Article Title: Arc-driven mGRASP highlights CA1 to CA3 synaptic engrams.

doi: 10.3389/fnbeh.2022.1072571

Figure Lengend Snippet: FIGURE 4 ArcCreERT2-dependent expression of mGRASP in dCA1 upon exposure to an Enriched Environment or Trace Fear Conditioning. Schematic description of the viral injection sites in ArcCreERT2 transgenic animals (A) and the viral constructs injected (B). (C) Experimental design to determine the expression levels of post-mGRASP in dCA1 under the control of Arc at two different time points after exposure to EE. (D) Confocal pictures, single Z-planes, of dCA1 at different time points after induction of post-mGRASP expression. Red, dTomato; blue, DAPI. White triangles indicate dTomato-positive cells. D, Dorsal, V, Ventral. Scale bar = 20 µm. (E) Percentage of dTomato-expressing over DAPI-positive cells in dCA1 3 and 7 days after exposure to EE. The level of dTomato at 7 days was significantly higher than at 3 days (p = 0.0095; n3 = 4, n7 = 6; Mann–Whitney U-test). (F) Percentage of dTomato-expressing over DAPI-positive cells in dCA1 3 and 7 days after exposure to EE in the cFostTA (striped) or ArcCreERT2 (solid) systems. The level of dTomato at 7 days was significantly higher in the ArcCreERT2 system than at 3 and 7 days in the cFostTA system (p7dArc7dFOS = 0.0005, p7dArc3dFOS = 0.017, all other p > 0.31; n7dArc = 6, n7dFOS = 5, n3dArc = 4, n3dFOS = 10; Kruskal–Wallis test after Dunn’s correction for multiple comparisons). (G) Confocal pictures, single Z-planes, of apical (right) and basal (left) dendritic segments of dCA1 pyramidal neurons at 7 days after induction of post-mGRASP expression showing GFP-fluorescent puncta colocalizing with dTomato-positive dendritic segments. Red, dTomato; green, GFP. White triangles indicate synaptic GFP reconstitution. D, Dorsal, V, Ventral. Scale bars = 5 µm. (H) Experimental design to determine the dCA1 and dCA3 expression levels of post-mGRASP under the control of Arc after TFC. (I) Confocal picture, single Z-plane, of dCA1 7 days after induction of post-mGRASP expression. Red, dTomato; blue, DAPI. White triangles indicate dTomato-positive cells. D, Dorsal, V, Ventral. Scale bar = 20 µm. (J) Percentage of dTomato- (dCA1) or mCerulean- (dCA3) expressing over DAPI- (dCA1) or Syto60- (dCA3) positive cells 7 days after exposure to FC. (K) Percentage of freezing time during the context probe 7 days after TFC training (p = 0.015, n = 7; Wilcoxon Signed-rank test). (L) Confocal pictures, single Z-planes, of a dCA1 pyramidal neuron and dendritic segments (insets) 7 days after induction of post-mGRASP expression showing GFP-fluorescent puncta colocalizing with dTomato-positive dendritic segments. Red, dTomato; green, GFP. White triangles indicate synaptic GFP reconstitution. Inset number 2 is rotated 90 degrees from the original orientation. Scale bars: left = 10 µm, middle and right = 5 µm. *p < 0.05, **p < 0.01, ***p < 0.001.

Article Snippet: On the training day mice were put into a square conditioning chamber (19 cm × 19 cm, black metal walls, stainless steel grid floor, white light illumination, and ethanol odor) (Panlab) which we defined as Context A.

Techniques: Expressing, Injection, Transgenic Assay, Construct, Control, MANN-WHITNEY