LAUSR

Fig. 1 This image illustrates the knockdown of cacna1c within the prelimbic (PrL) cortex to nucleus accumbens core (NAcC) projection in mice. a In cacna1c-floxed mice, an adeno associated virus (AAV) expressing flp-dependent cre recombinase and GFP (AAV-fDIO-Cre-GFP) and was stereotaxically injected into the PrL and a retrograde AAV expressing flp (pAAV-EF1a-mCherry-IRESFlpo) was injected into the NAcC (PrL-NAcC Cav1.2 KO). This led to selective expression of Cre in NAcC-projecting PrL cells. Control mice were injected with an AAV-GFP into the PrL (PrL-NAcC Cav1.2 Control). b RNAscope in situ hybridization was used in combination with immunohistochemistry to examine the expression of cacna1c in GFP-labeled cells. Shown in the top panel, control mice had robust labeling of cacan1c mRNA puncta (red) in GFP-labeled PrL cells. Illustrated in the bottom panel, experimental mice injected with the flpdependent cre (PrL) and retrograde flp (NAcC) show significantly reduced cacna1c puncta within GFP-expressing PrL cells, indicating knockdown of cacna1c within the PrL-NAcC projection (scale bar= 50 μm). c This viral strategy led to a significant reduction of cacna1c mRNA in GFP-positive PrL cells. These experiments demonstrate the ability of this dual-virus strategy for the manipulation of genes within specific neural circuits of the mouse brain. For more information on how this strategy can be utilized in combination with rodent behavior to study the role of projection-specific changes in gene expression, please refer to the paper by Bavley et al. on pages 2373–2391.